Definition
A flameout in a turbine engine caused by an air-to-fuel ratio that is too high — meaning too much air for the amount of fuel being supplied — so the mixture cannot sustain combustion and the flame in the combustion chamber goes out.
Plain English
The engine quits burning because the fuel is spread too thinly through the air going into it. There isn't enough fuel in the mix to keep the fire going, so the flame dies.
Context Anchor
Encountered in turbine engine discussions, especially when learning why a flameout can occur and how fuel-air balance affects engine operation.
Derivation
Lean' in engine work means a mixture with relatively more air and less fuel — the opposite of 'rich.' A 'flameout' is exactly what it sounds like: the flame inside the combustion chamber goes out. Put together, the term names the cause and the result.
Why Pilots Care
Results in sudden loss of thrust and requires prompt engine restart to avoid forced landing.
Analogy
A campfire with too much air and too little fuel will not keep burning. A turbine engine also needs the right fuel-air balance to keep its internal flame lit.
Grounding Statement
In a lean-condition flameout, the engine still has air moving through it, but the mixture is too fuel-poor for steady burning.
Intuition Check
“Lean” does not mean the airplane is tilted or banking here; it means the engine mixture has too little fuel. “Flameout” does not mean an outside fire; it means the engine’s internal burning has stopped.
Example Sentence 1
A rapid throttle reduction at high altitude can starve the combustor of fuel and produce a lean-condition flameout.
Example Sentence 2
The sudden drop in exhaust-gas temperature confirmed the lean-condition flameout and triggered the restart procedure.