Definition
In a jet engine, igniters are high-energy electrical devices mounted in the combustion chamber that produce a strong spark to start combustion of the fuel-air mixture during engine start. Once the engine is running and combustion is self-sustaining, the igniters are normally switched off, though they may be reactivated for certain conditions such as takeoff, landing, flight in heavy precipitation, or recovery from a flameout.
Plain English
Igniters are the spark-makers that light the fuel in a jet engine. They fire during start-up to get combustion going, and the engine keeps burning on its own afterward without their help.
Context Anchor
Seen in jet engine start procedures, engine system descriptions, and discussions of in-flight relight.
Derivation
From Latin ignis, meaning 'fire.' An igniter is literally something that sets fire to something else — in this case, the fuel-air mixture inside the engine.
Why Pilots Care
Reliable igniters are essential for consistent engine starts on the ground and for successful restarts after a flameout in flight.
Intuition Check
Igniters are not the engine's main source of power. They only provide the spark that starts, or helps restart, the burning inside the engine.
Example Sentence 1
After the fuel was introduced, the igniters fired and the engine lit off smoothly.
Example Sentence 2
After the engine flamed out, the crew used the igniters to relight it at altitude.