What happened
The incident occurred during a training session involving an instructor and a prospective student. The instructor had been maneuvering the airplane for approximately fifteen minutes when the engine began to cough and subsequently quit. Emergency restart procedures were attempted but proved unsuccessful. Consequently, the pilot initiated a forced landing. During this landing sequence, the aircraft nosed over.
The investigation
Post-accident examination of the aircraft revealed that 14 gallons of fuel had been recovered from the system. A mechanical inspection of the engine showed no evidence of pre-existing mechanical malfunctions or failures. However, the examination did identify that four of the spark plugs were lead fouled.
Findings
The recovery of a significant amount of fuel combined with the lack of mechanical failure suggests the engine stoppage was not due to equipment malfunction. The presence of lead-fouled spark plugs indicates potential maintenance issues affecting ignition reliability during the flight.