What happened
On 21 November 1998, a Grumman G164A, registered ZS-IRW, was conducting a ferry flight from Koppies toward a farm named "Uitkoms" near Petrus Steyn. During the flight, the pilot encountered a sudden and total loss of engine power. Despite the loss of propulsion, the aircraft maintained enough altitude to clear several power lines. The pilot subsequently performed a forced landing in a maize field located approximately two nautical miles from Petrus Steyn. While the landing itself was successful, the aircraft nosed over upon contact with the ground because the soil was soft and saturated from recent rainfall. The impact caused significant damage to the left-hand wing, as well as the vertical and horizontal stabilizers. There were no injuries to the pilot.
The investigation
Investigators examined the engine and fuel systems following the incident. During the inspection, fuel was drained from the carburettor, revealing the presence of water and a yellowish substance. Efforts were made to clean the carburettor, which allowed the engine to restart, though it initially operated with significant roughness. Additionally, investigators noted moisture within the magnetos. It was determined that this moisture likely entered the components after the aircraft had been left exposed to the elements following the accident.
Findings
- The primary cause of the engine failure was fuel contamination involving water and an unidentified yellowish substance within the carburettor.
- The aircraft's nose-over during the landing was caused by the soft, wet condition of the field surface.
- The engine's subsequent rough running was attributed to the initial contamination and the presence of moisture in the magnetos.