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Auxiliary Power Unit

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APU Panel

Description

The Auxiliary Power Unit (APU) is a small jet engine in the back of the aircraft which supplies the aircraft with pneumatic and electrical power.

Usage

MASTER SW

Controls the APU operation and its start- and shutdown sequence.

  • OFF:
    • The APU is off.
    • When pressed, the APU system is powered and the air-intake flap opens.
  • ON:
    • The APU is in operation.
    • When pressed, the APU shutdown sequence begins.
  • FAULT Lt:
    • The APU is failed, or
    • An automatic shutdown has occurred, or
    • An emergency shutdown has occurred.
    • Associated with an ECAM alert.

START

  • OFF:
    • The APU is not running.
  • ON:
    • The APU is starting.
    • When the APU reaches 95 % speed, the ON light goes off and the AVAIL light comes on.
  • AVAIL Lt:
    • The APU is started, and can provide electrical power, and/or bleed air.

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