Idle N1 may decrease below ______ when the generator and other aircraft systems are turned on.

Idle N1 may decrease below ______ when the generator and other aircraft systems are turned on.

• A. 60%
• B. 51%
• C. 95%
• D. 51-60%

Answer: (A)

Idle N1 is the engine speed at the low-power, stable idle point. When the generator and other aircraft systems are energized, they load the engine via the accessory gearbox. That additional demand can pull N1 downward from its normal idle level. To ensure there’s enough RPM to drive these accessories reliably and prevent loss of function or flameout, a minimum idle N1 of 60% is specified. So the blank is 60%. The other numbers don’t reflect the typical margin required under electrical load.

Idle N1 is the engine speed at the low-power, stable idle point. When the generator and other aircraft systems are energized, they load the engine via the accessory gearbox. That additional demand can pull N1 downward from its normal idle level. To ensure there’s enough RPM to drive these accessories reliably and prevent loss of function or flameout, a minimum idle N1 of 60% is specified. So the blank is 60%. The other numbers don’t reflect the typical margin required under electrical load.