-
T M 5 5 - 1 5 2 0 - 2 4 4 - B D
TECHNICAL MANUAL
OPERATORS, AVIATION UNIT,AND AVIATION
INTERMEDIATE MAINTENANCE
FOR
HELICOPTER,ATTACK
A H - 1 E1520-01-192-2478
AH-1 F1520-01-168-4260
A H - 1 P1520-01-168-4259
C H A P T E R 1 . G E N E R A L I N F O R M A T I O N
CHAPTER 2. ASSESSING BATTLEFIELD DAMAGE
C H A P T E R 3 . G E N E R A L R E P A I R
C H A P T E R 4 . A I R F R A M E
C H A P T E R 5 . A L I G H T I N G G E A R
CHAPTER 6 . POWER PLANT INSTALLATION
C H A P T E R 7 . R O T O R S
CHAPTER 8 . DRIVE TRAIN SYSTEM
C H A P T E R 9 . H Y D R A U L I C S Y S T E M S
CHAPTER 10. INSTRUMENT SYSTEMS
CHAPTER 11. ELECTRICAL & AVIONICS SYSTEMS
CHAPTER 12. FUEL SYSTEM
CHAPTER 13. FL IGHT CONTROLS SYSTEM
CHAPTER 14. UTIL ITY SYSTEMS
CHAPTER 15. ENVIRONMENTAL CONTROL SYSTEM
CHAPTER 16. MISSION EQUIPMENT
CHAPTER 17. EMERGENCY EQUIPMENT
A P P E N D I X A R E F E R E N C E S
APPENDIX B SPECIAL OR FABRICATED TOOLS
APPENDIX C EXPENDABLE/DURABLE SUPPLIES & MATERIALS
APPENDIX D SUBSTITUTE MATERIALS/PARTS
APPENDIX E BDAR TRAINING PROCEDURES
A P P E N D I X F A V I O N I C S C O N F I G U R A T I O N
S
H E A D Q U A R T E R S , D E P A R T M E N T O F T H E26
NOVEMBER 1990
A R M Y
-
TM 55-1520-244-BD
WARNING DATA
Personnel performing operations, procedures, and practices which
are included or implied in this technical manualshall observe the
general following warnings. Disregard of these warnings can cause
serious injury or death.
FLIGHT SAFETY
The standards contained herein allow aircraft to be flown with
battle damage substantially in excess of peacetimelimits. Under no
circumstances shall this manual be used entirely or in part for
peacetime maintenance of theaircraft. Assessment of aircraft battle
damage requires extreme care and diligence and strict adherence to
the in-structions and standards contained in this manual. If at any
stage of damage assessment the assessor believesthat oversights or
errors have been made, the assessment shall be stopped at that
point and repeated from thebeginning. Under no circumstances shall
the requirements of this manual be waived or circumvented without
theexpress approval of the commander or his designated
representative.
EXPLOSIVES
Battle damaged areas should be inspected for unexploded ordnance
before attempting repairs. Disposal of unex-ploded ordnance should
be accomplished by qualified personnel.
ARMAMENT
Loaded weapons or weapons being loaded or unloaded shall be
pointed in a direction which offers the least ex-posure to
personnel or property in the event of accidental firing. Personnel
shall remain clear of hazardous area.
CANOPY REMOVAL SYSTEM
Ground safety pins must be installed in pilot and gunner
arming/firing handles of canopy removal system when-ever the
helicopter is on the ground.
CLEANING SOLVENTS
Cleaning solvents may be flammable and toxic. Use only in
well-ventilated areas. Avoid inhalation of vapor andskin contact.
Do not use solvents near open flame or in areas where very high
temperatures prevail. Solvent flashpoint must not be less than
100°F.
COMPRESSED AIR
Compressed air can blow dust into eyes. Wear eye protection. Do
not exceed 30 psig air pressure.
a
-
TM 55-1520-244-BD
HIGH VOLTAGE
is used in equipment.
DEATH ON CONTACTmay result if personnel fail to observe safety
precautions.
Never work on electronic equipment unless there is another
person nearbv who isfamiliar with the operation and hazards of the
equipment and who is competent inadministering first aid. When the
technician is aided by operators, he must warnthem about dangerous
areas.
Whenever the nature of the operation permits, keep one hand away
from the equipmentas to reduce the hazard of current flowing
through vital organs of the body.
Do not be mislead by the term “low voltage.” Potentials as low
as 50 volts maycause death under adverse conditions. For Artificial
Respiration, refer to FM 21-11.
LIFTING
Lifting or moving heavy equipment incorrectly can cause serious
injury. Do not tryto lift or move more than 50 pounds by yourself.
Bend legs while lifting. Do notsupport heavy weight with your back.
Always use assistants during lifting opera-tions. Use guide ropes
to move hanging assemblies. Lack of attention or being inan
improper position during lifting operations can result in serious
injury. Payclose attention to movements of assemblies being lifted.
Do not stand under liftedassembly or in a position where you could
be pinned against another object. Watchyour footing.
b
-
TM 55-1520-244-BD
ELECTROLYTE
Battery Electrolyte (Potassium Hydroxide) is corrosive. Wear
rubber gloves, apron,and face shield when handling leaking
batteries. If potassium hydroxide is spilledon clothing or other
material, wash immediately with clean water. If spilled
onpersonnel, immediately start flushing the affected area with
clean water. Continuewashing until medical assistance arrives.
EXTERNAL STORES
Prior to any helicopter maintenance functions that require
external stores beremoved, JETTISON cartridge shall be removed. To
prevent injury to personneland damage to equipment, remove jettison
cartridges from stores ejection deviceprior to placing helicopter
in a hangar.
All ground safety pins must be removed before flight. Failure to
do so will preventemergency jettison of stores.
FIRE EXTINGUISHER
Exposure to high concentrations of monobromotrifluoromethane
(CF3BR) extinguishingagent or decomposition products should be
avoided. The liquid should not be allowedto come into contact with
the skin, as it may cause frost bite or low temperatureburns.
FUELING AND FUEL REPAIRS
When refueling helicopter, the refueling vehicle must be parked
a minimum of 20 feetfrom the helicopter. Before starting the
fueling operation, always insert fuelingnozzle grounding cable of
fuel truck into GROUND HERE receptacle. Refer to FM10-68. When
defueling, turn off all electrical switches and disconnect
externalpower from the helicopter. The helicopter must be
electrically grounded prior todefueling.
Fuel line and tank repairs often involve handling of
highlyMishandling can result in serious injury or death.
GROUNDING HELICOPTER
flammable material.
The helicopter should be electrically grounded when parked to
dissipate staticelectricity. Turn off all power switches before
making electrical connections ordisconnections.
HIGH PRESSURE
Extremely high pressure can occur during and after operation of
certain equipment.If this pressure is not relieved before working
on this equipment, serious injury ordeath may occur. Be sure to
open all drains and vents before beginning disassembly.
c
-
TM 55-1520-244-BD
HYDRAULIC FLUID
Prolonged contact with liquid or mist can irritate eyes and
skin. Wear rubber gloves when handling liquid. Aftercontact with
skin, immediately wash contacted area with soap and water. If
liquid contacts eyes, flush immediatelywith clear water. If liquid
is swallowed, do not induce vomiting. Get immediate medical
attention. If prolonged ex-posure with mist is likely, wear an
appropriate respirator. When fluid is decomposed by heating, toxic
gases arereleased.
N O I S E
Sound pressure levels in and around this aircraft during
operating conditions exceed the Surgeon General’s hear-ing
conservation criteria, as defined in TB MED 501. Hearing protection
devices such as aviator helmet or earplugs are required to be
worn.
SANDING DUST
Sanding on reinforced laminated glass produces fine dust that
may cause skin and lung irritations. Observe neces-sary protective
measures.
TOXIC POISONS
Turbine fuels, lubricating oils, and adhesives contain additives
which are poisonous and readily absorbed throughthe skin. Do not
allow them to remain on skin longer than necessary. Wear protective
equipment.
d
-
TM 55-1520-228-BD
LASER LIGHT
You can be blinded if you look into a laser beam when you are
not wearing lasersafety goggles. Never aim the laser range finder
(LRF) at personnel.
If laser beam reflects from a flat, mirror-like surface, it can
blind you unless youare wearing laser safety goggles.
RADIOACTIVE MATERIALS
contain radioactive materials. If suchunsealed, avoid personal
contact. Use
Self-luminous dials and ignition units mayan instrument or unit
is broken or becomesforceps or gloves made of rubber or
polyethylene to pick up-contaminated material.Place materials and
gloves in a plastic bag. Seal bag and dispose of it as radio-active
waste in accordance with AR 708-1 and TM 3-261 (Refer to TB
43-0108). Repairshall conform to requirements in AR 385-11.
e/(f blank)
-
TM 55-1520-244-BD
Technical Manual HEADQUARTERSDEPARTMENT OF THE ARMY
No. 55-1520-244-BD WASHINGTON, D. C., 26 November 1990
TECHNICAL MANUAL
OPERATORS, AVIATION UNIT, AND AVIATION INTERMEDIATE
MAINTENANCE
BATTLEFIELD DAMAGE ASSESSMENT AND REPAIR
FOR
HELlCOPTER, ATTACK
AH-1E 1520-01-192-2478AH-1F 1520-01-168-4260AH-1P
1520-01-168-4259
REPORTING ERRORS AND RECOMMENDING IMPROVEMENTSYou can help
improve this manual. If you find any mistake or if you know of a
way to im-prove the procedure, please let us know. Mail your letter
or DA Form 2028 (RecommendedChanges to Publications and Blank
Forms) directly to: Commander, U.S. Army AviationSystems Command,
ATTN: AMSAV-MC, 4300 Goodfellow Blvd., St. Louis, MO 63120-1798.A
reply will be provided to you.
CHAPTER 1-
Section I.Section Il.Section Ill.
CHAPTER 2-
Section I.Section II.
CHAPTER 3-
CHAPTER 4-
Section I.Section Il.
CHAPTER 5-
Section I.Section II.
CHAPTER 6-
Section I.Section Il.Section Ill.
TABLE OF CONTENTS
Page
HOW TO USE THIS MANUAL . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . .
GENERAL INFORMATION
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . .Standards and Practices . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . .Tasks and
Responsibilities . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . .
ASSESSING BATTLEFIELD DAMAGE
Introduction . . . . . . . . . . .General Fault Assessment
Table
GENERAL REPAIRS . . . . . . . .
AIRFRAME
Introduction . . . . . . . . . . .Airframe Repairs . . . . . . .
. .
ALIGHTING GEAR
Introduction . . . . . . . . . . .Skid Tube . . . . . . . . . .
. .
POWER PLANT INSTALLATION
Introduction . . . . . . . . . . .Oil Tanks . . . . . . . . . .
. . .Oil Pressure Indicator/Transmitter
. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
x
1-11-31-5
2-12-3
3-1
4-14-36
5-15-4
6-16-16-10
i
-
TM 55-1520-244-BD
TABLE OF CONTENTS (Cont)
Page
Section IV. Fuel Filter. . . . . . . . . . . . . . . . . . . . .
. . . .Section V. Fuel Control and Accessory Gearbox . . . . . . .
. . . . . .Section VI. Emergency Engine Start. . . . . . . . . . .
. . . . . . . .
CHAPTER 7 - ROTORS
Section I. Introduction. . . . . . . . . . . . . . . . . . . . .
. . .Section II. Main Rotor Hub and Blade. . . . . . . . . . . . .
. . . . .Section III. Tail Rotor System.. . . . . . . . . . . . . .
. . . . . . .
CHAPTER 8 - DRIVE TRAIN SYSTEM
Section I. Introduction. . . . . . . . . . . . . . . . . . . . .
. . .Section II. Transmission. . . . . . . . . . . . . . . . . . .
. . . . .Section III. Tail Rotor Driveshaft. . . . . . . . . . . .
. . . . . . . .
CHAPTER 9 - HYDRAULIC SYSTEMS
Section I. Introduction. . . . . . . . . . . . . . . . . . . . .
. . .Section II. Hoses. . . . . . . . . . . . . . . . . . . . . . .
. . . . .Section III. Metal Tubing. . . . . . . . . . . . . . . . .
. . . . . . .Section IV. Hydraulic Components . . . . . . . . . . .
. . . . . . . . .Section V. Hydraulic System Isolation . . . . . .
. . . . . . . . . . .Section VI. O-Ring, Packing, and Gaskets . . .
. . . . . . . . . . . . .Section VII. Hydraulic Fluid
Substitutions. . . . . . . . . . . . . . . .
CHAPTER 10 - INSTRUMENT SYSTEM.. . . . . . . . . . . . . . . . .
. . . .
CHAPTER 11 - ELECTRICAL AND AVIONICS SYSTEM
Section I. Introduction. . . . . . . . . . . . . . . . . . . . .
. . .Section II. Wire and Cable Splicing. . . . . . . . . . . . . .
. . . . .Section III. Connector Repair. . . . . . . . . . . . . . .
. . . . . . .Section IV. Overcurrent Protection Devices . . . . . .
. . . . . . . . .Section V. Bus Bars . .Section VI. Power
RelaysSection VII. Antennas . .Section VIII. Electrical
CHAPTER 12 - FUEL SYSTEM
Section I. Introduction
1 1 - 11 1 - 611-2411-2511-3011-3411-4611-50Wire Insulation
Section II. Lines and HosesSection III. Fuel Cells . .Section
IV. Fuel Boost Pumps Section V. Fuel Filters . . .
6-146-146-17
7-17-17-19
8-18-18-14
9-19-119-159-219-239-309-31
10-1
12-11 2 - 112-712-2312-23
i i
-
TM 55-1520-244-BD
TABLE OF CONTENTS (Cont)
CHAPTER 13 -
Section I.Section II.
CHAPTER 14 -
CHAPTER 15 -
Section I.Section II.Section III.Section IV.
CHAPTER 16-
Section I.Section II.Section III.Section IV.
CHAPTER 17 -
APPENDIX A -APPENDIX B -APPENDIX C -APPENDIX D -APPENDIX E
-APPENDIX F -GLOSSARY . . .INDEX . . . .
G L O S - 1INDEX-1
Figure
1-11-21-34-14-24-34-44-54-64-74-84-9
FLIGHT CONTROL SYSTEM
Introduction.. . . . . . . . . . . . . . . . . . . . . . . . . .
Flight Control Tubes. . . . . .. . . . . . . . . . . . . . . . . .
. . . . . .
UTILITY SYSTEMS . . . . . . . . . . .. . . . . . . . . . . . . .
. . . . .
ENVIRONMENTAL CONTROL SYSTEM
Introduction. . . . . . . . . . . . . . . . . . . . . . .
.Environmental Control Unit (ECU) . . . . . . . . . . . . .
.Ducting. . . . . . . . . . . . . . . . . . . . ....Bleed Airlines.
. . . . . . . . . . . . . . . . . . . . . .
MISSION EQUIPMENT
Introduction. . . . . . . . . . . . . . . . . . . . .Wiring. . .
. . . . . . . . . . . . . . . . . . . . . . .Hydraulics. . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Air
Data Subsystem. . . . . . . . . . . . . . . . . . . . . . . . .
EMERGENCY EQUIPMENT. . . . . . . .. . . . . . . . . . . . . . .
. . .
REFERENCES . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . SPECIAL OR FABRICATED TOOLS . . . . . . . . . . . . . . . . . .
. . . . . . . . . EXPENDABLE/DURABLE SUPPLIES AND MATERIALS . . . .
. . . . . . . . .SUBSTITUTE MATERIALS/PARTS. . . . . . . . . . . .
. . . . . . . . . . . . .BDAR TRAINING PROCEDURES. . . . . . . . .
. . . . . . . . . . . . . . . . .AVIONICS CONFIGURATION. . . . . .
. . . . . . ..
Page
13-113-5
14-1
15-115-115-615-9
16-116-316-516-5
17-1
A-1B-1C-1D-1E-1F-1
LIST OF ILLUSTRATIONS
Title
DA Form 2408-13. . . . . . . . . . . . . . . . . . . . . . DA
Form 2408-18. . . . . . . . . . . . . . . . . . .. . . . . . Damage
Assessment Markings (Sheet 1 of 3). . . . . . . . . .Aircraft
Zones. . . . . . . . . . . . . . . . . . . . . . . . DA Form 2404.
. . . . . . . . . . . . . . . . . . . Measuring Cap or Longeron
Damage . . . . . . . . . . . . . .Damaged Cross Section . . . . . .
. . . . . . . . . . . . .Measuring Skin Panel Damage . . . . . . .
. . . . . . . . . .Measuring Damage in Floors or Decks . . . . . .
. . . . . .Measuring Damage in Honeycomb Panels . . . . . . . . . .
. .Airframe Reference Lines . . . . . . . . . . . . . . . . .
.Primary Structural Caps L/H . . . . . . . . . . . . . . . .
Page
1-61-71-84-24-74-94-94-114-114-124-154-16
iii
-
TM 55-1520-244-BD
LIST OF ILLUSTRATIONS (Cont)
Figure
4-104-114-124-134-144-154-164-174-184-194-204-214-224-234-244-254-264-274-284-294-304-314-324-33
4-34
4-35
4-36
4-37
4-384-394-40
4-415-15-25-35-4
iv
Title
Structural WebsL/H . . . . . . . . . . . . . . . . . . .
.Primary Structural Caps R/H . . . . . . . . . . . . . . .
.Structural Webs R/H . . . . . . . . . . . . . . . . . . .
.Fuselage Box Beam Panels. . . . . . . . . . . . . . . . . .L/H
Fuselage Beam . . . . . . . . . . . . . . . . . . . . .R/HFuselage
Beam . . . . . . . . . . . . . . . . . . . . .Upper Panels. . . . .
. . . . . . . . . . . . . . . . . , .Lower Panels. . . . . . . . .
. . . . . . . . . . . . . . .Pylon Support . . . . . . . . . . . .
. . . . . . . . . . .Post Member Consisting of Three Elements . . .
. . . . , . .Tail Boom . . . . . . . . . . . . . . . . . . . . . .
. . .Fin. . . . . . . . . . . . . . . . . . . . . . . . . . . .
.Skin Panel Damage WL Versus Frame Spacing S. . . . . . . .
.Typical Skin Panel and Frame Damage . . . . . . . . . . . .AH-1S
Left Wing - Skins Removed . . . . . . . . . . . . . .Typical Former
Repair. . . . . . . . . . . . . . . . . . . .Cut and Drill Former
Repair. . . . . . . . . . . . . . . . .Cutout in Damaged Skin . . .
. . . . . . . . . . . . . .Stringer/Stiffener Repair. . . . . . . .
. . . . . . . . . .Expedient Cap/Longeron Repair . . . . . . . . .
. . . . . .Repair of Damage Bulkhead Flange . . . . . . . . . . . .
. .Typical Combination Repair (angle view). . . . . . . . . .
.Typical Combination Repair (side view) . . . . . . . . . .
.Damaged Honeycomb Core Panel - Small Damage to One Skin andand
Core. . . . . . . . . . . . . . . . . . . . . . . . . .Damaged
Honeycomb Core Panel, 2-8 Inch Damage - One Skinand Core. . . . . .
. . . . . . . . . . . . . . . . . . . .Repaired Honeycomb Core
Panel, 2-8 Inch Damage - One Skinand Core. . . . . . . . . . . . .
. . . . . . . . . . . . .Damaged Honeycomb Core Panel, 2-8 Inch
Damage - Both Skinsand Core. . . . . . . . . . . . . . . . . . . .
. . . . . .Repaired Honeycomb Core Panel, 2-8 Inch Damage - Both
Skinsand Core. . . . . . . . . . . . . . . . . . . . . . . . .
.Damage Repair, Accessible One Side Only. . . . . . . . . .
.Fabrication of Patch Plate. . . . . . . . . . . . ..O . .Repair of
Honeycomb Core Panel - Damage Over 8 Inches - BothSkins and Core. .
. . . . . . . . . . . . . . . . . . . . .Fracture Lacing with
Safety Wire . . . . . . . . . . . . . .Landing Gear and Support
Installation. . . . . . . . . . . .Skid Tube Damage Zones . . . . .
. . . . . . . . . . . . . .Skid Shoe Repair. . . . . . . . . . . .
. . . . . . . . . .Clamp Repair. . . . . . . . . . . . . . . . . .
. . . . . .Fabricated Clamp. . . . . . . . . . . . . . . . . . . .
. .Engine, Right-Hand View. . . . . . . . . . . . . . . . . .
.Engine, Left-HandView . . . . . . . . . . . . . . . . . . .Oil
Tank. . . . . . . . . . . . . . . . . . . . . . . . . .Wood Plug. .
. . . . . . . . . . . . . . . . . . . . . . . .Sealant Repair. . .
. . . . . . . . . . . . . . . . . . . .Screw, Washer, and Gasket..
. . . . . . . . . . . . . . .,
Page
4-164-174-174-184-194-204-214-224-264-284-304-314-344-344-364-394-404-424-424-444-464-474-48
4-50
4-50
4-51
4-52
4-524-544-54
5-56-16-26-36-46-56-6
6-26-36-56-76-86-8
-
TM 55-1520-244-BD
Figure
6-76-8
6-11
6-96-10
6-126-137-17-27-37-47-57-67-77-87-97-107-117-127-137-147-157-168-18-28-38-4
8-5
8-6
8-7
8-88-98-10
8-118-12
LIST OF ILLUSTRATIONS (Cont)
Title
Hose Assembly, Sealant, Nut, and Bolt . . . . . . . . . . . . .
. .Sheet Metal with Sealant or Blind Rivets . . . . . . . . . . . .
. .Oil Pressure Transmitter . . . . . . . . . . . . . . . . . . . .
.Torque Pressure Transmitter . . . . . . . . . . . . . . . . . .
.Fuel Control Assembly and Accessory Gearbox Assembly . . . . . .
.Tach Generator Removal . . . . . . . . . . . . . . . . . . .
.External Power Plug . . . . . . . . . . . . . . . . . . . . .
.Main Rotor System . . . . . . . . . . . . . . . . . . . . . .
.Application of Tape . . . . . . . . . . . . . . . . . . . . . .
.Marking Work Area . . . . . . . . . . . . . . . . . . . . . .
.Application of Adhesive and Position of PatchBalance Adjustment
for Patches (K747 Blade) (Sheet 1 or 2) . . . . . . . . .Maximum
Allowable Repairable Damage to Rotor Blade . . . . . . . .Typical
Double Plug Patch Repair . . . . . . . . . . . . . . . . .Marking
Work Area . . . . . . . . . . . . . . . . . . . . . . .Removal of
Damage Skin . . . . . . . . . . . . . . . . .Setting Router Depth .
. . . . . . . . . . . . . . . . . . . . .Insertion of Patch . . . .
. . . . . . . . . . . . . . . . . . .Drag Brace . . . . . . . . . .
. . . . . . . . . . . . . . . .Tail Rotor installation . . . . . .
. . . . . . . . . . . . . . . .Tail Rotor Blade-Area Authorized for
Patch-Type Repair . . . . . . . .Aluminum Skin Patch . . . . . . .
. . . . . . . . . . . . . . .Skin Patch Tape Cover . . . . . . . .
. . . . . . . . . . . . .Drive Train (Typical) . . . . . . . . . .
. . . . . . . . . . . .Transmission Oil Pressure Switch and
Transmitter Repair . . . . . . . .Transmission Assembly, Unaltered
. . . . . . . . . . . . . . . . .Altered Configuration
(Transmission Oil System) BypassingFilter and Outlet Hose . . . . .
. . . . . . . . . . . . . . . . .Altered Configuration
(Transmission Oil System) BypassingOil Filter . . . . . . . . . . .
. . . . . . . . . . . . . . . .Altered Configuration (Transmission
Oil System) BypassingFilter and lnlet Hose . . . . . . . . . . . .
. . . . . . . . . .Altered Configuration (Transmission Oil System)
SubstitutingHose at Sump Outlet (Sheet 1 of 2)Damage Passing
Through Center of Shaft . . . . . . . . . . . . . . .Damage Not
Passing Through Center of Shaft . . . . . . . . . . . .Balance
Restoring Repair for Damage Not Passing ThroughCenter of Shaft . .
. . . . . . . . . . . . . . . . . . . . . .Y and S Graph . . . . .
. . . . . . . . . . . . . . . . . . . .Area and Diameter Graph . .
. . . . . . . . . . . . . . . . . .
Page
6-96-116-126-136-156-166-187-27-57-77-77-97-117-127-137-147-157-167-187-207-217-217-228-28-58-6
8-7
8-9
8-11
8-128-168-17
8-188-198-19
v
-
TM 55-1520-244-BD
LIST OF ILLUSTRATIONS (Cent)
Figure
8-138-148-159-19-29-39-49-59-69-79-89-99-109-119-129-139-149-159-169-179-189-199-209-2111-111-211-311-411-511-611-711-811-911-1011-1111-1211-1311-1411-1511-1611-1711-1811-1911-2011-2111-2211-2311-2411-25
vi
Title
Damaged Shaft; Petals Straightened Smooth. . . . . . . . .
.Repaired Shaft. . . . . . . . . . . . . . . . . . . . . . .Shaft
Area (in*) vs. Number of Rivets. . . . . . . . . . . .Hydraulic
System Schematic (Sheet 1 of 2). . . . . . . . . .Hydraulic System
- SYSTEM No. 2 (Sheet 1 of 2) . . . . . . .Hydraulic System -
SYSTEM No. 1. . . . . . . . . . . . . . .Hydraulic System -
Armament (Sheet 1 of 2) . . . . . . . . .Emergency (Electric Motor
Driven) Hydraulic System . . . . .Two-Part Fitting. . . . . . . . .
. . . . . . . . . . . . .Four-Part Fitting. . . . . . . . . . . . .
. . . . . . . . .Installation of MS Hose Fitting Socket and Sleeve.
. . . . .Assembly of MS Fitting . . . . . . . . . . . . . . . . . .
.Using Tube Cutter. . . . . . . . . . . . . . . . . . . . .
.Properly Burred Tubing . . . . . . . . . . . . . . . . . .
.Damaged Tube Sections . . . . . . . . . . . . . . . . . . .MS Tube
Fitting Installation . . . . . . . . . . . . . . . .Completed
Tubing Installation. . . . . . . . . . . . . . . .Completed High
Pressure Hose Substitution. . . . . . . . . .MS Union Installation
. . . . . . . . . . . . . . . . . . .Lock-Out Valve Assembly. . . .
. . . . . . . . . . . . . . .Hydraulic System Unaltered . . . . . .
. . . . . . . . . . .Hydraulic System, Isolating No. 1 System . . .
. . . . . . .Hydraulic Pump and Drive Pad . . . . . . . . . . . . .
. . .Hydraulic System, Isolating No. 2 System . . . . . . . . .
.Circuit Identification.. . . . . . . . . . . . . . . . . .Crimp
Splice . . . . . . . . . . . . . . . . . . . . . . .Splicing with
Terminal Lug Barrel. . . . . . . . . . . . . .Twist Wire Splice . .
. . . . . . . . . . . . . . . . . . .Replacement Section; Twist
Wire Splice . . . . . . . . . . .Metal Casing Splice. . . . . . . .
. . . . . . . . . . . . .Replacement Section; Terminal Lug Repair .
. . . . . . . . .Ram Wire Repair . . . . . . . . . . . . . . . . .
. . . . .Shielded Cable Repair Preparation. . . . . . . . . . . . .
.Shielded Cable Splice Preparation. . . . . . . . . . . . .
.Completed Shielded Cable Splice. . . . . . . . . . . . . . .Sheath
Connector Splice. . . . . . . . . . . . . . . . . . .Pigtail Sheath
Splice . . . . . . . . . . . . . . . . . . .Substitute Shielded
Braid Splice . . . . . . . . . . . . . .Shield Terminator Repair
Preparation . . . . . . . . . . . .Shield Terminator Repair. . . .
. . . . . . . . . . . . . .Component Bypass. . . . . . . . . . . .
. . . . . . . . . .Connector Pin and Socket. . . . . . . . . . . .
. . . . . .Damaged Connector and Wire . . . . . . . . . . . . . . .
. .Typical Original Circuit Breaker Connection. . . . . . . .
.Construction of Fuse Link. . . . . . . . . . . . . . . . .
.Typical Fuses. . . . . . . . . . . . . . . . . . . . . . .
.Fabricated Fuse, Type A... . . . . . . . . . . . . . . .
.Fabricated Fuse, Type B. . . . . . . . . . . . . . . . . .
.Splicing Bus Bars. . . . . . . . . . . . . . . . . . . . . .
Page
8-218-228-239 - 29 - 49 - 69 -
79-99-129-129-149-149-169-169-189-199-199-209-219-229-249-259-279-2911-311-811-911-1111-1111-1211-1311-1411-1511-1611-1611-1711-1911-2011-2211-2211-2311-2411-2511-2611-2811-2911-3011-3011-32
-
TM 55-1520-244-BD
LIST OF ILLUSTRATIONS (Cont)
Title PageFigure
11-2611-2711-2811-2911-3011-3111-3211-3311-3411-3511-3611-3711-3811-3911-4012-112-212-312-412-512-612-712-812-912-1012-1112-1212-1312-1412-1512-1612-1712-1812-1912-2013-113-213-313-413-513-613-713-813-913-1013-11
15-115-2
Lengthening Bus Bars. . . . . . . . . . . . . . . . . . .
.Battery Cell Layout. . . . . . . . . . . . . . . . . . . . .Block
Diagram Power Relay, Check and Test. . . . . . . . . .AH-1 PROD
Battery Compartment, Forward View (Sheet 1 of 2) .AH-1 PROD Battery
Compartment, Side View (Sheet 1 of 2). . .AH-1 ECAS and MC Battery
Compartment (Sheet 1 of 2). . . . .AH-1 ECAS and MC Battery
Compartment (Sheet 1 of 3). . . . .Block Diagram, Typical Power
Relays. . . . . . . . . . . . .Jumper Wire Fabrication. . . . . . .
. . . . . . . . . . . .Frequency vs. Wavelength . . . . . . . . . .
. . . . . . . .Preparation of Coax . . . . . . . . . . . . . . . .
. . . .Installation of Field Expedient Antenna. . . . . . . . . .
.Pigtail Termination for Shielded Wire. . . . . . . . . . . .Heat
Shrinkable Tape. . . . . . . . . . . . . . . . . . . .Insulation
Repair with Sleeving. . . . . . . . . . . . . . .Fuel System . . .
. . . . . . . . . . . . . . . . . . . . .Use of String Bead. . . .
. . . . . . . . . . . . . . . . .Long Replacement Tube Section. . .
. . . . . . . . . . . . .Repair of Small Hole in Tube . . . . . . .
. . . . . . . . .Expedient Repair of Damaged Hose . . . . . . . . .
. . . . .Replacement of Damaged Hose Section. . . . . . . . . . . .
.Inlet Line to Fuel Control. . . . . . . . . . . . . . . .
.Emergency Mechanical Clamp Repair . . . . . . . . . . . . .Rubber
Repair Plug Assembly . . . . . . . . . . . . . . . .Plug
Modification for Three Plane (Corner) Repair. . . . . .Aft Cell
Isolation Access Panels . . . . . . . . . . . . . .Crossover Line
Flange Template . . . . . . . . . . . . . . .Blocked Off Crossover
Line . . . . . . . . . . . . . . . . .Fuel Manifold. . . . . . . .
. . . . . . . . . . . . . . . .Blocked Off Fuel Cell. . . . . . . .
. . . . . . . . . . . .Floor Baffle Assembly . . . . . . . . . . .
. . . . . . . .Fuel Quality Probe; Fuel Inlet . . . . . . . . . . .
. . . .External Fuel Filter Assembly. . . . . . . . . . . . . . .
.External Fuel Filter. . . . . . . . . . . . . . . . . . .
.Bypassing External Fuel Filter . . . . . . . . . . . . . . .Flight
Controls . . . . . . . . . . . . . . . . . . . . . .Stability and
Control Augmentation System (SCAS) . . . . . .Collective Flight
Controls . . . . . . . . . . . . . . . . .Cyclic, Lateral Controls
. . . . . . . . . . . . . . . . . .Cyclic, Fore and Aft Controls .
. . . . . . . . . . . . . .Tail Rotor Controls. . . . . . . . . . .
. . . . . . . . . .Control Tube Splice. . . . . . . . . . . . . . .
. . . . . .Control Rod with Bearing and Clevis Assemblies . . . . .
. .Flattened End of Fabricated Flight Control . . . . . . . .
.Corner Rounding on Fabricated Flight Control . . . . . . . .Bell
Crank or Lever Assembly Connection of FabricatedFlight Control . .
. . . . . . . . . . . . . . . . . . . . .Environmental Control
System . . . . . . . . . . . . . . .ECU Housing. . . . . . . . . .
. . . . . . . . . . . . . . .
11-3211-3311-3411-3611-3811-4011-4211-4511-4511-4711-4711-4911-5011-5211-5212-212-512-512-612-812-812-1012-1112-1312-1412-1612-1712-1812-1912-2212-2412-2512-2612-2812-2913-213-313-613-713-813-913-1213-1413-1513-15
13-1515-215-4
vii
-
TM 55-1520-244-BD
Figure
15-315-415-515-616-116-216-3F-1
F-2F-3
F-4F-5F-6F-7F-8F-9F-10F-11F-12F-13F-14F-15
Table No.
2-12-24-14-24-3
5-16-17-17-28-18-29-111-111-211-311-411-512-1
viii
LIST OF ILLUSTRATIONS (Cont)
Title
Ducts, Flexible Plastic . . . . . . . . . . . . . . . . .
.Ducts, Rigid Plastic. . . . . . . . . . . . . . . . . . . .Bleed
Air Lines. . . . . . . . . . . . . . . . . . . . . . .Bleed Line
Patch Repair. . . . . . . . . . . . . . . . . . .Turret Gun Brake
Toggle (ECAS and MC). . . . . . . . . . . .Outboard Wing Stores
Pylon.. . . . . . . . . . . . . . . .ADS Pneumatic Lines. . . . . .
. . . . . . . . . . . . . . .UHF Command Communication System
AN/ARC-116() or AN/ARC-164(Sheet l of 2) . . . . . . . . . . . . .
. . . . . . . . . .VHF Command Communication System AN/ARC-115
(Sheet 1 of 2) .VHF Command Commnunication System AN/ARC-115 or
AN/ARC-186(Sheet l of 2) . . . . . . . . . . . . . . . . . . . . .
. .FM Liaison Communication System AN/ARC-114 (Sheet 1 of 3). .FM
Liaison Communication System AN/ARC-114A (Sheet 1 of 3)
.Gyromagnetic Compass System AN/ASN-43 (Sheet 1 of 2) . . .
.Automatic Direction Finder AN/ARN-89B (Sheet 1 of 2) . . .
.VOR/MB/GS Receiving Set Radio AN/ARN-123(V)3 (Sheet 1 of
3).Doppler Navigation System AN/ASN-128 (MC) (Sheet 1 of 2) .
.Radar Altimeter System AN/APN-209 (Sheet 1 of 2) . . . . . .IFF
System AN/APX-72 (Sheet 1 of 2). . . . . . . . . . . . .IFF System
AN/APX-100(V) (Sheet 1 of 2). . . . . . . . . . .Radar Warning
System AN/APR-39(V)1 (Sheet 1 of 2). . . . . .Countermeasures Set
AN/ALQ-136 (MC) (Sheet 1 of 2) . . . . .Countermeasures Set
AN/ALQ-144(V) (MC) (Sheet 1 of 2). . . .
LIST OF TABLES
Title
General Decision Logic . . . . . . . . . . . . . . . . . .
.Assessment Table. . . . . . . . . . . . . . . . . . . . .
.Structure Damage Assessment Procedures . . . . . . . . . .
.Allowable Fuselage Damage Limits-Condition 1, Fuselage
Caps.Allowable Tail Boom Damage Limits-Condition 1, Tail
BoomLongerons. . . . . . . . . . . . . . . . . . . . . . . . .
.Alighting Gear Assessment Procedures . . . . . . . . . . . .Power
Plant Assessment Procedures. . . . . . . . . . . . . .Rotor
Assessment Procedures. . . . . . . . . . . . . . . . .Plug Patch
Kits. . . . . . . . . . . . . . . . . . . . . . .Drive Train
Assessment Procedures. . . . . . . . . . . . . .Shaft Area (in2)
vs. Number of Rivets. . . . . . . . . . . .Hydraulic System
Assessment Procedures . . . . . . . . . . .Electrical and Avionics
Assessment Procedures. . . . . . . .Function and Designation
Letters . . . . . . . . . . . . . .Unshielded Crimp Splice
Application. . . . . . . . . . . . .Shielded Cable Repair . . . . .
. . . . . . . . . . . . . .Fuse Link Strands. . . . . . . . . . . .
. . . . . . . . . .Fuel System Assessment Procedures. . . . . . . .
. . . . . .
Page
15-715-815-1015-1116-416-616-7
F-1F-5
F-7F-9F-14F-19F-23F-27F-37F-42F-45F-50F-54F-57F-59
Page
2-22-34-44-24
4-325-26-47-37-118-38-239-1011-211-311-711-1511-2712-3
-
TM 55-1520-244-BD
Table No.
13-113-213-314-115-116-1D-1D-2D-3D-4D-5D-6D-7D-8D-9F-1F-2F-3F-4
F-5F-6F-7F-8F-9F-10F-11F-12F-13F-14F-15F-16
LIST OF TABLES (Cont)
Title
Flight Control System Assessment Procedures. . . . . . . .
.Control Tube Dimensions. . . . . . . . . . . . . . . . . .
.Bolt/Drill Sizes for Control Tube Repairs. . . . . . . . .
.Utility Systems Assessment Procedures. . . . . . . . . . .
.Environmental Control System Assessment Procedures . . . .
.Mission Equipment Assessment Procedures. . . . . . . . . . .Spare
and Repair Parts . . . . . . . . . . . . . . . . . . .Armament
Parts. . . . . . . . . . . . . . . . . . . . . . .Packing Reference
and Temperature Guides Chart . . . . . . .Substitute U.S. Fuels. .
. . . . . . . . . . . . . . . . . .Substitute Foreign Fuels.. . . .
. . . . . . . . . . . . .Substitute Commercial Fuels. . . . . . . .
. . . . . . . . .Alternate and Expedient Fuel Blends. . . . . . . .
. . . . .Substitute Lubricants and Hydraulic Fluids . . . . . . . .
.Metal Substitution Chart.. . . . . . . . . . . . . . . . .UHF
AN/ARC-1160, Wire Chart . . . . . . . . . . . . . . . .UHF
AN/ARC-1640, Wire Chart . . . . . . . . . . . . . . . .VHF
AN/ARC-1150, Wire Chart . . . . . . . . . . . . . . . .VHF Command
Commnunication System AN/ARC-l15 or AN/ARC-186,Wire Chart. . . . .
. . . . . . . . . . . . . . . . . . . .FM AN/ARC-1140, Wire Chart
(with KY-28) PROD and ECAS . . .FM AN/ARC-1140, Wire Chart (with
KY-28) MC. . . . . . . . .AN/ASN-43,Wire Chart . . . . . . . . . .
. . . . . . . . . .AN/ARN-89B, Wire Chart, ADF. . . . . . . . . . .
. . . . . .AN/ARN-123(V)3, Wire Chart, MC, P, E . . . . . . . . . .
. .AN/ASN-128,Wire Chart... . . . . . . . . . . . . . . .
.AN/APN-209,Wire Chart... . . . . . . . . . . . . . . .
.AN/APX-72,Wire Chart . . . . . . . . . . . . . . . . . . .
.AN/APX-lOO,Wire Chart... . . . . . . . . . . . . . . .
.AN/APR-39,Wire Chart . . . . . . . . . . . . . . . . . . .
.AN/ALQ-136,Wire Chart... . . . . . . . . . . . . . . .
.AN/ALQ-144,Wire Chart... . . . . . . . . . . . . . . . .
Page
13-413-1013-1114-215-316-3D-2D-10D-12D-17D-18D-19D-20D-21D-24F-4F-4F-6
F-8F-12F-17F-21F-25F-30F-39F-44F-47F-52F-56F-58F-61
ix
-
TM 55-1520-244-BD
HOW TO USE THIS MANUAL
This manual is developed to assist the soldier in a battlefield
environment make assessment and repair ofdamage to the AH-1 attack
helicopter which cannot, due to asset availability or environmental
factors, berepaired in the normal prescribed manner. Within this
technical manual, the word shall is used to indicate a man-datory
requirement. The word should is used to indicate a nonmandatory but
preferred method of accomplish-ment. The word may is used to
indicate an acceptable method of accomplishment.
1. Organization of the Manual. This manual contains a general
information chapter (chapter 1), a generalassessment chapter
(chapter 2), and specific repair chapters (chapters 4 thru 17).
Chapter 3 is not used. It alsocontains five appendixes.
2. Chapter 2 is used to assess the helicopter in general and
references specific chapters for detailed repair pro-cedures of the
major functional groups. The major functional groups correspond
with the functional groups of the-23 series manuals that are
employed in routine repairs to the helicopter.
3. Chapter 3 is not used in this manual. It would normally
contain repairs for equipment which does not fall underone of the
standard helicopter functional groups.
4. Each functional group chapter is organized as follows:
a. Section I - Introduction.
(1) Scope. Purpose of the chapter.(2) Assessment Procedures.
General assessment information for the repairs covered therein.(3)
Repair Procedure Index.
b. Section II - Repair Item. A subsection is included for each
repair item covered in that functional group. Itcontains the
following:
(1) General. About the nature and cause of damage and repair.(2)
Item and trouble statement with:
(a) Limits given.(b) Personnel and time required to effect
repairs.(c) Materials and tools needed.(d) Procedural steps to
accomplish the repair.
(3) If more than one method of repair can be used, the various
options will be included next.
NOTE
The first option is the preferred choice, the second option is
the next preferred, etc. Selec-tion of the option should be the
most preferred method possible under the circumstancesand with the
available materials and manpower.
x
-
TM 55-1520-244-BD
HOW TO USE THIS MANUAL (Cont)
5. Finding Repairs in this Manual.
a. When the damage is obvious and known, find the functional
group chapter of which the damaged item is apart. Turn to the
repair procedure index, section I, subparagraph 3 of each chapter
to locate the item beingrepaired. Then turn to the repair section
and review each option to ascertain the appropriate fix. Read the
entiresection for the option, then effect the repairs following the
procedures given.
b. When the damage is hidden or unknown, follow the overall
assessment procedures provided in chapter 2,and follow the
procedures and directions provided.
6. Preparation.
a. Each mechanic/technician shall read chapters 1 and 2 and
shall be familiar with the repairs and layout ofthe manual prior to
attempting to accomplish BDAR repairs.
b. All warnings, cautions, and standard safety precautions shall
be followed, inasmuch as possible, at alltimes during BDAR
procedures so as not to further damage or jeopardize either
personnel or the equipmentduring or subsequent to the BDAR action.
Ensure all documentation is completed as directed in this manual
andby local command.
7. Expendable/Durable Supplies and Materials.
a. Each fix or repair option contains a short listing of
materials and tools considered basic to the repair. It is
im-portant to note that the expendable materials listed usually
cover a wide range for any one item.
Example: MATERIALS/TOOLS REQUIRED:● Drill with Bit● Sheet Metal
(items 131-142, App. C)• Rivets (items 98-115, App. C)
In this example, sheet metal covers the range of items 131 thru
142 listed in Appendix C. This means that,depending on the
circumstances and location of the fix, any one of these metals
could be used. Likewise any oneof the rivets, items 98 thru 115,
may be used to attach the patch plate depending on the
application.
b. One of the key points concerning successful BDAR repairs is
flexibility. The users of this manual shouldstrive to use the items
on hand, provided a safe repair is made. The stringent requirements
of normal main-tenance may be lifted.
xi/(xii blank)
-
TM 55-1520-244-BD
CHAPTER 1
GENERAL INFORMATION
BDAR FIXES SHALL BE USED ONLY IN COMBAT OR FOR TRAININGAT THE
DISCRETION OF THE COMMANDER.
(AUTHORIZED TRAINING FIXES ARE LISTED IN APPENDIX E.)IN EITHER
CASE, DAMAGES SHALL BE REPAIRED BY STANDARD
PROCEDURES AS SOON AS PRACTICABLE.
Section I.
1-1. PURPOSE. The purpose of BattlefieldDamage Assessment and
Repair (BDAR) is to quicklyreturn the disabled helicopter to the
operational com-mander by expediently fixing, bypassing, or
jury-rig-ging components to restore the minimum essentialsystems
required for the support of the specific com-bat mission or for
self-recovery. These repairs will betemporary and may not restore
full performancecapability. Standard repair will be completed as
soonas practical.
1-2. SCOPE.
a. This technical manual (TM) describes BDARprocedures
applicable to AH-1S attack helicopterseries and these procedures
are to be used by crew,operators, aviation unit maintenance (AVUM)
teams,and aviation intermediate maintenance (AVIM) sup-port
teams.
b. Standard repair techniques for the attackhelicopter are
included in other technical manualswhich are referenced in Appendix
A of this TM.Details of these procedures are not duplicated inwhole
in this TM. If the repairs are more than onepage in length, the
repairs may only be referenced inappropriate chapter.
c. All possible types of combat damage andfailure modes cannot
be predicted, nor are all effec-tive field expedient repairs known.
This TM providesguidelines for assessing and repairing
battlefield
INTRODUCTION
failures of helicopters and is not intended to be a com-plete
catalog of all possible emergency repairs. Therepairs described
here will serve as guidelines andwill stimulate the experienced
mechanic/operator todevise repairs as needed to rapidly return
equipmentto operation in a combat situation.
d. The direct replacement of a piece of equip-ment by its spare,
even under battlefield conditions, isnot a BDAR fix and may not be
covered is in this TM.A standard procedure should be performed
inpreference to a BDAR fix when time and spares areavailable.
1-3. APPLICATION.
a. The procedures in this manual are designedfor battlefield
environments and should be used insituations where standard
maintenance proceduresare impractical. These procedures are not
meant toreplace standard maintenance practices, but rather
tosupplement them strictly in a battlefield environment.Standard
maintenance procedures will provide themost effective means of
returning damaged equip-ment to ready status provided that adequate
time,replacement parts, necessary tools, andtrained/qualified
repair persons are available. BDARprocedures are only authorized
for use in an emergen-cy situation in a battlefield environment,
and only atthe direction of the commander. They are not to
becontinued after the equipment is out of the battle
en-vironment.
1-1
-
TM 55-1520-244-BD
b. BDAR techniques are not limited tosimple restoration of
minimum functionalcombat capability. If full functionalcapability
can be restored expedientlywith a limited expenditure of time
andassets, it will be accomplished.
c. Some of the special techniques inthis manual, if applied, may
result inshortened life or in further damage tomajor components of
the helicopter. Thecommander must decide whether the riskof having
one less helicopter availablefor combat outweighs the risk
ofapplying the potentially destructiveexpedient repair technique.
Each tech-nique gives appropriate warnings,cautions, and lists
systems limitationscaused by this action.
1-4. DEFINITIONS.
a. Battlefield Damage. Any incidentsuch as combat damage, random
failures,operator errors, accidents, and wear-outfailures which
occur on the battlefieldand which prevent the helicopter
fromaccomplishing its mission.
b. Repair or Fix. Any expedientaction that returns a damaged
part orassembly to a full or an acceptablydegraded operating
condition, including:
(1) Short cuts in parts removal orinstallation.
(2) Installation of componentsfrom other equipment that can
bemodified to fit or interchange withcomponents on the damaged
equipment.
(3) Repair using parts that servea noncritical function
elsewhere onthe same equipment for the purpose ofrestoring a
critical function.
(4) Bypassing of noncritical com-ponents in order to restore
basic func-tional capability.
(5) Expeditious cannibalizationprocedures.
(6) Fabrication of parts from kitsor readily available
materials.
(7) Jury-rigging.
(8) Use of substitute materials.
c. Damage Assessment. A procedure torapidly determine what is
damaged,whether it is repairable, what assetsare required to make
the repair, who cando the repair (e.g., crew, maintenanceteam or
maintenance support team), andwhere the repair should be made.
Theassessment procedure includes thefollowing steps:
(1) Determine if the repair can bedeferred, or if it must be
done.
(2) Isolate the damaged areas andcomponents.
(3) Determinemust be fixed.
(4) Prescribe
(5) Determineponents, materials,
which components
fixes.
if parts or com-and tools are
available.
(6) Estimateskill required.
(7) Estimatehours) required to
the manpower and
the total time (clockmake the repair.
(8) Establish the priority of thefixes.
(9) Decide where the fix shall beperformed.
(10) Decide if recovery or evacua-tion is necessary and to what
location.
d. Fully Mission Capable (FMC). Thehelicopter can perform all
its combatmissions. To be FMC, the helicopter mustbe complete and
fully operable with nofaults listed in the aircraft inspectionand
maintenance record as prescribed inDA PAM 738-751.
1-2
-
TM 55-1520-244-BD
e. Combat Capable.. Equipment meets the mini-mum functional
combat capability requirements. (Seeparagraph 1-8.)
f. Combat Emergency Capable. The equipmentmeets the needs for
specific tactical missions; how-ever, all systems are not
functional. Also, additionaldamage due to the nature of an
expedient repair mayoccur to the equipment if it is used. The
commandermust decide if these limitations are acceptable for
thatspecific emergency situation.
g.. Cannibalization or Controlled Exchange.Throughout this
manual, cannibalization and control-led exchange are used
interchangeably to mean theremoval of an item of materiel from one
piece ofequipment for immediate use in another. Generallythe rules
for cannibalization/controlled exchangeprovided in
TM55-1500-328-25, as modified by localauthority, will prevail.
h. Evacuation. A combat service support func-tion which involves
the movement of recoveredhelicopters from a main supply route,
maintenancecollection point, or maintenance activity to
highercategories of maintenance. The materiel may bereturned to the
user, to the supply system for reissue,or to property disposal
activities.
i. Recovery. The retrieval of immobile, inopera-tive, or
abandoned helicopter from the battlefield orimmediate vicinity, and
its movement to a main-tenance collection point, the main supply
route, or amaintenance activity for disposition, repair, or
evacua-tion.
j. Self-Recovery. The ability of the helicopter tofly at reduced
airspeed and altitude from the bat-tlefield, or immediate vicinity
to a maintenance collec-tion point, main supply route, or
maintenance activityfor disposition, repair, or evacuation.
k. Maintenance Co llection Point. A pointoperated by AVIM unit
for the collection of equipmentfor repair.
l. Maintenance Support Team (MST). A team ofAVIM mechanics and
technical specialists who aretrained in assessing battlefield
damage and fieldrepair procedures.
m. Maintenance Team (MT). Helicopter crewchief or AVUM
mechanics/technicians who are trainedin assessing battlefield
damage and field repair proce-dures.
1-5. QUALITY DEFICIENCY REPORT/EQUIP-MENT IMPROVEMENT
RECOMMENDATION(QDR/EIR). If your helicopter and equipment
needsimprovement, let us know. Send us an EIR. You, theuser, are
the only one who can tell us what you don’tlike about your
equipment. Let us know why you don’tlike the design. Put it on an
SF 368 (Quality Deficien-cy Report). Mail it to Commander, U.S.
Army AviationSystems Command, ATTN: AMSAV-QRF, 4300Goodfellow
Boulevard, St. Louis, MO 63120-1798.We’ll send you a reply.
Section Il. STANDARDS AND PRACTICES
1-6. BDAR CHARACTERISTICS. BDAR capa- practices. In a combat
emergency situation, greaterbility requires simplicity, speed, and
effectiveness. risks are sometimes necessary and acceptable.Some
BDAR procedures include repair techniques Refer to Appendix I of FM
1-500 for additional informa-that violate standard peacetime
maintenance tion concerning BDAR concepts.
1-3
-
TM 55-1520-244-BD
1-7. WAIVER OF PRECAUTIONS. Under combatconditions, BDAR may be
performed on helicopterswhich are in flight or which are under
power while onthe ground. While some of these BDAR actions
mayrequire waiving of safety precautions, the cautions toprotect
personnel life should not be overlooked.Other similar precautions
may be waived at the discre-tion of the commander. BDAR fixes maybe
requiredin a chemically toxic environment or under other ad-verse
battlefield conditions with severe limitations inpersonnel,
facilities, equipment, and materials. Perfor-mance of repair tasks
may be necessary while wear-ing protective gear. Decontamination
procedures aredescribed in FM 3-5.
1-8. OPERATING CHARACTERISTICS. Thismanual covers expedient
repairs for the helicopterand its components. It is entirely
possible that in acombat situation, the helicopter having
undergoneone or more of these repairs may suffer degradationof its
normal operating characteristics (e.g., reducedspeed, reduced load
capability, reduced range, etc.),and still be able to carry out all
or parts of an as-signed mission. The minimum functional
combatcapability (M FCC) criteria is as follows:
NOTE
These criteria may be waived for recoveryor to meet tactical
situation demands other-wise.
a. Flight Capability for Self-Recovery.
(1) Must have power delivered to main and tailrotor at minimum
acceptable limits.
(2) Lift capability for crew members.
(3) Flight controls at minimum function level ac-ceptable for
flight.
NOTE
Careful consideration shall be given to theoperation of the
Identify Friend or FOE(IFF), Mode 4, avionics system. Failure ofthe
IFF or failure to properly communicatewith area air defense command
prior to lift-off could result in an attack from friendlyforces due
to mistaken identity.
(4) Instruments/avionics as required to meetmission needs.
b. Flight Capability for Mission Completion.
(1) Sufficient power delivered to main and tailrotor to
accommodate lift capability for helicoptercrew and cargo.
(2) No fuel leaks which will curtail the intendedlength of
flight.
(3) No degradation of any component/systemwhich will end in
failure and curtailment of intendedmission.
(4) Communications. Must have intercomcommunications within
aircraft and at least two tacti-cal receiver-transmitter (R-T)
units operating at fullcapability.
1-9. TRAINING.
a. BDAR by its nature involves fixes, bypasses,or jury-rigging,
which is outside authorized standardrepairs, and may degrade the
inherent safety of thehelicopter. Therefore, BDAR actions are not
intendedto supplement, or replace standard maintenance prac-tices
during peacetime, nor should they be employedindiscriminately to
facilitate training.
b. Repairs described in this manual, which canbe appropriately
accomplished in order to providetraining, are listed in Appendix E
and are highlightedin each chapter’s repair procedure index.
Thetrainable repair in the index will be blocked in.
1-4
-
TM 55-1520-244-BD
Section Ill. TASKS AND RESPONSIBILITIES
1-10. TAGGING/IDENTIFYING BDAR REPAIRS.
a. All damage will be identified on aircraft inspec-tion and
maintenance record, DA Form 2408-13 andDA PAM 2408-18, per DA PAM
738-751. Refer toFigures 1-1 and 1-2.
b. Recording of BDAR repairs and the use ofstatus symbols, as
defined in DA PAM 738-750, willbe completed as soon as practical to
indicate anylimitations and restrictions or required
standardrepairs.
c. In addition to recording all damage, the areadamaged will be
marked on aircraft or componentpart using damage assessment
markings as shownFigure 1-3.
d. Status Symbols. Status symbols used in
in
aircraft logbooks to record defects are defined below.
(1) Red “X.” A red “X” shows that a defectexists and the
aircraft is unsafe for flight.
(2) Circled red “X.” A red “X’ inside a redcircle indicates a
limiting defect. The aircraft may beflown under specific limits as
directed by higherauthority, or as directed locally until
corrective actionis taken.
(3) Red horizontal dash (-).
(a) This symbol indicates an inspection, spe-cial inspection,
component replacement, maintenanceoperational check, or test flight
is needed. The sym-bol is also used to indicate that a normal
modificationwork order (MWO) is overdue.
(b) This symbol also shows that the condi-tion of the equipment
is unknown. A potentiallydangerous condition may exist. The
condition will be
(4) Red diagonal (/). This symbol indicates adefect exists that
is not serious enough to ground theaircraft.
e. Maintenance of Forms. Instructions for themaintenance of
forms, records, and reports are listedin DA PAM 738-751. When
battle damage repair(BDR) becomes necessary, the procedures in
DAPAM 738-750 will apply. Refer to Figures 1-1 and 1-2for
examples.
(1) In block 17 of DA Form 2408-13, list thefault.
(2) In block 16 of DA Form 2408-13, enter thestatus symbol.
(3) In block 18 of DA Form 2408-13, enter thecorrective action
taken.
(4) The individual completing the repair willsign the form in
block 19 opposite the first line of theaction taken, and will place
his last name initial overthe status symbol in block 16.
f. Temporary Repair. If the repair is temporary,take the
following additional action:
(1) In block 18 of DA Form 2408-13, enter thecorrective action
and a statement that the repair istemporary. Then make an entry in
DA Form 2408-14,block b. The entry will be a duplicate of the entry
inblock 17 of DA Form 2408-13 to include a statementthat a
temporary repair has been made.
(2) If the temporary repair limits the capabilityof the
aircraft, the following entry will be made on DAForm 2408-13:
(a) Place a circled red “X” in bolck 16.
corrected as soon as possible.
1-5
-
TM
55-1520-244-BD
Fig
ure
1
-1.
DA
Fo
rm 2408-13
1-6
-
TM 55-1520-244-BD
Figure 1-2.DA
Form 2408-18
1-7
-
TM 55-1520-244-BD
MEANINGS
TO INDICATE DAMAGE HAS BEEN ASSESSED AND EVALUATED:
Draw a circle around the damage.
TO INDICATE NO BDAR REPAIR REQUIRED:
Write “OK” inside the circle.
TO INDICATE STRUCTURAL REPAIRS ARE REQUIRED:
Draw a second line about 1/4 to 1/2way around the initial circle
thendraw slashes or crosshatch betweenthe two circular lines.
STRINGER REPAIR: Place an X to theleft and right of the
circle.
FRAME REPAIR: Place an X above andbelow the circle.
TO INDICATE DAMAGE TO SYSTEMS REQUIRING REPAIRS:
Draw a series of ’’curly cue” lines about1/4 to 1/2 way around
the initial circle.
TO INDICATE REPAIR INSTRUCTIONS:
For internal damage - draw a dashedcircle around the repair
instructions.
For external damage - write repairinstructions but do NOT
enclosewith a circle.
MARKINGS
REPAIRINSTRUCTIONS PARTIAL
Figure 1-3. Damage Assessment Markings (Sheet 1 of 3)
1-8
-
TM 55-1520-244-BD
WRITTEN INSTRUCTIONS MEANING
See me - print name & See assessor or whoever has signed
written instructionsrank. (Signature) for additional information.
-
Names of parts to Where compound damage occurs, the names or
abbreviation:be repaired, (item, of specific items can be written
adjacent to the damageskin, stringer. to clarify repair
instructions.
Full A full strength repair is required.
Partial Partial strength repair required in accordance
withspecific aircraft BDAR manual.
OK No repairs required - damage is within acceptable limit:for
battle conditions.
? Continual assessment or reinspection is required aftereach
sortie.
Instruction markings for system are in two parts:
(1) Repair instruction markings and meanings are shown on this
sheet and areused to indicate repair actions required.
(2) System Identification - When known, identify the system
using markingsshown on sheet 3 of this figure.
MARKINGS MEANING
Fix Repair the damaged system in accordance with
approvedstandard BDAR techniques for type of system, item,high
pressure, low pressure, etc.
Cap Terminate or block the system to prevent leakage.
Repl Replace damaged part - repairs not acceptable.
OK No repairs required.
Tag Repair instructions are written on tags tied to indivi-dual
damaged lines/components.
Figure 1-3. Damage Assessment Markings (Sheet 2 of 3)
1-9
-
TM 55-1520-244-BD
System identification markings are primarily abbreviations of
the system.
MARKINGS SYSTEM/MEANING
Sys Damage to unknown system.
Fuel Fuel
Hyd Hydraulic
HP High Pressure
LP Low Pressure
Elect Electrical
AV Avionics
Flt Cent Flight Control
Main Rotor Main Rotor Group
Tail Rotor Tail Rotor Group
Air Pneumatic
Air Cond Air Conditioning
BL Air Bleed Air System
BLC Boundary Layer Control
N2 Nitrogen
O2 Oxygen
Eng Contr Engine Control
Pow Tr Power Train
EJ Ejection
NOTE
More than one identification marking may be used to describethe
system (e.g., HP, Hyd).
Figure 1-3. Damage Assessment Markings (Sheet 3 of 3)
1-10
-
TM 55-1520-244-BD
(b) State the limitation inblock 17.
(3) If the temporary repairrequires an inspection at
intervals,list the required inspection on DA Form2408-18.
(a) Enter item to be inspectedin block 5.
(b) List the applicable TM inblock 6.
(c) State the frequency of theinspection in block 7.
1-11. REPORTS. All required writtenreports for BDAR fixes are
found in DAPAM 738-751. If communication capa-bility is damaged,
the aircraftcommander should approach the nearestfriendly radio and
make his reportif possible. The report shouldinclude these
essentials:
a. Aircraft damage (out-of-action orfunction partially
impared).
b. Location of aircraft.
c. Defense status.
d. Mobility.
e. Personnel report.
f. Current and anticipated hostileaction.
Anticipated BDAR fixes and repairtime.
1-11/(1-12 Blank)
-
TM 55-1520-244-BD
CHAPTER 2
ASSESSING BATTLEFIELD DAMAGE
BDAR FIXES SHALL BE USED ONLY IN COMBAT OR FOR TRAININGAT THE
DISCRETION OF THE COMMANDER.
(AUTHORIZED TRAINING FIXES ARE LISTED IN APPENDIX E.)IN EITHER
CASE, DAMAGES SHALL BE REPAIRED BY STANDARD
PROCEDURES AS SOON AS PRACTICABLE.
Section I. INTRODUCTION
2-1. SCOPE.
a. This chapter provides guidelines for use inassessing
battlefield damage to the AH-1 E/F/P attackhelicopter. It directs
you to an expedient BDAR fix orto the standard system fix toTM
55-1520-236-23 if anexpedient BDAR repair does not exist.
Generaldecision logic chart, Table 2-1, assists in BDAR
dis-cussions.
b. Each chapter will have a specific fault assess-ment table for
each functional group and this flowchart will direct you to
specific BDAR fixes for andwithin the functional group.
c. Use the following guidelines to find and fix sus-tained
damage or suspected damage to your helicop-ter. Keep in mind that
damage can be sustained whileon the ground or in flight. The
helicopter location canhave a considerable effect on the
assessment. Thefollowing appraisal shall be accomplished,
(1) If possible and if time permits, inspect, andcheck the
helicopter using operator’s checklist (CL),operator’s manual (–1
O), and other records and formskept in aircraft log book. At the
same time be lookingfor obvious damage to aircraft.
(3) If you find a problem, determine its effecton helicopter’s
mobility, and capability.
(4) If you cannot fix the problem with standardfixes, then apply
this TM and use general and specificassessment tables, charts, and
BDAR action.
(5) If the damage does not affect aircraft’sflying status, the
aircraft or flight commander willdecide whether to fix or defer
fix, and whether to con-tinue or to start a mission.
(6) If damage does affect flight status, do oneof the
following:
(a) Replace damaged part with a service-able part.
(b) Replace damaged part with suitable sub-stitute if it
exists.
(c) Apply a BDAR fix.
(7) After repairing the damage, replace all
lostfluids/lubricants. If one specified by aircraft TM is
notavailable, refer to Appendix D for
alternativematerials/parts.
(2) If applicable and possible, use standardtroubleshooting
recommendations in –23 series TMs.
2-1
-
TM 55-1520-244-BD
Figure 2-1. General Decision Logic
2 - 2
-
TM 55-1520-244-BD
Section II. GENERAL FAULT ASSESSMENT TABLE
2-2. GENERAL FAULT ASSESSMENT. The BDAR assessment procedure
will referAircraft assessment chart, Table 2-2, you to a guide fix
in this manual, aguides you through the aircraft’s standard TM
55-1520-236-23 repair if itcapability so that all the necessary is
feasible, or a higher AVIM level ofcapabilities are evaluated. If a
fault repair if extent of damage, time con-is found, Table 2-2
(assessment table) straint, tooling requirements, repairdirects you
to the chapter for the func- part or material, and any other
necessarytional group which contains the fault. requirements are
only available at a
higher level of maintenance.
Figure 2-2. Assessment Table 2-3
-
TM 55-1520-244-BD
Figure 2-2. Assessment Table (Cont)
2-4
-
TM 55-1520-244-BD
Figure 2-2. Assessment Table (Cent)2-5
-
TM 55-1520-244-BD
Figure 2-2. Assessment Table (Cent)
2-6
-
TM 55-1520-244-BD
Figure 2-2. Assessment Table (Cont)2-7
-
TM 55-1520-244-BD
Figure 2-2. Assessment Table (Cont)
2-8
-
2-9Figure 2-2.
CHPT 13
CHPT 15
CHPT 16
TM 55-1520-244-BD
-
TM 55-1520-244-BD
CHAPTER 3
GENERAL REPAIRS
BDAR FIXES SHALL BE USED ONLY IN COMBAT OR FOR TRAININGAT THE
DISCRETION OF THE COMMANDER.
(AUTHORIZED TRAINING FIXES ARE LISTED IN APPENDIX E.)IN EITHER
CASE, DAMAGES SHALL BE REPAIRED BY STANDARD
PROCEDURES AS SOON AS PRACTICABLE.
No general repairs have been identified Chapters 4 thru 17 for
functional groupfor this model helicopter. Proceed to assessment
and repair procedures.
3-1/(3-2 Blank)
-
TM 55-1520-244-BD
CHAPTER 4
AIRFRAME
4-1.
a.
BDAR FIXES SHALL BE USED ONLY IN COMBAT OR FOR TRAININGAT THE
DISCRETION OF THE COMMANDER.
(AUTHORIZED TRAINING FIXES ARE LISTED IN APPENDIX E.)IN EITHER
CASE, DAMAGES SHALL BE REPAIRED BY STANDARD
PROCEDURES AS SOON AS PRACTICABLE.
Section I. INTRODUCTION
SCOPE.
This chapter contains methods for assessingbattlefield damage to
the primary structure of the -
AH-1 airframe, classification of damage, rules fordeferring
repair, and expedient field fixes of battlefielddamaged airframe
structures.
b. Aircraft structure is classified as primary andsecondary
structure.
(1) The primary structure is the basic structurewhich holds the
aircraft together. Any serious damageto any element of the primary
structure will restrict thecombat capability of the aircraft. The
primary struc-tures for each major airframe subassembly aredefined
throughout this chapter.
(2) Secondary structures are mounted on theprimary structure. No
amount of structural damage tosecondary structures will restrict
combat capabilityfrom a structural safety point of view; however,
secon-dary structure may be required for aerodynamicreasons or to
accomplish or support mission functions.
4-2. ASSESSMENT PROCEDURES. The battle-field structural damage
assessment consists of twosteps: an initial assessment, and a
detailed assess-ment. The initial assessment is a quick visual
assess-ment to decide whether or not a detailed assessment
should be made. A detailed assessment involves theidentification
of all damage to primary structural ele-ments, possibly some
cleanup and measurement ofthe damage and of the damaged elements.
Thisprocess requires damage measurement and deter-mination of the
corresponding damage limits. An over-all view of all the aircraft
zones used in damageassessment is shown in Figure 4-1.
NOTE
The standards contained herein allowaircraft to be flown with
battle damage sub-stantially in excess of peacetime limits.Under no
circumstances shall this manualbe used wholly or in part for
peacetimemaintenance of the aircraft. Assessment ofaircraft battle
damage requires extremecare and diligence and strict adherence
tothe instructions and standards contained inthis manual. If at any
stage of damage as-sessment the assessor believes that over-sights
or errors have been made, theassessment shall be stopped at that
pointand repeated from the beginning. Underno circumstances shall
the requirements ofthis manual be waived or circumventedwithout the
express approval of the com-mander or his designated
representative.
4-1
-
TM 55-1520-244-BD
Figure 4-1. Aircraft Zones
4-2
-
● Battle damaged areas should be inspectedfor unexploded
ordnance before attempt-ing repairs. Disposal of unexplodedordnance
should be accomplished byqualified EOD personnel.
● Loaded weapons, or weapons beingloaded or unloaded, shall be
pointed in adirection which offers the least exposure topersonnel
or property in the event of ac-cidental firing. Personnel shall
remainclear of hazardous area of all loadedweapons.
● Ground safety pins must be installed inpilot and gunner
arming/firing handles ofcanopy removal system whenever
thehelicopter is on the ground. Pins should beinstalled by
crew.
a. Initial Assessment. Refer to Table 4-1. To per-form an
initial assessment, the assessor must be ac-quainted with
structural damage modes and theprimary structure. He shall be
capable of differentiat-ing between primary and secondary
structure, and hemust understand the function of primary structural
ele-ments. The initial assessment consists of a visual in-spection
of primary structure. The assessordetermines if any primary caps,
webs, or panels aredamaged or fractured and decides whether–
(1) The damage appears to be deferrable;
(2) A detailed assessment can be made andthe damage can be
repaired by BDAR techniqueswithin the time available to return the
aircraft to ser-vice in the ongoing battle;
TM 55-1520-244-BD
(3) An adequate assessment can be made andthe damage can be
repaired by BDAR techniques toenable the aircraft to
self-recover;
(4) A detailed assessment cannot be made orthe damage cannot be
repaired by BDAR techniqueswithin the available time; or
(5) The aircraft is damaged beyond repair, andits disposition
shall be arranged (e.g., recovery, canni-balization, or
destruction).
b. Detailed Assessment.
(1) Access to damaged structure. Locate alldamage to airframe
primary structure. Removeaccess panels, covers, and fairings in the
damagedarea. Remove aircraft components as required to in-spect the
structure. Use the location of entrance andexit wounds and the
estimates of projectile paths todetermine the areas where damage
may be presentand access to interior inspection will be needed. If
anarea of structure suspected of being damaged cannotbe reached by
other means, cut small inspectionholes in the exterior skin. Then
inspect internal mem-bers with an inspection light and mirror.
NOTE
Inspection holes cut in the exterior skin ifleft unrepaired will
have to be treated asdamaged structure in the damage evalua-tion.
Allow for access to the areas immedi-ately next to the area where
damage isknown to have occurred. This will ensurethat damage caused
by stray particles anddislodged sections of material can befound.
All significant damage to theairframe primary structure must be
lo-cated. Small damage can be critical tosome components.
4-3
-
Table 4-1.
TM 55-1520-244-BD
4-4
-
TM 55-1520-244-BD
(2) Inspecting for cracks.
(a) Impact cracks. Cracks maybe caused by projectile impact
orpenetration. They may also be caused asa direct result of blast
pressures.Battle damaged elements carrying reducedloads will place
more severe loads onsurviving members and may also producecracks.
When cracks are a result ofthese last two factors, they may occurin
regions away from the site of theprimary damage.
(b) Projectile damage sitecracks. Cracks will primarily be
foundat the site of the projectile damage.Holes, spans, and gouges
caused byricochets and embedded particles willoften have cracks
associated with them.These may be large and visible orhairline and
microscopic. Small cracksmay be as critical as large cracksbecause
they may grow rapidly undercontinued loading, particularly
whenlocated at the edge of a hole.
(c) Airframe structure cracks.Locate all cracks in airframe
primarystructure. At each damage site, inspectthe area for cracks.
Use inspectionaids such as magnifying glasses or dyepenetrant to
locate small cracks.Cracks may not go all the way throughthe
material, so it is necessary toinspect both sides. When a
structureshows signs of overstress, it is vitalto inspect for
cracks around fasteners.
(d) High explosive incendiary(HEI) explosion cracks. For
aircraftdamaged by an HEI strike, inspect all ofthe structure in
the area of the explo-sion. Aircraft may have been flown with
(3) Inspecting for structuralchanges.
(a) Structural changes.Inspect for structural changes when
theaircraft has taken an HEI hit or theaircraft has flown with
primary struc-ture damaged or missing. Inspect boththe damaged
structure and the surroundingundamaged area for evidence of
buckling,crippling, and misalignment. This typeof damage is usually
revealed by kinksor wrinkling and “oil canning” of skinpanels.
Sheared, pulled-through, andmissing fasteners are also
indicationsof structural changes.
(b) Buckling, crippling, andmisalignment. Structural changes in
theform of buckling, crippling, and misa-lignment can happen as a
result of blastpressures. These could be associatedwith a HEI
attack or as a result of theoverstress placed on a member.
Suchmembers may have to carry the load ofanother member which has
been broken orcrippled by projectile damage. Thistype of damage can
be critical to thestructural performance of a member andmay also
cause interference with mecha-nical moving components which may
bindor jam. This is especially true whenthe member has to support
compressionloads. A stringer that has been damagedcan continue to
support some tension;for example, but may be completely
inef-fective in compression.
(c) Twisting or bowing.Examine the component for alignment
andsigns of twisting or bowing. Use astraight edge to inspect these
con-ditions.
major structural battle damage or failure. (4) Inspecting for
embeddedIt is vital to inspect for cracks in all projectiles and
fragments.areas to which additional load may havebeen
distributed.
4-5
-
TM 55-1520-244-BD
(a) Embedded projectile. Theeffect of an embedded projectile
orfragment in a tension member can be assevere as that of a hole or
crack of thesame size. The embedded object createsan interruption
in the structural sec-tion. Since it is difficult to detect,it must
be assumed that the projectilehas nearly gone through the
structure.
(b) Embedded projectile inspec-tion. Inspect for embedded
projectilesand fragments when either of the follow-ing conditions
occur:
1 The aircraft has sufferedHEI damage.
2 Inspection of the aircraftindicates that a solid projectile
hasnot exited the aircraft, has brokenapart, or has created
shrapnel bystriking internal components.
(C) Projectile path deter-mination. The determination of
projec-tile paths will aid in identifyinginternal structures that
may containembedded projectiles or fragments.Inspect all structures
in the regionusing a bright light and magnifyingglass. Clearly mark
embedded objectsand record them on DA Form 2404, Figure4-2.
(5) Inspecting for fire damage.
(a) Armor piercing incendiary(API) and HEI fire damage. The API
andHEI threats include the possibility offire damage. These threats
have a fire-starting capability if flammablematerials are
present.
(b) Fire effects. Some firesmay not adversely effect metal
airframestructures. When aluminum is exposed totemperatures above
300°F (149°C) for aprolonged period, the temper andstrength of the
material will bereduced.
(c) Initial fire damage evi-dence. The first signs of possible
firedamage will be a discoloration of thestructure. Any
discoloration indicatesthat the member has been exposed to
hightemperature. Conduct a hardness test todetermine if the temper
of the materialhas changed. Such tests should be con-ducted in
accordance with standard prac-tices. If a hardness test showsheat
damage, record the information onDA Form 2408 and clearly mark
themember.
(6) Detecting substructural damagein adjoining areas.
(a) Secondary damage. When theairframe has been subjected to
severeoverstress, members undamaged by projec-tiles may bend or
buckle. This might becaused by explosive blast or maneuveringloads
imposed on damaged structures.Sometimes this secondary damage
willoccur in a region away from the primaryarea of damage. The
airframe near theprojectile damage should be inspectedfor evidence
of secondary damage.
(b) Secondary damage indicators.Inspect the skin for creases,
wrinkles,and dents. Inspect fasteners forchipped or flaked paint,
looseness, andserviceability. These conditions aresigns of damage
to structure. Open orremove access panels and doors, deter-mine
whether the frame is warped, andinspect the interior members for
cracksand structural changes. Clearly markand record all
damage.
(7) Inspecting for broken andmissing fasteners.
(a) Fastener damage or loss.Some fasteners join parts together
in anassembly, and some join one structuralmember to another.
Sheared, pulled-through, torn-out, elongated fastenerholes, and the
damage or loss of fas-teners can severely weaken the soundnessof a
structure.
4-6
-
TM 55-1520-244-BD
Figure 4-2. DA Form 2404
4-7
-
TM 55-1520-244-BD
(b) Riveted and bolted joints.Inspect all riveted and bolted
jointsnear the battle damage. Look forsheared, pulled-through,
torn-outfasteners, and elongated fastener holes.Carefully inspect
members showing signsof structural change and for fastenerswith
chipped or cracked paint. Wherepossible, inspect fasteners from
bothsides. Clearly mark and record alldamaged fasteners on DA Form
2404.
(8) Inspecting for delamination.To verify suspected damage to
honeycombstructures, use coin tapping method todetermine size and
shape ofdisbonds/delaminations.
NOTE
Resonation of coin tapping on thestructure will determine
hollow-ness or existence of delamination.
(9) Marking and recording damage.
(a) Damage recording. Accuraterecording of damage is an
important partof battle damage assessment. Record alldetected
damage on DA Form 2404. Deter-mine allowable damage limits.
Establishan order of repair on DA Form 2404.Record individual areas
of damage to asingle structural element separately onthe form. If a
structural member ismassively damaged or severed,
recordingindividual areas of damage isunnecessary.
(b) Damage diagrams. Show thelocation and extent of damage on
copiesof the diagrams given in this chapter.The damage can be drawn
by hand.Accurately locating damage on a diagramwill greatly help
the damage assessmentprocedure.
(c) Marking damage. Mark thedamaged structure using grease
pencil orpaint. Use the labeling scheme given inFigure 1-3.
CAUTION
Use of lead pencil in some areaswill cause corrosion.
1 Use a bright color tooutline each area of damage as it
islocated and recorded on the DA Form2404. Attempt to make the
outlinevisible from all angles.
2 Draw arrows on inside skinpanels, webs, and bulkheads to
pointtoward areas of damage that are hidden.
c. Damage Measurement. If the assess-ment indicates that the
damage should berepaired by BDAR or standard procedures,no damage
measurement isnecessary. Damage measurement isrequired to determine
if structuralrepair (other than cleanup) can bedeferred, or if
self-recovery of thedamaged aircraft is feasible. Damagemeasurement
may also be required if aBDAR repair does not restore
originalstrength. Begin damage measurement withthe largest
damage.
(1) Caps and longerons.
(a) The parameters involved inmeasuring damage to a cap or
longeronare shown in Figure 4-3. The pertinentvalues are as
follows:
CD = Depth of damage.CL = Length (width) of damage.A = CL x CD =
area of damage.D = Distance between damages.
In Figure 4-4, the length of the flat-tened cross section shown
is a+b.
If CD is the depth of the damage intothe flattened cross
section, then CS Isthe length of the remaining effectivecross
section still capable of support-ing load, and CS= (a+b)-CD.
Alwaysmeasure CD.
4-8
-
TM 55-1520-244-BD
Figure4-3. Measuring Cap or Longeron Damage
Figure 4-4. Damaged Cross Section
4-9
-
TM 55-1520-244-BD
(b) Damage measurements applyafter cleanup and smoothing or
afterBDAR has been accomplished; however, asa practical matter,
measurements mustoften be taken before smoothing to makea decision
on deferrability. Hence,when estimating damage limits beforecleanup
and smoothing, make allowancefor the material that will be removed
insmoothing. This applies particularly tocracks; the length of the
crack must beincluded in the depth (CD) and length(CL)
measurements. When measuringdamage, use the following procedures
ifpossible:
1 Clean all damaged areasthoroughly. Use brushes and rags
toremove dirt and film from small creviceswhere damage may be
present.
2 Smooth all jagged andrough edges and be sure to cut out
allradiated cracks. Use largest cornerradii possible in the
cut-outs; avoidsharp corners.
3 Measure damage aftersmoothing or if measuring beforesmoothing,
make allowance for thematerial which must be removed
duringsmoothing.
4 Use a steel rule graduatedin tenths of an inch and measure
eachdamage dimension to the next highertenth.
5 Include the size of thehole when measuring damage that
extendsinto a fastener hole or lightening hole.
6 Record on DA Form 2404.
(2) Webs, panels, floors, anddecks.
across the damage, regardless of direc-tion and must include all
radiatedcracks. “D” is the distance betweendamages. Take and record
measurementsas described in paragraph 4-2.c(1) (b).
(b) Honeycomb sandwich struc-tures. Refer to Figure 4-7 for
themeasurement of “WL” and “D.” If a pro-jectile hits a sandwich
panel at anangle, the damages in the two skins maybe off-set and of
different sizes.Measure the damage on the side with thelargest
damage (usually the exit side),and make sure that the
measurementincludes the damaged area on the otherside. “WL” is the
largest dimensionacross the damage (both sides),regardless of
direction, and mustinclude all radiated cracks. “D” is thedistance
between damages. Take andrecord the measurements as
previouslydescribed.
d. General Damage Limits.
(1) The allowable damage limitscorresponding to the damage
measurementsof paragraph 4-2.c are designated for agiven condition
as follows:
CD' = Allowable depth ofcap/longeron damage.
DL' = Allowable length (width) ofcap/longeron damage.
A' = Allowable area of damage.
D' = Minimum allowable distancebetween damages.
WL' = Allowable largest dimensionacross web/panel damage.
N = Minimum Damage Factor.
(a) Refer to Figures 4-5 and4-6 for the measurements of "WL"
and"D." "WL" is the largest dimension
4-10
-
TM 55-1520-244-BD
Figure 4-5. Measuring Skin Panel Damage
Figure 4-6. Measuring Damage in Floors and Decks
4-11
-
TM 55-1520-244-BD
Figure 4-7. Measuring Damage in Honeycomb Panels
(2) Allowable damage limits areassociated with the conditions
ofthe primary structural elements asdescribed below. A damage limit
for agiven condition is a measure of theamount of damage that a
structuralmember can sustain and still supportthe loads associated
with the givencondition. These limits were developedfrom the
aircraft manufacturer’s origi-nal engineering design
calculations.
(3) Condition is an indicator ofthe residual capacity of a
damaged struc-tural element to perform its function.Battlefield
damaged structures or BDARrepairthree
fullyrestriunder
damages. Therefore, aircraft with struc-tural damage whether
repaired or repairdeferred should be inspected after everyflight.
The inspector should look forcrack growth, evidence of
overstress,growth of allowable deformation, or thedevelopment of
new cracks at other loca-tions.
(b) Condition 2. Self-recoverycapable. Self-recovery may be
requiredto move a damaged aircraft to a repairsite or from one site
to another, whentowing is not feasible. Self-recoveryis preferable
to disassembly and boxingan aircraft for transportation. As
time
ed structures are classified in permits, proceed as
follows:conditions:
1 Mark all visible cracks(a) Condition 1. Aircraft and the
extent of other structural
flight capable. No flight damage with chalk, grease pencil,
paint,ctions; however, on a battlefield tape, or other available
means so thatthe pressures of time and tactical any growth in the
damage can be quickly
situations’, the assessment of structural recognized.damage may
not have revealed all the
4-12
-
TM 55-1520-244-BD
2 Perform any feasible on-site BDAR fixes as required for
self-recovery.
(c) Condition 3. Structuraldamage not repairable by BDAR
tech-niques, not self-recovery capable. Theairframe is so
extensively damaged thatno useful or needed functions can
berestored within the available time andresources. These aircraft
will be:
1 recovered or evacuated toa facility with the resources to
repairthe airframe,
2 used as a source of can-nibalized components, or
3 destroyed. This is a lastresort.
(d) These conditions apply tothe primary structure and should
not beconfused with the mission capabilityclassifications. Mission
capability isdependent on equipment condition.
(4) In a given condition if alldamages are equal to or less than
thecorresponding allowable damage limitsand the distance between
damages areequal to or greater than the correspond-ing minimal
allowable limit, that is,
CD < CD'CL < CL'WL < WL'D > D '
the aircraft may be released for flightin that condition. Repair
may bedeferred although some clean-up andsmoothing of the damage
will be requiredas will inspection for damage growthafter every
flight. Special con-sideration should be given to damageexposed to
the airstream, particularlyto the effects of ram air, rain, and
petaling. Petals may vibrate in thepassing airflow, rapidly
creating cracksin the supporting base metal. Largepieces of metal
may peel off and damageother parts of the aircraft. Thedistance D
between damage sites formost structures has a minimum
requiredspacing. The spacing requirement isexpressed as a multiple
factor (N) ofthe measured area of damage.
(a) The factor applies to thedamage actually measured not to
themaximum damage limit for the structure.
(b) The factor applies to thelargest dimension of the largest
damagebetween which separation is beingmeasured.
(c) The factor applies only ifthe dimensions of both damages,
whenadded together, exceed the single damagelimit.
(5) Continuous members. Allowabledamage limits for caps,
longerons, webs,floors, decks, and stiffness are giventhroughout
this section as appropriate.
(6) Damaged fittings, attachments,and splices are classified as
unservice-able and must be repaired, reinforced,or replaced if any
of the followingconditions exist:
(a) Damage to the fitting hasremoved more than 20 percent of
thestructural cross section at any onelocation.
(b) One or more fastenersconnecting the fitting to a
continuousaircraft component are bent, sheared,stripped, or
loose.
(c) The fitting shows signs ofoverstress or structural
distortion.
4-13
-
TM 55-1520-244-BD
(7) Damage limits are calculatedon the basis of the AH-1S
structuralanalysis and tend to be conservative.Assessors using
damage limits to preparedamage assessments should consider themas
guides and balance the damage limitsagainst the judgment resulting
fromtheir own experience.
e. Fuselage Damage Assessment.
(1) General.
(a) The fuselage midsectionprimary basic structure consists of
abox beam starting at FS 148.5 andextending to FS 300.68, Figure
4-8.Forward of the box beam (FS 148.5), twofuselage beams and
cockpit floors extendforward to FS 61.25 to support the cock-pit
and gun turret. The tail boomattaches to the fuselage at FS
300.68and extends to the fin which supportsthe tail rotor and the
stinger (tailbumper).
(b) The fuselage box beam con-sists of 4 caps (Figures 4-9 and
4-11)connected vertically by the webs of thefuselage beams (Figures
4-10 and 4-12)and connected horizontally by the upperand lower
panels (Figure 4-13). Bulk-head flanges act as spacers betweenthe
caps, both vertically and horizon-tally, and should be treated as
caps ina damage assessment. The bulkheads alsohold the shape of the
aircraft anddistribute concentrated loads into thevertical panels
and/or horizontalpanels. The concentrated loads includethe loads
from the landing gear, pylon,wing attachments, elevator, tail
rotor,fin, and tail bumper.
(2) Damage measurement.
(a) Reproduce Figures 4-14 to4-17 as required, and use to mark
updamaged areas.
(b) Refer to Figures 4-9 to4-13 for definition and
identificationof primary fuselage structural elements.
(c) Mark all detected damage onthe appropriate figure, and add
remarksto clarify markings as described inparagraph 4-2.b(9).
(d) Refer to paragraph 4-2. cand for each damaged element,
measurethe depth "CD" and the length (width)"CL" or "WL" of each
damage. Count thenumber of damages and measure the "D"between
damages. Start with the worstdamage. Record the values on DA
Form2404 and compare therewith the allowabledamage limits given in
this section.Select the set of allowable damagelimits which are
next larger than themeasured damage, determine thecorresponding
condition. Considerwhether damage could result in flightfailure of
other elements. Attempt tovisualize what effect large defectionsof
damaged member will have on adjacentstructure.
(e) Decide on whether repaircan be deferred or whether damage
shouldbe fixed and what the condition ofdeferred or repaired damage
would be.
(f) Determine the priority ofthe various required repairs based
onrepair time, difficulty of repair,resources available, tactical
situation,and need for the aircraft, etc. Thelongest repair time
normally is giventhe highest priority and is mostcritical.
(g) Enter repair requirementson DA Forms 2404.
(3) Allowable fueslage damage
4-14
-
TM 55-1520-244-BD
Figure 4-8. Airframe Reference Lines
4-15
-
TM 55-1520-244-BD
Figure 4-9. Primary Structural Caps L/H
Figure 4-10. Structural Webs L/H
4-16
-
TM 55-1520-244-BD
Figure 4-11. Primary Structural Caps R/H
Figure 4-12. Structural Webs R/H
4-17
-
TM 55-1520-244-BD
Figure 4-13. Fuselage Box Beam Panels
4-18