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39 Cards in this Set
- Front
- Back
The apu provides what functions for ground operation? |
Air to pressurize bleed air system, engine starting, air conditioning and other pneumatic systems, also drives a 40/50 KVA generator |
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All APU controls and indications are processed by?
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One of the two mission computers |
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What fuel tank gravity feeds the APU and what is the minimum fuel required to start?
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The #2 main tank requires a minimum of 2000 lbs for APU operation |
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What is the APU oil tank capacity? |
4 qts or 1 gallon |
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The cargo ramp manual control knob will be placed in which position? |
3N or 6N
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Inspect the area around the APU inlet and door for?
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Ice and foreign objects
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Which ecb's must be closed for APU operation?
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123 APU start relay, 124 APU run relay, 455 F/ODS chan b, 626 F/ODS chan a
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What position must the APU alarm switch be placed in prior to start?
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On
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What two forms of communication can be used for APU start?
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Visual with battery and comm cord with external power
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When battery switch is on, what is the minimum DC volts
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22 VDC (24 in-flight)
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What system in inoperative during battery start of APU?
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No fire warning protection during APU battery start until AC power is up and online
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The APU start light goes off at what RPM?
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APU start light goes off at 50% or within 90 seconds
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After the APU reaches 50% RPM, what it the minimum time to reach 98-105%?
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35 seconds
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After the APU reaches operating speed, what rpm should be maintained?
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Between 98-105% rpm |
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What is the maximum allowed EGT for the APU?
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680 degrees C
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Placing AC power switch to APU will result in?
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Aircraft electrical system self contained and external power can be removed
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What position is the floor switch placed during an APU run?
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To fan
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What is the minimum warm up and stabilization time before applying a bleed air load?
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1 minute, if the outside temp is below freezing, wait an additional 3
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What happens when the APU control switch is switched to run?
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The inlet door opens to 35 degrees
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During APU emergency start, how far does the inlet door open?
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15 degrees
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What action can be taken in the event the APU door will not open upon startup?
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Operation of APU with failed door actuator (1-1-2)
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How many seconds must the APU control switch be held to start?
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1 second and confirm start light
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On first start attempt- if APU start light does not go off within 90 sec or RPM reaches 50%, what action must be taken?
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APU control switch to stop, wait until turbine stops until second start attempt
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With a second failed APU start, what is the minimum time allowed before a third attempt?
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5 minutes |
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Third start fail, what is the minimum time allowed before initiating subsequent start attempts?
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60 minutes
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If an ESS DC BUS OVERLOAD message appears on the ACAWS, what mx action is required?
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No mx action required unless the ACAWS with an RTRU and/or another bus fail
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When the APU oil pressure reaches approx 3 psi or 10% RPM what is activated? |
APU fuel shutoff solenoid valve
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What must be performed prior to pressing the APU bleed air valve switch to open? |
clear personnel and equipment from all 4 engines |
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APU bleed air pressure should stabilize at what pressure? |
30 psi minimum |
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What is the minimum APU bleed down time? |
30 psi to 15 psi in 22 seconds or greater |
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What happens if the isolated DC power is interrupted while the APU is operating? |
The APU will stop. If that happens, place the control switch to stop, wait 4 minutes, then repeat starting procedure |
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If the bleed air press indicator drops during APU operation, what action should you take? |
Perform a normal APU shutdown to prevent a bleed air leak and a possible fire |
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During APU operation, an ACAWS displays an anti-icing system over temp; what action must be taken? |
APU must be shut down to prevent damage to the wing structure |
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After pressing the APU bleed air valve switch to closed, how many minutes before the APU control switch can be placed to stop? |
1 minute for the APU to stabilize |
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What is the result when the APU speed decreases to approx 18% RPM or low oil pressure switch actuates at approx 20 psi? |
The APU door closes |
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When the APU fire control handle is pulled, what is de-energized? |
All APU circuits are de-energized. APU door closes and the fire extinguishing system is energized |
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If APU FIRE WARNING message comes on or a situation requiring immediate shutdown occurs, what action must be taken? |
Pull the APU Fire Handle |
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If APU fire occurs, what action must be taken? |
Discharge. If the fire persists, discharge the other bottle |
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After the ground observer is notified and ground control is requested, what other mx is required in case of an apu emergency? |
APU control switch to stop, AC power switch to off, BTRY switch to off, and evacuate the aircraft |