PW4000 SERIES ENGINES

777 AIRCRAFT MAINTENANCE MANUAL

ENGINE STARTING -GENERAL DESCRIPTION

EFFECTIVITY BEJ ALL  80-00-00 
Page 5 
D633W101-BEJ  Sep 05/2002 

ENGINE STARTING -COMPONENT LOCATIONS -ENGINE

General
You open the fan cowls and thrust reversers to get access to these engine starting system components:
*
Starter air supply duct

*
Starter air valve

*
Starter

*
Starter air valve solenoid.

Starter Air Valve Solenoid
The starter air valve solenoid is on the intermediate case at the
1:00 position near the forward lower engine mount.
EFFECTIVITY BEJ ALL  80-00-00 
Page 6 
D633W101-BEJ  Sep 05/2002 

ENGINE STARTING -COMPONENT LOCATIONS -ENGINE

EFFECTIVITY BEJ ALL  80-00-00 
Page 7 
D633W101-BEJ  Sep 05/2002 

ENGINE STARTING -COMPONENT LOCATIONS -FLIGHT DECK

Engine Start Controls
The engine start/ignition selectors and the autostart switch are on the cargo fire/engine control panel on the P5 overhead panel.
EFFECTIVITY BEJ ALL  80-00-00 
Page 8 
D633W101-BEJ  Sep 05/2002 

ENGINE STARTING -COMPONENT LOCATIONS -FLIGHT DECK

EFFECTIVITY BEJ ALL  80-00-00 
Page 9 
D633W101-BEJ  Sep 05/2002 

ENGINE STARTING -STARTER AIR VALVE

Purpose
The starter air valve (SAV) opens to let air go to the starter.
Physical Description
The SAV is a poppet-type valve. It is pneumatically controlled and operated.
Functional Description
A spring holds the SAV closed. Servo air opens the SAV. How far the valve opens is related to the level of the servo air pressure that comes from the SAV solenoid.
Manual Override
You can manually open the SAV if it does not operate automatically. Use a 3/8 inch square drive to manually open the valve. You get access to the manual override through a guide tube behind the center thrust reverser latch access door.
EFFECTIVITY BEJ ALL  80-00-00 
Page 10 
D633W101-BEJ  Sep 05/2002 

PW4000 SERIES ENGINES

777 AIRCRAFT MAINTENANCE MANUAL

ENGINE STARTING -STARTER AIR VALVE

EFFECTIVITY BEJ ALL  80-00-00 
Page 11 
D633W101-BEJ  Sep 05/2002 

ENGINE STARTING -STARTER AIR VALVE SOLENOID AND FILTER

General
The starter air valve solenoid controls the servo air that opens the starter air valve (SAV). You get access to the starter air valve solenoid with the right thrust reverser half open.
Functional Description
The EEC controls a switch in the engine relay unit. When this switch closes, 28v dc power energizes the SAV solenoid that opens an internal valve. This lets the servo air supply go to the SAV to open it. A filter cleans the servo air.
　
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