APU Starter Duty Cycle Starter Attempt 3 requires an OFF time of which duration?

APU Starter Duty Cycle Starter Attempt 3 requires an OFF time of which duration?

• A. 1 min OFF
• B. 2 min OFF
• C. 5 min OFF
• D. 10 min OFF

Answer: (C)

APU start cycles are designed to protect the starter and the APU from overheating. Each start attempt places a heavy electrical and mechanical load on the starter motor, so a cooling period between attempts is required. After two unsuccessful start attempts, the specified OFF time before the third attempt is five minutes. That five-minute rest allows the starter and related components to cool, reducing the risk of damage and helping ensure a successful re-start. Shorter rests wouldn’t provide enough cooling, and a ten-minute rest isn’t the mandated cycle for this scenario. If the third attempt fails, follow the standard abort/maintenance procedures.

APU start cycles are designed to protect the starter and the APU from overheating. Each start attempt places a heavy electrical and mechanical load on the starter motor, so a cooling period between attempts is required. After two unsuccessful start attempts, the specified OFF time before the third attempt is five minutes. That five-minute rest allows the starter and related components to cool, reducing the risk of damage and helping ensure a successful re-start. Shorter rests wouldn’t provide enough cooling, and a ten-minute rest isn’t the mandated cycle for this scenario. If the third attempt fails, follow the standard abort/maintenance procedures.