FAA Aviation Mechanic Powerplant (AMP)Turbine EnginesMedium
During a ground start, a turbine engine's EGT rapidly rises above the specified start limit while N1 remains very low and slow to accelerate. Which start condition is being experienced?
- AHung start
- BFlameout
- CCompressor surge
- DHot start
Show answer & explanationAnswer & explanation
Correct answer: D. Hot start
A hot start occurs when excess fuel is introduced relative to the available airflow during start, causing EGT to exceed limits before the engine reaches self-sustaining speed. The technician must abort the start immediately to prevent turbine damage.
Why the other options are wrong
- A. A hung start is characterized by the engine stabilizing at a low RPM below idle without excessive EGT.
- B. A flameout is loss of combustion, which would cause EGT to drop, not rise.
- C. Compressor surge involves airflow reversal and loud banging, typically at higher power, not during a slow start.
Hot Start
A turbine engine start condition where EGT exceeds the specified limit due to excess fuel relative to airflow before the engine reaches idle.
- Caused by too much fuel or insufficient starter airflow
- Requires immediate abort to prevent turbine damage
- Different from a hung start, which involves low RPM, not high EGT
Memory trick: Hot start = 'too hot, too fast fuel' — EGT spikes before RPM catches up.