Primary finding
Probable cause
A loss of engine power due to the spark plug coming out of the cylinder head.
Investigator assessment
Analysis narrative
According to the sport pilot, during takeoff in his experimental light sport airplane equipped with a two cylinder engine, he noted a loss of engine power. During the forced off airport landing, the airplane struck a fence post followed by a hard landing. The airplane sustained substantial damage to the horizontal stabilizer and fuselage. A postaccident examination of the engine revealed that the number 2 spark plug had pulled out of the cylinder head and the threads from the cylinder head were still attached to the spark plug.
Source record
Factual narrative
According to the sport pilot, during takeoff in his experimental light sport airplane equipped with a two cylinder engine, he noted a loss of engine power. During the forced off airport landing, the airplane struck a fence post followed by a hard landing. The airplane sustained substantial damage to the horizontal stabilizer and fuselage. A postaccident examination of the engine revealed that the number 2 spark plug had pulled out of the cylinder head and the threads from the cylinder head were still attached to the spark plug.