Turbine APUs Flashcards
Where are most APUs located in modern jet transport aircraft?
In the tail cone of the fuselage.
What is the function of an APU?
An APU provides electric power and compressed air when the main engines are not operating.
What are two sources of compressed air from an APU?
From bleed air from the APU turbine compressor, or from a load compressor driven by a free turbine in the engine.
Where in maintenance information based on the ATA-100 system would you find instructions for inspecting and servicing the engine of an airborne APU?
In section 49 20.
How is most of the troubleshooting done for a modern APU?
By the fault codes generated by the FADEC.
What ensures that an APU will not be shut down while it is too hot?
The APU fuel control incorporates an automatic time-delay feature that closes the bleed air valve to remove most of the load and reduce the APU temperature before it is shut down.
What prevents the APU exceeding its safe operating limits when the bleed air valve is wide open?
The FADEC monitors the load and regulates the fuel going to the APU to prevent it from exceeding its safe limits.
What document would you use to find the safety procedures to follow when replacing an igniter plug in an APU engine?
The maintenance manual for the APU.
