L-1011 APU: Overview (49-1/2)

The Auxiliary Power Unit (APU) is installed on the L-1011 as an auxiliary power source to be used primarily on the ground. The APU can also be used in flight as a back-up for the aircraft's pneumatic, hydraulic, and electrical systems.

The APU will supply pneumatic power for air conditioning, engine starting and to power the ATM's for hydraulic power.

The APU generator can supply up to 81 KW to an altitude of 14,000 and 54 KW above 14,000 feet.