S 866-152

 (15)
 Put the system No. 3 HYD PUMPS ENG switch on the P5 overhead panel in the ON position.

 F.
Hydraulic System No. 3 - Total System Internal Leakage Check

 S 866-153
 (1)  Pressurize hydraulic system No. 3 to 3000 psig.
 S 866-669
 WARNING: MAKE SURE THAT PERSONS AND EQUIPMENT ARE CLEAR OF THE LE AND TE
_______ FLAPS AND FLAP DRIVE MECHANISMS BEFORE YOU MOVE THE FLAP CONTROL LEVER. WITH HYDRAULIC POWER REMOVED, THE FLAPS WILL MOVE AUTOMATICALLY BY ELECTRICAL POWER WHEN YOU MOVE THE FLAP CONTROL LEVER.
 (2)  
Operate the flight controls through four or five cycles.

 (3)  
Keep the flight controls in the neutral position.

 S 866-445
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747-400 MAINTENANCE MANUAL
 S 976-155
 (4)  Let the flow become stable for 3 minutes and write this flow as flow
 No. 1. Flow No. 1__________GPM
 If the internal leakage of system No. 3 (Flow No. 1) is more than 5 GPM, you must complete the remainder of this test.
 NOTE: If the gross internal leakage for either of the inboard
____ systems (2 or 3) exceeds 3 GPM the other inboard system must not exceed 3 GPM. Maximum gross internal leakage for a inboard system (2 or 3) is 5 GPM.
 G. Hydraulic System No. 3 - Pressure Module Check
 S 796-156
 (1)  
If the hydraulic service cart is used as a pressure source, monitor the HYD PUMPS DEMAND PRESS and HYD PUMPS ENGINE PRESS lights on the P5 Overhead Panel. If the demand pump is used as a pressure source, monitor the HYD PUMPS ENGINE PRESS light. If one of the lights that are monitored go off, replace the applicable check valve in the pressure module (AMM 29-11-23/201).

 S 796-157

 (2)  
Carefully feel the return line between the pressure module and the reservoir.

 (a)  
If the return line is hot, replace the pressure relief valve in the pressure module (AMM 29-11-23/201).

 H.
Empennage Hydraulic Control System - Internal Leakage Check

 S 866-158
 (1)  
Put the system No. 3 TAIL FLT CONTROL SHUTOFF switch in the OFF position.

 S 866-159

 (2)  
Put the system No. 3 WING FLT CONTROL SHUTOFF switch in the OFF position.

 S 976-160

 (3)
Let the flow become stable for one minute and write this flow as

 flow No. 2. Flow No. 2__________GPM
 NOTE: Flow No. 2 is the null leakage for the stabilizer pitch trim
____
 and the elevator feel computer.

 S 866-161
 (4)  Put the system No. 3 STAB TRIM switch in the CUTOUT position.
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A
747-400
MAINTENANCE MANUAL

 S 976-162
 (5)  Let the flow become stable for 1 minute and write this flow as flow
 No. 3. Flow No. 3__________GPM
 NOTE: Flow No. 3 is the null leakage for the elevator feel
____
 computer.

 S 976-163
 (6)  Subtract flow No. 3 from flow No. 2 and write this flow as flow
 No. 3A. Flow No. 2__________GPM Flow No. 3__________GPM
 Flow No. 3A__________GPM
 NOTE: Flow No. 3A is the null leakage for the stabilizer pitch
____
 trim.

 S 866-164
 (7)  
Put the system No. 3 STAB TRIM switch in the ON position.

 S 866-165

 (8)  
Put the system No. 3 WING FLT CONTROL SHUTOFF switch in the ON position.

 S 976-166

 (9)  
Let the flow become stable for 1 minute and write this flow as flow

 No. 4. Flow No. 4__________GPM
 S 976-167
 (10) Subtract flow No. 4 from flow No. 1 and write this flow as flow
 No. 4A. Flow No. 1__________GPM Flow No. 4__________GPM
 Flow No. 4A__________GPM
　
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