Auxiliary Power Unit. A device for providing alternate power to an aircraft, usually located in the aircraft's tail.
Questions tagged [apu]
70 questions
25
votes
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In what conditions is the APU used in midair?
In flight, engines provide all the needed energy (bleed air, hydraulic and electrical power). So the APU can be shut down shortly after engines are running. But I imagine that starting the APU in midair is a well known procedure because:
I…
Manu H
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Where does the APU draw its intake air?
In an airliner, where does the APU draw its intake air?
Is it a similar location for all airliners, or do different options exist?
florisla
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5
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What type of engine/motor is used in aircraft APU?
Is the APU a mini-jet engine, or some other type of motor? I know its purpose is to provide power when the engines are off, but what kind of motor/engine is used to generate the power?
I assume this differs from one type of aircraft to the other,…
Burhan Khalid
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Why we need 1 hour for cooling after 3 consecutive attempts for starting the APU?
As it's said here(APS-3200 training manual (pg 268)):
we need 1 hour for cooling after 3 consecutive attempts for starting the APU. But why?
why not after each attempt? and why 1 hour?
is it valid for all APUs?
What about the jet engines of…
Roh
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What's the starting envelope of APU?
I was reading the APS-3200 training manual (pg 268) and faced this part:
What's the starting envelope of APU?
What does mean "Normal start throughout the operating envelope: minus 300 m to 11900 m (minus 1000 ft to 39000 ft)"?
Roh
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