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21 Cards in this Set
- Front
- Back
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How many stages is the APU compressor? Turbine? |
Single stage compressor, single stage turbine |
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What type of combustion chamber? |
Reverse-flow annular combustion chamber |
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What is the voltage / amperage of the APU generator? |
28 V / 400 A |
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When is DC power available? |
95% RPM for seven seconds |
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How long after APU start until bleed air can be selected? |
3 minutes |
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Can APU bleed be used for anti-ice? |
No. |
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Which side of the pneumatic system is the APU connected to? |
Left
(Cross-bleed should be opened to operate PACK 2. Engine starts automatically open the cross-bleed valve set in AUTO mode.)
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At what temperature will the APU OIL HI TEMP caution be indicated? |
Above 166 C |
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At what pressure will the APU OIL LO PRESS caution be indicated? |
Below 6 psi |
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What are the primary differences (2) between Sundstrand -11 and -14 APUs? |
-11 Electronic Sequencing Unit
-14 FADEC and Modulating Bleed Valve |
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Which fuel tank does the APU take from? |
Tank 2
(Pump 1 On and Low 2 can be selected to take from Tank 1) |
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Describe the -11 start sequence. |
At ~3% (0% in flight) ESU commands ignition and Start Fuel Solenoid Valve to open.
At 14%, ESU commands the Main Fuel Solenoid Valve open.
At 70%, ESU disengages the starter and de-energizes the Start Fuel Solenoid Valve and ignition exciter. |
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Describe the -14 APU start sequence. |
At ~3% (0% in flight) FADEC commands ignition and Main Fuel Solenoid Valve open.
At 50%, FADEC de-energizes the starter.
At 70%, FADEC de-energizes the ignition exciter. |
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Should the APU be started with the AHRS 1-2 ALIGN advisory displayed? |
No
(AHRS Align takes about 30s after power-up) |
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What is the approximate fuel burn per hour of an APU providing DC power and bleed air? |
~160 pph (~3 lbs per minute) |
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When will the APU not shut down in flight? |
Any heat-related malfunction (including FIRE, EGT overtemp, oil overtemp)
Low oil pressure |
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How should the APU be shut-down? |
Press the Stop button. Monitor RPM / EGT Wait for 5% Turn off the APU master knob Check for APU FUEL SOV CLSD |
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Can BATT 1 be used to start the APU? |
No. (BATT 1 is isolated during APU starts to provide stable power for voltage-sensitive equipment) |
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What is Ground Safe Mode? |
APU Bleed - Off APU Gen - On Batteries - Off Emergency Lights - Off IRS - Off |
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What is the difference in stabilized rotor speed between the -11 and -14? |
-11: 103% -14: 100% |
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How is the aircraft protected from APU Fire? |
A titanium firewall. |
