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 36-11-02
 ALL  ú ú 01P Page 608 ú Oct 10/95
BOEING PROPRIETARY - Copyright (C) - Unpublished Work - See title page for details.
A
747-400 MAINTENANCE MANUAL
 ENGINE BLEED AIR PRESSURE REGULATING AND SHUTOFF VALVE (PRSOV) -
________________________________________________________________ MAINTENANCE PRACTICES
_____________________
 1.  General_______
 A.  This task gives the procedures to manually operate the engine bleed air pressure regulating and shutoff valve (PRSOV).
 B.  The PRSOV is installed in the strut. You can get access to the PRSOV manual override drive on the left side of the strut through a spring loaded circular door in the access panels (Fig. 201).
 C.  The PRSOV is spring loaded to the closed position. You can put the PRSOV in the open, closed, or locked closed position. If the PRSOV is locked in the closed position, you must put it in the open position to start the engine.
 TASK 36-11-04-702-045
 2.  Manually Operate the PRSOV (Fig. 201)__________________________
 A.  Special Tools and Equipment
 (1)
G71021-6 Drive Extension - Starter Valve and PRSOV (Recommended) 15MIT65B00717 - Wrench, Pylon Valve Manual Drive (Optional)

 B.  
References

 (1)  
AMM 36-00-00/201, Pneumatic System

 C.  
Access

 (1)  
Location Zone
 452 Engine 1 - Strut Torque Box
 462 Engine 2 - Strut Torque Box
 472 Engine 3 - Strut Torque Box
 482 Engine 4 - Strut Torque Box

 D.  
Lock the PRSOV in the closed position

 S 862-046
 WARNING: DO NOT OPERATE THE THRUST REVERSER DURING MANUAL OPERATION OF
_______ THE PRSOV. THRUST REVERSER OPERATION DURING MANUAL OPERATION OF THE PRSOV CAN CAUSE INJURY AND DAMAGE.
 (1)  
Put the applicable ENGINE BLEED switch on the P5 Overhead Panel to the OFF position.

 S 982-003

 (2)  
Push the manual override drive in approximately 1/4 inch with the drive extension.

 EFFECTIVITYùùùùùùùùùùùùùùùùùùùùùùùùùùùùùù. ú

 36-11-04
 ALL  ú ú 01 Page 201 ú Feb 18/00
BOEING PROPRIETARY - Copyright (C) - Unpublished Work - See title page for details.
A 747-400 MAINTENANCE MANUAL 
SEE  A 
SEE  B 
DRIVE EXTENSION 
RATCHET  A 
POSITION OPEN 
POSITION CLOSED  MANUAL OVERRIDE DRIVE
LOCKED CLOSED POSITION B Figure 201 PRSOV Manual Override Drive 

EFFECTIVITYùùùùùùùùùùùùùùùùùùùùùùùùùùùùùù. ú

 36-11-04
 ALL  ú ú 01 Page 202 ú Feb 10/93
BOEING PROPRIETARY - Copyright (C) - Unpublished Work - See title page for details.
A
747-400 MAINTENANCE MANUAL
 S 982-049
 (3)  Turn the manual override drive 90 degrees or more in the
 counterclockwise direction.

 NOTE: The valve will be locked in the closed position.
____
 E.  Unlock the PRSOV
 S 982-047 WARNING: DO NOT OPERATE THE THRUST REVERSER DURING MANUAL OPERATION OF
_______ THE PRSOV. THRUST REVERSER OPERATION DURING MANUAL OPERATION OF THE PRSOV CAN CAUSE INJURY AND DAMAGE.
 (1)  
Push the manual override drive in approximately 1/4 inch with the drive extension.

 S 982-050

 (2)  
Turn the manual override drive 90 degrees or more in the clockwise direction.

 NOTE: The valve will be released and in the spring loaded
____
 closed position.

 F.  Open the PRSOV
 S 862-048 WARNING: DO NOT OPERATE THE THRUST REVERSER DURING MANUAL OPERATION OF
_______ THE PRSOV. THRUST REVERSER OPERATION DURING MANUAL OPERATION OF THE PRSOV CAN CAUSE INJURY AND DAMAGE.
 (1)  Do one of the steps that follow: NOTE: The torque required to open the PRSOV depends on manifold
____ pneumatic pressure. If unpressurized, the valve normally opens easily. If pressurized, the valve may require up to 50 foot-pounds to open.
　
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