Airplane Flight Manual

10/16/12 AC 25.1581-1 Chg. 1 section of the AFM. Emergency or abnormal procedures should be located in the appropriate procedures section(s) of the AFM.

3 Detailed system descriptions and normal procedures that represent one means, but not the only means, of operation should be located in appropriate operating manuals with a reference placed in the procedures section of the AFM. This reference should include the document title, the document or part number, and the date of issue. The reference may also allow the use of later appropriate revisions of that document. An example wording would be: “Normal operating procedures are contained in the [ Manufacturer Unit Model ] System Pilot's Guide, P/N XXXX, dated XXXX (or later appropriate revision).” (c) AFM Used Directly. For those manufacturers and operators that do not produce other sources of procedures information (generally manufacturers and operators of small transports), the AFM is the only source of this information. In this circumstance, the AFM operating procedures information should be comprehensive and include information such as cockpit checklists, systems descriptions, and associated procedures.

(5) Emergency Procedures. The emergency procedures can be included either in a dedicated section of the AFM or in the non-normal procedures section. In either case, this section should include the procedures for handling any situation that is in a category similar to the following: (a) Engine failure with severe damage or separation.

(b) Multiple engine failure.

(c) Fire in flight.

(d) Smoke control. At least the following should be clearly stated in the AFM: After conducting the fire or smoke procedures, land at the nearest suitable airport, unless it is visually verified that the fire has been extinguished.

(e) Rapid decompression.

(f) Emergency descent.

(g) Uncommanded reverser deployment in flight.

(h) Crash landing or ditching.

(i) Emergency evacuation.

10/16/12 AC 25.1581-1 Chg. 1 d. Performance Section . This section of the AFM contains the performance limitations and other data required by parts 25 and 36, and any special conditions that may apply. Additional information may be provided to assist the operator in complying with the operating rules or for implementing unique operational needs. The performance information should cover the operating range of weights, altitudes, temperatures, winds, airplane configurations, power or thrust ratings, and any other operational variables stated as operational performance limitations for the airplane. If presenting additional performance information for operation at a specific altitude, these performance data should cover a pressure altitude span of at least the specific altitude  1,000 feet to allow an operator to adequately account for pressure altitude variations. It is recommended that such data be included as a separate section or appendix to the AFM.

(1) General. Include all descriptive information necessary to identify the configuration and conditions for which the performance data are applicable. Such information should include the type or model designations of the airplane and its engines, the approved flap settings, a brief description of airplane systems and equipment that affect performance (e.g., anti-skid, automatic spoilers, etc.), and a statement indicating whether such systems and equipment are operative or inoperative. This section should also include definitions of terms used in the Performance Section (e.g., IAS, CAS, ISA, configuration, net flight path, icing conditions, etc.), plus calibration data for airspeed (flight and ground), Mach number, altimeter, air temperature, and other pertinent information. The airspeed, altitude, and air temperature calibration data should be presented for the following ranges: (a) Takeoff configurations: 1 Ground run, 0.8 V to V 1MIN 2MAX 2 Inflight, V to V 2MIN FE (b) Approach and landing configurations: 1 Approach, 1.1 V to V SR1 FE 2 Landing, 1.23 V to V SRO FE (c) En route configuration: 1 Airspeed and Altimeter: For the takeoff/takeoff path altitude range, V FTO to V /M .

MO MO 2 Airspeed and Altimeter: For higher altitudes, from V or the speed for FTO 0.2 g margin to buffet onset, whichever is lower, to V /M .

MO MO 10/16/12 AC 25.1581-1 Chg. 1 3 Mach Number: From the lowest useful Mach number (generally in the range of 0.4 to 0.5) to M .

MO 4 Total or Static Air Temperature: For Mach numbers corresponding to the speed ranges noted in paragraphs 2d(1)(c)1 and 2d(1)(c)2 of this AC.

(2) Performance Procedures. The procedures, techniques, and other conditions used to compute the AFM performance data should be included.

(3) Power or Thrust Setting. Power or thrust settings should be provided for at least takeoff, maximum continuous, and go-around power or thrust, along with the power or thrust setting procedures necessary to obtain the performance shown in the AFM. These data should be shown for each applicable power or thrust setting parameter. If backing the airplane by reverse power or thrust is proposed, power or thrust setting limits should be established considering contaminated runway, foreign object damage potential, environmental control system impact, airplane weight and c.g., cockpit visibility, effect of braking, etc.

(4) Minimum Control Speeds. Minimum control speed data may be located in the Performance Section with a reference in the Limitations Section as to its location.

(5) Stall Speeds. The stall speeds established in showing compliance with certification requirements should be presented, together with associated conditions. Data should be presented in terms of calibrated airspeed.

(6) Takeoff Speeds. In accordance with § 25.1587(b), the takeoff speeds, V , V , and 1 R V , must be presented in the AFM, together with the associated conditions. These speeds should be presented in units consistent with cockpit instrument indications. V and V speeds should be 1 R based upon ground effect calibration data, while V speeds should be based upon free air calibration data. The takeoff speeds associated with the minimum control speeds and the maximum energy absorption capability of the brakes should be included. At the option of the applicant, the AFM may also include the V speeds associated with unbalanced field lengths.

(a) At all conditions and airplane configurations represented in the AFM (i.e., at all altitudes, temperatures, weights, winds, runway slopes, flap settings, etc.), the accuracy of the V speed should either: 1) be within 1.5 knots of the V speed used to calculate the takeoff and 1 1 accelerate-stop distances, or 2) not cause an increase to these distances of more than the greater of 100 feet or the incremental increase resulting from a 1.5 knot variation in V speed.

(b) The effects of airspeed lag in cockpit airspeed indications should be adequately addressed in the AFM speeds and distances. See paragraph 177a(1)(f) of AC 25-7C, “Flight Test Guide for Certification of Transport Category Airplanes” for further information on airspeed lag.

10/16/12 AC 25.1581-1 Chg. 1 (7) Takeoff and Accelerate-Stop Distances. In accordance with §§ 25.1533(a)(3), 25.1583(h), and 25.1587(b), takeoff and accelerate-stop distances complying with §§ 25.101, 25.105, 25.109 and 25.113 must be provided. At the option of the applicant, and with concurrence by the FAA, additional data may be provided for operations on other than smooth hard-surfaced runways.

(a) Grooved and porous friction course (PFC) wet runway accelerate-stop distances may also be presented in the AFM, but approval to use these distances is limited to runways that have been designed, constructed, and maintained in a manner acceptable to the FAA Administrator. The page(s) in the AFM containing the wet runway accelerate-stop distances for grooved and PFC runways should contain a note equivalent to the following: “These accelerate-stop distances apply only to runways that are grooved or treated with a porous friction course (PFC) overlay that the operator has determined have been designed, constructed, and maintained in a manner acceptable to the FAA Administrator.” Information should also be included describing the method and assumptions used in generating both the smooth and grooved/PFC wet runway information and generally describing the effect of operational variables on wet runway stopping performance (e.g., tire tread depth, runway surface texture, water depth, brakes-on speed).

(b) Sections 25.109(b) and 25.113(b) require the accelerate-stop and takeoff distances, respectively, on a wet runway (at the wet runway V speed and with the wet runway braking coefficient) to be at least as long as the corresponding distances on a dry runway (using the dry runway V speed and braking coefficient). These requirements are intended to ensure that the maximum takeoff weight of an airplane for a wet runway is not greater than the maximum takeoff weight for that airplane if the runway was dry, all other airplane configuration and atmospheric conditions being identical. To meet the intent of these requirements, either the wet runway distances furnished in the AFM must be at least as long as the corresponding dry runway distances, or the following procedure can be furnished in the AFM to determine the field length-limited takeoff weight and required takeoff field length when the runway surface is wet: Step 1: Conduct the takeoff performance analysis to determine the maximum takeoff weight assuming the runway is dry; Step 2: Repeat the takeoff performance analysis of step 1 assuming the runway is wet and using the appropriate wet runway V speed; Step 3: For the lowest takeoff weight determined in steps 1 and 2, determine and compare the accelerate-stop and takeoff distances applicable to a dry runway based on the dry runway V speed and a wet runway based on the wet runway V speed.

1 1 Step 4: Use the longer of the accelerate-stop and takeoff distances determined in step 3 to determine the maximum allowable runway length limited takeoff weight.

10/16/12 AC 25.1581-1 Chg. 1 Step 5: Regardless of which condition is limiting the weight (wet or dry), use wet runway takeoff speeds for the weight determined in step 3.

(8) Climb Limited Takeoff Weight. The climb limited takeoff weight, which is the most limiting weight showing compliance with § 25.121(a), (b), and (c), must be provided as required by §§ 25.1533(a)(1) and 25.1583(h).

(9) Miscellaneous Takeoff Weight Limits. Takeoff weight limits should be shown for any equipment or characteristic of the airplane that imposes an additional takeoff weight restriction (e.g., maximum tire speed, maximum brake energy, fuel jettison considerations, inoperative system(s), etc.).

(10) Takeoff Climb Performance. For the prescribed takeoff climb airplane configurations, the climb gradients must be presented, together with associated conditions, per § 25.1587(b). The scheduled climb speed(s) should be included.

(11) Takeoff Flight Path Data. Takeoff flight paths, or performance information necessary to construct such paths, together with the associated conditions (e.g., procedures, power or thrust setting, and speeds), should be presented for each approved takeoff configuration throughout the approved takeoff operating envelope. The presentation should include all flight path segments existing between the end of the takeoff distance and the end of the takeoff path, as defined in § 25.111(a). Also, provide instructions for how to use the takeoff flight path data to do a takeoff path analysis, including configuration/speed/thrust or power changes, accounting for wind, and explanations of the boundaries within which each set of data applies. For example, if, for a particular portion of the takeoff flight path, such as the second segment, the data (or use of it) is restricted to a particular altitude range, identify that altitude range and explain why the data may only be used within that altitude range. The takeoff flight path data must be based upon net performance, as prescribed in § 25.115(b) and (c).

(a) Although § 25.111(a) permits the takeoff path to be terminated as low as 1,500 feet above the takeoff surface, it is recommended that the flight path data, or associated AFM methodology, be presented so that the net flight path can be determined to 3,000 ft. above the takeoff surface. This will permit obstacle clearance analysis for distant obstacles of considerable elevation that may be encountered in operations from mountain airports.

(b) The § 25.115(b) net takeoff flight path data, required to be included in the AFM by § 25.1587(b), need not extend to the altitude specified in § 25.111(a). It may be terminated at a height, generally called “net height,” that is directly related to the actual airplane height specified in § 25.111(a). The “net height” is calculated using the actual airplane takeoff climb performance, to the point where the altitude requirements of § 25.111(a) are met, reduced by the climb gradient decrements specified in § 25.115(b).

(c) The height of the level flight acceleration segment should be presented in terms 10/16/12 AC 25.1581-1 Chg. 1 of pressure altitude increment above the takeoff surface. This information should allow the pressure altitude “increment” (  hp) to be determined for off-standard ambient temperatures so that the geometric height required for obstacle clearance can readily be determined. For example: Given : o Takeoff surface pressure altitude (hp) = 2,000 ft.

o Airport std. temp. abs. (T ) = 11º C+273.2º = 284.2 K S o Airport ambient temp. abs. (T ) = -20º C+273.2º = 253.2 K AM o Geometric height required (  h) = 1,700 ft. above the takeoff surface Find : o Pressure altitude increment (  hp) above the takeoff surface  hp =  h(T /T ) = 1,700 ft. (284.2º K/253.2 K) S AM  hp = 1,908 ft.

(d) With turns in the net takeoff flight path, obstacle clearance determination requires consideration of both radius of turn and climb gradient decrement. Radius of turn, for use in obstacle lateral separation, is not airplane dependent and can easily be calculated from speed and bank angle. Climb gradient decrements, however, are airplane dependent. Climb gradient decrements for bank angles up to at least 15 degrees should be provided in the AFM.

Consider providing coverage of higher bank angles as appropriate to the expected operation of the airplane.

(12) En Route Flight Path Data. The net flight path gradient data prescribed in § 25.123 must be presented, together with the associated conditions (e.g., procedures and speeds), per § 25.1587(b). Data must be presented for both one- and two-engines-inoperative cases, as applicable, throughout the approved operating altitude and temperature envelope. Credit for fuel dumping, if available and included in the flightcrew procedures, may be used to achieve the performance capability presented in the AFM. A conservative analysis should be used in taking into account the ambient conditions of temperature and wind existing along the flight path. All performance should be based on the net flight path and with maximum continuous power or thrust on the operating engine(s).

(13) Climb Limited Landing Weight. The climb limited landing weight, which is the most limiting weight showing compliance with §§ 25.119 and 25.121(d), should be provided.

(14) Miscellaneous Landing Weight Limits. Landing weight limits for any equipment or characteristic of the airplane configuration that imposes an additional landing weight restriction should be shown.

10/16/12 AC 25.1581-1 Chg. 1 (15) Approach Climb Performance. For the approach climb configuration(s), the climb gradients (§ 25.121(d)) and weights up to maximum takeoff weight (§ 25.1587(b)(3)) should be presented, together with associated conditions (e.g., procedures, power or thrust setting, and speeds). The effects of ice accretion on unprotected portions of the airframe, and the effects of engine and wing ice protection systems should be provided.

(16) Landing Climb Performance. Data for the landing climb configuration(s) should be presented in a manner similar to that described for the approach configuration above.

(17) Landing Approach Speeds. The scheduled speeds associated with the approved landing distances and operational landing runway lengths (see paragraph 2d(18) of this AC) should be presented, together with associated conditions. The airplane’s approach category, as defined in § 97.3, may also be listed.

(18) Landing Distance. In accordance with § 25.1587(b), the landing distance from a height of 50 feet must be presented either directly or with the factors required by the operating regulations, together with associated conditions and weights up to the maximum takeoff weight.

For all landplanes, landing distance data must be presented for level, smooth, dry, hard-surfaced runways for standard day temperatures. At the option of the applicant, and with concurrence by the FAA, additional data may be presented for other temperatures and runway slopes within the operational limits of the airplane, or for operations on other than smooth hard-surfaced runways.

For Category III operations, additional landing performance data may be required.

(19) Performance Limits and Information Variation with Center-of-Gravity. If performance information (e.g., buffet boundary) is not presented for the most critical c.g.

condition, the AFM should present the effect of variation with c.g.

(20) Noise Data. The noise levels achieved during type certification in accordance with the provisions of part 36 should be presented, together with associated conditions and with the note prescribed in § 36.1581(c). The noise levels achieved during type certification should be included in the AFM and consist of only one takeoff, one sideline, and one approach noise level for each airplane model (i.e., hardware build). The noise certification stage level should accompany the noise level information to indicate the compliance status. Supplementary information (labeled as such) may be added to the AFM concerning noise levels for other configurations or conditions.

(21) Miscellaneous Performance Data. Any performance information or data not covered in the previous items that are required for safe operation because of unusual design features or operating or handling characteristics should be furnished. For example, the maximum quick turnaround weight should be provided.

e. Loading Instructions . Section 25.1583 requires instructions necessary to ensure loading of the airplane within the established limits of weight and center-of-gravity, and to maintain the loading within such limits in flight to be presented either in the AFM or included in a separate 10/16/12 AC 25.1581-1 Chg. 1 weight and balance document referenced in the AFM Limitations Section. If applicable, the loading instructions should refer to the flight procedures that consider the change to the airplane’s center of gravity as fuel is consumed.

(1) Loading Instructions Presented in a Separate Document. If the loading instructions are presented in a separate document, the AFM Limitations Section should contain at least the following: (a) Maximum taxi gross weight limits.

(b) Maximum takeoff gross weight limits.

(c) Maximum landing gross weight limits.

(d) Maximum zero fuel weight limits.

(e) Minimum in-flight gross weight.

(f) Center-of-gravity limits.

(g) Information required to maintain the airplane within the above limits.

(2) Weight and Balance Data. Documentation of the weight and balance material outlined below is normally adequate for airplanes with conventional loading and fuel management techniques. For airplanes that require fuel to be redistributed (other than through normal consumption) to maintain loading within prescribed limits, the loading instructions should be expanded as necessary.

(a) Weight Limits. A list and identification of all weight limitations should be included.

(b) Center-of-Gravity Limits. The approved center-of-gravity range, or ranges, should be presented with due accounting for airplane configuration (i.e., landing gear position, passenger loading, cargo distribution, etc.) such that loading limits can be maintained.

(c) Dimensions, Datum, and MAC. The dimensions and relative location of airplane features associated with weighing and loading of the airplane and with weight and balance computations should be described or illustrated.

(d) Configuration Checklist or Equipment List. The airplane should be defined or described sufficiently to identify the presence or absence of optional systems, features, or installations that are not readily apparent. In addition, all other items of fixed or removable equipment included in the empty weight should be listed.

10/16/12 AC 25.1581-1 Chg. 1 (e) Fuel and Other Liquids. All fuel and other liquids, including passenger service liquids, that are included in the empty weight should be identified and listed, together with the information necessary to enable ready duplication of the particular condition.

(f) Weighing Computations. Computation of the empty weight and the empty weight c.g. location should be included.

(g) Loading Schedule. The loading schedule should be included, if appropriate.

(h) Loading Instructions. Complete instructions relative to the loading procedure or to the use of the loading schedule should be included.

(i) Compartment and floor load limits should be included.

3. Configuration deviation list (CDL). Operating the airplane without certain secondary airframe and engine parts is allowed through the use of an approved CDL. The CDL should be included in the AFM as a separate appendix. The CDL should be prepared in accordance with the guidance provided in Advisory Circular 25-7, “Flight Test Guide for Certification of Transport Category Airplanes.” 4. Specification and submittal of AFMs, revisions, appendices, and supplements. The format and contents of the AFM, revision, appendix, or supplement should be proposed by the applicant and accepted by the FAA well before submittal of AFM material. The time required for FAA review and approval, and the manner in which AFM material and supporting documentation (e.g., flight test results) will be submitted, should also be established well in advance of the actual submittal. Large submittals may be broken down into smaller packages of related material and submitted to the FAA as it becomes available.

5. Approval of AFMs, revisions, appendices, and supplements.

a. FAA Approval of an AFM Developed by a U.S. Manufacturer . AFMs, revisions, appendices, and supplements are to be approved by the manager of the appropriate Aircraft Certification Office (ACO) or his designated representative. As necessary, or at the request of the applicant, the ACO manager will convene a Flight Manual Review Board (FMRB) to determine whether the limitations, procedures, and performance information contained in the AFM provide for safe operation and are compatible with the airplane type design and certification basis. The Flight Test Branch (or equivalent) of the appropriate ACO is responsible for FAA coordination of AFM material, including coordination with the designated operations specialist or Aircraft Evaluation Group (AEG) personnel. Although the AEG participates in the review process, FAA approval of the AFM does not constitute approval for use in operations under part 121, 125, or 135.

10/16/12 AC 25.1581-1 Chg. 1 b. Foreign Civil Airworthiness Authority (FCAA) Approval of an AFM Developed by a U.S. Manufacturer .

(1) AFMs developed by a U.S. manufacturer for FCAA certification may be approved by the FAA in one of three ways, depending upon the formal agreements made between the FAA and the FCAA.

(a) Type I Approvals. In this case, the regulatory standard of the FCAA is 14 CFR part 25, with possibly some unique FCAA requirements of minor significance, and the FCAA has delegated approval authority to the FAA. The AFM is coordinated as described in paragraph 5a of this AC. The FAA assumes technical responsibility and approval is granted without consulting the FCAA, except in cases outside of formal agreements. Approval statements contained in the AFM should indicate that the AFM is “FAA Approved.” No reference to the FCAA is necessary.

(b) Type II Approvals. In this case, the regulatory standard of the FCAA is mostly 14 CFR part 25 with a limited number of FCAA requirements of major significance. An example of such a regulatory standard is the Joint Aviation Requirements (JAR). The AFM approval process is coordinated as described in paragraph 5a of this AC. Depending on the agreement with the FCAA, the FAA may assume technical responsibility for the AFM. The AFM should contain a preamble or introduction listing the unique, non-FAA requirements, and stating that the AFM satisfies the regulatory requirements of the FCAA, and that the AFM is approved by the FAA on behalf of the FCAA. For the first issue of the AFM, written concurrence is required from the FCAA that FAA approval may be granted. Depending upon the written agreement made between the FAA and FCAA, subsequent revisions may not require written authorization from the FCAA for the FAA to grant approval.

(c) Type III Approvals. In this case, the regulatory standard of the FCAA is extensively different from 14 CFR part 25. The FAA assumes limited technical responsibility for approving the AFM, in accordance with the written agreement between the FAA and FCAA.

(d) The AFM is not subject to the approval coordination process described in paragraph 5a of this AC. The AFM should contain a preamble or introduction stating that the AFM satisfies the regulatory requirements of the FCAA, and that the AFM is signed by the FAA on behalf of the FCAA. Written authorization should be obtained from the FCAA prior to FAA signature for the first issue and all subsequent revisions. The FCAA may choose to retain signature authority, whereupon the FAA will not be involved in any phase of the approval process. However, if the FCAA approved material is an appendix or supplement to an FAA approved basic AFM, the FCAA approved material may still be acknowledged on the basic AFM log of pages.

(e) Additionally, for Type II and III approvals, the FCAA may specify changes or inclusion of certain amendments. The FAA would then ensure that these changes were made, 10/16/12 AC 25.1581-1 Chg. 1 and would assume the responsibility only for assuring that they meet the specified FCAA requirements. If the FAA has knowledge of an unsafe condition resulting from the proposed limitations, procedures, or performance, the FAA will neither approve nor sign the AFM, and will notify the FCAA of the condition requiring further attention.

(2) When there is no formal agreement between authorities, the FCAA should assume AFM approval duties. In this case, the FAA could, if requested by the FCAA, oversee the administrative approval of the AFM, similar to a Type III approval, when notified by the FCAA that the AFM meets their requirements. Technical review of the AFM contents would be the responsibility of the FCAA, and a special preface page should explain the nature of the aforementioned approval and signature action.

c. FAA Approval of an AFM Developed by a Foreign Manufacturer .

(1) When an application is made for FAA certification of an airplane manufactured by a foreign country, the AFM that has been prepared will be assessed by the FAA certification team in accordance with the certification procedures for import, and notification will be made of any changes required to comply with the requirements of the FAA.

(2) The approval process will be consistent with the methods described in paragraph 5b of this AC.

d. Approval of Minor AFM Revisions by Designated Engineering Representatives (DERs) .

The approval of certain minor AFM revisions may be delegated to authorized Flight Analyst DERs. It is the responsibility of the ACO Flight Test Branch manager (or equivalent) to evaluate the capability, delegate the authority, and monitor the approval activities of the airplane manufacturer and authorized designees. The following guidelines specify the additional DER qualifications, the review process for the DER and the airplane manufacturer to follow, and the types of revisions that are eligible for DER approval: (1) Additional DER Qualifications. In addition to being a Flight Analyst DER, the nominee should possess the following characteristics: (a) Be an employee of a transport airplane manufacturer.

(b) Have sound general knowledge of the type certification process.

(c) Be familiar with the historical background of the airplane manufacturer’s AFMs.

(d) Have administrative ability.

10/16/12 AC 25.1581-1 Chg. 1 (e) Have the authority to coordinate the DER review process.

(2) DER/Airplane Manufacturer Review Process. The airplane manufacturer should institute a structured review process to ensure the integrity of DER-approved AFM revisions.

The manufacturer’s coordination records should be made available to the FAA to audit the process. The following procedures are recommended: (a) Identify whether the AFM revision is eligible for DER approval (see paragraph 5d(3) of this AC).

(b) Research and draft the revised material.

(c) Select the appropriate engineering disciplines/organizations within the company (e.g., aerodynamics, propulsion, etc.) for review.

(d) Conduct an initial review and make appropriate changes to the proposed AFM revision.

(e) Coordinate the final engineering and airworthiness approval.

(f) Have the authorized DER sign the AFM above the signature block. Clearly identify the signer as a DER rather than the ACO manager or Flight Test Branch manager.

(g) Send an advance copy of the approved AFM revision to the ACO, along with appropriate documentation identifying the coordination elements.

(h) Have the authorized DER sign the 8110-3 form and submit it to the ACO.

(i) Send final copies of the AFM revision to the ACO.

(3) Material Eligible for DER Approval. The following types of AFM revisions are eligible for approval by authorized Flight Analyst DERs: (a) The addition of airplane serial numbers to an existing AFM for which the airplane configuration, relative to the AFM, is identical to airplanes already covered by that AFM.

(b) Changes to weight limitations that are within all previously FAA-approved limitations (e.g., structural, noise, etc.).

(c) The addition of compatible and previously FAA-approved AFM appendices.

(d) Conversions of previously FAA-approved combinations of units of measure added to an AFM in a previously FAA-approved manner.

10/16/12 AC 25.1581-1 Chg. 1 (e) Minor editorial changes and corrections.

(f) The addition of previously FAA-approved optional equipment for the same airplane model with similar operability and compatibility characteristics, provided no additional compatibility testing is required.

(g) Revisions for which an FCAA has granted FAA/DER approval authority through specific FAA/FCAA agreements and procedural practices.

(h) The incorporation of information from an Airworthiness Directive into subsequent AFMs after the first such revision is approved by the ACO.

(4) Material Ineligible for DER Approval. New information of any kind, or any information not previously approved by the FAA, including limitations, operating procedures, and performance, are ineligible for DER approval. Other types of AFM revisions ineligible for DER approval include: (a) Any information that requires certification flight tests.

(b) Any revision for which approval or signature authority is contrary to existing FAA/FCAA agreements or procedural practices.

(c) Revisions associated with concurrent type certification activity.

(d) Changing units of measure to be incompatible with airplane indication systems (e.g., fuel quantity/flow gauges).

(e) Any revision not clearly identified in paragraph 5d(3) of this AC as eligible for DER approval.

10/16/12 AC 25.1581-1 Chg. 1 Appendix 1 Appendix 1 Computerized Airplane Flight Manual 1. Purpose. This appendix presents guidelines for obtaining approval of a computerized version of an AFM that would replace or supplement parts of the conventional paper AFM.

These guidelines also apply to computerized AFM appendices and supplements. The criteria provided in the main body of this Advisory Circular (AC) remain applicable except where modified by this appendix. These guidelines do not cover: a. Systems used on board the airplane during flight.

b. Systems that provide direct input to other airplane systems or equipment.

c. Supplementary software or software functions used to prepare documentation suitable for use in the operation of the airplane under the applicable operating rules (e.g., airport analysis software).

2. Applicability. This appendix applies to airplanes eligible to be certificated under part 25.

The guidelines contained herein pertain to generating and presenting AFM performance information by means of computer software. This appendix may be amended to include relevant aspects for other FAA approved information that is stored and presented through computer software. Updated pages are indicated by Change 1 and date of 10/16/12.

3. Definitions.

a. Computerized AFM . The computerized AFM software application used in conjunction with the hardware and software environment in which it is installed to generate computerized AFM information.

b. Computerized AFM Software Application. The computer programs and data, installation information, and operating guide that are used in generating computerized AFM information.

c. Computerized AFM Information . The information generated by the FAA-approved computerized AFM in lieu of or supplementing parts of the conventional paper AFM.

d. Software Environment . The additional computer programs (e.g., operating system) that provide services to the computerized AFM software application to input, process, and output the information to the user.

A1-1

10/16/12 AC 25.1581-1 Chg. 1 Appendix 1 e. Hardware Environment . The equipment (e.g., terminal, printer, keyboard, math co- processor, central processing unit, etc.) that enables the operation of the software environment and the computerized AFM software application to input, process, and output the information to the user.

f. Commercial-Off-the-Shelf (COTS) Computer. A multi-purpose computer (e.g., a standard personal computer) that is available, or can be made available, to all potential users of the respective computerized AFM.

g. Calculation. Data generation by means of any combination of table-lookup or arithmetic operations.

h. First Principles Calculation . A calculation using basic parameters such as lift, drag, power or thrust, etc. with the equations of motion.

4. General guidelines. The holder of the type certificate (TC) is responsible for obtaining approval of new and revised computerized AFMs. An applicant seeking a supplemental type certificate (STC) based on a computerized AFM should comply with the same guidelines as the TC holder. The criteria herein do not affect the status of computerized AFMs that have previously been FAA-approved. When such manuals are amended in the future, the concepts of this appendix should be applied, where practicable.

a. Official Reference .

(1) The conventional paper portion of the AFM should contain appropriate references about applicability of the FAA-approved computerized AFM software application. This reference should be revised each time the FAA-approved computerized AFM software application is changed (see paragraph 6d of this appendix).

(2) The Limitations Section of the conventional paper portion of the AFM should contain at least the following information: (a) A statement similar to the following: “The computerized AFM replaces or supplements portions of the paper AFM, and is an FAA-approved source for that AFM information. Any modification to the FAA-approved computerized AFM software application, or subsequent alteration to the generated output, will cancel the airworthiness approval of the information, unless this change was approved by the appropriate airworthiness authority. This A1-2

10/16/12 AC 25.1581-1 Chg. 1 Appendix 1 statement applies regardless of any approval notation printed on a generated output.” (b) The title, manufacturer, and version number of any unapproved software used in connection with the AFM software application per paragraph 6a(5) of this appendix. The version number reference may refer to future versions of the software (e.g., “Version XX and later”) if the verification check performed under paragraph 6c(1) of this appendix is designed such that improper operation of later software versions would be detected.

(c) The installation information referenced in paragraph 6c(2) or 6c(3) of this appendix, whichever is appropriate, and instructions for using the installation utility function or test set described in paragraph 6c(1) of this appendix.

(d) Instructions for the use of information provided in the paper portion of the AFM that need to be applied to or used in combination with the computerized AFM input or output (e.g., structural weight limitations, adjustments or correction factors to be applied in accordance with paragraph 5d(4) of this appendix, and airplane performance information not provided in computerized form).

(3) The information listed in paragraphs 4a(2)(a) through 4a(2)(d) above may appear in a user’s guide rather than the Limitations Section of the conventional paper portion of the AFM if a reference to the user’s guide is placed in the Limitations Section. The reference should make it clear what information is being referenced, and should include the title of the user’s guide, the document number or other identification means, and the date of issue. Reference may be made to the use of later appropriate revisions of the user’s guide.

b. Approved and Unapproved Information . Section 25.1581 requires that FAA-approved information be segregated, identified, and clearly distinguished from any unapproved information presented in the AFM. Therefore, the approval status of generated output should be clearly indicated on the screen and printed on each printout page of any calculated results by indication of: (1) Approved program version.

(2) Approved data version, if applicable.

(3) Approval status of results with respect to requirement basis of the computation (e.g., FAA-approved vs. not approved).

(4) Applicable certification basis, if the program is capable of generating results for more than one certification basis (e.g., FAR/Joint Aviation Requirements (JAR)).

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10/16/12 AC 25.1581-1 Chg. 1 Appendix 1 (5) Date of output data generation.

c. Software Usage Aspects . The applicant should substantiate that the computerized AFM is designed to: (1) Provide a generated output containing all the information required to be in the conventional paper AFM by part 25 for the part that is replaced or supplemented by the computerized AFM. This includes all relevant information (e.g., variables used for a specific condition) to determine the operating condition and applicability of the generated output.

(2) Provide equivalent or conservative results to that obtained by direct use of a first principles calculation using certified baseline parameters (e.g., lift, drag, power or thrust).

(3) Preclude calculations that would generate results identified as FAA-approved by: (a) Extrapolating data beyond computational bounds agreed to by the FAA and the applicant; or (b) Using unapproved flight test analysis or AFM expansion methods.

(4) Provide at least the standard of transparency (e.g., understanding of performance relations and limitations) that is available from a conventional paper AFM presentation, including the capability to make multiple point calculations and plot the results.

(5) Minimize mistakes or misunderstanding by a trained user during data input and interpretation of output.

5. Computerized airplane flight manual contents.

a. General .

(Reserved) b. Limitations Section .

(Reserved) c. Operating Procedures Section .

(Reserved) A1-4

10/16/12 AC 25.1581-1 Chg. 1 Appendix 1 d. Performance Section .

(1) The computerized AFM may be used to generate all of the FAA-approved performance information required to be in the AFM.

(2) The operating rules (§§ 91.9(b)(1), 121.141(b), and 125.75(b)) require operators to carry, in each transport category airplane, either the AFM or an operator-prepared manual that contains all of the information required to be in the AFM. The computerized AFM is not intended for use on board the airplane. Thus, any portions of the AFM that are provided only in computerized (i.e., electronic) form may not be used to satisfy these operating requirements.

This does not preclude printing out information calculated by the FAA-approved computerized AFM and subsequently using the paper printout on board the airplane.

(3) Configuration Deviation List (CDL) and Master Minimum Equipment List (MMEL) effects on performance may be included if they are FAA-approved and applications are clearly identified on the generated output.

(4) Although the output from the computerized AFM should be usable without adjustment, applying corrective factors that are provided in the paper AFM may be acceptable in the following cases: (a) CDL or MMEL information.

(b) Urgent temporary FAA-approved revisions made mandatory for safety reasons.

(c) Any case in which the appropriate data are unavailable from the computerized AFM and it is clear to the user that corrective factors are to be applied.

(d) Supplements produced by STC applicants.

(5) Supplementary performance information may be included in accordance with paragraph 4b of this appendix (e.g., for operation on runways contaminated with standing water, slush, snow, or ice).

(6) The applicant may request FAA approval of supplementary computerized AFM applications (e.g., optimized runway performance). This supplementary software application will not be required by the FAA for type certification.

6. Software integrity, development, and documentation requirements. The computerized AFM consists of the AFM software application used in conjunction with the hardware and software environment in which it is installed. This section provides guidelines that address the integrity, development process, and documentation requirements of the software.

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10/16/12 AC 25.1581-1 Chg. 1 Appendix 1 a. Software Integrity .

(1) The computation of hazardously misleading primary information, such as takeoff speeds, landing approach speeds, engine power or thrust , engine limit data, or other related airplane performance data, should be improbable (as defined in § 25.1309). The AFM software application should, as far as practicable, be protected from inadvertent, deliberate, or unauthorized alterations. For example, self-check features could be used to provide software verification and protection against deliberate or inadvertent alteration.

(2) The level of integrity established for the computerized AFM is the basis for the software development process and should be addressed in the plan for software aspects of certification (see paragraph 6b of this appendix).

(3) Each part of the FAA-approved AFM software application (e.g., program, data) should bear a unique notation, a unique date, or a revision number.

(4) A means to check the programs and data to avoid undetected failures should be provided (e.g., a checksum routine, tabular data to verify a check case, or provisions for a line- by-line file comparison).

(5) Commercially available software, such as operating systems (e.g., MS-DOS), word processors, and spreadsheets, will not be approved by the FAA. However, this software can be used to run the computerized AFM software application or process (i.e., edit, format, manipulate, etc.) AFM data to produce approved AFM information if: (a) The applicant demonstrates that the unapproved software does not interfere with the correct functioning of the FAA-approved computerized AFM software application; (b) The applicant demonstrates that the unapproved software produces reliable results when used with the specified hardware environment and the computerized AFM software application.

b. Software Development . The integrity of the software components of the computerized AFM is achieved through the software development processes used.

(1) The applicant should propose the software development process in the plan for software aspects of certification. Per AC 20-115B, RTCA/DO-178B provides an acceptable A1-6

10/16/12 AC 25.1581-1 Chg. 1 Appendix 1 means of compliance for the software components of the AFM. The applicant should document the methods, parameters, and allowable range of conditions contained in the computerized AFM.

The results obtained from the computerized AFM should be shown to meet all applicable part 25 requirements. This compliance may be shown using substantiation documentation, demonstrations, or other means mutually agreed to by the FAA and the applicant.

(2) The applicant should submit a description of the computerized AFM and the plan for software aspects of certification to the FAA for review early in the certification process. This plan proposes the schedule and means by which compliance with the requirements will be achieved and the means by which certification data and supporting records will be made available to the FAA for review.

c. Hardware and Software Environment . The computerized AFM software application may be FAA-approved independent of the hardware and software environment in which it is installed. A common example of this would be the development of a computerized AFM software application to be run in a commercial-off-the-shelf (COTS) hardware and software environment. The applicant should provide for item (1) as follows, plus either item (2) or (3), as appropriate: (1) A mechanism, such as an installation utility function or test set, that verifies the proper functioning of the computerized AFM software application in the target software and hardware environment. The verification check should include, but not be limited to, proper functioning with hardware specified in the AFM, including input and output devices, and with resident software, including terminate-and-stay-resident or other control programs such as Microsoft Windows, and with any operating system calls made by the AFM software.

(2) If the computerized AFM is intended for a COTS hardware and software environment, installation information that describes the minimum requirements, including limitations and constraints, for the software and hardware environment.

(3) If the computerized AFM is intended for a specific hardware/software system, installation information that describes the specific hardware and software environment in which the computerized AFM software application need to be installed. Additionally, the applicant should provide a configuration management scheme that ensures the hardware and software environment that will be used in service is identical to the environment specified in the FAA- approved installation data.

d. Revisions to a Computerized AFM Software Application.

(1) Revisions to an FAA-approved computerized AFM should be submitted for evaluation and FAA-approval in accordance with software development methodology A1-7

10/16/12 AC 25.1581-1 Chg. 1 Appendix 1 established in paragraph 6b of this appendix. A log of FAA-approved AFM software application parts should be furnished by the applicant. For historical purposes, the applicant should maintain records from which the information from any approved revision level of the computerized AFM can be reproduced, unless none of the affected airplanes remain in operational service.

(2) The applicant should submit a description of the proposed changes and an updated plan for software aspects of certification. In addition, the applicant should: (a) Re-assess the software integrity level (paragraph 6a of this appendix) of the revised computerized AFM; (b) Demonstrate that the revisions do not affect any of the unrevised portions of the computerized AFM; and (c) Demonstrate that the revisions are compatible with the hardware and software environment intended for the computerized AFM software application.

(3) The computerized AFM software application is not intended to be user-modifiable software (under the definition of user-modifiable software provided in DO-178B). Revisions to a computerized AFM can be made only by the TC or STC holder of that computerized AFM.

STC applicants may supplement but not revise a TC holder’s computerized AFM.

(4) When revisions are incorporated, a means (e.g., document) of indicating those parts of the software that have been changed should be provided.

(5) Each revised software element should be identified in the same manner as the original, with the exception of the new date or revision notation (see paragraph 6a(3) of this appendix).

e. Submittal and FAA-Approval of Software .

(1) The applicant will be considered the responsible party for all matters pertaining to the computerized AFM software application, including submittal to the FAA and obtaining FAA-approval.

(2) The applicant and the FAA should discuss and agree on the data structures and calculation models.

(3) The applicant should provide any part of the hardware environment necessary for operating the computerized AFM that is not readily available to the FAA.

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7/14/97 AC 25.1581-1 Appendix 1 f. Documentation Requirements . Documentation containing the following information should be provided by the applicant to the FAA: (1) Approval plan that describes the software aspects of certification, including time schedules, an outline of the desired applications, and design objectives for software and data integrity.

(2) Software development plan, including the methods used to accomplish the design objectives.

(3) Software descriptions, including justifications that program structures and calculation models are appropriate to their intended function.

(4) Data verification document, including a description of the scope and depth of the review, analysis, and tests used to determine that the developed software and generated output accurately reflect the airplane performance characteristics. This description should include the purpose of each test case and the set of inputs, expected results, test environment, and calculated results.

(5) Operating instructions, including all information for proper use of the computerized AFM, installation instructions, and identification of the suitable hardware and software environment.

(6) Software configuration reference, including a log of the approved software elements and a statement that design objectives of the approval plan and compliance with the guidelines of this appendix have been demonstrated.

7. Provisions for FAA post certification access to computerized AFM. In the plan for software aspects of certification, the applicant should propose which components of the computerized AFM will be submitted to the FAA. In cases where the AFM software application can be installed on FAA equipment, the applicant need only provide the computerized AFM software application, which includes the installation data and operating guide. However, if the computerized AFM software application requires a hardware and software environment that is not available to the FAA, the applicant should also provide the appropriate FAA certification offices with the necessary components to access the AFM software application.

8. Provisions for public access to computerized AFM. The AFM is necessary for the safe operation of an airplane and is considered public information. Public disclosure of AFM information is necessary. Recognizing that the computerized AFM software application may also contain data, analysis methods, and operating systems that are proprietary to the applicant, the FAA will not provide direct public access to the software, unless the applicant states that A1-9

7/14/97 AC 25.1581-1 Appendix 1 public access is authorized. To satisfy the need for public disclosure when public access to the software application is not authorized, the FAA will use the computerized AFM to generate a limited number of discrete computer results or other AFM information requested by the public.

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