Section VII - Engines - APU Flashcards
What actions occur when an Engine Start Selector is moved into the GND position?
- Opens the start valve to supply STARTER AIR
- Arms the selected ignitor(s)
What actions occur when an Engine Start Selector is moved to the CONT position?
The ‘selected’ ignitor will operate continuously.
What actions occur when an Engine Start selector is moved to the FLT position?
Both ignitors operate continuously regardless of ignition selector
According to system logic, describe two scenarios in which an ignitor would operate continuously without the Engine Start Selector in the CONT position.
In the AUTO position ignitor(s) operate continuously:
- With the Leading Edge Slats extended (FLAPS 1), or
- With ENGINE ANTI ICE selected on.
When is maximum motoring speed achieved?
Maximum motoring speed is reached when acceleration is less than approximately 1% in 5 seconds.
During the engine start cycle, when will an Engine Start Selector automatically spring back to AUTO?
50% N2
Starter operation limitations?
Normal Duty Cycle:
5 mins ON - 1 1⁄2 mins OFF
Extended Duty Cycle:
2 consecutive 5 mins cycles require a ten (10) minute cooling period before additional (5) minute cycle
What actions occur when a Fuel Control Switch is moved from CUT OFF to RUN?
- Opens engine and spar FUEL VALVES
- Activates selected ignitor(s).
What is the normal power source for the ignitors?
- Main AC power is the normal power source for ignition.
- Standby AC power provides a backup source.
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What is Electronic Engine Control (EEC)? What is its primary purpose?
Trims the fuel flow for limiting N1 RPM when engine is accelerating at or near any thrust mode limit.
The EEC provides N1 and N2 red line overspeed protection.
IT DOES NOT provide EGT overtemperature protection
When will the In-Flight Start Envelope appear on the EICAS primary display?
Whenever:
1. An Engine is not running in flight
2. The respective engine fire switch is not pulled
3. Both EICAS primary and secondary displays are selected.
What would cause a FUEL SPAR VAL light to illuminate on the throttle quadrant?
The valves do not agree with the fuel control switch after allowing for normal operating time.
The ENG VALVE and SPAR VALVE lights illuminate momentarily as the valves open or close (engine start).
How are the Thrust Reversers actuated?
a. 767-200: Hydraulically actuated fan air thrust reverser.
b. 767-300: Pneumatically actuated fan air thrust reverser.
Where can the engine vibration display be found? Are there any limitations?
The engine vibration display can be found on the lower EICAS page. Engine vibration display must not be blanked during takeoff.
When would a Standby Engine Indicator placard automatically display engine indications with the indicator selector in AUTO?
- Whenever AC power is lost
- Either CRT failed
- STATUS selected on the ground
- EICAS failed.
What actions occur when an APU selector is moved from OFF to ON?
a. FAULT light illuminates momentarily (disagreement between fuel valve and commanded position)
b. Opens the APU fuel valve and Inlet Door
c. Activates AC or DC fuel pump
d. Powers the APU controller
e. Permits the APU bleed valve to open if the APU bleed switch is on when APU reaches operating speed.
What is an indication that the APU has successfully started and is ready to power the electrical system?
The RUN light is illuminated on the APU panel. This light indicates the APU is at operating speed.
What are the altitude limitations with respect to APU operations for Electrical and Pneumatics?
APU Electrical power 43,100ft.
APU bleed air 17,000 feet.
Where does the APU draw its fuel supply from? What would cause a DC pump to operate in place of an AC pump?
a. Fuel for the APU is supplied from the left manifold.
b. A dedicated DC fuel pump is energized when the APU selector in the ON position if no AC power is available (no EXT PWR plugged in).
T/F: The APU will shut down immediately when the APU start selector is moved from the ON to OFF position.
FALSE;
To protect the unit from thermal shock the APU control system incorporates a time delay feature permitting APU cooling before shutdown.
While on the ground with the APU running, what happens if the battery switch is selected to OFF? What happens to the APU if the battery switch is selected off while in flight?
a. This results in an APU shutdown (after a cooldown cycle). This is not recommended because APU fire detection may not be available.
b. In flight, battery switch position does not affect APU operation.
How can an APU shutdown cycle be canceled
If the selector is inadvertently moved to OFF, but the RUN light is still illuminated, momentarily moving the selector to START cancels the shutdown signal.
What is the significance of an APU FAULT light when illuminated?
- It means the APU has automatically shutdown.
- APU fuel valve disagrees with the commanded position.
Do the ABORTED ENGINE START procedure
For the following reasons:
- No EGT Rise after Fuel Control in RUN after:
CF6 - 25 seconds
PW 4060 - 20 Seconds
RB 211 - 20 Seconds - No N1 Rotation by 30 secs after N2 at IDLE
- EGT Quickly nears or exceeds Limit
- Oil Press NOT Normal when stable at IDLE
