737ng n1 change while putting APU online
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Join Date: Oct 2014
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737ng n1 change while putting APU online
Hi there
I have been undergoing type rating training for 737. I have one question namely why while putting APU online, the FMC computed takeoff N1 value changes? Thanks in advance for yours replies guys.
I have been undergoing type rating training for 737. I have one question namely why while putting APU online, the FMC computed takeoff N1 value changes? Thanks in advance for yours replies guys.
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FMC takes the current bleed configuration into account when calculating N1 values. If the packs are running, it will give you bleeds ON N1 values, otherwise you get bleeds OFF values.
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FMC bleeds ON/OFF N1% is taken from the pack/bleed switches. The packs do not need to be running. Thus it could be affected by the position of one of those switches at the time you fiddle with the APU.
