APU STDY 01: General overview Flashcards
(Warnings)
Prior to operating the bleed air system what area must be cleared of personnel & equipment?
Prop area
must be cleared for all four engines before pressurizing the bleed air manifold.
Start light out at ___% rpm
or __ min
35% rpm
Or
1 min
APU oil is serviced to how much?
IAW 1C-130H-2-12JG-10-2, 12-15-01
6 quarts
4 in the tank
2 in the lines
How many anti-ice lights are tested?
7
Why is it important to wait 4 min prior to an APU restart?
1min on 4min off
To ensure the turbine stops rotating & the RPMs are at zero.
(Cautions)
What is the starter motor duty cycle for the APU?
Do not exceed the starter motor duty cycle of
1min on & 4min off
When operating AC systems, at what decibels do u require hearing protection?
0-84 -no hearing protection
85-109 - single hearing protection
110 & up - double hearing protection
How many fire handles are there?
1 for each engine and 1 for the APU.
TO & page for Emergency Shutdown Procedures.
49-00-3 (pg-62)
Cargo door handle clockwise to
3n or 6n
During run tach indicates _____RPM +-___
100RPM (+-2)
Ensure ____lbs in No.2 tank.
2,000 lbs
If No.2 tank does not have 2000 lbs you need to turn the ____ ____ on.
Boost pump
If outside temp is 32 degrees F or lower, wait __minutes to ____ _____.
…wait 4 minutes to apply load.
Allow APU to run with ____ ____ for __ minutes after on-spread light is on.
…with no load for 2 minutes.
Verify ___ ___ is reading ____V and FEQ is reading 400+-20Hz
APU GEN is reading 115+-3V
MIN B/A Press =
35PSI
Bleed down:
- Start timing when press drops to 30PSI
- End time at 15PSI
What are the time limits?
8.5 sec = prior to 83-846
16 sec = 83-846 and up
APU GEN is reading 115+-3V and FREQ is reading ____+-___Hz.
FEQ is reading 400+-20Hz
If the START light does not go out within one minute, place ____ sw to STOP.
APU CNTR/ APU
What lights do you observe when first starting the APU?
START light, ON SPEED LIGHT, tachometer, and EGT indicator.
What light is always on during the run?
the DOOR OPEN light.
the EGT (exhaust gas temp) should never go above how many degrees?
620 degrees Celsius
If the START light does not go out within one minute, place ____ sw to STOP.
APU CNTR/ APU
What lights do you observe when first starting the APU?
START light, ON SPEED LIGHT, tachometer, and EGT indicator.
What light is always on during the run?
the DOOR OPEN light.
the start light goes out when?
within one minute or 35 seconds
TACH indication indicates how many RPMs during the run?
100 +-2
during the run once the START light goes out the _____ light should comes on.
ON-SPEED light
Depending on the airplane the light may flicker on at the same time but generally once the START light goes out it is on-speed and the ON-SPEED light comes on.
What is the preferred method for starting the APU,BAT, or external power?
Use BAT power only when external power is not available.
If isolated DC power is interrupted while the APU is operating the control circuit will be opened and cause the APU to stop; what should you do,
Place the APU Control switch to stop and wait 4 minutes prior to starting procedures.
What must be removed prior to AC operation?
Plugs must be removed.
Is it acceptable to run the APU with frost in the inlet?
Yes.
DO NOT operate the APU with ICE or FOREIGN material in the inlet or on the inlet screen or with ice on the governed… FROST on the inlet SCREEN is acceptable.
What must be monitored during the operation of APU Bleed air?
Leading edge TEMP INDICATORS
&
BLEED AIR
What 4 switches do you turn on during a bleed down?
The 4 ENG BLD AIR REG sw’s
If bleed air pressure drops rapidly or
there is other evidence of excessive duct leakage what do you do?
APU must be shut down immediately and the problem corrected before proceeding.
Monitor BLEED MANIFOLD PRESS gage during APU operation. If gage shows evidence of _____ _____ shut down the APU.
Duct failure
Monitor _____ _____ ______ gage during APU operation. If gage shows evidence of duct failure, shut down the APU.
BLEED MANIFOLD PRESS gauge
Do not exceed the starter motor duty cycle of one minute
on, four minutes off. Do not attempt to reengage the starter as long as the _____ is rotating.
APU
Starting APU with control air _____ _______ open will reduce fuel flow and RPM and increase start time. Do not exceed the starter motor duty cycle of one minute on, four minutes off.
pressure valve
How is fuel fed into the APU?
Gravity fed
Why Do you NOT allow the APU to dwell at speeds between 1696 and 3186 RPM range any longer than necessary.
Excessive vibration that may damage the APU is more likely in this speed range.
Which t-handle only shows fire?
APU
