For an engine start or motoring attempt in flight on the 1st attempt, what is the on/off pattern?

For an engine start or motoring attempt in flight on the 1st attempt, what is the on/off pattern?

• A. 120 Seconds ON, 10 Seconds OFF
• B. 90 Seconds ON, 5 Minutes OFF
• C. 60 Seconds ON, 5 Minutes OFF
• D. 30 Seconds ON, 5 Minutes OFF

Answer: (A)

Engine start procedures are limited by the starter duty cycle to protect the starter and the engine during motoring. For a first-in-flight start attempt, you crank for a full 2 minutes (120 seconds) with the starter energized, then allow a brief 10-second off period. The 2-minute cranking window gives enough time for fuel delivery, ignition, and compressor speed to develop toward light-off, while the brief off interval cools the starter and purge any residual fuel, reducing the risk of a hot start. If the engine doesn’t start on this first attempt, subsequent attempts use different cooling intervals, but the first attempt centers on maximizing start chances within the 2-minute on, 10-second off pattern.

Engine start procedures are limited by the starter duty cycle to protect the starter and the engine during motoring. For a first-in-flight start attempt, you crank for a full 2 minutes (120 seconds) with the starter energized, then allow a brief 10-second off period. The 2-minute cranking window gives enough time for fuel delivery, ignition, and compressor speed to develop toward light-off, while the brief off interval cools the starter and purge any residual fuel, reducing the risk of a hot start. If the engine doesn’t start on this first attempt, subsequent attempts use different cooling intervals, but the first attempt centers on maximizing start chances within the 2-minute on, 10-second off pattern.