What happened
On 3 March 2021, a solo pilot operating a Rallye 235E, registration ZS-JSR, departed Orient Airfield (FAOI) in Gauteng Province, intending to land at Wonderboom Airport (FAWB). The flight proceeded normally through the initial climb until the aircraft reached approximately 500 feet above ground level. While performing a left turn, the pilot observed that the engine power readings were fluctuating.
In an attempt to rectify the issue, the pilot activated the booster pump and switched the fuel source from the left to the right tank, which temporarily restored full power. The pilot then decided to return to the departure airfield for a precautionary landing. However, during the subsequent turn, the power fluctuations recurred. Despite adjusting the fuel mixture to rich and checking engine temperature and pressure, the engine failed to maintain sufficient power. As the aircraft lost altitude and forward airspeed, the pilot determined that returning to the airfield was impossible and executed a forced landing into a nearby maize crop field.
During the impact, the aircraft's nose landing gear detached, and the propeller and the right-side leading edge of the wing sustained damage. The pilot was able to exit the aircraft unassisted and sustained no injuries.
The investigation
An investigation by the SACAA AIID examined the aircraft, the pilot's credentials, and the mechanical state of the engine. The investigation confirmed that the pilot held a valid Private Pilot Licence and that the aircraft possessed a valid Certificate of Airworthiness. The aircraft had been maintained by an approved organization, with the most recent service completed in October 2020.
Investigators noted that the aircraft had been parked for approximately four months prior to the flight. While such periods of inactivity can sometimes lead to fuel contamination via microbial growth, laboratory analysis of the fuel drained from the aircraft showed no evidence of contaminants. Furthermore, the investigation found no mechanical anomalies in the airframe or engine controls; all observed damage was attributed to the impact with the ground and crops.
Findings
- The pilot was properly licensed and qualified for the operation.
- The aircraft was airworthy and had been maintained according to regulatory standards.
- Sufficient fuel was on board for the intended flight duration, and no visual contamination was present.
- The specific cause of the engine power fluctuations could not be determined.
- The pilot's decision to execute a forced landing was prompted by a rapid loss of altitude and airspeed following the second instance of power instability.