Mooney M20C N6833N accident near Palm Coast, Florida

Probable cause

A crack in the No. 4 cylinder head, which resulted in engine roughness, a fuel leak, a loss of engine power, and the subsequent in-flight fire.

NTSB analysis

During takeoff and the initial climb for the personal flight, the commercial pilot noticed that the engine was losing power. When the airplane reached about 400 ft above ground level, the engine lost total power. During touchdown for the subsequent forced landing to a road, the pilot noticed flames coming into the cockpit near the passenger's feet; both occupants egressed as quickly as possible after landing. Postaccident examination of the airplane revealed that the cabin was consumed by fire; the fire appeared to have originated in the vicinity of the engine side of the firewall, forward of the copilot-side rudder pedals. Examination of the engine revealed that the No. 4 cylinder head was cracked from the exhaust valve to one of the spark plug holes. The fuel pressure gauge line was burnt about 3 inches from the carburetor. A witness had reported that the airplane's engine was running roughly and "shaking" before the accident. Thus, it is likely that increased engine vibration from the cracked No. 4 cylinder resulted in a loosened fuel line fitting and fuel leak, which subsequently led to the loss of engine power and in-flight fire.

Text from the NTSB. Open the NTSB docket for ERA17LA284 for the full record.