When does the rotating beacon assembly turn on?

When does the rotating beacon assembly turn on?

• A. When the engine RUN/STOP switch is set to RUN in preparation for engine start
• B. When the battery switches are turned on
• C. When the GPU is connected
• D. When the APU starts

Answer: (A)

The rotating beacon is turned on to indicate that the aircraft’s power systems are being energized as part of the engine start sequence, warning ground personnel that the engines may begin to rotate. It is wired to the engine start circuit, so energizing the engine RUN/STOP switch to RUN supplies power to the beacon and signals readiness for starting. That’s why it turns on specifically when the engine RUN/STOP switch is set to RUN in preparation for engine start. Merely turning on battery switches, connecting external power (GPU), or starting the APU does not universally trigger the beacon in the same sequence.

The rotating beacon is turned on to indicate that the aircraft’s power systems are being energized as part of the engine start sequence, warning ground personnel that the engines may begin to rotate. It is wired to the engine start circuit, so energizing the engine RUN/STOP switch to RUN supplies power to the beacon and signals readiness for starting.

That’s why it turns on specifically when the engine RUN/STOP switch is set to RUN in preparation for engine start. Merely turning on battery switches, connecting external power (GPU), or starting the APU does not universally trigger the beacon in the same sequence.