What is the difference between a flight cycle and an engine cycle?

What is the difference between a flight cycle and an engine cycle?

• A. Flight cycle is from takeoff to landing only
• B. They are the same
• C. Engine cycle is shorter than flight cycle
• D. Engine cycle is the duration from engine start to shut down

Answer: (D)

The difference hinges on what each timer measures. A flight cycle tracks the airframe’s mission from wheels up to wheels down, encompassing the takeoff, climb, cruise, descent, approach, landing, and typically the taxiing around on the ground. The engine cycle, however, tracks the engine’s own operating life, beginning when the engine is started and ending when it is shut down. That means the engine can be started for ground checks, run during taxi, and still be part of the cycle, or be started before flight and shut down after landing—the clock is tied to the engine’s on-and-off state, not the aircraft’s flight phases. So the duration from engine start to shutdown is the engine cycle, which is why that option best captures the intended distinction.

The difference hinges on what each timer measures. A flight cycle tracks the airframe’s mission from wheels up to wheels down, encompassing the takeoff, climb, cruise, descent, approach, landing, and typically the taxiing around on the ground. The engine cycle, however, tracks the engine’s own operating life, beginning when the engine is started and ending when it is shut down. That means the engine can be started for ground checks, run during taxi, and still be part of the cycle, or be started before flight and shut down after landing—the clock is tied to the engine’s on-and-off state, not the aircraft’s flight phases. So the duration from engine start to shutdown is the engine cycle, which is why that option best captures the intended distinction.