New answers tagged

3

You are getting the APU mixed up with the RAT: The Auxiliary Power Unit (APU) is an engine powered generator, either a gas turbine or a piston engine. APUs deliver enough power to start engines, power cabin lights, cockpit instruments and radios, and in some cases power hydraulics. Often the APU can only be run at lower altitudes where the air is thicker A ...


3

If it's the flap closing, you should be able to verify that from the APU ECAM page. Based on the time frame you mentioned, most likely it's the simulated overspeed, which is part of the shutdown sequence and is basically the signal that closes the fuel solenoid (which you can also verify from the APU page). APU flap closing comes later. For more on the ...


Top 50 recent answers are included