Engine Fire on the Ground
An engine fire on the ground most commonly occurs during engine start (carburettor flooding). Immediate, decisive action can extinguish the fire before it spreads to the aircraft.
Source: POH (binding), FAA-H-8083-3B Chapter 17 Emergency Procedures.
Causes
- Flooding on start (over-priming): excess fuel ignites in the intake.
- Carburettor backfire: combustion outside the cylinder.
- Defective fuel lines: leaking hose connections.
- Excessive oil loss with heat build-up.
Symptoms
- Visible smoke or flames from the cowling.
- Sudden RPM drop, rough running.
- Pop / bang (backfire), smell.
Standard procedure (POH-specific, typical Cessna 172)
If engine is running (most common during start):
- Mixture IDLE CUT-OFF (lean): cuts off fuel.
- Throttle FULL OPEN briefly: may suck the fire into the engine.
- Continue cranking with the starter (5-10 sec): if the engine catches, it "digests" the flame.
- If fire persists after about 30 sec of cranking: magnetos OFF, fuel selector OFF, master switch OFF.
- Evacuate crew and passengers.
- Alert fire services (standard airfield emergency call).
- Use fire extinguisher when safe (CO₂ or halon, never water on a fuel fire).
If engine is not running:
- Mixture IDLE CUT-OFF.
- Throttle CLOSED.
- Fuel selector OFF.
- Magnetos OFF.
- Master switch OFF.
- Evacuate immediately and move away from the aircraft.
- Alert fire services.
What not to do
- Never leave the cockpit with the engine running without setting the brakes.
- No water on fuel fires (splashes, spreads fire).
- Do not re-enter the aircraft after evacuation — secondary explosion possible.
Prevention
- Correct starting procedure per POH (right priming count, no flooding).
- Inspect fuel system regularly (annual / 100-hour inspection).
- Fuel cap correctly closed (prevents fuel leakage).
- Trained crew: emergency procedures briefed regularly.