What happened
On 01 June 2005, a Piper PA 22-150, registration ZU-AKE, was conducting a visual flight rule training flight departing from Empangeni Aerodrome. The flight, involving an instructor and a student, was intended to be a local circuit returning to the same aerodrome. During the initial climb and power check, the pilot noted the engine was operating at 2,300 RPM.
While leveling off at 1,500 feet above ground level, approximately 3 nautical miles from the airfield, a loud bang originated from the engine. This was immediately followed by oil spraying across the windscreen and smoke entering the cockpit, leading to a total loss of engine power. The pilot performed a forced landing in a sugarcane field located east of Empangeni. During the touchdown, the aircraft struck an irrigation ditch, causing the plane to bounce and rotate 90 degrees before coming to a halt. Both occupants survived the impact with no injuries.
The investigation
SACAA AIID investigators examined the wreckage and the engine components to determine the cause of the power loss. The investigation included a metallurgical analysis of the engine at the University of Pretoria. The inquiry also reviewed the aircraft's maintenance records, documentation, and the regulatory status of the flight operation.
Findings
- The primary cause of the engine failure was the fracture of the number 2 cylinder head.
- Metallurgical testing confirmed the failure was due to fatigue caused by cyclic tensile stress. Evidence suggested a crack had been present in the component for a significant period before the catastrophic failure occurred.
- The aircraft was operating without a valid Authority to Fly Certificate at the time of the accident.
- The training flight was not being conducted under the requirements of an approved aviation training organisation (ATO).
- There were several documentation issues, including missing aircraft records on board and a lack of traceable history for the engine.
Safety action
- It is recommended that the Commissioner for Civil Aviation monitor cylinder head failures to determine if maintenance standards or requirements need revision.
- A recommendation was made to enhance safety oversight regarding the certification and training requirements for owner type conversions.