APU Control Panel Flashcards

1
Q

MAINT light

Blue

A
  • low oil qty for the APU or starter-generator has a shorted rotating diode
  • when the oil level is at LOQ, there is enough oil in the APU for 30 - 50 hours of operation at the max oil consumption rate
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2
Q

LOW OIL PRESSURE light

A
  • illuminated = oil press low
  • auto shutdown occurs in 20 sec
  • illuminates during start until oil pressure is normal
  • if light is on when APU switch is placed to OFF, it extinguishes after 5 min
  • light is disarmed when the APU switch is in OFF position
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3
Q

FAULT light

A
  • a malfunction exists which causes the APU to initiate an automatic shutdown
  • shows that the APU ECU sensed a fault and a protective shutdown has occurred
  • if light is on when APU switch is placed to OFF, it extinguishes after 5 min
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4
Q

OVERSPEED light

A
  • illuminates if actual overspeed (106%),
  • auto shutdown and light stays on even with switch OFF
  • if light is on when APU switch is placed to OFF, it extinguishes after 5 min
  • maintenance must reset
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5
Q

APU Start switch (3)

Switched to off it:

A
  • starts cool-down cycle
  • APU generator breaker trips and the APU bleed air valve closes
  • APU continues to run for 60 sec then shuts down
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