APU indication @ 95% rpm @Aviation Nuggets

The percent rpm gauge is provided to give an indication of APU

rotational speed. Most of the automatic features of the

auxiliary power unit control unit are initiated by rpm values,

for instance:-

at 35% rpm the starter disengages,

at 95% rpm ignition is de-energised.

Also at 95% rpm the ready to load light will illuminate to

indicate that the APU is running at a sufficient speed for

electrical and pneumatic power to be applied to the aircraft.

indication@AviationNuggets