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Abnormal Autostart
If the EEC finds a problem during the first autostart try, it will do a second autostart try. Before it does another autostart try, it motors the engine to cool it and remove any fuel.
If an autostart problem occurs after the SAV closes, the EEC waits until the engine speed gets to the maximum starter re-engagement speed before it re-opens the SAV.
The EEC uses two igniters after the first autostart try.
Manual Start
When you do a manual start, the EEC only controls some of the start sequence. It does not monitor or control starting faults. You enable a manual start by doing these steps:
*
Push the autostart switch to OFF

*
Turn the start selector to START.

The EEC opens the SAV, which causes N2 to rotate.
At the maximum motoring N2 speed, you put the fuel control switch in the RUN position. When the fuel control switch is in the RUN position, the EEC opens the minimum pressure and shutoff valve and energizes one igniter.
When the engine speed gets to approximately 41 percent N2, the EEC closes the SAV and de-energizes the igniter. The EEC also sets the AIMS engine start signal to false. This causes the AIMS to de-energize the start/ignition selector latching solenoid. The selector goes back to the NORM position.
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ENGINE STARTING -FUNCTIONAL DESCRIPTION -START PROFILE

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PW4000 SERIES ENGINES

777 AIRCRAFT MAINTENANCE MANUAL

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Page 24 D633W101-BEJ Sep 05/2002

ENGINE STARTING -OPERATION

General
The engine starting system has these modes of operation:
*
Autostart

*
Manual start.

These are the flight deck controls you use for an engine start operation:
*
Start/ignition selectors

*
Autostart switch

*
Fuel control switches.

It is important to monitor the engine parameters to find or prevent these fault conditions:
*
Low starter air pressure

*
No light-up

*
Locked rotor(s)

*
Hung start

*
Hot start

*
Starter shaft breakage

*
Starter duty cycle exceedance.

Autostart Operation
This is a brief summary of the autostart operation procedure:
*
Put the autostart switch in ON

*
Put the engine start/ignition selector in START

*
Put the fuel control switch in RUN.

EFFECTIVITY
BEJ ALL

The EEC automatically controls and monitors the autostart operation. It will stop the operation for a fault condition. If the first autostart try fails, the EEC automatically does another start operation.
　
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