Engines - Ignition and Start

Question 1

Components

Answer 1

• Each engine is equipped with a bleed air starter motor (bleed air can be provided form a ground air cart, other engine or APU)
• Each engine has two igniters

Question 2

Engine igniters

Answer 2

• There 2 igniters per engine
• The EEC (electronic engine control) automatically uses one ignitor for engine starts on the ground
• Both igniters are used for inflight starts

Question 3

Auto start system

Answer 3

• Uses the engine electronic computer (EEC) to monitor the engine parameters during the start sequence
• Controls the fuel and ignition during the start and automictically stops the start if something goes wrong

Question 4

Engine start up sequence

Answer 4

1. The start valve opens to allow air to turn the starter
2. The left spar valve opens and the engine valve remains closed during autostart until the engine has reached sufficient speed
3. At the appropriate engine speed, the EEC opens the engine fuel valve and energizes an igniter (33.0 N2)

(The Engine Electronic Computer selects an appropriate igniter by alternating igniters for each start)

-The start switch remains engaged until starter cut out speed is reached (passed 60.0 N2) and closes the start valve subsequently