Chapter 23 - Starting, Ignition and Electrical System

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Chapter 23 - Starting, Ignition and Electrical System
2014-02-01 03:00:31
Chapter 23

Starting, Ignition and Electrical System
Show Answers:

  1. Can the engines be started with power from the other engine's generator?
    Yes, only if coupled with the aircraft battery.
  2. What's the rough sequence of events for an 'auto' start?
    When Engine Mode Selector (EMS) switch is moved from OFF to either IDLE or FLIGHT, the starter and igniters are turned on. The EECU manages fuel flow to reach the selected speed. When Ng reaches 50%, the starter and igniters turn off.
  3. Describe what happens during an engine shutdown?
    • When Engine Mode Selector (EMS) is selected to OFF, the EECU will command the stop electro-valve to cut fuel flow to the engine.
    • If this does not work the EECU will also close the metering valve.
  4. How would start the engine in 'manual' mode?
    With governor switch in 'manual', press the start button on the Engine Control Lever (ECL) to activate the starter and igniters.
  5. How would you shut the engine down manually?
    • Pull (not motor) the Engine Control Lever (ECL) down and over its OFF detent.
    • This will cut the fuel.
  6. How would you conduct a dry motoring engine run?
    • Eng Gov switch to AUTO, and Eng Mode Switch to OFF, press start button on ECL to motor over.
    • Caution 30 sec on duty cycle...
    • followed by 1 min OFF.
    • 3 Shots before a 30 min break.
  7. Describe stater-generator power supply?
    • When not acting as motors, they are the generators.
    • Bus 1 supplies engine 1 through Start 1 CB, and Bus 2 supplies engine 2 through Start 2 CB.
  8. What controls the Starter-Generator in 'AUTO' mode?
    The Generator Control Unit (GCU), located on the FWD bulkhead of the aft avionics bay.
  9. Describe the engine ignition system?
    • Two igniter plugs, close to start injectors, at 1 and 9 o'clock positions.
    • Only powered during start.
    • 28VDC from BUS 1 supplies engine 1 through IGN 1 CB.
    • 28VDC from BUS 2 supplies engine 2 through IGN 2 CB.
  10. What does the Permanent Magnet Alternator do?
    • Ensures normal engine operation is independent to the airframe electrical system.
    • PMA is driven by engine oil pump drive shaft, and electrically powers the EECU above 50% Ng.
    • Output frequency of PMA is also used by EECU as a backup for Ng signal.