What happened
On 23 February 2002, a CESSNA 172, registration ZS-OMN, was conducting a training flight when the aircraft experienced a sudden reduction in engine power. The flight, which originated from Grand Central Aerodrome (FAGC) with the intention of returning to the same airfield, was being operated by a commercial pilot and a student pilot. While approximately 5 nautical miles from the aerodrome, the engine failure necessitated an immediate forced landing. The aircraft came to rest at an elevation of 4,780 feet. Despite the loss of power, the landing was executed successfully, and both occupants were able to exit the aircraft without any injuries. There was no damage reported to the aircraft.
The investigation
An investigation into the incident examined the mechanical state of the aircraft and the operational circumstances of the flight. Investigators confirmed that the weather conditions at the time of the occurrence were fine. The pilot-in-command held a valid commercial license with the appropriate type rating and a current medical certificate. Furthermore, the investigation established that the operator held a valid Air Operator Certificate (AOC) and that the flight was properly authorized. Records indicated that the aircraft had been maintained according to required standards.
Findings
Technical analysis of the engine revealed that the No. 1 exhaust valve had become stuck in the open position, which directly caused the loss of engine power. Fortunately, this mechanical failure did not result in any secondary damage to the engine components.