Auxiliary Power Unit(APU)
Definition
A small gas turbine engine in the aircraft tail that provides electrical power and bleed air for air conditioning and engine starting on the ground. Some aircraft can use the APU as an inflight backup.
Why Auxiliary Power Unit Matters for Pilots
Operational knowledge like Auxiliary Power Unit is tested across multiple FAA and EASA exam subjects. Pilots who understand Auxiliary Power Unit can operate more safely and efficiently, whether flying light aircraft or commercial airliners. This concept comes up in both written tests and practical checkrides.
Exam Tip
This concept is commonly tested in operations-related questions on FAA and EASA exams. Make sure you can explain Auxiliary Power Unit in your own words for the oral exam. Practice applying this concept to real-world scenarios, not just memorizing the definition.
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