Spark plugs ignite the fuel-air mixture in reciprocating engines with a low-energy spark every revolution, but igniters in turbine engines are tailored to each specific engine model due to the difficulty of ignition. Igniters are designed specifically for each turbine engine model as an igniter for one engine likely will not function properly in another model due to the different ignition challenges of turbine engines compared to reciprocating engines.

1. Jet Propulsion
Ignition

2. Igniters
• They ignite the fuel-air mixture, but their
operating conditions are entirely different. In a
reciprocating engine, a relatively low-energy
spark must jump across the electrodes of a spark
plug every other revolution of the crankshaft.
• There are a few spark plug designs that are
usable in all aircraft reciprocating engines, but
because of the difficulty in igniting the fuel-air
mixture in a turbine engine, igniters are tailored
to the engine.
• Generally, an igniter designed for one engine will
not function properly in another model.

4. The basic sequence of the start cycle
Starter
Motor
External
Gearbox

5. Starter
Motor
Output
Shaft
Clutch
Mechanism
Reduction
Gear
Turbine
Air
In
Air
Out
Air
Out
Starter
Motor
External
Gearbox
Drive to
Engine Shaft