ATLAS 747 APU Exam Questions &
Answers (Grade A+)
What are the start sources for the APU and which one do we
normally use? -
correct answer ✅*TR (Transformer Rectifier Unit), when Utility Bus
4 is powered *APU Battery, when Utility Bus 4 is unpowered *Batt is
the normal switch position.
Can the APU be operated in flight? -
correct answer ✅Yes when left running for takeoff, it can be
operated up to 20,000 ft.
Is electrical power available from the APU in flight? How about APU
bleed? -
correct answer ✅*No, APU electric is not available in flight *Yes,
APU bleed air is available in one pack up to 15,000 ft
What APU components are powered by the APU battery? -
correct answer ✅*Inlet door *APU controller *DC fuel pump *APU
fire detection system
What APU components are powered by the main battery? -
correct answer ✅*APU fire extinguisher *APU fuel valve *Standby
power for the APU controller
Answers (Grade A+)
What are the start sources for the APU and which one do we
normally use? -
correct answer ✅*TR (Transformer Rectifier Unit), when Utility Bus
4 is powered *APU Battery, when Utility Bus 4 is unpowered *Batt is
the normal switch position.
Can the APU be operated in flight? -
correct answer ✅Yes when left running for takeoff, it can be
operated up to 20,000 ft.
Is electrical power available from the APU in flight? How about APU
bleed? -
correct answer ✅*No, APU electric is not available in flight *Yes,
APU bleed air is available in one pack up to 15,000 ft
What APU components are powered by the APU battery? -
correct answer ✅*Inlet door *APU controller *DC fuel pump *APU
fire detection system
What APU components are powered by the main battery? -
correct answer ✅*APU fire extinguisher *APU fuel valve *Standby
power for the APU controller
