Engines, APU Flashcards
Identify the conditions that would lead to an aborted engine start and accomplishment of the Aborted Engine Start checklist
- Oil pressure rise does not occur.
- Fuel flow is abnormally high or fluctuating.
- EGT does not increase by 20 seconds after the FUEL CONTROL
switch is positioned to RUN. - N1 fails to increase after EGT rise
- EGT quickly nears or exceeds the start limit.
- Oil pressure indication is not normal by the time the engine is stabilized at idle
Recall the required engine warm up period prior to the application of T/O thrust.
- Required warm up time is 3 minutes.
- Target warm up time is 5 minutes.
Note: Do not delay takeoff after 3 minute warm-up period
Recall the engine cool down recommendations prior to engine shutdown
- Run the engine for at least 3 minutes.
- Shutdown may be accomplished earlier for gate arrival
Describe when the FUEL CONTROL switch should be placed to RUN during an engine start
- Verify oil pressure increase and N2 rotation
- When N2 is at 25%, or if 25% N2 is not possible at maximum
motoring speed, attempt the start at a minimum of 18% N2 (757)or 15% N2 (767).
NOTE: A magenta bug (fuel on command bug) appears at:
18% N2 on the 757
15% N2 on th e767
Recall the APU starter duty cycle.
The starter duty cycle is a maximum of 3 consecutive starts or attempts within a 60 minute period
Recall the maximum altitude to use APU Electrics.
- Electrical power is available throughout the entire airplane
operating envelope
Recall the maximum altitude to use APU Pneumatics.
- In flight, APU bleed air is available up to approximately 17,000 feet
Recall the EEC’s provide overboost, N1 and N2
overspeed protection, but no EGT over temperature protection.
Recall the primary indication for setting thrust on PW engines.
EPR
Recall the primary indication for setting thrust on GE engines.
N1
Explain how to cancel the APU shutdown sequence if OFF is
selected and the RUN light is still illuminated.
- Momentarily move the APU selector to the START position.
Recall the meaning of an illuminated APU RUN light
The APU is at operating Speed
Recall the meaning of an illuminated APU FAULT light.
- Illuminated (amber):
- The APU has automatically shut down.
- The APU fuel valve disagrees with the commanded position.
- A fault is sensed.
Note: The FAULT light momentarily illuminates during an APU start because the APU fuel valve initially disagrees with the commanded
position.
Recall the engine starter duty cycle.
- Continuous for 5 minutes
- Cool for 30 seconds per minute of operation
Recall the meaning of an illuminated L or R ENG OIL PRESS light
- The respective oil pressure is at or below the minimum value.
- The oil pressure switch has malfunctioned.