APU Flashcards
What is the ground frequency on uhf that should be used during operation of the apu?
308.6
What job guide do you use for operation of the apu?
1c-130h-2-49jg-00-1
Where does the apu get its fuel from?
2 tank
T or F as a minimum the dc voltmeter should read 21 volts prior to operation of the apu
True
At what percentage rpm does the start light go out?
35%
At what percentage rpm does the on speed light illuminate?
95%
What is the operating range in volts for the apu generator during operation
112-118 volts
What is the duty cycle for the apu starter?
1 minute on 4 minutes off, do not engage starter until rpm is 0
What electrical bus powers the apu starter?
Essential dc bus
If a prop rotates when you open the bleed air manifold what should you do?
Rotate bleed air valve/BL AIR switch to OFF
Can you still operate the apu if the fire warning system does not operate?
No
Where is the apu located?
Left side of aircraft forward of MLG door
What must you inspect on the apu air inlet?
Inspect inlet for ice or foreign material on the inlet screen
Can you still operate the apu if the fuel shut-off valve had failed in the open position?why?
No, damage to equipment and injury to personnel could occur.
What mist be done prior to pressurizing the bleed air manifold?
Place all ac/bleed air switched to off and clear all props
How much oil is in the apu system?
6 us quarts
T or F There must be at least 1500lbs in any main tank before operating the apu?
False! At least 2000lbs in #2 tank
T or F Hold the agent discharge switch for three seconds after pulling fire handle when apu is on fire?
False! Dont hold agent discharge/agent disch switch No.1 or No.2 for more than two seconds.
How do you ensure the apu fuel shutoff valve is closed before the first start of the day?
Press the “fuel strainer valve” to fuel strainer. Verify fuel flow stops.
What happens at 35% rpm?
Start light goes out.
What happens at 95% rpm?
On speed light comes on and stays on.
What happens at 110% rpm?
Apu will shut down and may relight with a loud bang, this cycle will repeat until apu is shutdown and governed speed reduced.
Highest EGT limit of apu?
620 degrees Celsius
Bleed down time?
8.5 seconds no less
1 engine prop starts rotating when you turn the apu bleed air switch to the “on” position, what do you do now?
Turn bleed air switch to off position
Battery voltage reads 17.5V what do you have to do?
Use external power and or charge battery to at least 21V
When are the the ac plugs removed for apu operation?
Prior to start of apu
T or F external electrical power has to be on before apu operation.
False, equipment conditions does not require it and you can start apu with battery, but if available, yes.
Allow apu to run for at least __ minutes after on speed light comes on
Two
