Which value is associated with the starter becoming a generator?

Which value is associated with the starter becoming a generator?

• A. Speed of High Pressure Spool
• B. Pax emergency exit door
• C. 61.5%
• D. 2500 ft AGL

Answer: (C)

When starting an engine, the starter motor is used to spin the engine up. There’s a fixed threshold at which the starter’s role changes from turning the engine to generating electrical power for the aircraft. That transition happens at about 61.5% of the engine’s speed, so 61.5% is the value associated with the starter becoming a generator. The other options don’t indicate this electrical transition—the speed of the high‑pressure spool isn’t the defined switch point by itself, and a pax emergency exit door or altitude has no bearing on when generation begins.

When starting an engine, the starter motor is used to spin the engine up. There’s a fixed threshold at which the starter’s role changes from turning the engine to generating electrical power for the aircraft. That transition happens at about 61.5% of the engine’s speed, so 61.5% is the value associated with the starter becoming a generator. The other options don’t indicate this electrical transition—the speed of the high‑pressure spool isn’t the defined switch point by itself, and a pax emergency exit door or altitude has no bearing on when generation begins.