A300Capt. Another 757 question.

zombie5225

New Member
I was shutting the APU down tonight when I noticed something weird with the EGT. It was 380* while it was on. When I put it into the off position it went down to 300*, and when it finally shut down the EGT went over 800*. I was just wondering if this was normal. Thanks!
 

A300Capt

Freight Dawg
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When I put it into the off position it went down to 300*, and when it finally shut down the EGT went over 800*. I was just wondering if this was normal

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Well, it's been awhile since flying the B757 and my memory is a little fuzzy. When selecting the APU off a signal is sent to close the bleed valve (if opened) and a 60 second cool down begins before the APU actually shuts down.

About the 800 degrees you saw. I can tell you on the A300-600 that when you select the APU off a "false" overtemp signal is sent and the controller auto shuts down the APU. This is normal. I can't remember but the B757's APU may do the same thing and might explain the high EGT number you saw prior to shutdown.
 
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