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ERJ 170 APU syst.
APU questions
Question | Answer |
---|---|
What kind of APU is on the aircraft? | • Sundstrand APS 2300 |
Describe the APU | • Constant speed• Single-stage impeller with a 2-stage axial-flow turbine• Independent oil system |
What controls the APU? | • A dedicated FADEC |
What battery is used for the APU start? | • BATT 2 powers the starter• BATT 1 powers the FADEC and EICAS for monitoring |
What is the fuel source for the APU? | • Right fuel tank• Left fuel tank through the crossfeed valve |
What fuel pump is used for APU start? | • Batteries ‘ON’ only DC fuel pump in right tank• AC powered airplane ACMP 2 • Right engine running Ejector fuel pump |
Will the APU shutdown automatically if speed and acceleration rate isn’t reached in starting cycle time? | • Yes |
What does moving the APU start switch to ‘OFF’ do? | • Initiates normal APU shutdown• 1-minute cool down• No pneumatics (electrics only for 1 minute) |
Can the APU shutdown be cancelled? | • Yes, by moving the START switch back to ‘ON’ before the 1-minute cool down is over |
How is the APU shutdown immediately? | • APU emergency stop button• No 1-minute cool down period |
What will happen if batteries are turned OFF during the 1-minute cool-down period? | • APU will shut down immediately |
When will automatic shutdown of the APU occur?Ground: | • Ground: Overspeed Underspeed FADEC critical fault Fire Overheat Low oil pressure |
When will automatic shutdown of the APU occur?Flight: | • Flight: Overspeed Underspeed FADEC critical fault |
Can the APU be started after a critical fault? | NO |