Bell OH-58A User manual

TM 55-1520-228-BD
TECHNICAL MANUAL
OPERATORS, AVIATION UNIT,
AND AVIATION
INTERMEDIATE MAINTENANCE
FOR
HELlCOPTER,
OBSERVATION
OH-58A & OH-58C
ITEM NSN
INSIDE FRONT COVER
This publication supersedes
TM 55-1520-228-BD dated
17 August 1990.
CHAPTER 1. GENERAL INFORMATION
CHAPTER 2. ASSESSING BATTLEFIELD DAMAGE
CHAPTER 3. GENERAL REPAIR
CHAPTER 4. AIRFRAME
CHAPTER 5. ALIGHTING GEAR
CHAPTER 6. POWER PLANT
CHAPTER 7. ROTORS
CHAPTER 8. DRIVE TRAIN SYSTEM
CHAPTER 9. HYDRAULIC SYSTEM
CHAPTER 10: INSTRUMENT SYSTEMS
CHAPTER 11. ELECTRICAL SYSTEM
CHAPTER 12. FUEL SYSTEM
CHAPTER 13. FLIGHT CONTROLS
CHAPTER 14. UTILITY SYSTEM
CHAPTER 15. ENVIRONMENTAL CONTROL SYSTEM
CHAPTER 16. MISSION EQUIPMENT
CHAPTER 17. EMERGENCY EQUIPMENT
APPENDIX A . REFERENCES
APPENDIX B. SPECIAL OR FABRICATED TOOLS
APPENDIX C. EXPENDABLE/DURABLE SUPPLIES & MATERIALS
APPENDIX D. SUBSTITUTE MATERIALS/PARTS
APPENDIX E. BDAR TRAINING PROCEDURES
HEADQUARTERS, DEPARTMENT OF THE ARMY
4 January 1991
APPENDIX F. AVIONICS CONFIGURATIONS

TM 55-1520-228-BD
BDAR FIXES SHALL BE USED ONLY IN COMBAT
AT THE DISCRETION OF THE COMMANDER
AND SHALL BE REPAIRED BY STANDARD MAINTENANCE PROCEDURES
AS SOON AS PRACTICABLE AFTER THE MISSION IS COMPLETED.
BDAR TECHNIQUES IN THIS MANUAL PERTAIN to the following helicopters:
OH-58A Helicopter, Observation NSN 1520-00-169-7137
OH-58C Helicopter, Observation NSN 1520-01-020-4216

TM 55-1520-228-BD
WARNING DATA
Personnel performing operations, procedures, and practices which are included or
implied in this technical manual shall observe the general following warnings.
Disregard of these warnings can cause serious injury or death.
WARNINGS
FLIGHT SAFETY
The standards contained herein allow aircraft to be flown with battle damage
substantially in excess of peacetime limits. Under no circumstances shall this
manual be used entirely or in part for peacetime maintenance of the aircraft.
Assessment of aircraft battle damage requires extreme care and diligence and strict
adherence to the instructions and standards contained in this manual. If at any
stage of damage assessment the assessor believes that oversights or errors have
been made, the assessment shall be stopped at that point and repeated from the
beginning.
Under no circumstances shall the requirements of this manual be waived
or circumvented without the express approval of the commander or his designated
representative.
EXPLOSIVES
Battle damaged areas should be inspected for unexploded ordnance before attempting
repairs. Disposal of unexploded 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 exposure to personnel or property in the event of accidental
firing. Personnel shall remain clear of hazardous area.
CLEANING SOLVENTS
Cleaning solvents may be flammable and toxic. Use only in well-ventilated areas.
Avoid inhalation of vapor and skin contact. Do not use solvents near open flame or
in areas where very high temperatures prevail. Solvent flash point 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.
ELECTROLYTE
Battery Electrolyte (Potassium Hydroxide) is corrosive. Wear rubber gloves, apron,
and face shield when handling leaking batteries. If potassium hydroxide is spilled
on clothing or other material, wash immediately with clean water. If spilled on
personnel, immediately start flushing the affected area with clean water. Continue
washing until medical assistance arrives.
a

TM 55-1520-228-BD
HIGH VOLTAGE
is used in this equipment.
DEATH ON CONTACT
may result if personnel fail to observe safety precautions.
Never work on electronic equipment unless there is another person nearby who is
familiar with the operation and hazards of the equipment and who is competent in
administering first aid. When the technician is aided by operators, he must warn
them about dangerous areas.
Whenever the nature of the operation permits, keep one hand away from the equipment
as 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 may
cause death under adverse conditions. For Artificial Respiration, refer to FM 21-11.
b

TM 55-1520-228-BD
EXTERNAL STORES
Prior to any helicopter maintenance functions that require external stores be
removed, JETTISON cartridge shall be removed.To prevent injury to personnel
and damage to equipment, remove jettison cartridges from stores ejection device
prior to placing helicopter in a hangar.
All ground safety pins must be removed before flight.Failure to do so will prevent
emergency jettison of stores.
FIRE EXTINGUISHER
Exposure to high concentrations of monobromotrifluoromethane (CF3BR) extinguishing
agent or decomposition products should be avoided.The liquid should not be allowed
to come into contact with the skin, as it may cause frost bite or low temperature
burns.
FUELING AND FUEL REPAIRS
When refueling helicopter,the refueling vehicle must be parked a minimum of 20 feet
from the helicopter.Before starting the fueling operation, always insert fueling
nozzle grounding cable of fuel truck into GROUND HERE receptacle.Refer to FM
10-68.When defueling,turn off all electrical switches and disconnect external
power from the helicopter.The helicopter must be electrically grounded prior to
defueling.
Fuel line and tank repairs often involve handling of highly flammable material.
Mishandling can result in serious injury or death.
GROUNDING HELICOPTER
The helicopter should be electrically grounded when parked to dissipate static
electricity.Turn off all power switches before making electrical connections or
disconnections.
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 or
death may occur.Be sure to open all drains and vents before beginning disassembly.
HYDRAULIC FLUID
Prolonged contact with liquid or mist can irritate eyes and skin. Wear rubber
gloves when handling liquid.After contact with skin, inmmediately wash contacted
area with soap and water.If liquid contacts eyes,flush immediately with clear
water. If liquid is swallowed, do not induce vomiting, get immediate medical atten-
tion.If prolonged exposure with mist is likely, wear an appropriate respirator.
When fluid is decomposed by heating, toxic gases are released.
c

TM 55-1520-228-BD
LIFTING
Lifting or moving heavy equipment incorrectly can cause serious injury. Do not try
to lift or move more than 50 pounds by yourself. Bend legs while lifting. D
O not
support heavy weight with your back.
Always use assistants during lifting opera-
tions.
Use guide ropes to move hanging assemblies. Lack of attention or being in
an improper position during lifting operations can result in serious injury.
Pay
close attention to movements of assemblies being lifted. Do not stand under lifted
assembly or in a position where you could be pinned against another object. Watch
your footing.
NOISE
Sound pressure levels in and around this aircraft during operating conditions exceed
the Surgeon General’s hearing conservation criteria, as defined in TB MED 501.
Hearing protection devices such as aviator helmet or ear plugs are required to be
worn.
RADIOACTIVE MATERIALS
Self-luminous dials and ignition units may contain radioactive materials. If such
an instrument or unit is broken or becomes unsealed, avoid personal contact. Use
forceps 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). Repair
shall conform to requirements in AR 385-11.
SANDING DUST
Sanding on reinforced laminated glass produces fine dust that may cause skin
and lung irritations. Observe necessary protective measures.
STARTING HELICOPTER
Starting and operation of the helicopter will be performed only by authorized
personnel.
TOXIC POISONS
Turbine fuels, lubricating oils, and adhesives contain additives which are poisonous
and readily absorbed through the skin.
Do not allow them to remain on skin longer
than necessary. Wear protective equipment.
d

TM 55-1520-228-BD
C 1
CHANGE HEADQUARTERS
DEPARTMENT OF THE ARMY
NO. 1 WASHINGTON, D.C., 1 September 2005
TECHNICAL MANUAL
OPERATORS, AVIATION UNIT, AND AVIATION INTERMEDIATE
MAINTENANCE
BATTLEFIELD DAMAGE ASSESSMENT AND REPAIR
FOR HELICOPTER, OBSERVATION OH-58A & OH-58C
DISTRIBUTION STATEMENT A:Approved for public release; distribution is unlimited.
TM 55-1520-228-BD, dated 4 January 1991, is changed as follows:
1. Remove and insert pages as indicated below. New or changed text material is indicated by a vertical
bar in the margin. An illustration change is indicated by a miniature pointing hand.
Remove Pages Insert Pages
------------- A/(B blank)
i and ii i and ii
1-5 and 1-6 1-5 and 1-6
2. Retain this sheet in front of manual for reference purposes.
DISTRIBUTION:
To be distributed in accordance with Initial Distribution Number (IDN) 311704, requirements for
TM 55-1520-228-BD.
By Order of the Secretary of the Army:
PETER J. SCHOOMAKER
General, United States Army
Chief of Staff
Official:
SANDRA R. RILEY
Administrative Assistant to the
Secretaryof the Army
0518801

TM 55-1520-228-BD
*Zero in this column indicates an original page.
LIST OF EFFECTIVE PAGES
Insert latest changed pages. Dispose of superseded pages in accordance with regulations.
NOTE: On a changed page, the portion of the text affected by the latest change is indicated by a vertical
line, or other change symbol, in the outer margin of the page. Changes to illustrations are indicated by
miniature pointing hands. Changes to wiring diagrams are indicated by shaded areas.
Dates of issue for original and changed pages are:
Original………… 4 January 1991 Change 1……… 1 September 2005
TOTAL NUMBER OF PAGES IN THIS PUBLICATION IS 762. CONSISTING OF THE FOLLOWING:
Page *Change Page *Change
No. No. No. No.
Cover.....................................................0
A through d............................................0
i..............................................................1
ii through ix............................................0
x blank...................................................0
1-1 through 1-5......................................0
1-6.........................................................1
1-7 through 1-11....................................0
1-12 blank..............................................0
2-1 through 2-9......................................0
2-10 blank..............................................0
3-1.........................................................0
3-2 blank................................................0
4-1 through 4-70....................................0
5-1 through 5-6......................................0
6-1 through 6-12....................................0
7-1 through 7-8......................................0
8-1 through 8-12....................................0
9-1 through 9-17....................................0
9-18 blank ............................................0
10-1.......................................................0
10-2 blank..............................................0
11-1 through 11-49................................0
11-50 blank ...........................................0
12-1 through 12-9..................................0
12-10 blank ...........................................0
13-1 through 13-14................................0
14-1 and 14-2........................................0
15-1 through 15-11................................0
15-12 blank ...........................................0
16-1.......................................................0
16-2 blank..............................................0
17-1.......................................................0
17-2 blank..............................................0
A-1.........................................................0
A-2 blank...............................................0
B-1 and B-2...........................................0
C-1 through C-4 ....................................0
D-1 through D-11..................................0
D-12 blank.............................................0
E-1 and E-2...........................................0
F-1 through F-22...................................0
Index-1 through index-5........................0
Index-6 blank ........................................0
Glos-1 through Glos-8 ..........................0
Change 1 A/(B blank)