FAA Aviation Mechanic Powerplant (AMP)Ignition and Starting SystemsMedium
During flight through heavy rain and turbulence, a pilot selects the CONTINUOUS IGNITION switch on a turbine-powered aircraft. What is the primary purpose of this selection?
- ATo provide continuous sparking at the igniters to prevent flameout from water ingestion or airflow disturbances
- BTo increase igniter output voltage for improved cold-weather starting
- CTo bypass the starter-generator cutout relay so the generator remains engaged
- DTo reduce exhaust gas temperature during high power settings
Show answer & explanationAnswer & explanation
Correct answer: A. To provide continuous sparking at the igniters to prevent flameout from water ingestion or airflow disturbances
Turbine igniters normally spark only during the start cycle. Selecting continuous ignition energizes the exciter units continuously so any momentary flameout caused by water ingestion, severe turbulence, or icing is immediately relit, preventing a sustained flameout.
Why the other options are wrong
- B. Continuous ignition does not increase exciter output voltage; it changes duty cycle, not intensity.
- C. The starter-generator cutout relay is unrelated to the ignition switch function.
- D. EGT is controlled by fuel scheduling and power lever position, not by the ignition system.
Continuous Ignition (Turbine)
A pilot-selectable mode that keeps turbine igniter plugs firing continuously (instead of only during start) to prevent flameout during heavy precipitation, icing, or turbulence.
- Normally used during takeoff/landing in rain/icing conditions and severe turbulence
- Increases igniter duty cycle far beyond the short start-only duty cycle
- Does not affect fuel scheduling or EGT directly
Memory trick: Rain falls, sparks stay on — continuous ignition keeps the flame alive.