TM 1-1520-236-10 - Operators Manual for Army Model AH-1F Attack Helicopter

Dangerous winds are created by the main rotor blades when blades are at operating rpm. NOISE LEVEL Sound pressure levels in the helicopter during some operating conditions exceed the Surgeon General’s hearing conservation criteria as defined in TB MED 251. Hearing protection devices, such as the aviator helmet, ear plugs, or ear muffs shall be worn by all personnel in and around the helicopter during operation. WING STORES JETTISON All jettison safety pins shall be installed when the helicopter is on the ground. Serious injury can result from accidental ground jettison. Safety pins shall be removed prior to flight. Failure to do so will prevent emergency jettison of wing stores. TURRET When battery power is applied, the turret gun may stow at a very rapid rate and cause personnel injury. TM 1-1520-236-10 d HIGH VOLTAGE Serious burns and/or electrical shock can result from contact with exposed electrical wire or connections. RADIOACTIVE MATERIALS Self-luminous dials contain radioactive materials. If such an instrument is broken or becomes unsealed, avoid personnel contact. TOW MISSILE FIRING During night TOW missile firing, AN/AVS–6 NVGs should be utilized due to the increased mar- gin of safety provided when compared to the AN/PVS–5 NVGs. Electromagnetic Interference (EMI) can interfere with missile guidance. Avoidance require- ments are contained in HIRTA messages. Pilots shall be briefed and familiar with these require- ments. Firing of TOW missiles in a high EMI area should be avoided if possible. 10 Some of the FLIR optics inside the C-NITE telescopic sight unit (TSU) have a coating that is radioactive. Accidental inhaling or swallowing of this material is hazardous to health. If the C-NITE TSU has been ruptured (by crash damage, etc.), dispose of broken optics in accor- dance with AR 775-15 and TB 750-237. WARNING RADIATION HAZARD Thorium Fluoride NOTE: The portion of the text affected by the changes is indicated by a vertical line in the outer margins of the page. Changes to illustrations are indicated by miniature pointing hands. Changes to wiring diagrams are indicated by shaded areas. TM 1-1520-236-10 A/(B blank) Date of issue for original and change pages are: 26 January 2001 Original 0 26 January 2001 . . . . . . . . . . . . . . . .
TOTAL NUMBER OF PAGES IN THIS PUBLICATION IS 372 , CONSISTING OF THE FOLLOWING: Page *Change No. No. Cover . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0 a thru e . . . . . . . . . . . . . . . . . . . . . . . . . . . 0 f blank . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0 A . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0 B blank . . . . . . . . . . . . . . . . . . . . . . . . . . . 0 i thru iii . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0 iv blank . . . . . . . . . . . . . . . . . . . . . . . . . . . 0 1-1 and 1-2 . . . . . . . . . . . . . . . . . . . . . . . . 0 2-1 thru 2-47 . . . . . . . . . . . . . . . . . . . . . . . 0 2-48 blank . . . . . . . . . . . . . . . . . . . . . . . . 0 3-1 thru 3-45 . . . . . . . . . . . . . . . . . . . . . . . 0 3-46 blank . . . . . . . . . . . . . . . . . . . . . . . . . 0 4-1 thru 4-54 . . . . . . . . . . . . . . . . . . . . . . . 0 5-1 thru 5-7 . . . . . . . . . . . . . . . . . . . . . . . . 0 5-8 blank . . . . . . . . . . . . . . . . . . . . . . . . . . 0 6-1 thru 6-33 . . . . . . . . . . . . . . . . . . . . . . . 0 6-34 blank . . . . . . . . . . . . . . . . . . . . . . . . . 0 7-1 thru 7-47 . . . . . . . . . . . . . . . . . . . . . . . 0 7-48 blank . . . . . . . . . . . . . . . . . . . . . . . . . 0 7.1-1 thru 7.1-47 . . . . . . . . . . . . . . . . . . . 0 7.1-48 blank . . . . . . . . . . . . . . . . . . . . . . . 0 8-1 thru 8-21 . . . . . . . . . . . . . . . . . . . . . . . 0 8-22 blank . . . . . . . . . . . . . . . . . . . . . . . . . 0 9-1 thru 9-13 . . . . . . . . . . . . . . . . . . . . . . . 0 9-14 blank . . . . . . . . . . . . . . . . . . . . . . . . . 0 A-1 thru A-3 . . . . . . . . . . . . . . . . . . . . . . . 0 A-4 blank . . . . . . . . . . . . . . . . . . . . . . . . . . 0 B-1 thru B-4 . . . . . . . . . . . . . . . . . . . . . . . 0 Index-1 thru Index-9 . . . . . . . . . . . . . . . . 0 Index-10 blank . . . . . . . . . . . . . . . . . . . . . 0 *Zero in this column indicates an original page. LIST OF EFFECTIVE PAGES INSERT LATEST CHANGED PAGES: DESTROY SUPERCEDED PAGES. *TM 1-1520-236-10 *This manual supersedes TM 55-1520-236-10, dated 11 January 1980, including all changes: i HEADQUARTERS TECHNICAL MANUAL DEPARTMENT OF THE ARMY No. 1-1520-236-10 WASHINGTON, D.C., 26 January 2001 TECHNICAL MANUAL OPERATORS MANUAL FOR ARMY MODEL AH-1F ATTACK HELICOPTER REPORTING ERRORS AND RECOMMENDING IMPROVEMENTS You can help improve this manual. If you find any mistakes, or if you know of a way to improve these procedures, please let us know. Mail your letter, DA Form 2028 (Recommended Changes to Publications and Blank Forms) or DA Form 2028-2 located in the back of this manual directly to: Commander, U.S. Army Aviation and Missile Command, ATTN: AMSAM-MMC-LS-LP, Redstone Arsenal, AL 35898-5000. A reply will be furnished directly to you. You may also submit your recommended changes by E-mail directly to ls-lp@redstone.army.mil or by fax (256) 842-6546/DSN 788-6546. Instructions for sending an electronic 2028 may be found at the end of this manual immediately preceding the hard copy 2028s. DISTRIBUTION STATEMENT A: Approved for public release; distribution is unlimited. TABLE OF CONTENTS Page CHAPTER 1 INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1 CHAPTER 2 HELICOPTER AND SYSTEMS DESCRIPTION AND OPERATION Section I Helicopter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1 II Emergency Equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-10 III Engine and Related Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-12 IV Helicopter Fuel System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-19 V Flight Controls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-20 VI Hydraulic Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-22 VII Power Train System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-23 VIII Main and Tail Rotors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-24 IX Utility System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-24 X Heating, Ventilation, Cooling and Environmental Control Unit . . . . . . . . . . . . . . 2-26 XI Electrical Power Supply and Distribution System . . . . . . . . . . . . . . . . . . . . . . . . . 2-26 XII Lighting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-30 TM 1-1520-236-10 ii TABLE OF CONTENTS (Continued) XIII Flight Instruments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-35 XIV Servicing, Parking, and Mooring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-39 CHAPTER 3 AVIONICS Section I General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1 II Communications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1 III Navigation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-21 IV Transponder and Radar . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-34 CHAPTER 4 MISSION EQUIPMENT Section I Mission Avionics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-1 II Armament . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-2 III Active and Passive Defense Equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-51 CHAPTER 5 OPERATING LIMITS AND RESTRICTIONS Section I General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-1 II System Limits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-1 III Power Limits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-4 IV Loading Limits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-5 V Airspeed Limits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-5 VI Maneuvering Limits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-7 VII Environmental Restrictions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-7 VIII Height Velocity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-7 CHAPTER 6 WEIGHT/BALANCE AND LOADING Section I General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-1 II Weight and Balance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-3 III Personnel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-3 IV Mission Equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-5 V Cargo Loading (Not Applicable) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-29 VI Fuel/Oil . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-29 VII Allowable Loading . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-31 CHAPTER 7 PERFORMANCE DATA B540 Section I Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-1 II Performance Planning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-5 III Torque Available . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-7 IV Hover . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-12 V Cruise . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-18 *TM 1-1520-236-10 iii3/(4 blank) TABLE OF CONTENTS (Continued) VI Drag . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-42 VII Climb - Descent . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-44 VIII Idle Fuel Flow . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-46 CHAPTER 7.1 PERFORMANCE DATA K747 Section I Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.1-1 II Performance Planning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.1-5 III Torque Available . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.1-7 IV Hover . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.1-12 V Cruise . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.1-18 VI Drag . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.1-42 VII Climb - Descent . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.1-44 VIII Idle Fuel Flow . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.1-46 CHAPTER 8 NORMAL PROCEDURES Section I Crew Duties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-1 II Operating Procedures and Maneuvers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-4 III Instrument Flight . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-13 IV Flight Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-13 V Adverse Environmental Conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-19 CHAPTER 9 EMERGENCY PROCEDURES Section I Helicopter Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-1 II Mission Equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-11 APPENDIX A REFERENCE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-1 APPENDIX B ABBREVIATIONS AND TERMS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-1 INDEX . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Index 1 iii/(iv blank) TM 1-1520-236-10 1-3 CHAPTER 1 INTRODUCTION 2-1. GENERAL. These instructions are for use by the operator of the AH-1F helicopter. 2-2. WARNING, CAUTIONS, AND NOTES DEFINITION. Warnings, cautions, and notes are used to emphasize important and critical instructions and are used for the following conditions: WARNING An operating procedure, practice, etc., which, if not correctly followed, could result in personal injury or loss of life. ÈÈÈÈÈ ÈÈÈÈÈCAUTION An operating procedure, practice, etc., which, if not strictly observed could re- sult in damage to or destruction of equipment. NOTE An operating procedure, condition, etc., which it is essential to highlight. 2-3. DESCRIPTION. This manual contains the best operating instructions and procedures for the AH-1F helicopter under most circum- stances. The observance of limitations, performance and weight balance data provided is mandatory. The ob- servance of procedure is mandatory except when modifi- cation is required because of multiple emergencies, ad- verse weather, terrain, etc. Your flying experience is recognized, and therefore, basic flight principles are not included. THIS MANUAL SHALL BE CARRIED IN THE HELICOPTER AT ALL TIMES. 2-4. APPENDIX A. REFERENCES. Appendix A is a listing of official publications cited within the manual applicable to and available for flight crews. 2-5. APPENDIX B. ABBREVIATIONS AND TERMS. Appendix B provides a glossary of abbreviations and terms used throughout the text. 2-6. INDEX. The index lists, in alphabetical order, every titled para- graph, figure and table contained in this manual. Chap- ters 7 and 7.1 performance data have an additional index within each chapter. 2-7. ARMY AVIATION SAFETY PROGRAM Reports necessary to comply with the safety program are prescribed in AR 385-40. 2-8. DESTRUCTION OF ARMY MATERIAL TO PREVENT ENEMY USE. For information concerning destruction of Army material to prevent enemy use, refer to TM 750-244-1-5. 2-9. FORMS AND RECORDS. Army aviators flight record and helicopter maintenance records which are to be used by crewmembers are pre- scribed in DA PAM 738-751 and TM 55-1500-342-23. 2-10. EXPLANATION OF CHANGE SYM- BOLS. Changes, except as noted below, to the text and tables, including new material on added pages, are indicated by a vertical line in the outer margin extending close to the entire area of the material affected; exception: pages with emergency markings, which consist of black diago- nal lines around three edges, may have the vertical line or change symbol placed along the inner margins. Sym- bols show current changes only. A miniature pointing hand symbol is used to denote a change to an illustration. However, a vertical line in the outer margin, rather than miniature pointing hands, is utilized when there have been extensive changes to an illustration. Change sym- bols are utilized to indicate changes in the following: a. Introductory material. b. Indexes and tabular data where the change cannot be identified. c. Blank space resulting from the deletion of text, an illustration, or a table. d. Correction of minor inaccuracies, such as spelling, punctuation, relocation of material, etc., unless such TM 1-1520-236-10 1-4 correction changes the meaning of instructive informa- tion and procedures. 2-11. HELICOPTER DESIGNATION SYS- TEM. The designation system prescribed by AR 70-50 is used in helicopter designations as follows: Series Symbol Design Number Helicopter (Basic Mission) Attack (Modified Mission) 1 H - A F 2-12. SERIES AND EFFECTIVITY CODES. Designator symbols are used in conjunction with text contents, text headings and illustration titles to show lim- ited effectivity of the material. One or more designator symbols may follow a text heading or illustration title to indicate proper effectivity, unless the material applies to all series and configurations within the manual. Designa- tor symbol CN C-Nite precedes procedural steps in Chapters 4, 8, and 9 and other areas to indicate effectiv- ity. If the material applies to all series and configurations, no designator symbols will be used. Where practical, de- scriptive information is condensed and combined for all models to avoid duplication. Designator symbols for different types of main rotor blades are: B540 for the Bell main rotor blade and K747 for the Kaman main rotor blade. 2-13. USE OF SHALL, WILL, SHOULD, AND MAY. Use “shall” whenever it is necessary to express a provi- sion that is binding. Use “should” and “may” whenever it is necessary to express non-mandatory provisions. “Will” may be used to express a declaration of purpose. TM 1-1520-236-10 2-1 CHAPTER 2 HELICOPTER AND SYSTEMS DESCRIPTION AND OPERATION SECTION I. HELICOPTER 2-1. GENERAL DESCRIPTION. The AH-1F helicopter is a tandem seat, two place (pilot and gunner), single engine aerial weapon platform. a. Fuselage. The fuselage (forward section) em- ploys aluminum alloy skins and aluminum, titanium and fiberglass honeycomb panel construction. Honeycomb deck panels and bulkheads attached to two main beams produce a box-beam structure. These beams make up the primary structure and provide support for the cockpit, landing gear, wings, engine, pylon assembly, fuel cells, and tailboom. The nose section incorporates the turret system and telescopic sight unit. b. Wing. The fixed cantilever wings have a span of 129 inches (including tip) and a mean chord of 30 inches. The wings provide additional lift and support to the wing stores pylon. Each wing has two pylons. The inboard py- lons are fixed and the outboard pylons are articulated by hydraulic actuators. An ejector rack is attached to each pylon. Both inboard and outboard pylons will each sup- port 670 pounds of weight. c. Tailboom. The tailboom (aft section) is a tapered semimonocoque structure attached to the forward sec- tion by four bolts. The tailboom supports the cambered fin, tail skid, elevators, tail rotor and tail rotor drive sys- tem. d. Main Rotor Blades. (1) B540 The main rotor blades are metal, bonded assemblies. Each blade is attached in the hub with a retaining bolt assembly and is held in alignment by adjustable drag braces. (2) K747 The main rotor blades are glass fiber epoxy resin bonded assemblies with a rubber erosion guard. The skin is basket weave which will not be as smooth as a metal blade. Each blade is attached in the hub with a retaining bolt assembly and is held in align- ment by adjustable drag braces. e. Weight Classification. The weight classification of this helicopter is Class 2. (Refer to Chapter 6.) f. Controls and Indicators. Refer to applicable system for descriptive information. 2-2. GENERAL ARRANGEMENT. Figure 2-1 shows the general arrangement of the items which are referred to in the exterior check paragraph of Chapter 8, Section 11. 2-3. PRINCIPAL DIMENSIONS. Figure 2-2 shows the principal dimensions of the heli- copter to the nearest inch. 2-4. TURNING RADIUS. Figure 2-3 shows the minimum turning radius of the heli- copter. 2-5. MAIN DIFFERENCES. The main differences between the AH-1F and CN is the TSU FLIR Subsystem M65. 2-6. CREW COMPARTMENT DIAGRAMS. The upper forward portion between the fuselage is the crew compartment. Tandem seating is provided with the pilot elevated in the rear seat. a. Pilot Station. Figure 2-4 shows the location. b. Gunner Station. Figure 2-5 shows the locations of equipment in the gunner station. TM 1-1520-236-10 2-2 BOTTOM VIEW Turret Searchlight Lower cutter assembly Forward fuel cell drain door Aft fuel cell drain door Vent Chin cutter assembly Tail rotor Synchronized elevator IR jammer Anticollision light Pitot tube Upper cutter assembly Canopy Pitot door Battery compartment Main rotor blades and hub ADS TSU Skid Transmission compartment Engine compartment GPU receptacle ALT Receiver Skid landing light NGV position lights 1. 2. 2A. 3. 4. 5. 5A. 6. 7. 8. 9. 10. 10A. 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. 20A. 20B. 20C. MS018087 Figure 2-1. General Arrangement (Typical) (Sheet 1 of 2) TM 1-1520-236-10 2-3 Deflector Channel Upper cutter assembly Engine inlet shields Left wing position light (red) Pylons Gunner door latch Turret Searchlight 42 degree gearbox oil sight glass Engine air inlet-right: (left opposite) Deleted Fuel filler cap 21. 21A. 22. 22A 23. 24. 25. 26. 27. 28. 29. 30. 31. 32. 33. 34. 35. 36. 37. 38. 39. 40. 41. 42. 43. Ground receptacle Right static port (left opposite) Deleted Pilot door latch Right wing position light (green) Right tail position light (white) (left opposite) 90 Degree gearbox oil sight glass Countermeasures set, transmit ant. Countermeasures set, receive ant. Laser detecting set, sensor unit GPS receive ant. AIM-1/EXL laser MS018088 Figure 2-1. General Arrangement (Typical) (Sheet 2 of 2) TM 1-1520-236-10 2-4 MS018089 Figure 2-2. Principal Dimensions - Airframe TM 1-1520-236-10 2-5 MS018090 Figure 2-3. Turning Radius (Typical) 2-7. LANDING GEAR. a. Main Landing Gear. The main landing gear con- sists of two aluminum lateral mounted arched cross- tubes and two aluminum longitudinal skid tubes attached to the cross tubes. Each crosstube is enclosed in a fiber- glass fairing for aerodynamic purposes. Each skid tube has a steel skid shoe on the bottom to minimize skid wear. b. Tail Skid. The steel tubular type tail skid is installed on the aft end of the tailboom to protect the tail rotor blades during tail-low landing. 2-8. INSTRUMENTS AND CONTROLS. a. Pilot Instrument Panel. Figure 2-6 shows the locations of instruments, switches, panels, and decals in the pilot instrument panel. b. Gunner Instrument Panel. Figure 2-7 shows the locations of instruments, switches, panels, and de- cals in the gunner instrument panel. c. Other Instruments and Controls. These items are shown in the chapter/section which describes their related systems. 2-9. CANOPY. The canopy is the transparent panels on the upper por- tion of the fuselage which encloses the crew compart- ment. The canopy consists of a three piece windshield extending from the nose of the helicopter (over the gun- ner and pilot heads) to the pylon, the gunner door and pi- lot window on the left side, and the gunner window and pilot door on the right side. The canopy removal system is used to remove the pilot and gunner windows and doors during emergencies. The system is covered in Chapter 2, Section II. 2-10. PERSONNEL DOORS. Two access doors are hinged on top and swing outward and up to provide access. The doors have gas operated struts that will hold the doors in the full open position with a force of approximately 70 pounds. TM 1-1520-236-10 2-6 MS018091 Figure 2-4. Pilot Station Diagram (Typical) TM 1-1520-236-10 2-7 MS018092 Figure 2-5. Gunner Station Diagram (Typical) TM 1-1520-236-10 2-8 MS018093 Figure 2-6. Pilot Instrument and Control Panel TM 1-1520-236-10 2-9 MS018094 Figure 2-7. Gunner Instrument and Control Panel TM 1-1520-236-10 2-10 2-11. SEATS. a. Construction. The seats, side-shoulder panels, and head protective panels are of armor material which provides protection. Both seats are equipped with con- toured seat cushions and back supports made of foam and open mesh for vibration attenuation and crew com- fort. b. Pilot Seat. The pilot seat is vertically adjustable nonreclining type. The vertical adjustment is reclined at 15 degrees. The vertical height adjustable handle (Figure 2-8) is under the left side of the seat. The seat is equipped with a lap safety belt and inertia reel shoulder harness. c. Gunner Seat. The gunner seat is a fixed seat (non-adjustable and nonreclining). The seat is equipped with a lap safety belt and inertia reel shoulder harness. The seat also has arm rests. d. Inertia Reel Shoulder Harness. An inertia reel shoulder harness is incorporated in the pilot and gunner seats with a manual lock-unlock control handle (Figure 2-8). The handles are located to left front of each seat. With the control in the unlocked position, the reel cable will extend allowing the occupant to lean forward; however, the reel will automatically lock when helicopter encounters an impact force of two to three “g” decelera- tion. Locking of the reel can be accomplished from any position and the reel will automatically take up the slack in the harness. To release the lock, it is necessary to lean back slightly to release tension on the lock and then un- lock position. It is possible to have pressure against the seat back whereby no additional movement can be ac- complished and the lock cannot be released. If this con- dition occurs, it will be necessary to loosen shoulder har- ness. Manual locking of the reel should be accomplished for emergency landings. SECTION II. EMERGENCY EQUIPMENT 2-12. PORTABLE FIRE EXTINGUISHER. A portable hand-operated fire extinguisher is located for- ward of the gunner seat (Figure 9-1). 2-13. FIRST AID KIT. An aeronautical type first aid kit is located behind the pilot seat (Figure 9-1). 2-14. SURVIVAL KIT. Aircraft Modular Survival System (AMSS) AH-1 tow tube survival kit can be installed on the aircraft. Refer to TM 1-1680-354-10 for fabrication instructions and limita- tions. NOTE The preferred installation position for the AMSS tow survival kit is the upper right and/or left side outboard position of the tow launcher. However, if these positions are occupied by training de- vices (i.e., air to ground engagement simulator/air defense (AGES/AD) then the AMSS tow survival kit can be installed in any of the remaining posi- tions of the tow launchers. 2-15. CANOPY REMOVAL SYSTEM. WARNING Debris may be expelled 50 feet outward when system is actuated. Cutting assemblies are mounted in the pilot and gunner doors and windows frames. The linear explosive is con- tained with the cutting assemblies. The cutting assem- blies are controlled by the pilot or gunner arming/firing mechanisms. Rotating the arming/firing mechanism handle 90 degrees counterclockwise (torque required 6 to 12 inch-pounds) will arm the cutting assemblies. Pull- ing the handle (20 to 35 pounds tension) will fire the per- cussion primer causing the cutting assemblies to be det- onated. The explosive force will be outward and remove two windows and two doors from the helicopter simulta- neously. If handle has been rotated but not pulled, the handle can be rotated clockwise and the safety pin installed DA Form 2408-13-1 entry required. Refer to Chapter 9 for emergency procedure and Figure 9-1 for equipment location. 2-16. WING STORES JETTISON. Wing stores jettison capability is provided by explosive cartridges installed at each wing stores pylon. TM 1-1520-236-10 2-11 MS018095 Figure 2-8. Pilot Seat Installation (Typical) TM 1-1520-236-10 2-12 SECTION III. ENGINE AND RELATED SYSTEMS 2-17. ENGINE. The helicopter is equipped with a T53-L-703 engine (Figure 2-9). The engine, in this installation, is derated by limitation of the helicopter transmission to 100% (1290 SHP) torque for 30 minutes and 88% (1134 SHP) torque for continuous operation at 100% rpm. The en- gine compartment is cooled by ram and ambient air. 2-18. ENGINE PROTECTION. Armor material is located on the left and right engine compartment doors to provide armor protection for the engine compressor, fuel control, oil filter, and fuel filter. 2-19. AIR INDUCTION SYSTEM. Ambient air enters the transmission compartment door air inlet, then is routed through the improved particle sep- arator. The particle separator prevents debris and dirt particles from entering the engine air inlet and causing in- gestion damage to the engine. Bleed air from the engine is used to purge the separator and eject the particle over- board. 2-20. ENGINE INLET ANTI-ICING/DEICING SYSTEM. WARNING The system will not deice or prevent ic- ing of the particle separator. A power loss will occur if the formation of ice in the particle separator obstructs the flow of ambient air to the engine. a. Description. The system prevents ice from forming in the engine air inlet. The system consists of a hot air solenoid valve on the engine, controlled by the pi- lot or gunner ENG DEICE switch (Figure 2-10 and Figure 2-12) powered by the dc essential bus, and pro- tected by the ENG DEICE circuit breaker. b. Operation. If ice accumulation is suspected, the pilot or gunner ENG DEICE switch is placed in the DEICE position. This action causes the hot air solenoid valve to route engine bleed air to the engine air inlet. A rise in the turbine gas temperature (TGT) will occur when the pilot or gunner ENG DEICE switch is in the DEICE position. Deice operation will become continuous if the hot air so- lenoid valve (ENG DEICE) circuit fails or if ENG DEICE circuit breaker is out (extended). TM 1-1520-236-10 2-13 Figure 2-9. Power Plant Installation - (Sheet 1 or 4) TM 1-1520-236-10 2-14 View B* *After incorporation of MWO 55-1520-236-50-12. Left Side MS018097 Figure 2-9. Power Plant Installation - (Sheet 2 of 4) TM 1-1520-236-10 2-15 Figure 2-9. Power Plant Installation - (Sheet 3 of 4) TM 1-1520-236-10 2-16 View A* *After incorporation of MWO 55-1520-236-50-12. Right Side MS018099 Figure 2-9. Power Plant Installation - (Sheet 4 of 4) TM 1-1520-236-10 2-17 MS018100 Figure 2-10. Pilot Engine Control Panel 2-21. ENGINE FUEL CONTROL SYSTEM a. Engine Mounted Component. The fuel con- trol assembly is mounted on the left side of the engine. This unit is controlled by the pilot or gunner throttle and GOV switch. The assembly consists of a metering sec- tion, a computer section, and an overspeed governor. The metering section pumps fuel to the engine. The computer section determines the rate of fuel delivery. The overspeed governor maintains a constant N2 rpm. b. Crew Controls. (1) Throttles. Setting the pilot or gunner throttle to the full open position allows the engine to oper- ate up to full power available. Rotating the throttle back toward idle position decreases the allowable N2 and power which, if below that demanded by collective pitch input, results in proportional N2 speed decrease. Rotat- ing the throttle past the engine idle stop to the fully closed position shuts off fuel flow. A solenoid operated idle stop is incorporated to prevent inadvertent throttle closure. The idle stop is controlled by the pilot IDLE STOP REL switch (Figure 2-15) or the gunner IDLE STOP RE- LEASE switch (Figure 2-12). The engine idle stop re- lease circuit is powered by the dc essential bus and pro- tected by the IDLE STOP SOL circuit breaker. Friction can be induced into both throttles by rotating the pilot throttle friction (Figure 2-15) counterclockwise. (2) Governor Switches. The pilot or gunner GOV Switches (Figure 2-11 and Figure 2-12) AUTO position, permits the overspeed governor to automatical- ly control fuel metering and engine speeds (N1 and N2). The EMER position permits the pilot and gunner to manually control the engine rpm. The governor circuit is powered by the dc essential bus and protected by the GOV CONTR circuit breaker. 2-22. IGNITION-STARTER SYSTEM. The pilot ignition-starter trigger switch (Figure 2-15) is pressed and held to start the engine. The switch must be released manually when the engine starts or the time limit expires. The pilot FUEL switch (Figure 2-10) must be in the FUEL position and the pilot ignition keylock switch (Figure 2-6) in the ON position to complete the ignition and start fuel circuit. The GEN switch must be in OFF position for normal starting. The circuits are pow- ered by the dc essential bus and protected by the START RLY and IGN SOL circuit breakers. 2-23. RPM INCREASE-DECREASE (INCR- DECR) SWITCHES. The pilot RPM INCR-DECR or gunner INC-DECR switch (Figure 2-11 and Figure 2-12) is a three-position, mo- mentary-type switch located in the pilot collective switch box and gunner miscellaneous control panel. The switch is held forward to increase and aft to decrease the power turbine speed. The circuit is powered by the dc essential bus and protected by the GOV CONTR circuit breaker. 2-24. DROOP COMPENSATOR. A droop compensator maintains engine rpm (N2) as power demand is increased by the pilot. The compensa- tor is a direct mechanical linkage between the collective stick and the speed selector lever on the N2 governor. No crew controls are provided or required. The compen- sator will hold N2 rpm to
0.6% when properly rigged. Droop is defined as the speed change in engine rpm (N2) as power is increased from a no-load condition and is an inherent characteristic of the governor system. Without this characteristic, instability would develop as engine output is increased resulting in N1 speed overshooting or hunting the value necessary to satisfy the new power condition. Design droop of the engine governor system is as much as 4.5 to 6% (flat pitch to full power). If N2 power were allowed to droop, other than momentarily, the reduction in rotor speed could become critical. TM 1-1520-236-10 2-18 M65/C-NITE TSU FLIR INTENSITY LEVEL SETTING CONTROL/INDICATOR FUNCTION ARMT LT RHEOSTAT NVG SW M65/C-NITE FLIR OFF LT NORM DAY (HIGH) ON LT NORM NIGHT (MED) ON NVG NVG (LOW) MS018101 Figure 2-11. Gunner Miscellaneous Control Panel (Typical) 2-25. ENGINE OIL SUPPLY SYSTEM. a. Description. The engine oil system is a dry sump, pressure type, and completely automatic. The oil tank is located in the upper pylon fairing. It will self-seal a 30 caliber projectile hole and is equipped with deaera- tion provisions. Oil is gravity fed from tank to engine driv- en oil pump which provides pressure and scavenging for the system. On helicopters with ODDS, an external oil separator, with integral chip detector, and a 3-micron oil filter are installed downstream of the sump. MS018102 Figure 2-12. Gunner Miscellaneous Control Panel (Typical) b. Cooling. Engine oil cooling is accomplished by an oil cooler and a bleed air driven turbine fan. The en- gine and transmission oil coolers use the same fan. c. Switching Action. The pilot ENG OIL BYP switch (Figure 2-10) AUTO position permits the oil to au- tomatically bypass the oil cooler when the oil tank is approximately 3.8 quarts low. The OFF position deacti- vates the automatic bypass feature causing the oil to pass through the oil cooler regardless of the oil tank level. The switch circuit is powered by the dc essential bus and protected by the FUEL OIL VALVE circuit breaker. 2-26. ENGINE INSTRUMENTS AND INDICA- TORS. a. Torquemeters. The pilot and gunner torqueme- ters (Figure 2-6 and Figure 2-7) play percent of torque TM 1-1520-236-10 2-19 imposed upon the engine output shaft. Each torqueme- ter is powered by a separate transducer. The circuit is powered by the dc essential bus and protected by the TRQ IND circuit breaker. b. Turbine Gas Temperature (TGT) Indica- tors. The pilot and gunner indicators (Figure 2-6 and Figure 2-7) display the temperature in degrees Celsius of the air in the first stage N2 nozzle. The circuits are powered by the dc essential bus and protected by the TGT IND circuit breaker. c. Dual Tachometers. The pilot and gunner tachometers (Figure 2-6 and Figure 2-7) display the rpm of the engine and main rotor speed in percent. The tachometer outer scale is marked ENGINE and the inner scale is marked ROTOR. The ENGINE and ROTOR needles are synchronized during normal helicopter op- eration. The circuit is powered by the dc essential bus and protected by the TACHDUAL circuit breaker. d. Gas Producer N1 Tachometers. The pilot and gunner tachometers (Figure 2-6 and Figure 2-7) display the rpm of the gas producer turbine speed in percent. The circuit is powered by the dc essential bus and pro- tected by the GAS PROD circuit breaker. e. Oil Pressure/Temperature Indicator. The pilot indicator (Figure 2-6) displays the psi pressure of the oil at the pressure side of the oil pump and the temperature as degrees Celsius of the oil at the engine oil inlet. The circuit is powered by the dc essential bus and protected by the TEMP IND ENG XMSN circuit breaker. f. Oil Pressure Caution Light. The pilot ENG OIL PRESS and gunner ENGINE OIL PRESS (Figure 2-23) will illuminate when the engine oil pressure is below safe limits. g. Oil Bypass Caution Light. The pilot ENG OIL BYPASS caution light (Figure 2-23) illuminates when oil tank level is approximately 3.8 quarts low. h. Engine Oil Chip Detector Caution Light. The caution lights, ENG CHIP in pilot caution panel and CHIP DETECTOR in gunner caution panel, illuminate when sufficient metal chips to complete the electrical circuit are collected from the engine oil. i. Fuel Pump Caution Lights. The pilot and gun- ner ENG FUEL PUMP caution lights (Figure 2-23) illumi- nate when either element of the engine driven fuel pump fails. j. Governor Caution Lights. The pilot and gunner GOV EMERG caution lights (Figure 2-23) illuminate when the pilot GOV switch is in EMER (Figure 2-10) or when the gunner GOV switch is in EMERG (Figure 2-12). SECTION IV. HELICOPTER FUEL SYSTEM 2-27. FUEL SUPPLY SYSTEM. The helicopter is equipped with a crashworthy fuel sys- tem. The system is designed with the potential of con- taining fuel during a severe, but survivable, crash impact to reduce the possibility of fire. The system has a 50 cali- ber ballistic protection level. Fuel grades and specifica- tions are included in Section XIV. 2-28. CONTROLS AND INDICATORS. a. Fuel Switch. The pilot FUEL switch (Figure 2-10) FUEL position energizes the forward and aft boost pumps, opens the fuel shutoff valve, and com- pletes the ignition and start fuel circuit. The aft fuel boost pump circuit is powered by the dc nonessential bus. The other circuits are powered by the dc essential bus. The circuits are protected by the START RLY, IGN SOL, FUEL/OIL VALVE, FUEL BOOST FWD, and FUEL BOOST AFT circuit breakers. b. Fuel Quantity Indicator. The pilot indicator (Figure 2-6) displays the pounds of fuel in the fuel cells. The circuit is powered by the ac system and protected by the FUEL QTY circuit breaker. c. Fuel Quantity Indicator Test Switch. The pilot FUEL GAGE TEST switch (Figure 2-13) is used to test the fuel quantity indicator operation. Pressing the switch causes the indicator pointer to move from the actual reading to a lesser reading. Releasing the switch will cause the pointer to return to the actual reading. The cir- cuit is powered by an ac system and protected by the FUEL QTY circuit breaker. TM 1-1520-236-10 2-20 NOTE Low fuel caution systems alert the pilot that the fuel level in the tank has reached a specified level (capacity). Differences in fuel densities due to tem- perature and fuel type will vary the weight of the fuel remaining and the ac- tual time the aircraft engine(s) may op- erate. Differences in fuel consumption rates, aircraft attitude and operational condition of the fuel subsystem will also affect actual time the aircraft en- gine(s) may operate. d. Low Quantity Caution Lights. The pilot and gunner FUEL LOW caution lights (Figure 2-23) illumi- nate when there is approximately 209 pounds of fuel re- maining. The illumination of this light does not mean a fixed time period remains before fuel exhaustion, but is an indication that a low fuel condition exists. e. Low Fuel Pressure Caution Lights. The pilot FWD FUEL BOOST and AFT FUEL BOOST caution lights (Figure 2-23) illuminate when the boost pumps in the forward/aft fuel cell fail. f. Fuel Filter Caution LIghts. The pilot and gunner FUEL FILTER caution lights (Figure 2-23) illuminate when the filter in the fuel supply line becomes partially obstructed. MS018103 Figure 2-13. Pilot Miscellaneous Control Panel SECTION V. FLIGHT CONTROLS 2-29. DESCRIPTION. The flight control system is a positive mechanical type, actuated by cyclic, collective, and tail rotor controls. Complete controls are provided for both pilot and gunner. The gunner controls are slaved to the pilot controls. The system includes a cyclic system, a collective control sys- tem, a tail rotor system, a force trim system, and a stabil- ity and control augmentation system (SCAS). 2-30. CYCLIC CONTROL SYSTEM. The pilot and gunner cyclic sticks (Figure 2-14) have a built-in operating friction. The cyclic control movements are not mixed, but are transmitted directly to the swash- plate. The longitudinal cyclic control linkage is routed from the cyclic stick through the SCAS actuator, the dual boost hydraulic actuator to the right horn of the fixed swashplate ring. The lateral is similarly routed to the left horn. Control “feel” is provided by the force trim units. The fore and aft movement also changes the synchro- nized elevator (Figure 2-1) attitude to assist controllabili- ty and lengthen c.g. range. TM 1-1520-236-10 2-21 Figure 2-14. Pilot and Gunner Cyclic Control Stick 2-31. COLLECTIVE CONTROL SYSTEM. The pilot and gunner collective pitch controls (Figure 2-15) are located on the left side of the pilot and gunner seats and control vertical mode of flight. Moving the stick up or down changes the angle of attack and lift developed by the main rotor resulting in the ascent or de- scent of the helicopter. The collective assembly consists of a collective stick, with adjustable friction system (pilot only), twist grip-type throttle with friction adjuster, and switch box assembly (pilot only). The switch box assem- bly incorporates the ignition starter switch, rpm increase- decrease switch, jettison, searchlight switches, wire cut switch, and idle stop release switch. A collective hold down strap is provided for the pilot collective. 2-32. TAIL ROTOR CONTROL SYSTEM. Pushing a pedal changes the pitch of the tail rotor result- ing in directional control and is used to pivot the helicop- ter on its own vertical axis and trim the helicopter in flight. A pedal adjuster is provided to adjust the pedal distance for individual comfort. Heel rests are provided for the gunner to prevent inadvertent pedal operation. 2-33. FORCE TRIM SYSTEM. The system incorporates a magnetic brake and force gradient in the cyclic and directional control systems to provide artificial feel into the systems. Also, it provides a means to trim the controls. Placing the FORCE TRIM switch (Figure 2-10) in the FORCE TRIM position will in- duce artificial feel into the systems. Depressing the cy- clic stick force trim switch (Figure 2-14) will cause the magnetic brake and force gradient to be repositioned to correspond to the positions of the cyclic stick and pedals thus providing trim. The system is powered by the dc es- sential bus and protected by the FORCE TRIM circuit breaker. 2-34. STABILITY AND CONTROL AUG- MENTATION SYSTEM (SCAS). a. Description. The SCAS is a three-axis, limited authority rate reference augmentation system. The SCAS cancels undesired motion of the helicopter during flight. This is accomplished by inducing an electrical in- put into the flight control system to augment the pilot me- chanical input. Figure 2-15. Pilot Collective Control Stick b. Control Panel. The SCAS control panel (Figure 2-16) contains a POWER switch for applying dc (essential bus) and ac power to the system. The circuits are protected by the SCAS POWER dc and SCAS PWR ac circuit breakers. The panel also contains three chan- nel engage switches which energize electric solenoid TM 1-1520-236-10 2-22 valves controlling hydraulic pressure to the system. The panel has three amber colored NO-GO lights, one asso- ciated with each PITCH, ROLL, and YAW channel en- gage switch. These lights are illuminated during the war- mup to indicate the presence of current in each associated channel actuator. Should an engagement be attempted during this warmup period, the actuator may make an abrupt input to the flight controls at the moment of engagement. When engagement is made, the NO- GO lights are locked out of the circuit and do not operate as malfunction indicators. Disengaging a channel, how- ever, restores the associated light to operation. The NO- GO lights have a built-in press-to-test feature for ensur- ing that the indicator is operational, but this feature works only prior to channel engagement. c. SCAS (SAS) Release Switch. The cyclic grip mounted switch (Figure 2-14) is used to disengage the pitch, roll, and yaw channels simultaneously. The chan- nels are re-engaged by the PITCH, ROLL, and YAW switches on the SCAS control panel. d. RECOIL COMP Switch. The RECOIL COMP switch is a three position switch (LO-MED-HI) located on the right side of the pilot instrument panel. It may be used to vary the magnitude of the signals from the Armament Compensation Unit to the SCAS to compensate for a lower/higher than average M197 firing rate. Figure 2-16. Pilot SCAS Control Panel SECTION VI. HYDRAULIC SYSTEMS 2-35. DESCRIPTION. The hydraulic system is a dual system (No.1 and No. 2 system) used to minimize the force required by the pilot to move the cyclic, collective, and pedal controls. The No. 1 and No. 2 systems are installed to provide maxi- mum separation to reduce the probability of a single pro- jectile from incapacitating both systems. 2-36. HYDRAULIC SYSTEM NO. 1. The No. 1 system provides hydraulic power to the cyclic controls, collective controls, pedal controls, and SCAS yaw controls. The No. 1 system is located on the left side of the helicopter. 2-37. HYDRAULIC SYSTEM NO. 2. The No. 2 system provides hydraulic power to the cyclic controls, collective controls, SCAS pitch and roll con- trols, articulated wing pylons. The No. 2 system is lo- cated on the right side of the helicopter. 2-38. TEST SWITCH. The pilot HYD TEST switch (Figure 2-10) is used to test the No. 1 and No. 2 hydraulic systems. Holding the switch in the SYS 1 position will cause the No. 1 system to be the only system supplying hydraulic pressure. Sim- ilar action occurs when the switch is held in the SYS 2 position. 2-39. RESERVOIR FLUID SIGHT GASSES. The No. 1 and No. 2 reservoirs are provided with a fluid sight glass. Both sight glasses can be seen only from the left hydraulic compartment door. 2-40. FILTER INDICATORS. The No. 1 and No. 2 pressure and return filters are pro- vided with a differential pressure indicator. The red indi- cator pops out when the filter needs changing or during cold weather operation. 2-41. LOW PRESSURE CAUTION LIGHTS. The pilot NO. 1 HYD PRESS and NO. 2 HYD PRESS, and gunner #1 HYD PRESS and #2 HYD PRESS caution lights (Figure 2-23) will illuminate when hydraulic pres- sure is below safe limits. 2-42. ELECTRICAL CIRCUIT. The hydraulic electrical circuit is powered by the dc es- sential bus and protected by the HYD CONTR circuit breaker. 2-43. EMERGENCY HYDRAULIC SYSTEM. The emergency hydraulic system serves two functions. It provides hydraulic power to outboard pylons for bore- sighting, or to the collective pitch control if both hydraulic systems fail. The system is controlled by the EMER HYD PUMP switches (Figure 2-7 and Figure 2-13) powered by the dc essential bus and protected by the EMER HYD PUMP circuit breaker. TM 1-1520-236-10 2-23 2-44. ARMAMENT HYDRAULIC SYSTEM. The TOW missile system is powered by the No. 2 system and is used to position the outboard articulated wing py- lons during TOW missile operations. The system is con- trolled by the TOW missile controls. The system electri- cal circuits are powered by the dc essential bus and the ac system. The circuits are protected by the HYD CONTR, ac TMS PWR, and SECU PWR circuit break- ers. SECTION VII. POWER TRAIN SYSTEM 2-45. TRANSMISSION. The transmission transfers engine power to the main ro- tor through the mast assembly and to the tail rotor through a series of driveshafts and gearboxes. The transmission has a self-contained pressure oil system. The oil is cooled by an oil cooler and bleed air turbine fan. The transmission and engine oil coolers use the same fan. The oil system has an automatic bypass system which causes the oil to bypass the cooler when a leak is sensed in the oil cooler circuit. Two oil level sight glasses, an oil fill cap, and a magnetic chip detector are provided. On helicopters with ODDS, a full-flow debris monitor with integral chip detector replaces an integral oil filter and a 3-micron filter replaces a 25-micron external filter. 2-46. GEAR BOXES. a. Intermediate Gearbox - 42 Degree. The gear- box is located at the base of the vertical fin (Figure 2-1). It provides a 42 degree change of direction of the tail rotor driveshaft. The gearbox has a self-contained wet sump oil system. An oil level sight glass, a filler cap, and a mag- netic chip detector are provided. b. Tail Rotor Gearbox - 90 Degree. The gearbox is located near the top of the vertical fin (Figure 2-1). It pro- vides a 90 degree change of direction of the tail rotor dri- veshaft. The gearbox has a self-contained wet sump oil system. An oil level sight glass, a filler cap, and a mag- netic chip detector are provided. 2-47. DRIVESHAFTS. a. Main Driveshaft. The main driveshaft connects the engine output shaft to the transmission input drive quill. b. Tail Rotor Driveshaft. The tail rotor driveshaft consists of five driveshafts and three hanger bearing as- semblies. The assemblies and the 42 and 90 degree gearboxes connect the transmission tail rotor drive quill to the tail rotor. 2-48. INDICATORS AND CAUTION LIGHTS. a. Transmission Oil Pressure/Temperature Indi- cator (Figure 2-6). The pilot indictor displays the pres- sure in psi and temperature in degrees Celsius of the transmission oil. The electrical circuit is powered by the dc essential bus and protected by the INDTEMP ENG/ XMSN circuit breaker. b. Transmission Oil Low Pressure Caution Lights. The TRANS OIL PRESS caution lights (Figure 2-23) illuminate when the transmission oil pres- sure drops below safe limits. c. Transmission Oil Hot Caution Lights. The TRANS OIL HOT caution lights (figure 2-23) illuminate when the transmission oil temperature exceeds the safe limits. d. Transmission and Gearboxes Chip Detectors. (1) The pilot chip detector caution lights (Figure 2-23) illuminate when sufficient metal chips are detected in the 42 degree gearbox, 90 degree gearbox, or the transmission oil. On aircraft equipped with Oil De- bris Detection System (ODDS), when a chip gap is bridged by conductive particles, a power module pro- vides an electrical pulse which burns away normal wear particles. (2) The pilot caution lights are worded: 42° CHIP, 90° CHIP, and TRANS CHIP for the respective unit. (3) The gunner chip detector caution light (Figure 2-23) will only illuminate CHIP DETECTOR. This caution light does not identify the contaminated component. TM 1-1520-236-10 2-24 SECTION VIII. MAIN AND TAIL ROTORS 2-49. MAIN ROTOR. a. Description. (1) B540 The main rotor blades are metal, bonded assemblies. Each blade is attached in the hub with a retaining bolt assembly and is held in alignment by adjustable drag braces. (2) K747 The main rotor blades are glass fiber epoxy resin bonded assemblies with a rubber erosion guard. The skin is basket weave which will not be as smooth as a metal blade. Each blade is attached in the hub with a retaining bolt assembly and is held in align- ment by adjustable drag braces. (3) The main rotor is driven by the mast which is connected to the transmission. The rotor rpm is gov- erned by the engine rpm during powered flight. The rotor tip path plane is controlled by the cyclic stick. The rotor pitch is controlled by the collective stick. b. Hub Moment Spring. As an aid in controlling ro- tor flapping, a hub moment spring kit has been installed in the rotor system. Two nonlinear elastomeric springs are attached to a support affixed to the mast. The hub moment springs provide an additional margin of safety in the event of an inadvertent excursion of the helicopter beyond the approved flight envelope. c. RPM Indicators. The pilot and gunner indicators are part of the dual tachometers (Figure 2-6 and Figure 2-7). The tachometer inner scale displays per- cent rotor rpm. 2-50. TAIL ROTOR. The tail rotor is driven by the 90 degree gearbox which is connected to the transmission by the tail rotor drive- shaft assemblies and the 42 degree gearbox. The rotor rpm is governed by the transmission rpm. The rotor blade pitch is controlled by the pedals. SECTION IX. UTILITY SYSTEM 2-51. PITOT TUBE/AIR DATA SYSTEM HEATER. a. Pitot Tube Heater. The pitot tube (Figure 2-1) is equipped with an electrical heater. The PITOT/ADS switch (Figure 2-17) in HTR position activates the heater in the tube and prevents ice from accumulating in the pi- tot tube. The OFF position deactivates the heater. The electrical circuit is powered by the dc nonessential bus and protected by the PITOT HTR circuit breaker. b. Air Data System (ADS) Heater. The air data system sensing head contains an electrical heater. The pilot PITOT/ADS switch (Figure 2-17) in the HTR posi- tion activates the ADS heater, in addition to the pitot tube heater, and prevents ice from accumulating in the pitot tube and air data system. The OFF position deactivates the heater. The system is powered by the dc nonessen- tial bus, ac system, and protected by the ADS PWR and ADS ANTI-ICE circuit breaker. 2-52. CANOPY DEFROSTING, DEICING AND RAIN REMOVAL SYSTEMS. These systems are considered to be part of the environ- mental control system. See Section X of this chapter. TM 1-1520-236-10 2-25 MS018107 SWITCH/CONTROL POSITION FUNCTION COOL/WARM COOL to WARM Controls temperature (35°F - 180°F) in the crew compartment when the ECU/RAIN RMV switch is in the ECU position. ECU/RAIN RMV RAIN RMV Removes rain from canopy. Only ambient air ven- tilation enters the crew compartment. May be used to defrost, defog, or deice the for- ward area of the canopy. ECU Heats or cools the crew compartment. OFF Ambient air ventilation enters the crew compart- ment. HEAT OR VENT AIR PULL OUT Directs maximum air to the defrost slots, air vents, and pilot/gunner seat cushions. IN Directs maximum air to the pilot seat cushion. Air Vent Open/Closed Controls the volume/direction of air to the crew compartment. Defrost Slot Lever Aft (Open)/Forward (closed) Controls the volume of air directed to the inner surfaces of the canopy for defogging, defrosting, and deicing. Figure 2-17. ECS Controls (Typical) TM 1-1520-236-10 2-26 SECTION X. HEATING, VENTILATION, COOLING, ENVIRONMENTAL CONTROL UNIT 2-53. ENVIRONMENTAL CONTROL SYS- TEM (ECS). a. ECS Functions. (1) Heats/cools the crew compartment. (2) Removes moisture from the air supplied to the crew compartment. (3) Defrosts, defogs, and deices the canopy. (4) Rain removal. (5) Provides ambient air ventilation to the crew compartment. b. ECS Power Source. The ECS is electrically con- trolled and engine bleed air powered. The circuit is pow- ered by the dc nonessential bus and protected by the ECS CONTR circuit breaker. c. ECS Controls. NOTE Under certain conditions a plume may be observed at the air vents in the crew compartment. The plume may appear to be smoke, but is actually condensa- tion. (1) The pilot ECS controls and their functions are shown on Figure 2-17. (2) Adjustable air vents are provided for the pi- lot and gunner to control the volume and direction of the air entering the crew compartment. (3) Air entering the pilot and gunner seat cush- ions is controlled by a valve at the top of each seat. (4) Rain removal. The rain removal does not remove rain in flight. SECTION XI. ELECTRICAL POWER SUPPLY AND DISTRIBUTION SYSTEM 2-54. DC AND AC POWER DISTRIBUTION. Figure 2-18 depicts the general schematic of the dc and ac power distribution system. The dc power is supplied by the battery, starter-generator, alternator through the transformer rectifier unit (TRU), or an external power source through the external power receptacle. The 115 vac power is supplied by the alternator or inverter. The 26 vac power is supplied by the 28 vac transformer. 2-55. BATTERY. The battery (Figure 2-18) supplies 24 vdc power to the power distribution system when the starter-generator, TRU and the external power receptacle are not in opera- tion. 2-56. STARTER-GENERATOR. The starter-generator is mounted on and driven by the engine. The starter-generator supplies 28 vdc power to the power distribution system and recharges the battery. 2-57. ALTERNATOR. A 10kVA alternator is mounted on and driven by the transmission. The alternator supplies 115 vac 3-phase power to the ac buses and transformer rectifier unit (TRU). 2-58. TRANSFORMER RECTIFIER UNIT (TRU). The transformer rectifier unit converts ac (from alterna- tor) to 28 vdc, thereby powering the TRU bus. TM 1-1520-236-10 2-27 MS018108 Figure 2-18. DC and AC Power Distribution Schematic (Sheet 1 of 2) TM 1-1520-236-10 2-28 MS018109 Figure 2-18. DC and AC Power Distribution Schematic (Sheet 2 of 2)