Aircraft testing procedure

TM 55-4920-442-13&P

CAUTION

Do not exceed the rated volume flow for the aircraft system pumps. Refer to the aircraft

publication for pump capacities.

h. The controls in the aircraft must be continually cycled to make certain all air is bled from the aircraft system by

the bleeding procedure.

i. Replace the hydraulic fluid used during the bleed operation to maintain a sufficient supply in the stand reservoir

(over one-half full) while filling is in progress.

j. When the bleeding process is complete, use standard operating procedures to shut down the test stand. Refer to

2-16. Aircraft testing procedure. For testing aircraft use the following procedures.

a. Connect hoses to the aircraft.

b. Set the following controls to the positions indicated.

(1) 4-way valve aircraft reservoir.

(2) HP flow control open.

(3) HP bypass valve closed.

c. Operate the test stand in the manner described in paragraph 2-9.

d. Set the HP compensator control to the desired pressure.

NOTE

HP relief valve must be adjusted to 10 percent lower than compensator control to achieve

desired pressure.

e. Open HP bypass valve.

f. Adjust the HP volume control to the flow required by the aircraft being serviced. Observe the flowmeter.

g. Slowly close HP bypass valve.

2-17. To test an aircraft system, proceed as follows:

a. Make certain that the test stand has been prepared for operation as described in paragraphs 2-9 and is properly

connected to the aircraft.

b. Make certain that the aircraft system is filled, free of entrapped air and correctly pressurized.

2-6