Appendix B: CONVERTING THE AH-1G/UH-1C/M HELICOPTER HYDRAULIC SYSTEMS FROM MIL-H-5606 TO MIL-H-83282 HYDRAULIC FLUID

TB 55-1500-334-25

APPENDIX B

CONVERTING THE AH-1G/UH-1C/M HELICOPTER HYDRAULIC SYSTEMS

FROM MIL-H-5606 TO MIL-H-83282 HYDRAULIC FLUID

B-1. Ground Servicing Equipment Required.

c. Disconnect the tail rotor servo at the control

tube and actuate the piston four full strokes to discharge

AH-1G/Q/S, series/UH-1C/M helicopter hydraulic

residual fluid from the cylinder.

systems from MIL-H-5606 to MIL-H-83282 hydraulic fluid.

d. Drain all hydraulic fluid from the emergency

B-2. Items to be Manufactured.

accumulator. Refill the accumulator with MIL-H-83282,

slosh fluid and drain.

Drain line from ground test coupling (return) on

the aircraft.

B-5. Component Replacement.

B-3. Removal of Components.

a. Install both hydraulic pumps. Fill pumps with

MIL-H-83282 through the case drain port. Install all

a. Disconnect the suction hose from the reservoir

remaining hoses to the pumps.

to the hydraulic pump, # 1 System, at the pump. Allow

the fluid from the reservoir to drain into a receptacle.

b. Install pressure and return hoses to the

Repeat the above for the I# 2 system hydraulic pump.

hydraulic servo cylinders.

NOTE

CAUTION

Drain the fluid from each system

Do not Inter-connect hydraulic hoses

reservoir sump using the drain plugs at

from one cylinder to the other.

the bottom of the reservoirs,

c. Connect control rods to the swashplates.

b. Disconnect all remaining hoses at the pumps

and remove the pumps. Drain all hydraulic hoses of fluid.

d. Install pressure and return hoses to the anti-

torque servo cylinder. Connect the control rod to the

c. Remove filter elements (4) from the hydraulic

piston rod.

modules. Clean and reinstall the bowls without the filter

elements.

e. Install the accumulator and hydraulic hose to

the accumulator. Charge the accumulator with nitrogen.

d. Discharge the accumulator and disconnect

hose at the accumulator, loosen holdown nuts and

B-6. Filling, Bleeding and Functional Testing.

remove accumulator. Drain hydraulic hose of fluid.

Refer to Appendix D or E for specific instructions

e. Disconnect and drain hydraulic hoses from

concerning conversion of ground servicing units.

main rotor servo cylinders (3).

a. Disconnect the return hose to the reservoir at

f. Disconnect and drain hydraulic hoses from

the ground test coupling, #1 system, and allow the hose to

anti-torque servo cylinder.

drain.

B-4. Component Flushing.

b. Connect drain line to the ground test coupling

and place unattached end in an open container.

a. To drain all hydraulic fluid from both hydraulic

pumps turn the splined shaft while pump is inverted. Turn

c. Attach pressure hose from hydraulic ground

shaft until fluid no longer drains from pressure and return

servicing unit to ground test coupling (pressure) #1

ports in the pump body. Fill pump through return port with

system.

MIL-H-83282 and repeat the above procedure with both

pumps.

d. Bring hydraulic pressure to 1000 psi and meter

hydraulic fluid into the aircraft hydraulic system while

b. Disconnect the control tube from each control

actuating the cyclic, collective, and

cylinder at the swashplate. Actuate the piston on each

cylinder four full strokes to discharge residual fluid from

the cylinder.

Change 5

B-1