Misc Flashcards
What is an APU used for?
To power up the ACs electrical system and to provide pneumatic pressure to spin up the compressors in the main engine(s) during startup.
Most big planes have a little jet hidden in the tail. The APU starts this, and the little jet generates enough power to bring the compressors up to speed in the main engines.
What do you need to get a turbine engine started?
A good flow of air, typically up to 12% of the normal compressor speed, before introducing and igniting the fuel.
If you are parked into a tailwind you would need to face it into the wind before starting, as the air must be flowing in the right direction.
What is a ‘hot start’?
When the fuel is injected into the burner before the compressor is spinning fast enough, the fuel can end up burning out of control.
This is because not enough pressure is in the engine to throw all the hot air out towards the back and through the turbine.
This will cause the fuel to burn in the burner area and can melt your engine fast.
