14 CFR Part 33 — Airworthiness Standards: Aircraft Engines

Federal Aviation Administration, DOT § 33.5 A PPENDIX B TO P ART 33—C ERTIFICATION Subpart D—Block Tests; Reciprocating S TANDARD A TMOSPHERIC C ONCENTRATIONS Aircraft Engines OF R AIN AND H AIL 33.41 Applicability. A PPENDIX C TO P ART 33 [R ESERVED ] 33.42 General.

A PPENDIX D TO P ART 33—M IXED P HASE AND 33.43 Vibration test.

I CE C RYSTAL I CING E NVELOPE (D EEP C ON - 33.45 Calibration tests.

VECTIVE C LOUDS ) 33.47 Detonation test.

A UTHORITY : 49 U.S.C. 106(g), 40113, 44701, 33.49 Endurance test.

44702, 44704.

33.51 Operation test.

33.53 Engine system and component tests.

S OURCE : Docket No. 3025, 29 FR 7453, June 33.55 Teardown inspection.

10, 1964, unless otherwise noted.

33.57 General conduct of block tests.

: For miscellaneous amendments to NOTE cross references in this Part 33, see Amdt. 33– Subpart E—Design and Construction; 2, 31 FR 9211, July 6, 1966.

Turbine Aircraft Engines 33.61 Applicability. Subpart A—General 33.62 Stress analysis.

33.63 Vibration. § 33.1 Applicability.

33.64 Pressurized engine static parts.

(a) This part prescribes airworthiness 33.65 Surge and stall characteristics.

standards for the issue of type certifi- 33.66 Bleed air system.

cates and changes to those certificates, 33.67 Fuel system.

33.68 Induction system icing. for aircraft engines.

33.69 Ignitions system.

(b) Each person who applies under 33.70 Engine life-limited parts.

part 21 for such a certificate or change 33.71 Lubrication system.

must show compliance with the appli- 33.72 Hydraulic actuating systems.

cable requirements of this part and the 33.73 Power or thrust response.

applicable requirements of part 34 of 33.74 Continued rotation.

33.75 Safety analysis. this chapter.

33.76 Bird ingestion.

[Amdt. 33–7, 41 FR 55474, Dec. 20, 1976, as 33.77 Foreign object ingestion—ice.

amended by Amdt. 33–14, 55 FR 32861, Aug. 10, 33.78 Rain and hail ingestion.

1990] 33.79 Fuel burning thrust augmentor.

§ 33.3 General.

Subpart F—Block Tests; Turbine Aircraft Engines Each applicant must show that the aircraft engine concerned meets the 33.81 Applicability.

applicable requirements of this part.

33.82 General.

33.83 Vibration test.

§ 33.4 Instructions for Continued Air- 33.84 Engine overtorque test.

worthiness.

33.85 Calibration tests.

33.87 Endurance test.

The applicant must prepare Instruc- 33.88 Engine overtemperature test.

tions for Continued Airworthiness in 33.89 Operation test.

accordance with appendix A to this 33.90 Initial maintenance inspection test.

part that are acceptable to the Admin- 33.91 Engine system and component tests.

istrator. The instructions may be in- 33.92 Rotor locking tests.

complete at type certification if a pro- 33.93 Teardown inspection.

33.94 Blade containment and rotor unbal- gram exists to ensure their completion ance tests.

prior to delivery of the first aircraft 33.95 Engine-propeller systems tests.

with the engine installed, or upon 33.96 Engine tests in auxiliary power unit issuance of a standard certificate of (APU) mode.

airworthiness for the aircraft with the 33.97 Thrust reversers.

engine installed, whichever occurs 33.99 General conduct of block tests.

later.

Subpart G—Special Requirements: Turbine [Amdt. 33–9, 45 FR 60181, Sept. 11, 1980] Aircraft Engines § 33.5 Instruction manual for installing 33.201 Design and test requirements for and operating the engine.

Early ETOPS eligibility.

Each applicant must prepare and A PPENDIX A TO P ART 33—I NSTRUCTIONS FOR C ONTINUED A IRWORTHINESS make available to the Administrator 14 CFR Ch. I (1–1–25 Edition) § 33.7 prior to the issuance of the type cer- (5) A description of the primary and tificate, and to the owner at the time all alternate modes, and any back-up of delivery of the engine, approved in- system, together with any associated structions for installing and operating limitations, of the engine control sys- the engine. The instructions must in- tem and its interface with the aircraft clude at least the following: systems, including the propeller when applicable.

(a) Installation instructions. (1) The lo- (c) Safety analysis assumptions. The cation of engine mounting attach- assumptions of the safety analysis as ments, the method of attaching the en- described in § 33.75(d) with respect to gine to the aircraft, and the maximum the reliability of safety devices, instru- allowable load for the mounting at- mentation, early warning devices, tachments and related structure.

maintenance checks, and similar (2) The location and description of equipment or procedures that are out- engine connections to be attached to side the control of the engine manufac- accessories, pipes, wires, cables, ducts, turer.

and cowling.

(3) An outline drawing of the engine [Amdt. 33–6, 39 FR 35463, Oct. 1, 1974, as including overall dimensions.

amended by Amdt. 33–9, 45 FR 60181, Sept. 11, 1980; Amdt. 33–24, 47 FR 50867, Sept. 4, 2007; (4) A definition of the physical and Amdt. 33–25, 73 FR 48123, Aug. 18, 2008; Amdt.

functional interfaces with the aircraft 33–26, 73 FR 48284, Aug. 19, 2008] and aircraft equipment, including the propeller when applicable.

§ 33.7 Engine ratings and operating (5) Where an engine system relies on limitations.

components that are not part of the en- (a) Engine ratings and operating lim- gine type design, the interface condi- itations are established by the Admin- tions and reliability requirements for istrator and included in the engine cer- those components upon which engine tificate data sheet specified in § 21.41 of type certification is based must be this chapter, including ratings and lim- specified in the engine installation in- itations based on the operating condi- structions directly or by reference to tions and information specified in this appropriate documentation.

section, as applicable, and any other (6) A list of the instruments nec- information found necessary for safe essary for control of the engine, includ- operation of the engine.

ing the overall limits of accuracy and (b) For reciprocating engines, ratings transient response required of such in- and operating limitations are estab- struments for control of the operation lished relating to the following: of the engine, must also be stated so (1) Horsepower or torque, r.p.m., that the suitability of the instruments manifold pressure, and time at critical as installed may be assessed.

pressure altitude and sea level pressure (b) Operation instructions. (1) The op- altitude for— erating limitations established by the (i) Rated maximum continuous power Administrator.

(relating to unsupercharged operation (2) The power or thrust ratings and or to operation in each supercharger procedures for correcting for non- mode as applicable); and standard atmosphere.

(ii) Rated takeoff power (relating to (3) The recommended procedures, unsupercharged operation or to oper- under normal and extreme ambient ation in each supercharger mode as ap- conditions for— plicable).

(i) Starting; (2) Fuel grade or specification.

(ii) Operating on the ground; and (3) Oil grade or specification.

(iii) Operating during flight.

(4) Temperature of the— (4) For rotorcraft engines having one (i) Cylinder; or more OEI ratings, applicants must (ii) Oil at the oil inlet; and provide data on engine performance (iii) Turbosupercharger turbine wheel characteristics and variability to en- inlet gas.

able the aircraft manufacturer to es- (5) Pressure of— tablish aircraft power assurance proce- (i) Fuel at the fuel inlet; and dures. (ii) Oil at the main oil gallery.

Federal Aviation Administration, DOT § 33.15 (6) Accessory drive torque and over- (13) Inlet air distortion at the engine hang moment. inlet.

(7) Component life. (14) Transient rotor shaft overspeed (8) Turbosupercharger turbine wheel r.p.m., and number of overspeed occur- r.p.m.

rences.

(c) For turbine engines, ratings and (15) Transient gas overtemperature, operating limitations are established and number of overtemperature occur- relating to the following: rences.

(1) Horsepower, torque, or thrust, (16) Transient engine overtorque, and r.p.m., gas temperature, and time for— number of overtorque occurrences.

(i) Rated maximum continuous power (17) Maximum engine overtorque for or thrust (augmented); turbopropeller and turboshaft engines (ii) Rated maximum continuous incorporating free power turbines.

power or thrust (unaugmented); (18) For engines to be used in super- (iii) Rated takeoff power or thrust sonic aircraft, engine rotor (augmented); windmilling rotational r.p.m.

(iv) Rated takeoff power or thrust (d) In determining the engine per- (unaugmented); formance and operating limitations, (v) Rated 30-minute OEI power; the overall limits of accuracy of the (vi) Rated 2 ⁄2 -minute OEI power; engine control system and of the nec- (vii) Rated continuous OEI power; essary instrumentation as defined in and § 33.5(a)(6) must be taken into account.

(viii) Rated 2-minute OEI Power; (ix) Rated 30-second OEI power; and [Amdt. 33–6, 39 FR 35463, Oct. 1, 1974, as (x) Auxiliary power unit (APU) mode amended by Amdt. 33–10, 49 FR 6850, Feb. 23, 1984; Amdt. 33–11, 51 FR 10346, Mar. 25, 1986; of operation.

Amdt. 33–12, 53 FR 34220, Sept. 2, 1988; Amdt.

(2) Fuel designation or specification.

33–18, 61 FR 31328, June 19, 1996; Amdt. 33–26, (3) Oil grade or specification.

73 FR 48284, Aug. 19, 2008; Amdt. 33–30, 74 FR (4) Hydraulic fluid specification.

45310, Sept. 2, 2009] (5) Temperature of— (i) Oil at a location specified by the § 33.8 Selection of engine power and applicant; thrust ratings.

(ii) Induction air at the inlet face of (a) Requested engine power and a supersonic engine, including steady thrust ratings must be selected by the state operation and transient over- applicant.

temperature and time allowed; (b) Each selected rating must be for (iii) Hydraulic fluid of a supersonic the lowest power or thrust that all en- engine; gines of the same type may be expected (iv) Fuel at a location specified by to produce under the conditions used to the applicant; and determine that rating.

(v) External surfaces of the engine, if specified by the applicant.

[Amdt. 33–3, 32 FR 3736, Mar. 4, 1967] (6) Pressure of— (i) Fuel at the fuel inlet; Subpart B—Design and (ii) Oil at a location specified by the Construction; General applicant; (iii) Induction air at the inlet face of § 33.11 Applicability.

a supersonic engine, including steady This subpart prescribes the general state operation and transient over- design and construction requirements pressure and time allowed; and for reciprocating and turbine aircraft (iv) Hydraulic fluid.

engines.

(7) Accessory drive torque and over- hang moment.

§ 33.13 [Reserved] (8) Component life.

(9) Fuel filtration.

§ 33.15 Materials.

(10) Oil filtration.

(11) Bleed air. The suitability and durability of ma- (12) The number of start-stop stress terials used in the engine must— cycles approved for each rotor disc and (a) Be established on the basis of ex- spacer. perience or tests; and 14 CFR Ch. I (1–1–25 Edition) § 33.17 (b) Conform to approved specifica- must be fire resistant or fireproof, as tions (such as industry or military determined by the Administrator.

specifications) that ensure their having (f) Unintentional accumulation of the strength and other properties as- hazardous quantities of flammable sumed in the design data.

fluid within the engine must be pre- vented by draining and venting.

(Secs. 313(a), 601, and 603, 72 Stat. 759, 775, 49 (g) Any components, modules, or U.S.C. 1354(a), 1421, and 1423; sec. 6(c), 49 equipment, which are susceptible to or U.S.C. 1655(c)) are potential sources of static dis- [Amdt. 33–8, 42 FR 15047, Mar. 17, 1977, as charges or electrical fault currents amended by Amdt. 33–10, 49 FR 6850, Feb. 23, must be designed and constructed to be 1984] properly grounded to the engine ref- § 33.17 Fire protection.

erence, to minimize the risk of ignition in external areas where flammable (a) The design and construction of fluids or vapors could be present.

the engine and the materials used must minimize the probability of the occur- [Doc. No. FAA–2007–28503, 74 FR 37930, July rence and spread of fire during normal 30, 2009] operation and failure conditions, and § 33.19 Durability.

must minimize the effect of such a fire.

In addition, the design and construc- (a) Engine design and construction tion of turbine engines must minimize must minimize the development of an the probability of the occurrence of an unsafe condition of the engine between internal fire that could result in struc- overhaul periods. The design of the tural failure or other hazardous effects.

compressor and turbine rotor cases (b) Except as provided in paragraph must provide for the containment of (c) of this section, each external line, damage from rotor blade failure. En- fitting, and other component, which ergy levels and trajectories of frag- contains or conveys flammable fluid ments resulting from rotor blade fail- during normal engine operation, must ure that lie outside the compressor and be fire resistant or fireproof, as deter- turbine rotor cases must be defined.

mined by the Administrator. Compo- (b) Each component of the propeller nents must be shielded or located to blade pitch control system which is a safeguard against the ignition of leak- part of the engine type design must ing flammable fluid.

meet the requirements of §§ 35.21, 35.23, (c) A tank, which contains flammable 35.42 and 35.43 of this chapter.

fluids and any associated shut-off [Doc. No. 3025, 29 FR 7453, June 10, 1964, as means and supports, which are part of amended by Amdt. 33–9, 45 FR 60181, Sept. 11, and attached to the engine, must be 1980; Amdt. 33–10, 49 FR 6851, Feb. 23, 1984; fireproof either by construction or by Amdt. 33–28, 73 FR 63346, Oct. 24, 2008] protection unless damage by fire will not cause leakage or spillage of a haz- § 33.21 Engine cooling.

ardous quantity of flammable fluid.

Engine design and construction must For a reciprocating engine having an provide the necessary cooling under integral oil sump of less than 23.7 liters conditions in which the airplane is ex- capacity, the oil sump need not be fire- pected to operate.

proof or enclosed by a fireproof shield.

(d) An engine component designed, § 33.23 Engine mounting attachments constructed, and installed to act as a and structure.

firewall must be: (a) The maximum allowable limit (1) Fireproof; and ultimate loads for engine mount- (2) Constructed so that no hazardous ing attachments and related engine quantity of air, fluid or flame can pass structure must be specified.

around or through the firewall; and, (b) The engine mounting attach- (3) Protected against corrosion; ments and related engine structure (e) In addition to the requirements of must be able to withstand— paragraphs (a) and (b) of this section, engine control system components that (1) The specified limit loads without are located in a designated fire zone permanent deformation; and Federal Aviation Administration, DOT § 33.27 (2) The specified ultimate loads with- duration is acceptable if the required out failure, but may exhibit permanent maximum overspeed is achieved.

deformation.

(b) When determining the maximum overspeed condition applicable to each [Amdt. 33–10, 49 FR 6851, Feb. 23, 1984] rotor in order to comply with para- graphs (a) and (c) of this section, the § 33.25 Accessory attachments.

applicant must evaluate the following The engine must operate properly rotor speeds taking into consideration with the accessory drive and mounting the part’s operating temperatures and attachments loaded. Each engine ac- temperature gradients throughout the cessory drive and mounting attach- engine’s operating envelope: ment must include provisions for seal- (1) 120 percent of the maximum per- ing to prevent contamination of, or un- missible rotor speed associated with acceptable leakage from, the engine in- any of the engine ratings except one- terior. A drive and mounting attach- engine-inoperative (OEI) ratings of less ment requiring lubrication for external than 2 ⁄2 minutes.

drive splines, or coupling by engine oil, (2) 115 percent of the maximum per- must include provisions for sealing to missible rotor speed associated with prevent unacceptable loss of oil and to any OEI ratings of less than 2 ⁄2 min- prevent contamination from sources utes.

outside the chamber enclosing the (3) 105 percent of the highest rotor drive connection. The design of the en- speed that would result from either: gine must allow for the examination, (i) The failure of the component or adjustment, or removal of each acces- system which, in a representative in- sory required for engine operation.

stallation of the engine, is the most [Amdt. 33–10, 49 FR 6851, Feb. 23, 1984] critical with respect to overspeed when operating at any rating condition ex- § 33.27 Turbine, compressor, fan, and 1 cept OEI ratings of less than 2 ⁄2 min- turbosupercharger rotor overspeed.

utes, or (a) For each fan, compressor, turbine, (ii) The failure of any component or and turbosupercharger rotor, the appli- system in a representative installation cant must establish by test, analysis, of the engine, in combination with any or a combination of both, that each other failure of a component or system rotor will not burst when operated in that would not normally be detected the engine for 5 minutes at whichever during a routine pre-flight check or of the conditions defined in paragraph during normal flight operation, that is (b) of this section is the most critical the most critical with respect to over- with respect to the integrity of such a speed, except as provided by paragraph rotor. (c) of this section, when operating at any rating condition except OEI rat- (1) Test rotors used to demonstrate ings of less than 2 ⁄2 minutes.

compliance with this section that do not have the most adverse combination (4) 100 percent of the highest rotor of material properties and dimensional speed that would result from the fail- tolerances must be tested at conditions ure of the component or system which, which have been adjusted to ensure the in a representative installation of the minimum specification rotor possesses engine, is the most critical with re- the required overspeed capability. This spect to overspeed when operating at can be accomplished by increasing test any OEI rating of less than 2 ⁄ 2 min- speed, temperature, and/or loads. utes.

(2) When an engine test is being used (c) The highest overspeed that results to demonstrate compliance with the from a complete loss of load on a tur- overspeed conditions listed in para- bine rotor, except as provided by para- graph (b)(3) or (b)(4) of this section and graph (f) of this section, must be in- the failure of a component or system is cluded in the overspeed conditions con- sudden and transient, it may not be sidered by paragraphs (b)(3)(i), possible to operate the engine for 5 (b)(3)(ii), and (b)(4) of this section, re- minutes after the failure. Under these gardless of whether that overspeed re- circumstances, the actual overspeed sults from a failure within the engine 14 CFR Ch. I (1–1–25 Edition) § 33.28 or external to the engine. The over- be analyzed by well-established and speed resulting from any other single validated stress analysis techniques.

failure must be considered when select- (3) Determines, based on an assess- ing the most limiting overspeed condi- ment of the environment surrounding tions applicable to each rotor. Over- the shaft section, that environmental speeds resulting from combinations of influences are unlikely to cause a shaft failures must also be considered unless failure. This assessment must include the applicant can show that the prob- complexity of design, corrosion, wear, ability of occurrence is not greater vibration, fire, contact with adjacent than extremely remote (probability components or structure, overheating, ¥ 7 ¥ 9 range of 10 to 10 per engine flight and secondary effects from other fail- hour).

ures or combination of failures.

(d) In addition, the applicant must (4) Identifies and declares, in accord- demonstrate that each fan, compressor, ance with § 33.5, any assumptions re- turbine, and turbosupercharger rotor garding the engine installation in mak- complies with paragraphs (d)(1) and ing the assessment described above in (d)(2) of this section for the maximum paragraph (f)(3) of this section.

overspeed achieved when subjected to (5) Assesses, and considers as appro- the conditions specified in paragraphs priate, experience with shaft sections (b)(3) and (b)(4) of this section. The ap- of similar design.

plicant must use the approach in para- (6) Does not exclude the entire shaft.

graph (a) of this section which specifies (g) If analysis is used to meet the the required test conditions.

overspeed requirements, then the ana- (1) Rotor Growth must not cause the lytical tool must be validated to prior engine to: overspeed test results of a similar (i) Catch fire, rotor. The tool must be validated for (ii) Release high-energy debris each material. The rotor being cer- through the engine casing or result in tified must not exceed the boundaries a hazardous failure of the engine cas- of the rotors being used to validate the ing, analytical tool in terms of geometric (iii) Generate loads greater than shape, operating stress, and tempera- those ultimate loads specified in ture. Validation includes the ability to § 33.23(a), or accurately predict rotor dimensional (iv) Lose the capability of being shut growth and the burst speed. The pre- down.

dictions must also show that the rotor (2) Following an overspeed event and being certified does not have lower after continued operation, the rotor burst and growth margins than rotors may not exhibit conditions such as used to validate the tool.

cracking or distortion which preclude [Doc. No. FAA–2010–0398, Amdt. 33–31, 76 FR continued safe operation.

42023, July 18, 2011] (e) The design and functioning of en- gine control systems, instruments, and § 33.28 Engine control systems.

other methods not covered under § 33.28 (a) Applicability. These requirements must ensure that the engine operating are applicable to any system or device limitations that affect turbine, com- that is part of engine type design, that pressor, fan, and turbosupercharger controls, limits, or monitors engine op- rotor structural integrity will not be exceeded in service. eration, and is necessary for the con- (f) Failure of a shaft section may be tinued airworthiness of the engine.

excluded from consideration in deter- (b) Validation —(1) Functional aspects.

mining the highest overspeed that The applicant must substantiate by would result from a complete loss of tests, analysis, or a combination there- load on a turbine rotor if the applicant: of, that the engine control system per- (1) Identifies the shaft as an engine forms the intended functions in a man- life-limited-part and complies with ner which: § 33.70.

(i) Enables selected values of rel- (2) Uses material and design features evant control parameters to be main- that are well understood and that can tained and the engine kept within the Federal Aviation Administration, DOT § 33.28 approved operating limits over chang- (1) The rate for Loss of Thrust (or ing atmospheric conditions in the de- Power) Control (LOTC/LOPC) events, clared flight envelope; consistent with the safety objective as- (ii) Complies with the operability re- sociated with the intended application quirements of §§ 33.51, 33.65 and 33.73, as can be achieved; appropriate, under all likely system in- (2) In the full-up configuration, the puts and allowable engine power or system is single fault tolerant, as de- thrust demands, unless it can be dem- termined by the Administrator, for onstrated that failure of the control electrical or electronic failures with function results in a non-dispatchable respect to LOTC/LOPC events; condition in the intended application; (3) Single failures of engine control (iii) Allows modulation of engine system components do not result in a power or thrust with adequate sensi- hazardous engine effect; and tivity over the declared range of engine (4) Foreseeable failures or malfunc- operating conditions; and tions leading to local events in the in- (iv) Does not create unacceptable tended aircraft installation, such as power or thrust oscillations.

fire, overheat, or failures leading to (2) Environmental limits. The applicant damage to engine control system com- must demonstrate, when complying ponents, do not result in a hazardous with §§ 33.53 or 33.91, that the engine engine effect due to engine control sys- control system functionality will not tem failures or malfunctions.

be adversely affected by declared envi- (e) S ystem safety assessment. When ronmental conditions, including elec- complying with this section and § 33.75, tromagnetic interference (EMI), High the applicant must complete a System Intensity Radiated Fields (HIRF), and Safety Assessment for the engine con- lightning. The limits to which the sys- trol system. This assessment must tem has been qualified must be docu- identify faults or failures that result in mented in the engine installation in- a change in thrust or power, trans- structions.

mission of erroneous data, or an effect (c) Control transitions. (1) The appli- on engine operability producing a surge cant must demonstrate that, when or stall together with the predicted fre- fault or failure results in a change quency of occurrence of these faults or from one control mode to another, failures.

from one channel to another, or from (f) Protection systems. (1) The design the primary system to the back-up sys- and functioning of engine control de- tem, the change occurs so that: vices and systems, together with en- (i) The engine does not exceed any of gine instruments and operating and its operating limitations; maintenance instructions, must pro- (ii) The engine does not surge, stall, vide reasonable assurance that those or experience unacceptable thrust or engine operating limitations that af- power changes or oscillations or other fect turbine, compressor, fan, and tur- unacceptable characteristics; and bosupercharger rotor structural integ- (iii) There is a means to alert the rity will not be exceeded in service.

flight crew if the crew is required to (2) When electronic overspeed protec- initiate, respond to, or be aware of the tion systems are provided, the design control mode change. The means to must include a means for testing, at alert the crew must be described in the least once per engine start/stop cycle, engine installation instructions, and to establish the availability of the pro- the crew action must be described in tection function. The means must be the engine operating instructions; such that a complete test of the system (2) The magnitude of any change in can be achieved in the minimum num- thrust or power and the associated ber of cycles. If the test is not fully transition time must be identified and automatic, the requirement for a man- described in the engine installation in- ual test must be contained in the en- structions and the engine operating in- gine instructions for operation.

structions.

(d) Engine control system failures. The (3) When overspeed protection is pro- applicant must design and construct vided through hydromechanical or me- the engine control system so that: chanical means, the applicant must 14 CFR Ch. I (1–1–25 Edition) § 33.29 demonstrate by test or other accept- tion must meet the requirements of able means that the overspeed function paragraph (i)(1) of this section. The en- remains available between inspection gine control system must be capable of and maintenance periods. resuming normal operation when air- (g) Software. The applicant must de- craft-supplied power returns to within sign, implement, and verify all associ- the declared limits.

ated software to minimize the exist- (j) Air pressure signal. The applicant ence of errors by using a method, ap- must consider the effects of blockage proved by the FAA, consistent with the or leakage of the signal lines on the en- criticality of the performed functions. gine control system as part of the Sys- (h) Aircraft-supplied data. Single fail- tem Safety Assessment of paragraph ures leading to loss, interruption or (e) of this section and must adopt the corruption of aircraft-supplied data appropriate design precautions.

(other than thrust or power command (k) Automatic availability and control signals from the aircraft), or data of engine power for 30-second OEI rating.

shared between engines must: Rotorcraft engines having a 30-second (1) Not result in a hazardous engine OEI rating must incorporate a means, effect for any engine; and or a provision for a means, for auto- (2) Be detected and accommodated.

matic availability and automatic con- The accommodation strategy must not trol of the 30-second OEI power within result in an unacceptable change in its operating limitations.

thrust or power or an unacceptable (l) Engine shut down means. Means change in engine operating and start- must be provided for shutting down the ing characteristics. The applicant must engine rapidly.

evaluate and document in the engine (m) Programmable logic devices. The installation instructions the effects of development of programmable logic de- these failures on engine power or vices using digital logic or other com- thrust, engine operability, and starting plex design technologies must provide characteristics throughout the flight a level of assurance for the encoded envelope.

logic commensurate with the hazard (i) Aircraft-supplied electrical power. (1) associated with the failure or malfunc- The applicant must design the engine tion of the systems in which the de- control system so that the loss, mal- vices are located. The applicant must function, or interruption of electrical provide evidence that the development power supplied from the aircraft to the of these devices has been done by using engine control system will not result a method, approved by the FAA, that is in any of the following: consistent with the criticality of the (i) A hazardous engine effect, or performed function.

(ii) The unacceptable transmission of [Amdt. 33–26, 73 FR 48284, Aug. 19, 2008] erroneous data.

(2) When an engine dedicated power § 33.29 Instrument connection.

source is required for compliance with (a) Unless it is constructed to pre- paragraph (i)(1) of this section, its ca- vent its connection to an incorrect in- pacity should provide sufficient margin strument, each connection provided for to account for engine operation below powerplant instruments required by idle where the engine control system is aircraft airworthiness regulations or designed and expected to recover en- necessary to insure operation of the en- gine operation automatically.

gine in compliance with any engine (3) The applicant must identify and limitation must be marked to identify declare the need for, and the character- it with its corresponding instrument.

istics of, any electrical power supplied from the aircraft to the engine control (b) A connection must be provided on system for starting and operating the each turbojet engine for an indicator engine, including transient and steady system to indicate rotor system unbal- state voltage limits, in the engine in- ance.

structions for installation. (c) Each rotorcraft turbine engine (4) Low voltage transients outside having a 30-second OEI rating and a 2- the power supply voltage limitations minute OEI rating must have a means declared in paragraph (i)(3) of this sec- or a provision for a means to: Federal Aviation Administration, DOT § 33.35 (1) Alert the pilot when the engine is (1) Other existing instrumentation at the 30-second OEI and the 2-minute provides adequate warning of failure or OEI power levels, when the event be- impending failure; gins, and when the time interval ex- (2) Failure of the cooling system pires; would not lead to hazardous engine ef- fects before detection; or (2) Automatically record each usage (3) The probability of failure of the and duration of power at the 30-second cooling system is extremely remote.

OEI and 2-minute OEI levels; (3) Alert maintenance personnel in a [Amdt. 33–5, 39 FR 1831, Jan. 15, 1974, as positive manner that the engine has amended by Amdt. 33–6, 39 FR 35465, Oct. 1, 1974; Amdt. 33–18, 61 FR 31328, June 19, 1996; been operated at either or both of the Amdt. 33–25, 73 FR 48123, Aug. 18, 2008; Amdt.

30-second and 2-minute OEI power lev- 33–26, 73 FR 48285, Aug. 19, 2008] els, and permit retrieval of the re- corded data; and Subpart C—Design and Construc- (4) Enable routine verification of the tion; Reciprocating Aircraft proper operation of the above means.

Engines (d) The means, or the provision for a means, of paragraphs (c)(2) and (c)(3) of § 33.31 Applicability.

this section must not be capable of This subpart prescribes additional de- being reset in flight.

sign and construction requirements for (e) The applicant must make provi- reciprocating aircraft engines.

sion for the installation of instrumen- tation necessary to ensure operation in § 33.33 Vibration.

compliance with engine operating limi- The engine must be designed and con- tations. Where, in presenting the safe- structed to function throughout its ty analysis, or complying with any normal operating range of crankshaft other requirement, dependence is rotational speeds and engine powers placed on instrumentation that is not without inducing excessive stress in otherwise mandatory in the assumed any of the engine parts because of vi- aircraft installation, then the appli- bration and without imparting exces- cant must specify this instrumentation sive vibration forces to the aircraft in the engine installation instructions structure.

and declare it mandatory in the engine approval documentation.

§ 33.34 Turbocharger rotors.

(f) As part of the System Safety As- Each turbocharger case must be de- sessment of § 33.28(e), the applicant signed and constructed to be able to must assess the possibility and subse- contain fragments of a compressor or quent effect of incorrect fit of instru- turbine that fails at the highest speed ments, sensors, or connectors. Where that is obtainable with normal speed necessary, the applicant must take de- control devices inoperative.

sign precautions to prevent incorrect configuration of the system.

[Amdt. 33–22, 72 FR 50860, Sept. 4, 2007] (g) The sensors, together with associ- § 33.35 Fuel and induction system.

ated wiring and signal conditioning, must be segregated, electrically and (a) The fuel system of the engine physically, to the extent necessary to must be designed and constructed to ensure that the probability of a fault supply an appropriate mixture of fuel propagating from instrumentation and to the cylinders throughout the com- monitoring functions to control func- plete operating range of the engine tions, or vice versa, is consistent with under all flight and atmospheric condi- the failure effect of the fault.

tions.

(h) The applicant must provide in- (b) The intake passages of the engine strumentation enabling the flight crew through which air or fuel in combina- to monitor the functioning of the tur- tion with air passes for combustion bine cooling system unless appropriate purposes must be designed and con- inspections are published in the rel- structed to minimize the danger of ice evant manuals and evidence shows accretion in those passages. The engine that: must be designed and constructed to

14 CFR Ch. I (1–1–25 Edition) § 33.37 permit the use of a means for ice pre- Subpart D—Block Tests; vention.

Reciprocating Aircraft Engines (c) The type and degree of fuel fil- § 33.41 Applicability.

tering necessary for protection of the engine fuel system against foreign par- This subpart prescribes the block ticles in the fuel must be specified. The tests and inspections for reciprocating applicant must show that foreign par- aircraft engines.

ticles passing through the prescribed § 33.42 General.

filtering means will not critically im- pair engine fuel system functioning. Before each endurance test required by this subpart, the adjustment setting (d) Each passage in the induction sys- and functioning characteristic of each tem that conducts a mixture of fuel component having an adjustment set- and air must be self-draining, to pre- ting and a functioning characteristic vent a liquid lock in the cylinders, in that can be established independent of all attitudes that the applicant estab- installation on the engine must be es- lishes as those the engine can have tablished and recorded.

when the aircraft in which it is in- stalled is in the static ground attitude. [Amdt. 33–6, 39 FR 35465, Oct. 1, 1974] (e) If provided as part of the engine, § 33.43 Vibration test.

the applicant must show for each fluid injection (other than fuel) system and (a) Each engine must undergo a vi- bration survey to establish the tor- its controls that the flow of the in- sional and bending vibration character- jected fluid is adequately controlled.

istics of the crankshaft and the pro- [Doc. No. 3025, 29 FR 7453, June 10, 1964, as peller shaft or other output shaft, over amended by Amdt. 33–10, 49 FR 6851, Feb. 23, the range of crankshaft speed and en- 1984] gine power, under steady state and transient conditions, from idling speed § 33.37 Ignition system.

to either 110 percent of the desired Each spark ignition engine must maximum continuous speed rating or have a dual ignition system with at 103 percent of the maximum desired least two spark plugs for each cylinder takeoff speed rating, whichever is high- and two separate electric circuits with er. The survey must be conducted separate sources of electrical energy, using, for airplane engines, the same or have an ignition system of equiva- configuration of the propeller type which is used for the endurance test, lent in-flight reliability.

and using, for other engines, the same § 33.39 Lubrication system.

configuration of the loading device type which is used for the endurance (a) The lubrication system of the en- test.

gine must be designed and constructed (b) The torsional and bending vibra- so that it will function properly in all tion stresses of the crankshaft and the flight attitudes and atmospheric condi- propeller shaft or other output shaft tions in which the airplane is expected may not exceed the endurance limit to operate. In wet sump engines, this stress of the material from which the requirement must be met when only shaft is made. If the maximum stress one-half of the maximum lubricant in the shaft cannot be shown to be supply is in the engine.

below the endurance limit by measure- (b) The lubrication system of the en- ment, the vibration frequency and am- gine must be designed and constructed plitude must be measured. The peak to allow installing a means of cooling amplitude must be shown to produce a the lubricant.

stress below the endurance limit; if (c) The crankcase must be vented to not, the engine must be run at the con- dition producing the peak amplitude the atmosphere to preclude leakage of until, for steel shafts, 10 million stress oil from excessive pressure in the reversals have been sustained without crankcase.

fatigue failure and, for other shafts, until it is shown that fatigue will not Federal Aviation Administration, DOT § 33.49 occur within the endurance limit stress out detonation throughout its range of of the material. intended conditions of operation.

(c) Each accessory drive and mount- § 33.49 Endurance test.

ing attachment must be loaded, with the loads imposed by each accessory (a) General. Each engine must be sub- used only for an aircraft service being jected to an endurance test that in- the limit load specified by the appli- cludes a total of 150 hours of operation cant for the drive or attachment point. (except as provided in paragraph (e)(1)(iii) of this section) and, depend- (d) The vibration survey described in ing upon the type and contemplated paragraph (a) of this section must be use of the engine, consists of one of the repeated with that cylinder not firing series of runs specified in paragraphs which has the most adverse vibration (b) through (e) of this section, as appli- effect, in order to establish the condi- cable. The runs must be made in the tions under which the engine can be op- order found appropriate by the Admin- erated safely in that abnormal state.

istrator for the particular engine being However, for this vibration survey, the tested. During the endurance test the engine speed range need only extend engine power and the crankshaft rota- from idle to the maximum desired tional speed must be kept within ± 3 takeoff speed, and compliance with percent of the rated values. During the paragraph (b) of this section need not runs at rated takeoff power and for at be shown.

least 35 hours at rated maximum con- [Amdt. 33–6, 39 FR 35465, Oct. 1, 1974, as tinuous power, one cylinder must be amended by Amdt. 33–10, 49 FR 6851, Feb. 23, operated at not less than the limiting 1984] temperature, the other cylinders must be operated at a temperature not lower § 33.45 Calibration tests.

than 50 degrees F. below the limiting (a) Each engine must be subjected to temperature, and the oil inlet tempera- the calibration tests necessary to es- ture must be maintained within ± 10 de- tablish its power characteristics and grees F. of the limiting temperature.

the conditions for the endurance test An engine that is equipped with a pro- specified in § 33.49. The results of the peller shaft must be fitted for the en- power characteristics calibration tests durance test with a propeller that form the basis for establishing the thrust-loads the engine to the max- characteristics of the engine over its imum thrust which the engine is de- entire operating range of crankshaft signed to resist at each applicable op- rotational speeds, manifold pressures, erating condition specified in this sec- fuel/air mixture settings, and altitudes.

tion. Each accessory drive and mount- Power ratings are based upon standard ing attachment must be loaded. During atmospheric conditions with only those operation at rated takeoff power and accessories installed which are essen- rated maximum continuous power, the tial for engine functioning.

load imposed by each accessory used (b) A power check at sea level condi- only for an aircraft service must be the tions must be accomplished on the en- limit load specified by the applicant durance test engine after the endur- for the engine drive or attachment ance test. Any change in power charac- point.

teristics which occurs during the en- (b) Unsupercharged engines and en- durance test must be determined.

gines incorporating a gear-driven single- Measurements taken during the final speed supercharger. For engines not in- portion of the endurance test may be corporating a supercharger and for en- used in showing compliance with the gines incorporating a gear-driven sin- requirements of this paragraph.

gle-speed supercharger the applicant [Doc. No. 3025, 29 FR 7453, June 10, 1964, as must conduct the following runs: amended by Amdt. 33–6, 39 FR 35465, Oct. 1, (1) A 30-hour run consisting of alter- 1974] nate periods of 5 minutes at rated take- off power with takeoff speed, and 5 § 33.47 Detonation test.

minutes at maximum best economy Each engine must be tested to estab- cruising power or maximum rec- lish that the engine can function with- ommended cruising power.

14 CFR Ch. I (1–1–25 Edition) § 33.49 (2) A 20-hour run consisting of alter- ical altitude manifold pressure and nate periods of 1 ⁄2 hours at rated max- takeoff speed, and 5 minutes at 70 per- imum continuous power with max- cent high ratio rated maximum contin- imum continuous speed, and ⁄2 hour at uous power and 89 percent high ratio 75 percent rated maximum continuous maximum continuous speed.

power and 91 percent maximum contin- (2) A 15-hour run consisting of alter- uous speed.

nate periods in the lower gear ratio of (3) A 20-hour run consisting of alter- 1 hour at rated maximum continuous nate periods of 1 ⁄2 hours at rated max- power with maximum continuous imum continuous power with max- speed, and ⁄ 2 hour at 75 percent rated imum continuous speed, and ⁄2 hour at maximum continuous power and 91 per- 70 percent rated maximum continuous cent maximum continuous speed.

power and 89 percent maximum contin- (3) A 15-hour run consisting of alter- uous speed.

nate periods in the lower gear ratio of (4) A 20-hour run consisting of alter- 1 hour at rated maximum continuous nate periods of 1 ⁄2 hours at rated max- power with maximum continuous imum continuous power with max- speed, and ⁄ 2 hour at 70 percent rated imum continuous speed, and ⁄2 hour at maximum continuous power and 89 per- 65 percent rated maximum continuous cent maximum continuous speed.

power and 87 percent maximum contin- (4) A 30-hour run in the higher gear uous speed.

ratio at rated maximum continuous (5) A 20-hour run consisting of alter- power with maximum continuous nate periods of 1 ⁄2 hours at rated max- speed.

imum continuous power with max- (5) A 5-hour run consisting of alter- imum continuous speed, and ⁄2 hour at nate periods of 5 minutes in each of the 60 percent rated maximum continuous supercharger gear ratios. The first 5 power and 84.5 percent maximum con- minutes of the test must be made at tinuous speed.

maximum continuous speed in the (6) A 20-hour run consisting of alter- higher gear ratio and the observed nate periods of 1 ⁄2 hours at rated max- horsepower obtainable with 90 percent imum continuous power with max- of maximum continuous manifold pres- imum continuous speed, and ⁄2 hour at sure in the higher gear ratio under sea 50 percent rated maximum continuous level conditions. The condition for op- power and 79.5 percent maximum con- eration for the alternate 5 minutes in tinuous speed.

the lower gear ratio must be that ob- (7) A 20-hour run consisting of alter- tained by shifting to the lower gear nate periods of 2 ⁄2 hours at rated max- ratio at constant speed.

imum continuous power with max- 1 (6) A 10-hour run consisting of alter- imum continuous speed, and 2 ⁄ 2 hours nate periods in the lower gear ratio of at maximum best economy cruising 1 hour at rated maximum continuous power or at maximum recommended power with maximum continuous cruising power.

speed, and 1 hour at 65 percent rated (c) Engines incorporating a gear-driven maximum continuous power and 87 per- two-speed supercharger. For engines in- cent maximum continuous speed.

corporating a gear-driven two-speed su- (7) A 10-hour run consisting of alter- percharger the applicant must conduct nate periods in the lower gear ratio of the following runs: 1 hour at rated maximum continuous (1) A 30-hour run consisting of alter- power with maximum continuous nate periods in the lower gear ratio of speed, and 1 hour at 60 percent rated 5 minutes at rated takeoff power with maximum continuous power and 84.5 takeoff speed, and 5 minutes at max- percent maximum continuous speed.

imum best economy cruising power or at maximum recommended cruising (8) A 10-hour run consisting of alter- power. If a takeoff power rating is de- nate periods in the lower gear ratio of sired in the higher gear ratio, 15 hours 1 hour at rated maximum continuous of the 30-hour run must be made in the power with maximum continuous higher gear ratio in alternate periods speed, and 1 hour at 50 percent rated of 5 minutes at the observed horse- maximum continuous power and 79.5 power obtainable with the takeoff crit- percent maximum continuous speed.

Federal Aviation Administration, DOT § 33.49 (9) A 20-hour run consisting of alter- percent maximum continuous speed or nate periods in the lower gear ratio of at rated takeoff power with 103 percent 2 hours at rated maximum continuous takeoff speed, whichever results in the power with maximum continuous greater speed.

speed, and 2 hours at maximum best (6) A 15-hour run at 105 percent rated economy cruising power and speed or maximum continuous power with 105 at maximum recommended cruising percent maximum continuous speed or power.

at full throttle and corresponding (10) A 5-hour run in the lower gear speed at standard sea level carburetor ratio at maximum best economy cruis- entrance pressure, if 105 percent of the ing power and speed or at maximum rated maximum continuous power is recommended cruising power and not exceeded.

speed.

(e) Turbosupercharged engines. For en- Where simulated altitude test equip- gines incorporating a turbo- ment is not available when operating supercharger the following apply ex- in the higher gear ratio, the runs may cept that altitude testing may be simu- be made at the observed horsepower ob- lated provided the applicant shows that tained with the critical altitude mani- the engine and supercharger are being fold pressure or specified percentages subjected to mechanical loads and op- thereof, and the fuel-air mixtures may erating temperatures no less severe be adjusted to be rich enough to sup- than if run at actual altitude condi- press detonation.

tions: (d) Helicopter engines. To be eligible (1) For engines used in airplanes the for use on a helicopter each engine applicant must conduct the runs speci- must either comply with paragraphs fied in paragraph (b) of this section, ex- (a) through (j) of § 29.923 of this chap- cept— ter, or must undergo the following se- (i) The entire run specified in para- ries of runs: graph (b)(1) of this section must be (1) A 35-hour run consisting of alter- made at sea level altitude pressure; nate periods of 30 minutes each at (ii) The portions of the runs specified rated takeoff power with takeoff speed, in paragraphs (b)(2) through (7) of this and at rated maximum continuous section at rated maximum continuous power with maximum continuous power must be made at critical alti- speed.

tude pressure, and the portions of the (2) A 25-hour run consisting of alter- runs at other power must be made at nate periods of 2 ⁄2 hours each at rated 8,000 feet altitude pressure; and maximum continuous power with max- (iii) The turbosupercharger used dur- imum continuous speed, and at 70 per- ing the 150-hour endurance test must cent rated maximum continuous power be run on the bench for an additional 50 with maximum continuous speed.

hours at the limiting turbine wheel (3) A 25-hour run consisting of alter- 1 inlet gas temperature and rotational nate periods of 2 ⁄2 hours each at rated speed for rated maximum continuous maximum continuous power with max- power operation unless the limiting imum continuous speed, and at 70 per- temperature and speed are maintained cent rated maximum continuous power during 50 hours of the rated maximum with 80 to 90 percent maximum contin- continuous power operation.

uous speed.

(2) For engines used in helicopters (4) A 25-hour run consisting of alter- 1 the applicant must conduct the runs nate periods of 2 ⁄2 hours each at 30 per- specified in paragraph (d) of this sec- cent rated maximum continuous power tion, except— with takeoff speed, and at 30 percent (i) The entire run specified in para- rated maximum continuous power with graph (d)(1) of this section must be 80 to 90 percent maximum continuous made at critical altitude pressure; speed.

(5) A 25-hour run consisting of alter- (ii) The portions of the runs specified nate periods of 2 ⁄2 hours each at 80 per- in paragraphs (d)(2) and (3) of this sec- cent rated maximum continuous power tion at rated maximum continuous with takeoff speed, and at either rated power must be made at critical alti- maximum continuous power with 110 tude pressure and the portions of the 14 CFR Ch. I (1–1–25 Edition) § 33.51 runs at other power must be made at are able to perform the intended func- 8,000 feet altitude pressure; tions in all declared environmental and (iii) The entire run specified in para- operating conditions.

graph (d)(4) of this section must be (b) Temperature limits must be es- made at 8,000 feet altitude pressure; tablished for each component that re- (iv) The portion of the runs specified quires temperature controlling provi- in paragraph (d)(5) of this section at 80 sions in the aircraft installation to as- percent of rated maximum continuous sure satisfactory functioning, reli- power must be made at 8,000 feet alti- ability, and durability.

tude pressure and the portions of the [Doc. No. 3025, 29 FR 7453, June 10, 1964, as runs at other power must be made at amended by Amdt. 33–26, 73 FR 48285, Aug. 19, critical altitude pressure; 2008] (v) The entire run specified in para- graph (d)(6) of this section must be § 33.55 Teardown inspection.

made at critical altitude pressure; and After completing the endurance (vi) The turbosupercharger used dur- test— ing the endurance test must be run on (a) Each engine must be completely the bench for 50 hours at the limiting disassembled; turbine wheel inlet gas temperature (b) Each component having an ad- and rotational speed for rated max- justment setting and a functioning imum continuous power operation un- characteristic that can be established less the limiting temperature and independent of installation on the en- speed are maintained during 50 hours of gine must retain each setting and func- the rated maximum continuous power tioning characteristic within the limits operation.

that were established and recorded at [Amdt. 33–3, 32 FR 3736, Mar. 4, 1967, as the beginning of the test; and amended by Amdt. 33–6, 39 FR 35465, Oct. 1, (c) Each engine component must con- 1974; Amdt. 33–10, 49 FR 6851, Feb. 23, 1984] form to the type design and be eligible for incorporation into an engine for § 33.51 Operation test.

continued operation, in accordance The operation test must include the with information submitted in compli- testing found necessary by the Admin- ance with § 33.4.

istrator to demonstrate backfire char- acteristics, starting, idling, accelera- [Amdt. 33–6, 39 FR 35466, Oct. 1, 1974, as tion, overspeeding, functioning of pro- amended by Amdt. 33–9, 45 FR 60181, Sept. 11, 1980] peller and ignition, and any other oper- ational characteristic of the engine. If § 33.57 General conduct of block tests.

the engine incorporates a multispeed supercharger drive, the design and con- (a) The applicant may, in conducting struction must allow the supercharger the block tests, use separate engines of to be shifted from operation at the identical design and construction in lower speed ratio to the higher and the the vibration, calibration, detonation, power appropriate to the manifold endurance, and operation tests, except pressure and speed settings for rated that, if a separate engine is used for maximum continuous power at the the endurance test it must be subjected higher supercharger speed ratio must to a calibration check before starting be obtainable within five seconds.

the endurance test.

(b) The applicant may service and [Doc. No. 3025, 29 FR 7453, June 10, 1964, as make minor repairs to the engine dur- amended by Amdt. 33–3, 32 FR 3737, Mar. 4, 1967] ing the block tests in accordance with the service and maintenance instruc- § 33.53 Engine system and component tions submitted in compliance with tests.

§ 33.4. If the frequency of the service is (a) For those systems and compo- excessive, or the number of stops due nents that cannot be adequately sub- to engine malfunction is excessive, or a stantiated in accordance with endur- major repair, or replacement of a part ance testing of § 33.49, the applicant is found necessary during the block must conduct additional tests to dem- tests or as the result of findings from onstrate that systems or components the teardown inspection, the engine or Federal Aviation Administration, DOT § 33.67 its parts may be subjected to any addi- (2) Exhibit fracture or burst when tional test the Administrator finds subjected to the greater of the fol- necessary. lowing pressures: (i) 1.15 times the maximum possible (c) Each applicant must furnish all pressure; testing facilities, including equipment (ii) 1.5 times the maximum working and competent personnel, to conduct pressure; or the block tests.

(iii) 35 kPa (5 p.s.i.) above the max- [Doc. No. 3025, 29 FR 7453, June 10, 1964, as imum possible pressure.

amended by Amdt. 33–6, 39 FR 35466, Oct. 1, (b) Compliance with this section 1974; Amdt. 33–9, 45 FR 60181, Sept. 11, 1980] must take into account: (1) The operating temperature of the Subpart E—Design and Construc- part; tion; Turbine Aircraft Engines (2) Any other significant static loads in addition to pressure loads; § 33.61 Applicability.

(3) Minimum properties representa- tive of both the material and the proc- This subpart prescribes additional de- esses used in the construction of the sign and construction requirements for part; and turbine aircraft engines.

(4) Any adverse geometry conditions allowed by the type design.

§ 33.62 Stress analysis.

[Amdt. 33–27; 73 FR 55437, Sept. 25, 2008; A stress analysis must be performed Amdt. 33–27, 73 FR 57235, Oct. 2, 2008] on each turbine engine showing the de- sign safety margin of each turbine en- § 33.65 Surge and stall characteristics.

gine rotor, spacer, and rotor shaft.

When the engine is operated in ac- [Amdt. 33–6, 39 FR 35466, Oct. 1, 1974] cordance with operating instructions required by § 33.5(b), starting, a change § 33.63 Vibration.

of power or thrust, power or thrust Each engine must be designed and augmentation, limiting inlet air dis- constructed to function throughout its tortion, or inlet air temperature may declared flight envelope and operating not cause surge or stall to the extent range of rotational speeds and power/ that flameout, structural failure, over- thrust, without inducing excessive temperature, or failure of the engine to stress in any engine part because of vi- recover power or thrust will occur at bration and without imparting exces- any point in the operating envelope.

sive vibration forces to the aircraft [Amdt. 33–6, 39 FR 35466, Oct. 1, 1974] structure.

§ 33.66 Bleed air system.

[Doc. No. 28107, 61 FR 28433, June 4, 1996] The engine must supply bleed air § 33.64 Pressurized engine static parts.

without adverse effect on the engine, excluding reduced thrust or power out- (a) Strength. The applicant must es- put, at all conditions up to the dis- tablish by test, validated analysis, or a charge flow conditions established as a combination of both, that all static limitation under § 33.7(c)(11). If bleed parts subject to significant gas or liq- air used for engine anti-icing can be uid pressure loads for a stabilized pe- controlled, provision must be made for riod of one minute will not: a means to indicate the functioning of (1) Exhibit permanent distortion be- the engine ice protection system.

yond serviceable limits or exhibit leak- age that could create a hazardous con- [Amdt. 33–10, 49 FR 6851, Feb. 23, 1984] dition when subjected to the greater of § 33.67 Fuel system.

the following pressures: (i) 1.1 times the maximum working (a) With fuel supplied to the engine pressure; at the flow and pressure specified by (ii) 1.33 times the normal working the applicant, the engine must func- pressure; or tion properly under each operating (iii) 35 kPa (5 p.s.i.) above the normal condition required by this part. Each working pressure. fuel control adjusting means that may 14 CFR Ch. I (1–1–25 Edition) § 33.68 not be manipulated while the fuel con- (5) The applicant must demonstrate trol device is mounted on the engine that the filtering means has the capac- must be secured by a locking device ity (with respect to engine operating and sealed, or otherwise be inacces- limitations) to ensure that the engine sible. All other fuel control adjusting will continue to operate within ap- proved limits, with fuel contaminated means must be accessible and marked to the maximum degree of particle size to indicate the function of the adjust- and density likely to be encountered in ment unless the function is obvious.

service. Operation under these condi- (b) There must be a fuel strainer or tions must be demonstrated for a pe- filter between the engine fuel inlet riod acceptable to the Administrator, opening and the inlet of either the fuel beginning when indication of impend- metering device or the engine-driven ing filter blockage is first given by ei- positive displacement pump whichever ther: is nearer the engine fuel inlet. In addi- (i) Existing engine instrumentation; tion, the following provisions apply to or each strainer or filter required by this (ii) Additional means incorporated paragraph (b): into the engine fuel system.

(1) It must be accessible for draining (6) Any strainer or filter bypass must and cleaning and must incorporate a be designed and constructed so that the screen or element that is easily remov- release of collected contaminants is able.

minimized by appropriate location of (2) It must have a sediment trap and the bypass to ensure that collected drain except that it need not have a contaminants are not in the bypass drain if the strainer or filter is easily flow path.

removable for drain purposes.

(c) If provided as part of the engine, (3) It must be mounted so that its the applicant must show for each fluid weight is not supported by the con- injection (other than fuel) system and necting lines or by the inlet or outlet its controls that the flow of the in- connections of the strainer or filter, jected fluid is adequately controlled.

unless adequate strength margins [Amdt. 33–6, 39 FR 35466, Oct. 1, 1974, as under all loading conditions are pro- amended by Amdt. 33–10, 49 FR 6851, Feb. 23, vided in the lines and connections.

1984; Amdt. 33–18, 61 FR 31328, June 19, 1996; (4) It must have the type and degree Amdt. 33–25, 73 FR 48123, Aug. 18, 2008; Amdt.

of fuel filtering specified as necessary 33–26, 73 FR 48285, Aug. 19, 2008] for protection of the engine fuel system § 33.68 Induction system icing.

against foreign particles in the fuel.

The applicant must show: Each engine, with all icing protec- (i) That foreign particles passing tion systems operating, must: through the specified filtering means (a) Operate throughout its flight do not impair the engine fuel system power range, including the minimum functioning; and descent idle rotor speeds achievable in (ii) That the fuel system is capable of flight, in the icing conditions defined sustained operation throughout its for turbojet, turbofan, and turboprop flow and pressure range with the fuel engines in Appendices C and O of part initially saturated with water at 80 ° F 25 of this chapter, and Appendix D of (27 ° C) and having 0.025 fluid ounces per this part, and for turboshaft engines in gallon (0.20 milliliters per liter) of free Appendix C of part 29 of this chapter, water added and cooled to the most without the accumulation of ice on the critical condition for icing likely to be engine components that: encountered in operation. However, (1) Adversely affects engine operation this requirement may be met by dem- or that causes an unacceptable perma- onstrating the effectiveness of speci- nent loss of power or thrust or unac- fied approved fuel anti-icing additives, ceptable increase in engine operating or that the fuel system incorporates a temperature; or fuel heater which maintains the fuel (2) Results in unacceptable tem- temperature at the fuel strainer or fuel porary power loss or engine damage; or inlet above 32 ° F (0 ° C) under the most (3) Causes a stall, surge, or flameout critical conditions. or loss of engine controllability. The Federal Aviation Administration, DOT § 33.68 applicant must account for in-flight (ii) At engine power below that which ram effects in any critical point anal- can sustain level flight: ysis or test demonstration of these (A) Demonstration in altitude flight flight conditions. simulation test facility: A duration of (b) Operate throughout its flight 10 minutes consistent with a simulated power range, including minimum de- flight descent of 10,000 ft (3 km) in alti- scent idle rotor speeds achievable in tude while operating in Continuous flight, in the icing conditions defined Maximum icing conditions defined in for turbojet, turbofan, and turboprop Appendix C of part 25 of this chapter engines in Appendices C and O of part for turbojet, turbofan, and turboprop 25 of this chapter, and for turboshaft engines, and for turboshaft engines in engines in Appendix C of part 29 of this the icing conditions defined in Appen- chapter. In addition: dix C of part 29 of this chapter, plus 40 (1) It must be shown through Critical percent liquid water content margin, Point Analysis (CPA) that the com- at the critical level of airspeed and air plete ice envelope has been analyzed, temperature; or and that the most critical points must (B) Demonstration in ground test fa- be demonstrated by engine test, anal- cility: A duration of 3 cycles of alter- ysis, or a combination of the two to op- nating icing exposure corresponding to erate acceptably. Extended flight in the liquid water content levels and critical flight conditions such as hold, standard cloud lengths starting in descent, approach, climb, and cruise, Intermittent Maximum and then in must be addressed, for the ice condi- Continuous Maximum icing conditions tions defined in these appendices. defined in Appendix C of part 25 of this (2) It must be shown by engine test, chapter for turbojet, turbofan, and tur- analysis, or a combination of the two boprop engines, and for turboshaft en- that the engine can operate acceptably gines in the icing conditions defined in for the following durations: Appendix C of part 29 of this chapter, (i) At engine powers that can sustain at the critical level of air temperature.

level flight: A duration that achieves (c) In addition to complying with repetitive, stabilized operation for tur- paragraph (b) of this section, the fol- bojet, turbofan, and turboprop engines lowing conditions shown in Table 1 of in the icing conditions defined in Ap- this section unless replaced by similar pendices C and O of part 25 of this CPA test conditions that are more crit- chapter, and for turboshaft engines in ical or produce an equivalent level of the icing conditions defined in Appen- severity, must be demonstrated by an dix C of part 29 of this chapter. engine test: T ABLE 1—C ONDITIONS T HAT M UST BE DEMONSTRATED BY AN E NGINE T EST Supercooled water Condition Total air temperature concentrations Median volume drop diameter Duration (minimum) 1. Glaze ice condi- 21 to 25 ° F ( ¥ 6 to 2 g/m ........................ 25 to 35 microns ................... (a) 10-minutes for tions. ¥ 4 ° C). power below sus- tainable level flight (idle descent).

(b) Must show repet- itive, stabilized op- eration for higher powers (50%, 75%, 100%MC).

2. Rime ice conditions ¥ 10 to 0 ° F ( ¥ 23 to 1 g/m ........................ 15 to 25 microns ................... (a) 10-minutes for ¥ 18 ° C). power below sus- tainable level flight (idle descent).

(b) Must show repet- itive, stabilized op- eration for higher powers (50%, 75%, 100%MC).

14 CFR Ch. I (1–1–25 Edition) § 33.69 T ABLE 1—C ONDITIONS T HAT M UST B E D EMONSTRATED BY AN E NGINE T EST—Continued Supercooled water Condition Total air temperature concentrations Median volume drop diameter Duration (minimum) 3. Glaze ice holding Turbojet and Tur- Alternating cycle: First 20 to 30 microns ................... Must show repetitive, conditions. bofan, only: 10 to 1.7 g/m (1 minute), stabilized operation (Turbojet, turbofan, 18 ° F ( ¥ 12 to ¥ 8 Then 0.3 g/m (6 (or 45 minutes and turboprop only). ° C). minute). max).

Turboprop, only: 2 to .

10 ° F ( ¥ 17 to ¥ 12 ° C).

4. Rime ice holding Turbojet and Tur- 0.25 g/m ................... 20 to 30 microns ................... Must show repetitive, conditions. bofan, only: ¥ 10 to stabilized operation (Turbojet, turbofan, 0 ° F ( ¥ 23 to ¥ 18 (or 45 minutes and turboprop only). ° C). max).

Turboprop, only: 2 to .................................... ................................................

10 ° F ( ¥ 17 to ¥ 12 ° C).

(d) Operate at ground idle speed for a Administrator. Analysis may be used minimum of 30 minutes at each of the to show ambient temperatures below following icing conditions shown in the tested temperature are less crit- Table 2 of this section with the avail- ical. The applicant must document any able air bleed for icing protection at its demonstrated run ups and minimum critical condition, without adverse ef- ambient temperature capability in the fect, followed by acceleration to take- engine operating manual as mandatory off power or thrust. During the idle op- in icing conditions. The applicant must eration, the engine may be run up peri- demonstrate, with consideration of ex- odically to a moderate power or thrust pected airport elevations, the fol- setting in a manner acceptable to the lowing: T ABLE 2—D EMONSTRATION M ETHODS FOR S PECIFIC ICING C ONDITIONS Supercooled water Mean effective particle di- Condition Total air temperature concentrations Demonstration ameter (minimum) 1. Rime ice condition 0 to 15 ° F ( ¥ 18 to Liquid—0.3 g/m ........ 15–25 microns ....................... By engine test.

¥ 9 ° C).

2. Glaze ice condition 20 to 30 ° F ( ¥ 7 to Liquid—0.3 g/m ........ 15–25 microns ....................... By engine test.

¥ 1 ° C).

3. Snow ice condition 26 to 32 ° F ( ¥ 3 to 0 Ice—0.9 g/m ............ 100 microns ........................... By test, analysis or ° C). (minimum) .............................. combination of the two.

4. Large drop glaze 15 to 30 ° F (-9 to -1 Liquid—0.3 g/m ........ 100 microns (minimum) ......... By test, analysis or ice condition (Tur- ° C). combination of the bojet, turbofan, and two.

turboprop only).

(e) Demonstrate by test, analysis, or § 33.69 Ignitions system.

combination of the two, acceptable op- Each engine must be equipped with eration for turbojet, turbofan, and tur- an ignition system for starting the en- boprop engines in mixed phase and ice gine on the ground and in flight. An crystal icing conditions throughout electric ignition system must have at Appendix D of this part, icing envelope least two igniters and two separate sec- throughout its flight power range, in- ondary electric circuits, except that cluding minimum descent idling only one igniter is required for fuel speeds.

burning augmentation systems.

[Amdt. 33–34, 79 FR 66536, Nov. 4, 2014] [Amdt. 33–6, 39 FR 35466, Oct. 1, 1974] Federal Aviation Administration, DOT § 33.71 become part of the Instructions for § 33.70 Engine life-limited parts.

Continued Airworthiness.

By a procedure approved by the FAA, operating limitations must be estab- [Amdt. 33–22, 72 FR 50860, Sept. 4, 2007] lished which specify the maximum al- lowable number of flight cycles for § 33.71 Lubrication system.

each engine life-limited part. Engine (a) General. Each lubrication system life-limited parts are rotor and major must function properly in the flight at- static structural parts whose primary titudes and atmospheric conditions in failure is likely to result in a haz- which an aircraft is expected to oper- ardous engine effect. Typically, engine ate.

life-limited parts include, but are not (b) Oil strainer or filter. There must be limited to disks, spacers, hubs, shafts, an oil strainer or filter through which high-pressure casings, and non-redun- all of the engine oil flows. In addition: dant mount components. For the pur- (1) Each strainer or filter required by poses of this section, a hazardous en- this paragraph that has a bypass must gine effect is any of the conditions list- be constructed and installed so that oil ed in § 33.75 of this part. The applicant will flow at the normal rate through will establish the integrity of each en- the rest of the system with the strainer gine life-limited part by: or filter element completely blocked.

(a) An engineering plan that contains (2) The type and degree of filtering the steps required to ensure each en- necessary for protection of the engine gine life-limited part is withdrawn oil system against foreign particles in from service at an approved life before the oil must be specified. The applicant hazardous engine effects can occur.

must demonstrate that foreign par- These steps include validated analysis, ticles passing through the specified fil- test, or service experience which en- tering means do not impair engine oil sures that the combination of loads, system functioning.

material properties, environmental in- (3) Each strainer or filter required by fluences and operating conditions, in- this paragraph must have the capacity cluding the effects of other engine (with respect to operating limitations parts influencing these parameters, are established for the engine) to ensure sufficiently well known and predictable that engine oil system functioning is so that the operating limitations can not impaired with the oil contaminated be established and maintained for each to a degree (with respect to particle engine life-limited part. Applicants size and density) that is greater than must perform appropriate damage tol- that established for the engine in para- erance assessments to address the po- graph (b)(2) of this section.

tential for failure from material, man- (4) For each strainer or filter re- ufacturing, and service induced anoma- quired by this paragraph, except the lies within the approved life of the strainer or filter at the oil tank outlet, part. Applicants must publish a list of there must be means to indicate con- the life-limited engine parts and the tamination before it reaches the capac- approved life for each part in the Air- ity established in accordance with worthiness Limitations Section of the paragraph (b)(3) of this section.

Instructions for Continued Airworthi- ness as required by § 33.4 of this part. (5) Any filter bypass must be de- (b) A manufacturing plan that identi- signed and constructed so that the re- fies the specific manufacturing con- lease of collected contaminants is straints necessary to consistently minimized by appropriate location of produce each engine life-limited part the bypass to ensure that the collected with the attributes required by the en- contaminants are not in the bypass gineering plan. flow path.

(c) A service management plan that (6) Each strainer or filter required by defines in-service processes for mainte- this paragraph that has no bypass, ex- nance and the limitations to repair for cept the strainer or filter at an oil each engine life-limited part that will tank outlet or for a scavenge pump, maintain attributes consistent with must have provisions for connection those required by the engineering plan. with a warning means to warn the pilot These processes and limitations will of the occurance of contamination of 14 CFR Ch. I (1–1–25 Edition) § 33.72 the screen before it reaches the capac- (ii) The amount of trapped oil must ity established in accordance with be enough to accomplish the feathering paragraph (b)(3) of this section. opeation and must be available only to the feathering pump; and (7) Each strainer or filter required by (iii) Provision must be made to pre- this paragraph must be accessible for vent sludge or other foreign matter draining and cleaning.

from affecting the safe operation of the (c) Oil tanks. (1) Each oil tank must propeller feathering system.

have an expansion space of not less than 10 percent of the tank capacity. (d) Oil drains. A drain (or drains) must be provided to allow safe drainage (2) It must be impossible to inadvert- of the oil system. Each drain must— ently fill the oil tank expansion space.

(1) Be accessible; and (3) Each recessed oil tank filler con- (2) Have manual or automatic means nection that can retain any appreciable for positive locking in the closed posi- quantity of oil must have provision for tion.

fitting a drain.

(e) Oil radiators. Each oil radiator (4) Each oil tank cap must provide an must withstand, without failure, any oil-tight seal. For an applicant seeking vibration, inertia, and oil pressure load eligibility for an engine to be installed to which it is subjected during the on an airplane approved for ETOPS, block tests.

the oil tank must be designed to pre- vent a hazardous loss of oil due to an [Amdt. 33–6, 39 FR 35466, Oct. 1, 1974, as incorrectly installed oil tank cap.

amended by Amdt. 33–10, 49 FR 6852, Feb. 23, (5) Each oil tank filler must be 1984; Amdt. 33–21, 72 FR 1877, Jan. 16, 2007; Amdt. 33–27, 73 FR 55437, Sept. 25, 2008; Amdt.

marked with the word ‘‘oil.’’ 33–27, 73 FR 57235, Oct. 2, 2008] (6) Each oil tank must be vented from the top part of the expansion § 33.72 Hydraulic actuating systems.

space, with the vent so arranged that Each hydraulic actuating system condensed water vapor that might must function properly under all condi- freeze and obstruct the line cannot ac- tions in which the engine is expected to cumulate at any point.

operate. Each filter or screen must be (7) There must be means to prevent accessible for servicing and each tank entrance into the oil tank or into any must meet the design criteria of § 33.71.

oil tank outlet, of any object that might obstruct the flow of oil through [Amdt. 33–6, 39 FR 35467, Oct. 1, 1974] the system.

§ 33.73 Power or thrust response.

(8) There must be a shutoff valve at the outlet of each oil tank, unless the The design and construction of the external portion of the oil system (in- engine must enable an increase— cluding oil tank supports) is fireproof.

(a) From minimum to rated takeoff (9) Each unpressurized oil tank may power or thrust with the maximum not leak when subjected to a maximum bleed air and power extraction to be operating temperature and an internal permitted in an aircraft, without over- pressure of 5 p.s.i., and each pressurized temperature, surge, stall, or other det- oil tank must meet the requirements of rimental factors occurring to the en- § 33.64.

gine whenever the power control lever (10) Leaked or spilled oil may not ac- is moved from the minimum to the cumulate between the tank and the re- maximum position in not more than 1 mainder of the engine.

second, except that the Administrator (11) Each oil tank must have an oil may allow additional time increments quantity indicator or provisions for for different regimes of control oper- one.

ation requiring control scheduling; and (12) If the propeller feathering system (b) From the fixed minimum flight depends on engine oil— idle power lever position when pro- (i) There must be means to trap an vided, or if not provided, from not more amount of oil in the tank if the supply than 15 percent of the rated takeoff becomes depleted due to failure of any power or thrust available to 95 percent part of the lubricating system other rated takeoff power or thrust in not than the tank itself; over 5 seconds. The 5-second power or Federal Aviation Administration, DOT § 33.75 thrust response must occur from a sta- plicant to assess the total rate for haz- bilized static condition using only the ardous engine effects, compliance may bleed air and accessories loads nec- be shown by demonstrating that the essary to run the engine. This takeoff probability of a hazardous engine effect rating is specified by the applicant and arising from an individual failure can ¥ need not include thrust augmentation.

be predicted to be not greater than 10 per engine flight hour. In dealing with [Amdt. 33–1, 36 FR 5493, Mar. 24, 1971] probabilities of this low order of mag- nitude, absolute proof is not possible, § 33.74 Continued rotation.

and compliance may be shown by reli- If any of the engine main rotating ance on engineering judgment and pre- systems continue to rotate after the vious experience combined with sound engine is shutdown for any reason design and test philosophies.

while in flight, and if means to prevent (4) The applicant must show that that continued rotation are not pro- major engine effects are predicted to vided, then any continued rotation dur- occur at a rate not in excess of that de- ing the maximum period of flight, and fined as remote (probability range of in the flight conditions expected to ¥ 5 ¥ 7 10 to 10 per engine flight hour).

occur with that engine inoperative, (b) The FAA may require that any as- may not result in any condition de- sumption as to the effects of failures scribed in § 33.75(g)(2)(i) through (vi) of and likely combination of failures be this part.

verified by test.

[Amdt. 33–24, 72 FR 50867, Sept. 4, 2007] (c) The primary failure of certain sin- gle elements cannot be sensibly esti- § 33.75 Safety analysis.

mated in numerical terms. If the fail- (a) (1) The applicant must analyze ure of such elements is likely to result the engine, including the control sys- in hazardous engine effects, then com- tem, to assess the likely consequences pliance may be shown by reliance on of all failures that can reasonably be the prescribed integrity requirements expected to occur. This analysis will of §§ 33.15, 33.27, and 33.70 as applicable.

take into account, if applicable: These instances must be stated in the (i) Aircraft-level devices and proce- safety analysis.

dures assumed to be associated with a (d) If reliance is placed on a safety typical installation. Such assumptions system to prevent a failure from pro- must be stated in the analysis.

gressing to hazardous engine effects, (ii) Consequential secondary failures the possibility of a safety system fail- and latent failures.

ure in combination with a basic engine (iii) Multiple failures referred to in failure must be included in the anal- paragraph (d) of this section or that re- ysis. Such a safety system may include sult in the hazardous engine effects de- safety devices, instrumentation, early fined in paragraph (g)(2) of this section.

warning devices, maintenance checks, (2) The applicant must summarize and other similar equipment or proce- those failures that could result in dures. If items of a safety system are major engine effects or hazardous en- outside the control of the engine manu- gine effects, as defined in paragraph (g) facturer, the assumptions of the safety of this section, and estimate the prob- analysis with respect to the reliability ability of occurrence of those effects.

of these parts must be clearly stated in Any engine part the failure of which the analysis and identified in the in- could reasonably result in a hazardous stallation instructions under § 33.5 of engine effect must be clearly identified this part.

in this summary.

(e) If the safety analysis depends on (3) The applicant must show that one or more of the following items, hazardous engine effects are predicted those items must be identified in the to occur at a rate not in excess of that analysis and appropriately substan- defined as extremely remote (prob- ¥ 7 ¥ 9 tiated.

ability range of 10 to 10 per engine flight hour). Since the estimated prob- (1) Maintenance actions being carried ability for individual failures may be out at stated intervals. This includes insufficiently precise to enable the ap- the verification of the serviceability of 14 CFR Ch. I (1–1–25 Edition) § 33.76 items that could fail in a latent man- (iii) Significant thrust in the oppo- ner. When necessary to prevent haz- site direction to that commanded by ardous engine effects, these mainte- the pilot; nance actions and intervals must be (iv) Uncontrolled fire; (v) Failure of the engine mount sys- published in the instructions for con- tem leading to inadvertent engine sep- tinued airworthiness required under aration; § 33.4 of this part. Additionally, if er- (vi) Release of the propeller by the rors in maintenance of the engine, in- engine, if applicable; and cluding the control system, could lead (vii) Complete inability to shut the to hazardous engine effects, the appro- engine down.

priate procedures must be included in (3) An effect whose severity falls be- the relevant engine manuals.

tween those effects covered in para- (2) Verification of the satisfactory graphs (g)(1) and (g)(2) of this section functioning of safety or other devices will be regarded as a major engine ef- at pre-flight or other stated periods.

fect.

The details of this satisfactory func- tioning must be published in the appro- [Amdt. 33–24, 72 FR 50867, Sept. 4, 2007] priate manual.

§ 33.76 Bird ingestion.

(3) The provisions of specific instru- (a) General. Compliance with para- mentation not otherwise required.

graphs (b) through (e) of this section (4) Flight crew actions to be specified shall be in accordance with the fol- in the operating instructions estab- lowing: lished under § 33.5.

(1) Except as specified in paragraphs (f) If applicable, the safety analysis (d) and (e) of this section, all ingestion must also include, but not be limited tests must be conducted with the en- to, investigation of the following: gine stabilized at no less than 100 per- (1) Indicating equipment; cent takeoff power or thrust, for test (2) Manual and automatic controls; day ambient conditions prior to the in- (3) Compressor bleed systems; gestion. In addition, the demonstration (4) Refrigerant injection systems; of compliance must account for engine (5) Gas temperature control systems; operation at sea level takeoff condi- (6) Engine speed, power, or thrust tions on the hottest day that a min- governors and fuel control systems; imum engine can achieve maximum rated takeoff thrust or power.

(7) Engine overspeed, overtempera- (2) The engine inlet throat area as ture, or topping limiters; used in this section to determine the (8) Propeller control systems; and bird quantity and weights will be es- (9) Engine or propeller thrust rever- tablished by the applicant and identi- sal systems.

fied as a limitation in the installation (g) Unless otherwise approved by the instructions required under § 33.5.

FAA and stated in the safety analysis, (3) The impact to the front of the en- for compliance with part 33, the fol- gine from the large single bird, the sin- lowing failure definitions apply to the gle largest medium bird which can engine: enter the inlet, and the large flocking (1) An engine failure in which the bird must be evaluated. Applicants only consequence is partial or com- must show that the associated compo- plete loss of thrust or power (and asso- nents when struck under the condi- ciated engine services) from the engine tions prescribed in paragraphs (b), (c) will be regarded as a minor engine ef- or (d) of this section, as applicable, will fect.

not affect the engine to the extent that (2) The following effects will be re- the engine cannot comply with the re- garded as hazardous engine effects: quirements of paragraphs (b)(3), (c)(6) (i) Non-containment of high-energy and (d)(4) of this section.

debris; (4) For an engine that incorporates (ii) Concentration of toxic products an inlet protection device, compliance in the engine bleed air intended for the with this section shall be established cabin sufficient to incapacitate crew or with the device functioning. The en- passengers; gine approval will be endorsed to show Federal Aviation Administration, DOT § 33.76 that compliance with the requirements (c) Small and medium flocking bird.

has been established with the device Compliance with the small and me- functioning. dium bird ingestion requirements shall be in accordance with the following: (5) Objects that are accepted by the (1) Analysis or component test, or Administrator may be substituted for both, acceptable to the Administrator, birds when conducting the bird inges- shall be conducted to determine the tion tests required by paragraphs (b) critical ingestion parameters affecting through (e) of this section.

power loss and damage. Critical inges- (6) If compliance with the require- tion parameters shall include, but are ments of this section is not estab- not limited to, the effects of bird speed, lished, the engine type certification critical target location, and first stage documentation will show that the en- rotor speed. The critical bird ingestion gine shall be limited to aircraft instal- speed should reflect the most critical lations in which it is shown that a bird condition within the range of airspeeds cannot strike the engine, or be in- used for normal flight operations up to gested into the engine, or adversely re- 1,500 feet above ground level, but not strict airflow into the engine.

less than V minimum for airplanes.

(b) Large single bird. Compliance with (2) Medium bird engine tests shall be the large bird ingestion requirements conducted so as to simulate a flock en- shall be in accordance with the fol- counter, and will use the bird weights lowing: and quantities specified in Table 2.

(1) The large bird ingestion test shall When only one bird is specified, that be conducted using one bird of a weight bird will be aimed at the engine core determined from Table 1 aimed at the primary flow path; the other critical most critical exposed location on the locations on the engine face area must first stage rotor blades and ingested at be addressed, as necessary, by appro- a bird speed of 200-knots for engines to priate tests or analysis, or both. When be installed on airplanes, or the max- two or more birds are specified in Table imum airspeed for normal rotorcraft 2, the largest of those birds must be flight operations for engines to be in- aimed at the engine core primary flow stalled on rotorcraft.

path, and a second bird must be aimed (2) Power lever movement is not per- at the most critical exposed location mitted within 15 seconds following in- on the first stage rotor blades. Any re- gestion of the large bird.

maining birds must be evenly distrib- (3) Ingestion of a single large bird uted over the engine face area.

tested under the conditions prescribed (3) In addition, except for rotorcraft in this section may not result in any engines, it must also be substantiated condition described in § 33.75(g)(2) of by appropriate tests or analysis or this part.

both, that when the full fan assembly (4) Compliance with the large bird in- is subjected to the ingestion of the gestion requirements of this paragraph quantity and weights of bird from may be shown by demonstrating that Table 3, aimed at the fan assembly’s the requirements of § 33.94(a) constitute most critical location outboard of the a more severe demonstration of blade primary core flowpath, and in accord- containment and rotor unbalance than ance with the applicable test condi- the requirements of this paragraph. tions of this paragraph, that the engine can comply with the acceptance cri- T ABLE 1 TO § 33.76—L ARGE B IRD W EIGHT teria of this paragraph.

R EQUIREMENTS (4) A small bird ingestion test is not required if the prescribed number of Engine Inlet Throat Area medium birds pass into the engine (A)—Square-meters (square- Bird weight kg. (lb.)

inches) rotor blades during the medium bird test.

1.35 (2,092)>A ....................... 1.85 (4.07) minimum, unless (5) Small bird ingestion tests shall be a smaller bird is deter- mined to be a more severe conducted so as to simulate a flock en- demonstration.

counter using one 85 gram (0.187 lb.)

1.35 (2,092) ≤ A<3.90 (6,045) 2.75 (6.05) bird for each 0.032 square-meter (49.6 3.90 (6,045) ≤ A ....................... 3.65 (8.03) square-inches) of inlet area, or fraction 14 CFR Ch. I (1–1–25 Edition) § 33.76 thereof, up to a maximum of 16 birds. (vi) The durations specified are times The birds will be aimed so as to ac- at the defined conditions with the count for any critical exposed locations power being changed between each con- on the first stage rotor blades, with dition in less than 10 seconds.

any remaining birds evenly distributed (9) Engines intended for use in multi- over the engine face area. engine rotorcraft are not required to (6) Ingestion of small and medium comply with the medium bird ingestion birds tested under the conditions pre- portion of this section, providing that scribed in this paragraph may not the appropriate type certificate docu- cause any of the following: mentation is so endorsed.

(i) More than a sustained 25-percent (10) If any engine operating limit(s) is power or thrust loss; exceeded during the initial 2 minutes (ii) The engine to be shut down dur- without power lever movement, as pro- ing the required run-on demonstration vided by paragraph (c)(7)(ii) of this sec- prescribed in paragraphs (c)(7) or (c)(8) tion, then it shall be established that of this section; the limit exceedence will not result in (iii) The conditions defined in para- an unsafe condition.

graph (b)(3) of this section.

T ABLE 2 TO § 33.76—M EDIUM FLOCKING B IRD (iv) Unacceptable deterioration of en- W EIGHT AND Q UANTITY REQUIREMENTS gine handling characteristics.

(7) Except for rotorcraft engines, the Engine Inlet Throat Area (A)— Bird Bird weight following test schedule shall be used: Square-meters (square-inches) quantity kg. (lb.)

(i) Ingestion so as to simulate a flock 0.05 (77.5)>A ................................... none .....

encounter, with approximately 1 sec- 0.05 (77.5) ≤ A <0.10 (155) ............... 1 ........... 0.35 (0.77) ond elapsed time from the moment of 0.10 (155) ≤ A <0.20 (310) ................ 1 ........... 0.45 (0.99) the first bird ingestion to the last.

0.20 (310) ≤ A <0.40 (620) ................ 2 ........... 0.45 (0.99) 0.40 (620) ≤ A <0.60 (930) ................ 2 ........... 0.70 (1.54) (ii) Followed by 2 minutes without 0.60 (930) ≤ A <1.00 (1,550) ............. 3 ........... 0.70 (1.54) power lever movement after the inges- 1.00 (1,550) ≤ A <1.35 (2,092) .......... 4 ........... 0.70 (1.54) tion.

1.35 (2,092) ≤ A <1.70 (2,635) .......... 1 ........... 1.15 (2.53) (iii) Followed by 3 minutes at 75-per- plus 3 ... 0.70 (1.54) cent of the test condition. 1.70 (2,635) ≤ A <2.10 (3,255) .......... 1 ........... 1.15 (2.53) plus 4 ... 0.70 (1.54) (iv) Followed by 6 minutes at 60-per- 2.10 (3,255) ≤ A <2.50 (3,875) .......... 1 ........... 1.15 (2.53) cent of the test condition.

plus 5 ... 0.70 (1.54) (v) Followed by 6 minutes at 40-per- 2.50 (3,875) ≤ A <3.90 (6045) ........... 1 ........... 1.15 (2.53) cent of the test condition. plus 6 ... 0.70 (1.54) 3.90 (6045) ≤ A <4.50 (6975) ............ 3 ........... 1.15 (2.53) (vi) Followed by 1 minute at ap- 4.50 (6975) ≤ A .................................. 4 ........... 1.15 (2.53) proach idle.

(vii) Followed by 2 minutes at 75-per- T ABLE 3 TO § 33.76—A DDITIONAL INTEGRITY cent of the test condition.

A SSESSMENT (viii) Followed by stabilizing at idle and engine shut down.

Engine Inlet Throat Area (A)— Bird Bird weight (ix) The durations specified are times square-meters (square-inches) quantity kg. (lb.)

at the defined conditions with the 1.35 (2,092)>A ................................. none .....

power being changed between each con- 1.35 (2,092) ≤ A <2.90 (4,495) .......... 1 ........... 1.15 (2.53) dition in less than 10 seconds.

2.90 (4,495) ≤ A <3.90 (6,045) .......... 2 ........... 1.15 (2.53) (8) For rotorcraft engines, the fol- 3.90 (6,045) ≤ A ................................. 1 ........... 1.15 (2.53) plus 6 ... 0.70 (1.54) lowing test schedule shall be used: (i) Ingestion so as to simulate a flock (d) Large flocking bird. An engine test encounter within approximately 1 sec- will be performed as follows: ond elapsed time between the first in- (1) Large flocking bird engine tests gestion and the last.

will be performed using the bird mass (ii) Followed by 3 minutes at 75-per- and weights in Table 4, and ingested at cent of the test condition.

a bird speed of 200 knots.

(iii) Followed by 90 seconds at de- (2) Prior to the ingestion, the engine scent flight idle.

must be stabilized at no less than the (iv) Followed by 30 seconds at 75-per- mechanical rotor speed of the first ex- cent of the test condition.

posed stage or stages that, on a stand- (v) Followed by stabilizing at idle ard day, would produce 90 percent of and engine shut down.

Federal Aviation Administration, DOT § 33.76 the sea level static maximum rated tion, into the large single bird test takeoff power or thrust. demonstration specified in paragraph (3) The bird must be targeted on the (b)(1) of this section; or first exposed rotating stage or stages (ii) Use of an engine subassembly test at a blade airfoil height of not less at the ingestion conditions specified in than 50 percent measured at the lead- paragraph (b)(1) of this section if: ing edge.

(A) All components critical to com- (4) Ingestion of a large flocking bird plying with the requirements of para- under the conditions prescribed in this graph (d) of this section are included in paragraph must not cause any of the the subassembly test; following: (B) The components of paragraph (i) A sustained reduction of power or (d)(6)(ii)(A) of this section are installed thrust to less than 50 percent of max- in a representative engine for a run-on imum rated takeoff power or thrust demonstration in accordance with during the run-on segment specified paragraphs (d)(4) and (d)(5) of this sec- under paragraph (d)(5)(i) of this sec- tion; except that section (d)(5)(i) is de- tion.

leted and section (d)(5)(ii) must be 14 (ii) Engine shutdown during the re- minutes in duration after the engine is quired run-on demonstration specified started and stabilized; and in paragraph (d)(5) of this section.

(C) The dynamic effects that would (iii) The conditions specified in para- have been experienced during a full en- graph (b)(3) of this section.

gine ingestion test can be shown to be (5) The following test schedule must negligible with respect to meeting the be used: requirements of paragraphs (d)(4) and (i) Ingestion followed by 1 minute (d)(5) of this section.

without power lever movement.

(7) Applicants must show that an un- (ii) Followed by 13 minutes at not safe condition will not result if any en- less than 50 percent of maximum rated gine operating limit is exceeded during takeoff power or thrust.

the run-on period.

(iii) Followed by 2 minutes between 30 and 35 percent of maximum rated T ABLE 4 TO § 33.76—L ARGE F LOCKING B IRD takeoff power or thrust. M ASS AND W EIGHT (iv) Followed by 1 minute with power Bird Bird mass or thrust increased from that set in Engine inlet throat area quan- and weight (square meters/square inches) paragraph (d)(5)(iii) of this section, by tity (kg (lbs)) between 5 and 10 percent of maximum A <2.50 (3875) ................................ none rated takeoff power or thrust.

2.50 (3875) ≤ A <3.50 (5425) ........... 1 1.85 (4.08) (v) Followed by 2 minutes with power 3.50 (5425) ≤ A <3.90 (6045) ........... 1 2.10 (4.63) 3.90 (6045) ≤ A ................................. 1 2.50 (5.51) or thrust reduced from that set in paragraph (d)(5)(iv) of this section, by (e) Core flocking bird test. Except as between 5 and 10 percent of maximum provided in paragraph (e)(4) of this sec- rated takeoff power or thrust.

tion, for turbofan engines, an engine (vi) Followed by a minimum of 1 test must be performed in accordance minute at ground idle then engine with either paragraph (e)(1) or (2) of shutdown. The durations specified are this section. The test specified in para- times at the defined conditions. Power graph (e)(2) must be conducted if test- lever movement between each condi- ing or validated analysis shows that no tion will be 10 seconds or less, except bird material will be ingested into the that power lever movements allowed engine core during the test under the within paragraph (d)(5)(ii) of this sec- conditions specified in paragraph (e)(1).

tion are not limited, and for setting (1) Climb flocking bird test. (i) Test re- power under paragraph (d)(5)(iii) of this quirements are as follows: section will be 30 seconds or less.

(6) Compliance with the large flock- (A) Before ingestion, the engine must ing bird ingestion requirements of this be stabilized at the mechanical rotor paragraph (d) may also be dem- speed of the first exposed stage or onstrated by: stages that produce the lowest ex- (i) Incorporating the requirements of pected power or thrust required during paragraph (d)(4) and (d)(5) of this sec- climb through 3,000 feet above mean 14 CFR Ch. I (1–1–25 Edition) § 33.76 sea level (MSL) at standard day condi- movement in this condition is unlim- tions. ited.

(E) Followed by 2 minutes at 30–35 (B) The climb flocking bird test shall percent maximum rated takeoff power be conducted using one bird of the or thrust.

highest weight specified in table 2 to (F) Followed by 1 minute with power this section for the engine inlet area.

or thrust increased from that set in (C) Ingestion must be at 261-knots paragraph (e)(1)(iii)(E) of this section, true airspeed.

by 5–10 percent maximum rated takeoff (D) The bird must be aimed at the power or thrust.

first exposed rotating stage or stages, (G) Followed by 2 minutes with at the blade airfoil height, as measured power or thrust reduced from that set at the leading edge that will result in in paragraph (e)(1)(iii)(F) of this sec- maximum bird material ingestion into tion, by 5–10 percent maximum rated the engine core.

takeoff power or thrust.

(ii) Ingestion of a flocking bird into (H) Followed by 1 minute minimum the engine core under the conditions at ground idle.

prescribed in paragraph (e)(1)(i) of this (I) Followed by engine shutdown.

section must not cause any of the fol- (2) Approach flocking bird test. (i) Test lowing: requirements are as follows: (A) Sustained power or thrust reduc- (A) Before ingestion, the engine must tion to less than 50 percent maximum be stabilized at the mechanical rotor rated takeoff power or thrust during speed of the first exposed stage or the run-on segment specified under stages that produce approach idle paragraph (e)(1)(iii)(B) of this section, thrust when descending through 3,000 that cannot be restored only by move- feet MSL at standard day conditions.

ment of the power lever.

(B) The approach flocking bird test (B) Sustained power or thrust reduc- shall be conducted using one bird of the tion to less than flight idle power or highest weight specified in table 2 to thrust during the run-on segment spec- this section for the engine inlet area.

ified under paragraph (e)(1)(iii)(B) of (C) Ingestion must be at 209-knots this section.

true airspeed.

(C) Engine shutdown during the re- (D) The bird must be aimed at the quired run-on demonstration specified first exposed rotating stage or stages, in paragraph (e)(1)(iii) of this section.

at the blade airfoil height measured at (D) Any condition specified in the leading edge that will result in § 33.75(g)(2).

maximum bird material ingestion into (iii) The following test schedule must the engine core.

be used (power lever movement be- (ii) Ingestion of a flocking bird into tween conditions must occur within 10 the engine core under the conditions seconds or less, unless otherwise prescribed in paragraph (e)(2)(i) of this noted): section may not cause any of the fol- N OTE 1 TO PARAGRAPH ( E)( 1 )( III ) INTRO- lowing: DUCTORY TEXT . Durations specified are (A) Power or thrust reduction to less times at the defined conditions in para- than flight idle power or thrust during graphs (e)(1)(iii)(A) through (I) of this the run-on segment specified under section.

paragraph (e)(2)(iii)(B) of this section.

(A) Ingestion.

(B) Engine shutdown during the re- (B) Followed by 1 minute without quired run-on demonstration specified power lever movement.

in paragraph (e)(2)(iii) of this section.

(C) Followed by power lever move- (C) Any condition specified in ment to increase power or thrust to not § 33.75(g)(2).

less than 50 percent maximum rated (iii) The following test schedule must takeoff power or thrust, if the initial be used (power lever movement be- bird ingestion resulted in a reduction tween conditions must occur within 10 in power or thrust below that level.

seconds or less, unless otherwise (D) Followed by 13 minutes at not noted): less than 50 percent maximum rated NOTE 2 TO PARAGRAPH ( E)( 2)( III ) INTRO- takeoff power or thrust. Power lever DUCTORY TEXT . Durations specified are Federal Aviation Administration, DOT § 33.77 times at the defined conditions in para- § 33.77 Foreign object ingestion—ice.

graphs (e)(2)(iii)(A) through (H) of this (a) Compliance with the require- section.

ments of this section must be dem- (A) Ingestion.

onstrated by engine ice ingestion test (B) Followed by 1 minute without or by validated analysis showing power lever movement.

equivalence of other means for dem- (C) Followed by 2 minutes at 30–35 onstrating soft body damage tolerance.

percent maximum rated takeoff power or thrust. Power lever movement in (b) [Reserved] this condition is unlimited. (c) Ingestion of ice under the condi- (D) Followed by 1 minute with power tions of this section may not— or thrust increased from that set in (1) Cause an immediate or ultimate paragraph (e)(2)(iii)(C) of this section, unacceptable sustained power or thrust by 5–10 percent maximum rated takeoff loss; or power or thrust.

(2) Require the engine to be shut- (E) Followed by 2 minutes with power down.

or thrust reduced from that set in (d) For an engine that incorporates a paragraph (e)(2)(iii)(D) of this section, protection device, compliance with this by 5–10 percent maximum rated takeoff section need not be demonstrated with power or thrust.

respect to ice formed forward of the (F) Followed by 1 minute minimum protection device if it is shown that— at ground idle.

(G) Followed by engine shutdown. (1) Such ice is of a size that will not (H) Power lever movement between pass through the protective device; each condition must be 10 seconds or (2) The protective device will with- less, except that any power lever move- stand the impact of the ice; and ments are allowed within the time pe- (3) The ice stopped by the protective riod of paragraph (e)(2)(iii)(C) of this device will not obstruct the flow of in- section.

duction air into the engine with a re- (3) Results of exceeding engine-oper- sultant sustained reduction in power or ating limits. Applicants must show that thrust greater than those values de- an unsafe condition will not result if fined by paragraph (c) of this section.

any engine-operating limit is exceeded (e) Compliance with the require- during the run-on period.

ments of this section must be dem- (4) Combining tests. The climb flock- onstrated by engine ice ingestion test ing bird test of paragraph (e)(1) of this under the following ingestion condi- section may be combined with the me- dium flocking bird test of paragraph (c) tions or by validated analysis showing of this section, if the climb first stage equivalence of other means for dem- rotor speed calculated in paragraph onstrating soft body damage tolerance.

(e)(1) of this section is within 3 percent (1) The minimum ice quantity and di- of the first stage rotor speed required mensions will be established by the en- by paragraph (c)(1) of this section. As gine size as defined in Table 1 of this used in this paragraph (e)(4), ‘‘com- section.

bined’’ means that, instead of sepa- (2) The ingested ice dimensions are rately conducting the tests specified in determined by linear interpolation be- paragraphs (c) and (e)(1) of this section, tween table values, and are based on the test conducted under paragraph (c) the actual engine’s inlet hilite area.

of this section satisfies the require- (3) The ingestion velocity will simu- ments of paragraph (e) of this section if late ice from the inlet being sucked the bird aimed at the core of the engine into the engine.

meets the bird ingestion speed criteria (4) Engine operation will be at the of paragraph (e)(1)(i)(C) of this section.

maximum cruise power or thrust un- [Doc. No. FAA–1998–4815, 65 FR 55854, Sept.

less lower power is more critical.

14, 2000, as amended by Amdt. 33–20, 68 FR 75391, Dec. 31, 2003; Amdt. 33–24, 72 FR 50868, Sept. 4, 2007; Amdt. 33–23, 72 FR 58974, Oct. 17, 2007; Amdt. 33–36, 88 FR 19810, Apr. 4, 2023] 14 CFR Ch. I (1–1–25 Edition) § 33.78 T ABLE 1—M INIMUM I CE S LAB D IMENSIONS B ASED ON E NGINE I NLET S IZE Engine Inlet Hilite area Thickness Width Length (sq. inch) (inch) (inch) (inch) 0 ....................................................................................................................... 0.25 0 3.6 80 ..................................................................................................................... 0.25 6 3.6 300 ................................................................................................................... 0.25 12 3.6 700 ................................................................................................................... 0.25 12 4.8 2800 ................................................................................................................. 0.35 12 8.5 5000 ................................................................................................................. 0.43 12 11.0 7000 ................................................................................................................. 0.50 12 12.7 7900 ................................................................................................................. 0.50 12 13.4 9500 ................................................................................................................. 0.50 12 14.6 11300 ............................................................................................................... 0.50 12 15.9 13300 ............................................................................................................... 0.50 12 17.1 16500 ............................................................................................................... 0.5 12 18.9 20000 ............................................................................................................... 0.5 12 20.0 [Doc. No. 16919, 49 FR 6852, Feb. 23, 1984, as ating envelope when subjected to sud- amended by Amdt. 33–19, 63 FR 14798, Mar. 26, den encounters with the certification 1998; 63 FR 53278, Oct. 5, 1998; Amdt. 33–20, 65 standard concentrations of rain and FR 55856, Sept. 14, 2000; Amdt. 33–34, 79 FR hail, as defined in appendix B to this 65537, Nov. 4, 2014] part. Acceptable engine operation pre- cludes flameout, run down, continued § 33.78 Rain and hail ingestion.

or non-recoverable surge or stall, or (a) All engines. (1) The ingestion of loss of acceleration and deceleration large hailstones (0.8 to 0.9 specific grav- capability, during any three minute ity) at the maximum true air speed, up continuous period in rain and during to 15,000 feet (4,500 meters), associated any 30 second continuous period in with a representative aircraft oper- hail. It must also be shown after the ating in rough air, with the engine at ingestion that there is no unacceptable maximum continuous power, may not mechanical damage, unacceptable cause unacceptable mechanical damage power or thrust loss, or other adverse or unacceptable power or thrust loss engine anomalies.

after the ingestion, or require the en- (b) Engines for rotorcraft. As an alter- gine to be shut down. One-half the native to the requirements specified in number of hailstones shall be aimed paragraph (a)(2) of this section, for randomly over the inlet face area and rotorcraft turbine engines only, it the other half aimed at the critical must be shown that each engine is ca- inlet face area. The hailstones shall be pable of acceptable operation during ingested in a rapid sequence to simu- and after the ingestion of rain with an late a hailstone encounter and the overall ratio of water droplet flow to number and size of the hailstones shall airflow, by weight, with a uniform dis- be determined as follows: tribution at the inlet plane, of at least (i) One 1-inch (25 millimeters) diame- four percent. Acceptable engine oper- ter hailstone for engines with inlet ation precludes flameout, run down, areas of not more than 100 square continued or non-recoverable surge or inches (0.0645 square meters).

stall, or loss of acceleration and decel- (ii) One 1-inch (25 millimeters) di- eration capability. It must also be ameter and one 2-inch (50 millimeters) shown after the ingestion that there is diameter hailstone for each 150 square no unacceptable mechanical damage, inches (0.0968 square meters) of inlet unacceptable power loss, or other ad- area, or fraction thereof, for engines verse engine anomalies. The rain inges- with inlet areas of more than 100 tion must occur under the following square inches (0.0645 square meters).

static ground level conditions: (2) In addition to complying with paragraph (a)(1) of this section and ex- (1) A normal stabilization period at cept as provided in paragraph (b) of take-off power without rain ingestion, this section, it must be shown that followed immediately by the suddenly each engine is capable of acceptable op- commencing ingestion of rain for three eration throughout its specified oper- minutes at takeoff power, then Federal Aviation Administration, DOT § 33.83 (2) Continuation of the rain ingestion § 33.79 Fuel burning thrust augmentor.

during subsequent rapid deceleration Each fuel burning thrust augmentor, to minimum idle, then including the nozzle, must— (3) Continuation of the rain ingestion (a) Provide cutoff of the fuel burning during three minutes at minimum idle thrust augmentor; power to be certified for flight oper- (b) Permit on-off cycling; ation, then (c) Be controllable within the in- (4) Continuation of the rain ingestion tended range of operation; during subsequent rapid acceleration (d) Upon a failure or malfunction of to takeoff power.

augmentor combustion, not cause the (c) Engines for supersonic airplanes. In engine to lose thrust other than that addition to complying with paragraphs provided by the augmentor; and (a)(1) and (a)(2) of this section, a sepa- (e) Have controls that function com- rate test for supersonic airplane en- patibly with the other engine controls gines only, shall be conducted with and automatically shut off augmentor three hailstones ingested at supersonic fuel flow if the engine rotor speed drops cruise velocity. These hailstones shall below the minimum rotational speed at be aimed at the engine’s critical face which the augmentor is intended to area, and their ingestion must not function.

cause unacceptable mechanical damage or unacceptable power or thrust loss [Amdt. 33–6, 39 FR 35468, Oct. 1, 1974] after the ingestion or require the en- gine to be shut down. The size of these Subpart F—Block Tests; Turbine hailstones shall be determined from Aircraft Engines the linear variation in diameter from 1- inch (25 millimeters) at 35,000 feet § 33.81 Applicability.

(10,500 meters) to ⁄4 -inch (6 millime- This subpart prescribes the block ters) at 60,000 feet (18,000 meters) using tests and inspections for turbine en- the diameter corresponding to the low- gines.

est expected supersonic cruise altitude.

[Doc. No. 3025, 29 FR 7453, June 10, 1964, as Alternatively, three larger hailstones amended by Amdt. 33–6, 39 FR 35468, Oct. 1, may be ingested at subsonic velocities 1974] such that the kinetic energy of these larger hailstones is equivalent to the § 33.82 General.

applicable supersonic ingestion condi- Before each endurance test required tions.

by this subpart, the adjustment setting (d) For an engine that incorporates and functioning characteristic of each or requires the use of a protection de- component having an adjustment set- vice, demonstration of the rain and ting and a functioning characteristic hail ingestion capabilities of the en- that can be established independent of gine, as required in paragraphs (a), (b), installation on the engine must be es- and (c) of this section, may be waived tablished and recorded.

wholly or in part by the Administrator if the applicant shows that: [Amdt. 36–6, 39 FR 35468, Oct. 1, 1974] (1) The subject rain and hail con- stituents are of a size that will not § 33.83 Vibration test.

pass through the protection device; (a) Each engine must undergo vibra- (2) The protection device will with- tion surveys to establish that the vi- stand the impact of the subject rain bration characteristics of those compo- and hail constituents; and nents that may be subject to mechani- (3) The subject of rain and hail con- cally or aerodynamically induced vi- stituents, stopped by the protection de- bratory excitations are acceptable vice, will not obstruct the flow of in- throughout the declared flight enve- duction air into the engine, resulting lope. The engine surveys shall be based in damage, power or thrust loss, or upon an appropriate combination of ex- other adverse engine anomalies in ex- perience, analysis, and component test cess of what would be accepted in para- and shall address, as a minimum, graphs (a), (b), and (c) of this section.

blades, vanes, rotor discs, spacers, and [Doc. No. 28652, 63 FR 14799, Mar. 26, 1998] rotor shafts.

14 CFR Ch. I (1–1–25 Edition) § 33.84 (b) The surveys shall cover the fault conditions (such as, but not lim- ranges of power or thrust, and both the ited to, out-of balance, local blockage physical and corrected rotational or enlargement of stator vane passages, speeds for each rotor system, cor- fuel nozzle blockage, incorrectly sched- responding to operations throughout ule compressor variables, etc.) shall be evaluated by test or analysis, or by ref- the range of ambient conditions in the erence to previous experience and shall declared flight envelope, from the min- be shown not to create a hazardous imum rotational speed up to 103 per- condition.

cent of the maximum physical and cor- (f) Compliance with this section shall rected rotational speed permitted for be substantiated for each specific in- rating periods of two minutes or stallation configuration that can affect longer, and up to 100 percent of all the vibration characteristics of the en- other permitted physical and corrected gine. If these vibration effects cannot rotational speeds, including those that be fully investigated during engine cer- are overspeeds. If there is any indica- tification, the methods by which they tion of a stress peak arising at the can be evaluated and methods by which highest of those required physical or compliance can be shown shall be sub- corrected rotational speeds, the sur- stantiated and defined in the installa- veys shall be extended sufficiently to tion instructions required by § 33.5.

reveal the maximum stress values present, except that the extension need [Doc. No. 28107, 61 FR 28433, June 4, 1996, as not cover more than a further 2 per- amended by Amdt. 33–33, 77 FR 39624, July 5, centage points increase beyond those 2012; 77 FR 58301, Sept. 20, 2012] speeds.

§ 33.84 Engine overtorque test.

(c) Evaluations shall be made of the following: (a) If approval of a maximum engine (1) The effects on vibration charac- overtorque is sought for an engine in- teristics of operating with scheduled corporating a free power turbine, com- changes (including tolerances) to vari- pliance with this section must be dem- able vane angles, compressor bleeds, onstrated by testing.

accessory loading, the most adverse (1) The test may be run as part of the inlet air flow distortion pattern de- endurance test requirement of § 33.87.

clared by the manufacturer, and the Alternatively, tests may be performed most adverse conditions in the exhaust on a complete engine or equivalent duct(s); and testing on individual groups of compo- (2) The aerodynamic and nents.

aeromechanical factors which might (2) Upon conclusion of tests con- induce or influence flutter in those sys- ducted to show compliance with this tems susceptible to that form of vibra- section, each engine part or individual tion.

groups of components must meet the (d) Except as provided by paragraph requirements of § 33.93(a)(1) and (a)(2).

(e) of this section, the vibration (b) The test conditions must be as stresses associated with the vibration follows: characteristics determined under this (1) A total of 15 minutes run at the section, when combined with the ap- maximum engine overtorque to be ap- propriate steady stresses, must be less proved. This may be done in separate than the endurance limits of the mate- runs, each being of at least 2 ⁄ 2 minutes rials concerned, after making due al- duration.

lowances for operating conditions for (2) A power turbine rotational speed the permitted variations in properties equal to the highest speed at which the of the materials. The suitability of maximum overtorque can occur in these stress margins must be justified service. The test speed may not be for each part evaluated. If it is deter- more than the limit speed of take-off mined that certain operating condi- or OEI ratings longer than 2 minutes.

tions, or ranges, need to be limited, op- (3) For engines incorporating a reduc- erating and installation limitations tion gearbox, a gearbox oil tempera- shall be established. ture equal to the maximum tempera- (e) The effects on vibration charac- ture when the maximum engine over- teristics of excitation forces caused by torque could occur in service; and for Federal Aviation Administration, DOT § 33.87 all other engines, an oil temperature ments of this section for these OEI rat- within the normal operating range. ings.

(4) A turbine entry gas temperature [Doc. No. 3025, 29 FR 7453, June 10, 1964, as equal to the maximum steady state amended by Amdt. 33–6, 39 FR 35468, Oct. 1, temperature approved for use during 1974; Amdt. 33–18, 61 FR 31328, June 19, 1996] periods longer than 20 seconds when op- § 33.87 Endurance test.

erating at conditions not associated with 30-second or 2 minutes OEI rat- (a) General. Each engine must be sub- ings. The requirement to run the test jected to an endurance test that in- at the maximum approved steady state cludes a total of at least 150 hours of operation and, depending upon the type temperature may be waived by the and contemplated use of the engine, FAA if the applicant can demonstrate consists of one of the series of runs that other testing provides substan- specified in paragraphs (b) through (g) tiation of the temperature effects when of this section, as applicable. For en- considered in combination with the gines tested under paragraphs (b), (c), other parameters identified in para- (d), (e) or (g) of this section, the pre- graphs (b)(1), (b)(2) and (b)(3) of this scribed 6-hour test sequence must be section.

conducted 25 times to complete the re- [Doc. No. 2007–28502, 74 FR 45310, Sept. 2, 2009] quired 150 hours of operation. Engines for which the 30-second OEI and 2- § 33.85 Calibration tests.

minute OEI ratings are desired must be further tested under paragraph (f) of (a) Each engine must be subjected to this section. The following test re- those calibration tests necessary to es- quirements apply: tablish its power characteristics and (1) The runs must be made in the the conditions for the endurance test order found appropriate by the FAA for specified § 33.87. The results of the the particular engine being tested.

power characteristics calibration tests (2) Any automatic engine control form the basis for establishing the that is part of the engine must control characteristics of the engine over its the engine during the endurance test entire operating range of speeds, pres- except for operations where automatic sures, temperatures, and altitudes.

control is normally overridden by man- Power ratings are based upon standard ual control or where manual control is atmospheric conditions with no otherwise specified for a particular test airbleed for aircraft services and with run.

only those accessories installed which (3) Except as provided in paragraph are essential for engine functioning.

(a)(5) of this section, power or thrust, (b) A power check at sea level condi- gas temperature, rotor shaft rotational tions must be accomplished on the en- speed, and, if limited, temperature of durance test engine after the endur- external surfaces of the engine must be ance test and any change in power at least 100 percent of the value associ- characteristics which occurs during the ated with the particular engine oper- endurance test must be determined.

ation being tested. More than one test Measurements taken during the final may be run if all parameters cannot be portion of the endurance test may be held at the 100 percent level simulta- used in showing compliance with the neously.

requirements of this paragraph.

(4) The runs must be made using fuel, (c) In showing compliance with this lubricants and hydraulic fluid which section, each condition must stabilize conform to the specifications specified before measurements are taken, except in complying with § 33.7(c).

as permitted by paragraph (d) of this (5) Maximum air bleed for engine and section.

aircraft services must be used during (d) In the case of engines having 30- at least one-fifth of the runs, except for second OEI, and 2-minute OEI ratings, the test required under paragraph (f) of measurements taken during the appli- this section, provided the validity of cable endurance test prescribed in the test is not compromised. However, § 33.87(f) (1) through (8) may be used in for these runs, the power or thrust or showing compliance with the require- the rotor shaft rotational speed may be 14 CFR Ch. I (1–1–25 Edition) § 33.87 less than 100 percent of the value asso- torque. If the number of occurrences is ciated with the particular operation not limited, half the required accelera- being tested if the FAA finds that the tions must be made at the limiting validity of the endurance test is not overspeed, overtemperature or over- compromised. torque.

(6) Each accessory drive and mount- (9) For each engine type certificated ing attachment must be loaded in ac- for use on supersonic aircraft the fol- cordance with paragraphs (a)(6)(i) and lowing additional test requirements (ii) of this section, except as permitted apply: by paragraph (a)(6)(iii) of this section (i) To change the thrust setting, the for the test required under paragraph power control lever must be moved (f) of this section. from the initial position to the final (i) The load imposed by each acces- position in not more than one second sory used only for aircraft service must except for movements into the fuel be the limit load specified by the appli- burning thrust augmentor augmenta- cant for the engine drive and attach- tion position if additional time to con- ment point during rated maximum con- firm ignition is necessary.

tinuous power or thrust and higher (ii) During the runs at any rated aug- output. mented thrust the hydraulic fluid tem- (ii) The endurance test of any acces- perature must be maintained at the sory drive and mounting attachment limiting temperature except where the under load may be accomplished on a test periods are not long enough to separate rig if the validity of the test allow stabilization.

is confirmed by an approved analysis. (iii) During the simulated supersonic (iii) The applicant is not required to runs the fuel temperature and induc- load the accessory drives and mounting tion air temperature may not be less attachments when running the tests than the limiting temperature.

under paragraphs (f)(1) through (f)(8) of (iv) The endurance test must be con- this section if the applicant can sub- ducted with the fuel burning thrust stantiate that there is no significant augmentor installed, with the primary effect on the durability of any acces- and secondary exhaust nozzles in- sory drive or engine component. How- stalled, and with the variable area ex- ever, the applicant must add the equiv- haust nozzles operated during each run alent engine output power extraction according to the methods specified in from the power turbine rotor assembly complying with § 33.5(b).

to the engine shaft output. (v) During the runs at thrust settings (7) During the runs at any rated for maximum continuous thrust and power or thrust the gas temperature percentages thereof, the engine must and the oil inlet temperature must be be operated with the inlet air distor- maintained at the limiting tempera- tion at the limit for those thrust set- ture except where the test periods are tings.

not longer than 5 minutes and do not (b) Engines other than certain rotor- allow stabilization. At least one run craft engines. For each engine except a must be made with fuel, oil, and hy- rotorcraft engine for which a rating is draulic fluid at the minimum pressure desired under paragraph (c), (d), or (e) limit and at least one run must be of this section, the applicant must con- made with fuel, oil, and hydraulic fluid duct the following runs: at the maximum pressure limit with (1) Takeoff and idling. One hour of al- fluid temperature reduced as necessary ternate five-minute periods at rated to allow maximum pressure to be at- takeoff power or thrust and at idling tained. power or thrust. The developed powers (8) If the number of occurrences of ei- or thrusts at takeoff and idling condi- ther transient rotor shaft overspeed, tions and their corresponding rotor transient gas overtemperature or tran- speed and gas temperature conditions sient engine overtorque is limited, that must be as established by the power number of the accelerations required control in accordance with the sched- by paragraphs (b) through (g) of this ule established by the applicant. The section must be made at the limiting applicant may, during any one period, overspeed, overtemperature or over- manually control the rotor speed, Federal Aviation Administration, DOT § 33.87 power, or thrust while taking data to tion to the other in not more than one check performance. For engines with second, except that, if different re- augmented takeoff power ratings that gimes of control operations are incor- involve increases in turbine inlet tem- porated necessitating scheduling of the perature, rotor speed, or shaft power, power-control lever motion in going this period of running at takeoff must from one extreme position to the other, be at the augmented rating. For en- a longer period of time is acceptable, gines with augmented takeoff power but not more than two seconds.

ratings that do not materially increase (6) Starts. One hundred starts must be operating severity, the amount of run- made, of which 25 starts must be pre- ning conducted at the augmented rat- ceded by at least a two-hour engine ing is determined by the FAA. In shutdown. There must be at least 10 changing the power setting after each false engine starts, pausing for the ap- period, the power-control lever must be plicant’s specified minimum fuel drain- moved in the manner prescribed in age time, before attempting a normal paragraph (b)(5) of this section.

start. There must be at least 10 normal (2) Rated maximum continuous and restarts with not longer than 15 min- takeoff power or thrust. Thirty minutes utes since engine shutdown. The re- at— maining starts may be made after com- (i) Rated maximum continuous power pleting the 150 hours of endurance test- or thrust during fifteen of the twenty- ing.

five 6-hour endurance test cycles; and (c) Rotorcraft engines for which a 30- (ii) Rated takeoff power or thrust minute OEI power rating is desired. For during ten of the twenty-five 6-hour en- each rotorcraft engine for which a 30- durance test cycles.

minute OEI power rating is desired, the (3) Rated maximum continuous power or applicant must conduct the following thrust. One hour and 30 minutes at rated maximum continuous power or series of tests: thrust.

(1) Takeoff and idling. One hour of al- (4) Incremental cruise power or thrust.

ternate 5-minute periods at rated take- Two hours and 30 minutes at the suc- off power and at idling power. The de- cessive power lever positions cor- veloped powers at takeoff and idling responding to at least 15 approximately conditions and their corresponding equal speed and time increments be- rotor speed and gas temperature condi- tween maximum continuous engine ro- tions must be as established by the tational speed and ground or minimum power control in accordance with the idle rotational speed. For engines oper- schedule established by the applicant.

ating at constant speed, the thrust and During any one period, the rotor speed power may be varied in place of speed.

and power may be controlled manually If there is significant peak vibration while taking data to check perform- anywhere between ground idle and ance. For engines with augmented maximum continuous conditions, the takeoff power ratings that involve in- number of increments chosen may be creases in turbine inlet temperature, changed to increase the amount of run- rotor speed, or shaft power, this period ning made while subject to the peak vi- of running at rated takeoff power must brations up to not more than 50 percent be at the augmented power rating. In of the total time spent in incremental changing the power setting after each running.

period, the power control lever must be (5) Acceleration and deceleration runs.

moved in the manner prescribed in 30 minutes of accelerations and decel- paragraph (c)(6) of this section.

erations, consisting of six cycles from (2) Rated maximum continuous and idling power or thrust to rated takeoff takeoff power. Thirty minutes at— power or thrust and maintained at the (i) Rated maximum continuous power takeoff power lever position for 30 sec- during fifteen of the twenty-five 6-hour onds and at the idling power lever posi- endurance test cycles; and tion for approximately four and one- half minutes. In complying with this (ii) Rated takeoff power during ten of paragraph, the power-control lever the twenty-five 6-hour endurance test must be moved from one extreme posi- cycles.

14 CFR Ch. I (1–1–25 Edition) § 33.87 (3) Rated maximum continuous power. applicant must conduct the following One hour at rated maximum contin- series of tests: uous power. (1) Takeoff and idling. One hour of al- (4) Rated 30-minute OEI power. Thirty ternate 5-minute periods at rated take- minutes at rated 30-minute OEI power. off power and at idling power. The de- (5) Incremental cruise power. Two veloped powers at takeoff and idling hours and 30 minutes at the successive conditions and their corresponding power lever positions corresponding rotor speed and gas temperature condi- with not less than 15 approximately tions must be as established by the equal speed and time increments be- power control in accordance with the tween maximum continuous engine ro- schedule established by the applicant.

tational speed and ground or minimum During any one period the rotor speed idle rotational speed. For engines oper- and power may be controlled manually ating at constant speed, power may be while taking data to check perform- varied in place of speed. If there are ance. For engines with augmented significant peak vibrations anywhere takeoff power ratings that involve in- between ground idle and maximum creases in turbine inlet temperature, continuous conditions, the number of rotor speed, or shaft power, this period increments chosen must be changed to of running at rated takeoff power must increase the amount of running con- be at the augmented power rating. In ducted while subject to peak vibrations changing the power setting after each up to not more than 50 percent of the period, the power control lever must be total time spent in incremental run- moved in the manner prescribed in ning. paragraph (d)(6) of this section.

(6) Acceleration and deceleration runs. (2) Rated maximum continuous and Thirty minutes of accelerations and de- takeoff power. Thirty minutes at— celerations, consisting of six cycles (i) Rated maximum continuous power from idling power to rated takeoff during fifteen of the twenty-five 6-hour power and maintained at the takeoff endurance test cycles; and power lever position for 30 seconds and (ii) Rated takeoff power during ten of at the idling power lever position for the twenty-five 6-hour endurance test approximately 4 ⁄2 minutes. In com- cycles.

plying with this paragraph, the power (3) Rated continuous OEI power. One control lever must be moved from one hour at rated continuous OEI power.

extreme position to the other in not (4) Rated maximum continuous power.

more than one second. If, however, dif- One hour at rated maximum contin- ferent regimes of control operations uous power.

are incorporated that necessitate (5) Incremental cruise power. Two scheduling of the power control lever hours at the successive power lever po- motion from one extreme position to sitions corresponding with not less the other, then a longer period of time than 12 approximately equal speed and is acceptable, but not more than two time increments between maximum seconds. continuous engine rotational speed and (7) Starts. One hundred starts, of ground or minimum idle rotational which 25 starts must be preceded by at speed. For engines operating at con- least a two-hour engine shutdown. stant speed, power may be varied in There must be at least 10 false engine place of speed. If there are significant starts, pausing for the applicant’s spec- peak vibrations anywhere between ified minimum fuel drainage time, be- ground idle and maximum continuous fore attempting a normal start. There conditions, the number of increments must be at least 10 normal restarts not chosen must be changed to increase the more than 15 minutes after engine amount of running conducted while shutdown. The remaining starts may being subjected to the peak vibrations be made after completing the 150 hours up to not more than 50 percent of the of endurance testing. total time spent in incremental run- (d) Rotorcraft engines for which a con- ning.

tinuous OEI rating is desired. For each (6) Acceleration and deceleration runs.

rotorcraft engine for which a contin- Thirty minutes of accelerations and de- uous OEI power rating is desired, the celerations, consisting of six cycles Federal Aviation Administration, DOT § 33.87 from idling power to rated takeoff power control lever must be moved in power and maintained at the takeoff the manner prescribed in paragraph power lever position for 30 seconds and (b)(5), (c)(6), or (d)(6) of this section, as at the idling power lever position for applicable.

approximately 4 ⁄2 minutes. In com- (2) The tests required in paragraphs plying with this paragraph, the power (b)(2) through (b)(6), or (c)(2) through control lever must be moved from one (c)(7), or (d)(2) through (d)(7) of this extreme position to the other in not section, as applicable, except that in more than 1 second, except that if dif- one of the 6-hour test sequences, the ferent regimes of control operations last 5 minutes of the 30 minutes at are incorporated necessitating sched- takeoff power test period of paragraph uling of the power control lever motion (b)(2) of this section, or of the 30 min- in going from one extreme position to utes at 30-minute OEI power test pe- the other, a longer period of time is ac- riod of paragraph (c)(4) of this section, ceptable, but not more than 2 seconds.

or of the l hour at continuous OEI (7) Starts. One hundred starts, of power test period of paragraph (d)(3) of which 25 starts must be preceded by at this section, must be run at 2 ⁄2 -minute least a 2-hour engine shutdown. There OEI power.

must be at least 10 false engine starts, (f) Rotorcraft Engines for which 30-sec- pausing for the applicant’s specified ond OEI and 2-minute OEI ratings are de- minimum fuel drainage time, before at- sired. For each rotorcraft engine for tempting a normal start. There must which 30-second OEI and 2-minute OEI be at least 10 normal restarts with not power ratings are desired, and fol- longer than 15 minutes since engine lowing completion of the tests under shutdown. The remaining starts may paragraphs (b), (c), (d), or (e) of this be made after completing the 150 hours of endurance testing. section, the applicant may disassemble (e) Rotorcraft engines for which a 2 ⁄2 - the tested engine to the extent nec- minute OEI power rating is desired. For essary to show compliance with the re- each rotorcraft engine for which a 2 ⁄2 - quirements of § 33.93(a). The tested en- minute OEI power rating is desired, the gine must then be reassembled using applicant must conduct the following the same parts used during the test series of tests: runs of paragraphs (b), (c), (d), or (e) of (1) Takeoff, 2 ⁄2 -minute OEI, and idling.

this section, except those parts de- One hour of alternate 5-minute periods scribed as consumables in the Instruc- at rated takeoff power and at idling tions for Continued Airworthiness. Ad- power except that, during the third and ditionally, the tests required in para- sixth takeoff power periods, only 2 ⁄ 2 graphs (f)(1) through (f)(8) of this sec- minutes need be conducted at rated tion must be run continuously. If a takeoff power, and the remaining 2 ⁄2 stop occurs during these tests, the in- minutes must be conducted at rated terrupted sequence must be repeated 2 ⁄2 -minute OEI power. The developed unless the applicant shows that the se- powers at takeoff, 2 ⁄2 -minute OEI, and verity of the test would not be reduced idling conditions and their cor- if it were continued. The applicant responding rotor speed and gas tem- must conduct the following test se- perature conditions must be as estab- quence four times, for a total time of lished by the power control in accord- not less than 120 minutes: ance with the schedule established by (1) Takeoff power. Three minutes at the applicant. The applicant may, dur- rated takeoff power.

ing any one period, control manually (2) 30-second OEI power. Thirty sec- the rotor speed and power while taking onds at rated 30-second OEI power.

data to check performance. For engines (3) 2-minute OEI power. Two minutes with augmented takeoff power ratings at rated 2-minute OEI power.

that involve increases in turbine inlet (4) 30-minute OEI power, continuous temperature, rotor speed, or shaft OEI power, or maximum continuous power, this period of running at rated takeoff power must be at the aug- power. Five minutes at whichever is mented rating. In changing the power the greatest of rated 30-minute OEI setting after or during each period, the power, rated continuous OEI power, or 14 CFR Ch. I (1–1–25 Edition) § 33.87 rated maximum continuous power, ex- imum continuous augmented thrust cept that, during the first test se- followed by 10 minutes at the thrust quence, this period shall be 65 minutes.

obtained with the power control lever However, where the greatest rated set at the position for 90 percent of power is 30-minute OEI power, that rated maximum continuous augmented sixty-five minute period shall consist thrust. The end of this period in the of 30 minutes at 30-minute OEI power first five runs must be made with the followed by 35 minutes at whichever is induction air temperature at the lim- the greater of continuous OEI power or iting condition of transient over- maximum continuous power.

temperature, but need not be repeated (5) 50 percent takeoff power. One during the periods specified in para- minute at 50 percent takeoff power.

graphs (g)(2)(ii) through (iv) of this sec- (6) 30-second OEI power. Thirty sec- tion; onds at rated 30-second OEI power.

(ii) One period repeating the run (7) 2-minute OEI power. Two minutes specified in paragraph (g)(2)(i) of this at rated 2-minute OEI power.

section, except that it must be followed (8) Idle. One minute at flight idle.

by 10 minutes at the thrust obtained (g) Supersonic aircraft engines. For with the power control lever set at the each engine type certificated for use on position for 80 percent of rated max- supersonic aircraft the applicant must imum continuous augmented thrust; conduct the following: (1) Subsonic test under sea level ambient (iii) One period repeating the run atmospheric conditions. Thirty runs of specified in paragraph (g)(2)(i) of this one hour each must be made, con- section, except that it must be followed sisting of— by 10 minutes at the thrust obtained (i) Two periods of 5 minutes at rated with the power control lever set at the takeoff augmented thrust each fol- position for 60 percent of rated max- lowed by 5 minutes at idle thrust; imum continuous augmented thrust (ii) One period of 5 minutes at rated and then 10 minutes at not more than takeoff thrust followed by 5 minutes at 15 percent of rated takeoff thrust; not more than 15 percent of rated take- (iv) One period repeating the runs off thrust; specified in paragraphs (g)(2)(i) and (ii) (iii) One period of 10 minutes at rated of this section; and takeoff augmented thrust followed by 2 (v) One period of 30 minutes with 25 minutes at idle thrust, except that if of the runs made at the thrust obtained rated maximum continuous augmented with the power control lever set at the thrust is lower than rated takeoff aug- position for rated maximum contin- mented thrust, 5 of the 10-minute peri- uous augmented thrust, each followed ods must be at rated maximum contin- by idle thrust and with the remaining uous augmented thrust; and 5 runs at the thrust obtained with the (iv) Six periods of 1 minute at rated power control lever set at the position takeoff augmented thrust each fol- lowed by 2 minutes, including accelera- for rated maximum continuous aug- tion and deceleration time, at idle mented thrust for 25 minutes each, fol- thrust. lowed by subsonic operation at not (2) Simulated supersonic test. Each run more than 15 percent or rated takeoff of the simulated supersonic test must thrust and accelerated to rated takeoff be preceded by changing the inlet air thrust for 5 minutes using hot fuel.

temperature and pressure from that at- (3) Starts. One hundred starts must be tained at subsonic condition to the made, of which 25 starts must be pre- temperature and pressure attained at ceded by an engine shutdown of at supersonic velocity, and must be fol- least 2 hours. There must be at least 10 lowed by a return to the temperature false engine starts, pausing for the ap- attained at subsonic condition. Thirty plicant’s specified minimum fuel drain- runs of 4 hours each must be made, age time before attempting a normal consisting of— start. At least 10 starts must be normal (i) One period of 30 minutes at the restarts, each made no later than 15 thrust obtained with the power control minutes after engine shutdown. The lever set at the position for rated max- Federal Aviation Administration, DOT § 33.91 starts may be made at any time, in- (3) The minimum power or thrust re- cluding the period of endurance test- sponse time to 95 percent rated takeoff ing. power or thrust, from power lever posi- tions representative of minimum idle [Doc. No. 3025, 29 FR 7453, June 10, 1964, as and of minimum flight idle, starting amended by Amdt. 33–3, 32 FR 3737, Mar. 4, from stabilized idle operation, under 1967; Amdt. 33–6, 39 FR 35468, Oct. 1, 1974; the following engine load conditions: Amdt. 33–10, 49 FR 6853, Feb. 23, 1984; Amdt.

(i) No bleed air and power extraction 33–12, 53 FR 34220, Sept. 2, 1988; Amdt. 33–18, 61 FR 31328, June 19, 1996; Amdt. 33–25, 73 FR for aircraft use.

48123, Aug. 18, 2008; Amdt. 33–30, 74 FR 45311, (ii) Maximum allowable bleed air and Sept. 2, 2009; Amdt. 33–32, 77 FR 22187, Apr.

power extraction for aircraft use.

13, 2012] (iii) An intermediate value for bleed air and power extraction representa- § 33.88 Engine overtemperature test.

tive of that which might be used as a (a) Each engine must run for 5 min- maximum for aircraft during approach utes at maximum permissible rpm with to a landing.

the gas temperature at least 75 ° F (42 (4) If testing facilities are not avail- ° C) higher than the maximum rating’s able, the determination of power ex- steady-state operating limit, excluding traction required in paragraph (a)(3)(ii) maximum values of rpm and gas tem- and (iii) of this section may be accom- perature associated with the 30-second plished through appropriate analytical OEI and 2-minute OEI ratings. Fol- means.

lowing this run, the turbine assembly (b) The operation test must include must be within serviceable limits. all testing found necessary by the Ad- (b) In addition to the test require- ministrator to demonstrate that the ments in paragraph (a) of this section, engine has safe operating characteris- each engine for which 30-second OEI tics throughout its specified operating and 2-minute OEI ratings are desired, envelope.

that incorporates a means for auto- [Amdt. 33–4, 36 FR 5493, Mar. 24, 1971, as matic temperature control within its amended by Amdt. 33–6, 39 FR 35469, Oct. 1, operating limitations in accordance 1974; Amdt. 33–10, 49 FR 6853, Feb. 23, 1984] with § 33.28(k), must run for a period of § 33.90 Initial maintenance inspection 4 minutes at the maximum power-on test.

rpm with the gas temperature at least 35 ° F (19 ° C) higher than the maximum Each applicant, except an applicant operating limit at 30-second OEI rat- for an engine being type certificated ing. Following this run, the turbine as- through amendment of an existing type sembly may exhibit distress beyond the certificate or through supplemental limits for an overtemperature condi- type certification procedures, must tion provided the engine is shown by complete one of the following tests on analysis or test, as found necessary by an engine that substantially conforms the FAA, to maintain the integrity of to the type design to establish when the turbine assembly.

the initial maintenance inspection is (c) A separate test vehicle may be required: used for each test condition.

(a) An approved engine test that sim- ulates the conditions in which the en- [Doc. No. 26019, 61 FR 31329, June 19, 1996, as gine is expected to operate in service, amended by Amdt. 33–25, 73 FR 48124, Aug. 18, including typical start-stop cycles.

2008; Amdt. 33–26, 73 FR 48285, Aug. 19, 2008] (b) An approved engine test con- § 33.89 Operation test.

ducted in accordance with § 33.201 (c) through (f).

(a) The operation test must include testing found necessary by the Admin- [Doc. No. FAA–2002–6717, 72 FR 1877, Jan. 16, istrator to demonstrate— 2007] (1) Starting, idling, acceleration, § 33.91 Engine system and component overspeeding, ignition, functioning of tests.

the propeller (if the engine is des- ignated to operate with a propeller); (a) For those systems or components (2) Compliance with the engine re- that cannot be adequately substan- sponse requirements of § 33.73; and tiated in accordance with endurance 14 CFR Ch. I (1–1–25 Edition) § 33.92 testing of § 33.87, the applicant must § 33.93 Teardown inspection.

conduct additional tests to dem- (a) After completing the endurance onstrate that the systems or compo- testing of § 33.87 (b), (c), (d), (e), or (g) nents are able to perform the intended of this part, each engine must be com- functions in all declared environmental pletely disassembled, and and operating conditions.

(1) Each component having an adjust- (b) Temperature limits must be es- ment setting and a functioning char- tablished for those components that re- acteristic that can be established inde- quire temperature controlling provi- pendent of installation on the engine sions in the aircraft installation to as- must retain each setting and func- sure satisfactory functioning, reli- tioning characteristic within the limits ability, and durability.

that were established and recorded at (c) Each unpressurized hydraulic the beginning of the test; and fluid tank may not fail or leak when (2) Each engine part must conform to subjected to a maximum operating the type design and be eligible for in- temperature and an internal pressure corporation into an engine for contin- of 5 p.s.i., and each pressurized hydrau- ued operation, in accordance with in- lic fluid tank must meet the require- formation submitted in compliance ments of § 33.64.

with § 33.4.

(d) For an engine type certificated (b) After completing the endurance for use in supersonic aircraft, the sys- tems, safety devices, and external com- testing of § 33.87(f), each engine must be ponents that may fail because of oper- completely disassembled, and ation at maximum and minimum oper- (1) Each component having an adjust- ating temperatures must be identified ment setting and a functioning char- and tested at maximum and minimum acteristic that can be established inde- operating temperatures and while tem- pendent of installation on the engine perature and other operating condi- must retain each setting and func- tions are cycled between maximum and tioning characteristic within the limits minimum operating values.

that were established and recorded at the beginning of the test; and [Doc. No. 3025, 29 FR 7453, June 10, 1964, as amended by Amdt. 33–6, 39 FR 35469, Oct. 1, (2) Each engine may exhibit deterio- 1974; Amdt. 33–26, 73 FR 48285, Aug. 19, 2008; ration in excess of that permitted in Amdt. 33–27, 73 FR 55437, Sept. 25, 2008; Amdt.

paragraph (a)(2) of this section, includ- 33–27, 73 FR 57235, Oct. 2, 2008] ing some engine parts or components that may be unsuitable for further use.

§ 33.92 Rotor locking tests.

The applicant must show by inspec- If continued rotation is prevented by tion, analysis, test, or by any combina- a means to lock the rotor(s), the engine tion thereof as found necessary by the must be subjected to a test that in- FAA, that structural integrity of the cludes 25 operations of this means engine is maintained; or under the following conditions: (c) In lieu of compliance with para- (a) The engine must be shut down graph (b) of this section, each engine from rated maximum continuous for which the 30-second OEI and 2- thrust or power; and minute OEI ratings are desired, may be (b) The means for stopping and lock- subjected to the endurance testing of ing the rotor(s) must be operated as §§ 33.87 (b), (c), (d), or (e) of this part, specified in the engine operating in- and followed by the testing of § 33.87(f) structions while being subjected to the without intervening disassembly and maximum torque that could result inspection. However, the engine must from continued flight in this condition; comply with paragraph (a) of this sec- and tion after completing the endurance (c) Following rotor locking, the testing of § 33.87(f).

rotor(s) must be held stationary under these conditions for five minutes for [Doc. No. 26019, 61 FR 31329, June 19, 1996, as each of the 25 operations. amended by Amdt. 33–25, 73 FR 48124, Aug. 18, 2008] [Doc. No. 28107, 61 FR 28433, June 4, 1996] Federal Aviation Administration, DOT § 33.96 (b) Negative torque and thrust sys- § 33.94 Blade containment and rotor unbalance tests. tem operation: 25 cycles from rated maximum continuous power.

(a) Except as provided in paragraph (c) Automatic decoupler operation: 25 (b) of this section, it must be dem- cycles from rated maximum contin- onstrated by engine tests that the en- uous power (if repeated decoupling and gine is capable of containing damage recoupling in service is the intended without catching fire and without fail- function of the device).

ure of its mounting attachments when (d) Reverse thrust operation: 175 cy- operated for at least 15 seconds, unless cles from the flight-idle position to full the resulting engine damage induces a reverse and 25 cycles at rated max- self shutdown, after each of the fol- imum continuous power from full for- lowing events: ward to full reverse thrust. At the end (1) Failure of the most critical com- of each cycle the propeller must be op- pressor or fan blade while operating at erated in reverse pitch for a period of maximum permissible r.p.m. The blade 30 seconds at the maximum rotational failure must occur at the outermost re- speed and power specified by the appli- cant for reverse pitch operation.

tention groove or, for integrally-bladed rotor discs, at least 80 percent of the [Doc. No. 3025, 29 FR 7453, June 10, 1964, as blade must fail.

amended by Amdt. 33–3, 32 FR 3737, Mar. 4, (2) Failure of the most critical tur- 1967] bine blade while operating at max- § 33.96 Engine tests in auxiliary power imum permissible r.p.m. The blade fail- unit (APU) mode.

ure must occur at the outermost reten- If the engine is designed with a pro- tion groove or, for integrally-bladed peller brake which will allow the pro- rotor discs, at least 80 percent of the peller to be brought to a stop while the blade must fail. The most critical tur- gas generator portion of the engine re- bine blade must be determined by con- mains in operation, and remain stopped sidering turbine blade weight and the during operation of the engine as an strength of the adjacent turbine case auxiliary power unit (‘‘APU mode’’), in at case temperatures and pressures as- addition to the requirements of § 33.87, sociated with operation at maximum the applicant must conduct the fol- permissible r.p.m.

lowing tests: (b) Analysis based on rig testing, (a) Ground locking: A total of 45 component testing, or service experi- hours with the propeller brake engaged ence may be substitute for one of the in a manner which clearly dem- engine tests prescribed in paragraphs onstrates its ability to function with- (a)(1) and (a)(2) of this section if— out adverse effects on the complete en- (1) That test, of the two prescribed, gine while the engine is operating in produces the least rotor unbalance; and the APU mode under the maximum (2) The analysis is shown to be equiv- conditions of engine speed, torque, alent to the test.

temperature, air bleed, and power ex- traction as specified by the applicant.

(Secs. 313(a), 601, and 603, Federal Aviation (b) Dynamic braking: A total of 400 Act of 1958 (49 U.S.C. 1354(a), 1421, and 1423); application-release cycles of brake en- and 49 U.S.C. 106(g) Revised, Pub. L. 97–449, gagements must be made in a manner Jan. 12, 1983) which clearly demonstrates its ability [Amdt. 33–10, 49 FR 6854, Feb. 23, 1984] to function without adverse effects on the complete engine under the max- § 33.95 Engine-propeller systems tests.

imum conditions of engine accelera- If the engine is designed to operate tion/deceleration rate, speed, torque, with a propeller, the following tests and temperature as specified by the ap- must be made with a representative plicant. The propeller must be stopped propeller installed by either including prior to brake release.

the tests in the endurance run or oth- (c) One hundred engine starts and erwise performing them in a manner stops with the propeller brake engaged.

acceptable to the Administrator: (d) The tests required by paragraphs (a) Feathering operation: 25 cycles. (a), (b), and (c) of this section must be 14 CFR Ch. I (1–1–25 Edition) § 33.97 performed on the same engine, but this (b) Each applicant may service and engine need not be the same engine make minor repairs to the engine dur- used for the tests required by § 33.87. ing the block tests in accordance with the service and maintenance instruc- (e) The tests required by paragraphs tions submitted in compliance with (a), (b), and (c) of this section must be § 33.4. If the frequency of the service is followed by engine disassembly to the excessive, or the number of stops due extent necessary to show compliance to engine malfunction is excessive, or a with the requirements of § 33.93(a) and major repair, or replacement of a part § 33.93(b).

is found necessary during the block [Amdt. 33–11, 51 FR 10346, Mar. 25, 1986] tests or as the result of findings from the teardown inspection, the engine or § 33.97 Thrust reversers.

its parts must be subjected to any addi- (a) If the engine incorporates a re- tional tests the Administrator finds verser, the endurance, calibration, op- necessary.

eration, and vibration tests prescribed (c) Each applicant must furnish all in this subpart must be run with the testing facilities, including equipment reverser installed. In complying with and competent personnel, to conduct this section, the power control lever the block tests.

must be moved from one extreme posi- [Doc. No. 3025, 29 FR 7453, June 10, 1964, as tion to the other in not more than one amended by Amdt. 33–6, 39 FR 35470, Oct. 1, second except, if regimes of control op- 1974; Amdt. 33–9, 45 FR 60181, Sept. 11, 1980] erations are incorporated necessitating scheduling of the power-control lever Subpart G—Special Requirements: motion in going from one extreme posi- Turbine Aircraft Engines tion to the other, a longer period of time is acceptable but not more than S OURCE : Docket No. FAA–2002–6717, 72 FR three seconds. In addition, the test pre- 1877, Jan. 16, 2007, unless otherwise noted.

scribed in paragraph (b) of this section must be made. This test may be sched- § 33.201 Design and test requirements uled as part of the endurance run.

for Early ETOPS eligibility.

(b) 175 reversals must be made from An applicant seeking type design ap- flight-idle forward thrust to maximum proval for an engine to be installed on reverse thrust and 25 reversals must be a two-engine airplane approved for made from rated takeoff thrust to max- ETOPS without the service experience imum reverse thrust. After each rever- specified in part 25, appendix K, K25.2.1 sal the reverser must be operated at of this chapter, must comply with the full reverse thrust for a period of one following: minute, except that, in the case of a re- (a) The engine must be designed verser intended for use only as a brak- using a design quality process accept- ing means on the ground, the reverser able to the FAA, that ensures the de- need only be operated at full reverse sign features of the engine minimize thrust for 30 seconds.

the occurrence of failures, malfunc- [Doc. No. 3025, 29 FR 7453, June 10, 1964, as tions, defects, and maintenance errors amended by Amdt. 33–3, 32 FR 3737, Mar. 4, that could result in an IFSD, loss of 1967; Amdt. No. 33–35, 87 FR 75711, Dec. 9, thrust control, or other power loss.

2022; 88 FR 2813, Jan. 18, 2023] (b) The design features of the engine must address problems shown to result § 33.99 General conduct of block tests.

in an IFSD, loss of thrust control, or (a) Each applicant may, in making a other power loss in the applicant’s block test, use separate engines of other relevant type designs approved identical design and construction in within the past 10 years, to the extent the vibration, calibration, endurance, that adequate service data is available and operation tests, except that, if a within that 10-year period. An appli- separate engine is used for the endur- cant without adequate service data ance test it must be subjected to a cali- must show experience with and knowl- bration check before starting the en- edge of problem mitigating design durance test. practices equivalent to that gained Federal Aviation Administration, DOT § 33.201 from actual service experience in a of this section. The test may be con- manner acceptable to the FAA. ducted using any rotor speed step in- (c) Except as specified in paragraph crement from 60 to 200 rpm provided (f) of this section, the applicant must the test encompasses the applicable conduct a simulated ETOPS mission speed range. For incremental steps cyclic endurance test in accordance greater than 60 rpm the minimum with an approved test plan on an en- number of vibration cycles must be lin- gine that substantially conforms to the early increased up to 1 million for a 200 type design. The test must: rpm incremental step.

(1) Include a minimum of 3,000 rep- (5) Include vibration surveys at peri- resentative service start-stop mission odic intervals throughout the test. The cycles and three simulated diversion equivalent value of the peak vibration cycles at maximum continuous thrust level observed during the surveys must or power for the maximum diversion meet the minimum vibration require- time for which ETOPS eligibility is ment of § 33.201(c)(2).

sought. Each start-stop mission cycle (d) Prior to the test required by para- must include the use of take-off, climb, graph (c) of this section, the engine cruise, descent, approach, and landing must be subjected to a calibration test thrust or power and the use of thrust to document power and thrust charac- reverse (if applicable). The diversions teristics.

must be evenly distributed over the du- (e) At the conclusion of the testing ration of the test. The last diversion required by paragraph (c) of this sec- must be conducted within 100 cycles of tion, the engine must: the completion of the test. (1) Be subjected to a calibration test (2) Be performed with the high speed at sea-level conditions. Any change in and low speed main engine rotors inde- power or thrust characteristics must pendently unbalanced to obtain a min- be within approved limits.

imum of 90 percent of the rec- (2) Be visually inspected in accord- ommended field service maintenance ance with the on-wing inspection rec- vibration levels. For engines with three ommendations and limits contained in main engine rotors, the intermediate the Instructions for Continued Air- speed rotor must be independently un- worthiness submitted in compliance balanced to obtain a minimum of 90 with § 33.4.

percent of the recommended produc- (3) Be completely disassembled and tion acceptance vibration level. The re- inspected— quired peak vibration levels must be (i) In accordance with the applicable verified during a slow acceleration and inspection recommendations and limits deceleration run of the test engine cov- contained in the Instructions for Con- ering the main engine rotor operating tinued Airworthiness submitted in speed ranges. compliance with § 33.4; (3) Include a minimum of three mil- (ii) With consideration of the causes lion vibration cycles for each 60 rpm of IFSD, loss of thrust control, or other incremental step of the typical high- power loss identified by paragraph (b) speed rotor start-stop mission cycle. of this section; and The test may be conducted using any (iii) In a manner to identify wear or rotor speed step increment from 60 to distress conditions that could result in 200 rpm provided the test encompasses an IFSD, loss of thrust control, or the typical service start-stop cycle other power loss not specifically iden- speed range. For incremental steps tified by paragraph (b) of this section greater than 60 rpm, the minimum or addressed within the Instructions number of vibration cycles must be lin- for Continued Airworthiness.

early increased up to ten million cycles (4) Not show wear or distress to the for a 200 rpm incremental step. extent that could result in an IFSD, (4) Include a minimum of 300,000 vi- loss of thrust control, or other power bration cycles for each 60 rpm incre- loss within a period of operation before mental step of the high-speed rotor ap- the component, assembly, or system proved operational speed range be- would likely have been inspected or tween minimum flight idle and cruise functionally tested for integrity while power not covered by paragraph (c)(3) in service. Such wear or distress must 14 CFR Ch. I (1–1–25 Edition) Pt. 33, App. A A 33.3 CONTENT have corrective action implemented through a design change, a change to The contents of the manual or manuals maintenance instructions, or oper- must be prepared in the English language.

ational procedures before ETOPS eligi- The Instructions for Continued Airworthi- ness must contain the following manuals or bility is granted. The type and fre- sections, as appropriate, and information: quency of wear and distress that occurs (a) Engine Maintenance Manual or Section.

during the engine test must be con- (1) Introduction information that includes an sistent with the type and frequency of explanation of the engine’s features and data wear and distress that would be ex- to the extent necessary for maintenance or pected to occur on ETOPS eligible en- preventive maintenance.

gines.

(2) A detailed description of the engine and its components, systems, and installations.

(f) An alternative mission cycle en- (3) Installation instructions, including durance test that provides an equiva- proper procedures for uncrating, lent demonstration of the unbalance deinhibiting, acceptance checking, lifting, and vibration specified in paragraph (c) and attaching accessories, with any nec- of this section may be used when ap- essary checks.

proved by the FAA.

(4) Basic control and operating information (g) For an applicant using the simu- describing how the engine components, sys- lated ETOPS mission cyclic endurance tems, and installations operate, and informa- tion describing the methods of starting, run- test to comply with § 33.90, the test ning, testing, and stopping the engine and its may be interrupted so that the engine parts including any special procedures and may be inspected by an on-wing or limitations that apply.

other method, using criteria acceptable (5) Servicing information that covers de- to the FAA, after completion of the tails regarding servicing points, capacities of test cycles required to comply with tanks, reservoirs, types of fluids to be used, § 33.90(a). Following the inspection, the pressures applicable to the various systems, locations of lubrication points, lubricants to ETOPS test must be resumed to com- be used, and equipment required for serv- plete the requirements of this section.

icing.

(6) Scheduling information for each part of the engine that provides the recommended periods at which it should be cleaned, in- A PPENDIX A TO P ART 33—I NSTRUCTIONS spected, adjusted, tested, and lubricated, and FOR C ONTINUED A IRWORTHINESS the degree of inspection the applicable wear tolerances, and work recommended at these A 33.1 GENERAL periods. However, the applicant may refer to an accessory, instrument, or equipment (a) This appendix specifies requirements manufacturer as the source of this informa- for the preparation of Instructions for Con- tion if the applicant shows that the item has tinued Airworthiness as required by § 33.4.

an exceptionally high degree of complexity (b) The Instructions for Continued Air- requiring specialized maintenance tech- worthiness for each engine must include the niques, test equipment, or expertise. The rec- Instructions for Continued Airworthiness for ommended overhaul periods and necessary all engine parts. If Instructions for Contin- cross references to the Airworthiness Limi- ued Airworthiness are not supplied by the tations section of the manual must also be engine part manufacturer for an engine part, included. In addition, the applicant must in- the Instructions for Continued Airworthiness clude an inspection program that includes for the engine must include the information the frequency and extent of the inspections essential to the continued airworthiness of necessary to provide for the continued air- the engine.

worthiness of the engine.

(c) The applicant must submit to the FAA (7) Troubleshooting information describing a program to show how changes to the In- probable malfunctions, how to recognize structions for Continued Airworthiness made those malfunctions, and the remedial action by the applicant or by the manufacturers of for those malfunctions.

engine parts will be distributed.

(8) Information describing the order and method of removing the engine and its parts A 33.2 FORMAT and replacing parts, with any necessary pre- (a) The Instructions for Continued Air- cautions to be taken. Instructions for proper worthiness must be in the form of a manual ground handling, crating, and shipping must or manuals as appropriate for the quantity also be included.

of data to be provided. (9) A list of the tools and equipment nec- (b) The format of the manual or manuals essary for maintenance and directions as to must provide for a practical arrangement. their method of use.

Federal Aviation Administration, DOT Pt. 33, App. B (b) Engine Overhaul Manual or Section. (1) reads: ‘‘The Airworthiness Limitations sec- Disassembly information including the order tion is FAA approved and specifies mainte- and method of disassembly for overhaul. nance required under §§ 43.16 and 91.403 of (2) Cleaning and inspection instructions Title 14 of the Code of Federal Regulations that cover the materials and apparatus to be unless an alternative program has been FAA used and methods and precautions to be approved.’’ taken during overhaul. Methods of overhaul (b) For rotorcraft engines having 30-second inspection must also be included.

OEI and 2-minute OEI ratings: (3) Details of all fits and clearances rel- (1) The Airworthiness Limitations section evant to overhaul.

must also prescribe the mandatory post- (4) Details of repair methods for worn or flight inspections and maintenance actions otherwise substandard parts and components associated with any use of either 30-second along with the information necessary to de- OEI or 2-minute OEI ratings.

termine when replacement is necessary.

(2) The applicant must validate the ade- (5) The order and method of assembly at quacy of the inspections and maintenance overhaul.

actions required under paragraph (b)(1) of (6) Instructions for testing after overhaul.

this section A33.4.

(7) Instructions for storage preparation, in- (3) The applicant must establish an in-serv- cluding any storage limits.

ice engine evaluation program to ensure the (8) A list of tools needed for overhaul.

continued adequacy of the instructions for (c) ETOPS Requirements. For an applicant mandatory post-flight inspections and main- seeking eligibility for an engine to be in- tenance actions prescribed under paragraph stalled on an airplane approved for ETOPS, (b)(1) of this section A33.4 and of the data for the Instructions for Continued Airworthiness § 33.5(b)(4) pertaining to power availability.

must include procedures for engine condition The program must include service engine monitoring. The engine condition moni- tests or equivalent service engine test expe- toring procedures must be able to determine rience on engines of similar design and eval- prior to flight, whether an engine is capable uations of service usage of the 30-second OEI of providing, within approved engine oper- or 2-minute OEI ratings.

ating limits, maximum continuous power or thrust, bleed air, and power extraction re- [Amdt. 33–9, 45 FR 60181, Sept. 11, 1980, as quired for a relevant engine inoperative di- amended by Amdt. 33–13, 54 FR 34330, Aug. 18, version. For an engine to be installed on a 1989; Amdt. 33–21, 72 FR 1878, Jan. 16, 2007; two-engine airplane approved for ETOPS, the Amdt. 33–25, 73 FR 48124, Aug. 18, 2008] engine condition monitoring procedures must be validated before ETOPS eligibility A PPENDIX B TO P ART 33—C ERTIFICATION is granted.

S TANDARD A TMOSPHERIC C ON- CENTRATIONS OF R AIN AND H AIL A33.4 airworthiness limitations section Figure B1, Table B1, Table B2, Table B3, The Instructions for Continued Airworthi- and Table B4 specify the atmospheric con- ness must contain a section titled Airworthi- centrations and size distributions of rain and ness Limitations that is segregated and hail for establishing certification, in accord- clearly distinguishable from the rest of the ance with the requirements of § 33.78(a)(2). In manual.

(a) For all engines: conducting tests, normally by spraying liq- (1) The Airworthiness Limitations section uid water to simulate rain conditions and by must set forth each mandatory replacement delivering hail fabricated from ice to simu- time, inspection interval, and related proce- late hail conditions, the use of water drop- dure required for type certification. If the In- lets and hail having shapes, sizes and dis- structions for Continued Airworthiness con- tributions of sizes other than those defined sist of multiple documents, the section re- in this appendix B, or the use of a single size quired under this paragraph must be in- or shape for each water droplet or hail, can cluded in the principal manual. be accepted, provided that applicant shows (2) This section must contain a legible that the substitution does not reduce the se- statement in a prominent location that verity of the test.

14 CFR Ch. I (1–1–25 Edition) Pt. 33, App. B T ABLE B1—C ERTIFICATION STANDARD T ABLE B3—C ERTIFICATION S TANDARD ATMOS- A TMOSPHERIC R AIN C ONCENTRATIONS PHERIC R AIN D ROPLET S IZE D ISTRIBUTION Rain water content (RWC) Rain droplet diameter (mm) Contribution total RWC (%) Altitude (feet) (grams water/meter air) 0 ................................................. 20.0 0.50–0.99 ................................... 2.25 20,000 ........................................ 20.0 1.00–1.49 ................................... 8.75 26,300 ........................................ 15.2 1.50–1.99 ................................... 16.25 32,700 ........................................ 10.8 2.00–2.49 ................................... 19.00 39,300 ........................................ 7.7 2.50–2.99 ................................... 17.75 46,000 ........................................ 5.2 3.00–3.49 ................................... 13.50 3.50–3.99 ................................... 9.50 RWC values at other altitudes may be determined by linear 4.00–4.49 ................................... 6.00 interpolation.

4.50–4.99 ................................... 3.00 N OTE : Source of data—Results of the Aerospace Industries 5.00–5.49 ................................... 2.00 Association (AIA) Propulsion Committee Study, Project PC 338–1, June 1990. 5.50–5.99 ................................... 1.25 6.00–6.49 ................................... 0.50 6.50–7.00 ................................... 0.25 T ABLE B2—C ERTIFICATION STANDARD A TMOSPHERIC HAIL C ONCENTRATIONS Total ............................ 100.00 Median diameter of rain droplets in 2.66 mm Hail water content (HWC) Altitude (feet) 3 N OTE : Source of data—Results of the Aerospace Industries (grams water/meter air) Association (AIA Propulsion Committee (PC) Study, Project PC 338–1, June 1990.

0 ................................................. 6.0 7,300 .......................................... 8.9 T ABLE B4—C ERTIFICATION S TANDARD 8,500 .......................................... 9.4 10,000 ........................................ 9.9 A TMOSPHERIC HAIL S IZE DISTRIBUTION 12,000 ........................................ 10.0 15,000 ........................................ 10.0 Hail diameter (mm) Contribution total HWC (%) 16,000 ........................................ 8.9 19,300 ........................................ 6.6 5.0–9.9 ....................................... 17.00 21,500 ........................................ 5.6 10.0–14.9 ................................... 25.00 24,300 ........................................ 4.4 15.0–19.9 ................................... 22.50 29,000 ........................................ 3.3 20.0–24.9 ................................... 16.00 46,000 ........................................ 0.2 25.0–29.9 ................................... 9.75 30.0–34.9 ................................... 4.75 HWC values at other altitudes may be determined by linear 35.0–39.9 ................................... 2.50 interpolation. The hail threat below 7,300 feet and above 40.0–44.9 ................................... 1.50 29,000 feet is based on linearly extrapolated data.

45.0–49.9 ................................... 0.75 N OTE : Source of data—Results of the Aerospace Industries Association (AIA Propulsion Committee (PC) Study, Project 50.0–55.0 ................................... 0.25 PC 338–1, June 1990.

Federal Aviation Administration, DOT Pt. 33, App. D [Doc. No. 28652, 63 FR 14799, Mar. 26, 1998] T ABLE B4—C ERTIFICATION S TANDARD ATMOS- PHERIC H AIL S IZE D ISTRIBUTION —Continued A PPENDIX C TO P ART 33 [R ESERVED ] Hail diameter (mm) Contribution total HWC (%) A PPENDIX D TO P ART 33—M IXED P HASE Total ............................ 100.00 AND I CE C RYSTAL I CING E NVELOPE Median diameter of hail is 16 mm (D EEP C ONVECTIVE C LOUDS ) N OTE : Source of data—Results of the Aerospace Industries Association (AIA Propulsion Committee (PC) Study, Project The ice crystal icing envelope is depicted PC 338–1, June 1990.

in Figure D1 of this Appendix.

Within the envelope, total water content of 17.4 nautical miles. Figure D2 of this Ap- (TWC) in g/m has been determined based pendix displays TWC for this distance over a upon the adiabatic lapse defined by the con- range of ambient temperature within the vective rise of 90% relative humidity air boundaries of the ice crystal envelope speci- from sea level to higher altitudes and scaled fied in Figure D1 of this Appendix.

by a factor of 0.65 to a standard cloud length 14 CFR Ch. I (1–1–25 Edition) Pt. 33, App. D Ice crystal size median mass dimension T ABLE 1—S UPERCOOLED L IQUID P ORTION OF (MMD) range is 50–200 microns (equivalent TWC—Continued spherical size) based upon measurements near convective storm cores.

Temperature range— Horizontal cloud LWC— deg C length—nautical miles g/m The TWC can be treated as completely gla- ciated (ice crystal) except as noted in the 0 to ¥ 20 ...................... Indefinite ...................... ≤ 0.5 Table 1 of this Appendix.

T ABLE 1—S UPERCOOLED L IQUID P ORTION OF The TWC levels displayed in Figure D2 of TWC this Appendix represent TWC values for a Temperature range— Horizontal cloud LWC— standard exposure distance (horizontal cloud deg C length—nautical miles g/m length) of 17.4 nautical miles that must be adjusted with length of icing exposure.

0 to ¥ 20 ...................... ≤ 50 .............................. ≤ 1.0

Federal Aviation Administration, DOT Pt. 34

[Amdt. 33–34, 79 FR 65538, Nov. 4, 2014] 34.21 Standards for exhaust emissions.

34.23 Exhaust Emission Standards for En- gines Manufactured on and after July 18,

PART 34—FUEL VENTING AND EX-

2012.

HAUST EMISSION REQUIREMENTS

34.25 Non-volatile particulate emissions

FOR TURBINE ENGINE POWERED

standards (nvPM).

AIRPLANES

Subpart D—Exhaust Emissions (In-Use Subpart A—General Provisions Aircraft Gas Turbine Engines) Sec.

34.30 Applicability.

34.1 Definitions.

34.31 Standards for exhaust emissions.

34.2 Abbreviations.

34.3 General requirements.

Subpart E—Certification Provisions 34.4 Incorporation by reference.

34.5 Special test procedures.

34.48 Derivative engines for emissions cer- 34.6 Aircraft safety.

tification purposes.

34.7 Exemptions.

34.9 Exceptions.

Subpart F [ Reserved ] Subpart B—Engine Fuel Venting Emissions Subpart G—Test Procedures for Engine Ex- (New and In-Use Aircraft Gas Turbine haust Gaseous Emissions (Aircraft and Engines) Aircraft Gas Turbine Engines) 34.10 Applicability.

34.60 Introduction.

34.11 Standard for fuel venting emissions.

Subpart C—Exhaust Emissions (New Aircraft Gas Turbine Engines) 34.20 Applicability.