What happened
On 26 April 2019, a Beech A35 (registration ZU-DLW) departed Wesselsbron Aerodrome in the Free State for a short private flight to a nearby farm. The mission involved assessing agricultural damage following recent heavy rains. Approximately 18 minutes into the flight, while flying over the destination, the engine suddenly ceased operation. Despite the pilot's attempts to restart the engine by activating the auxiliary fuel pump and switching the fuel selector from the left to the right tank, the engine failed to respond.
Recognizing the emergency, the pilot identified a straight section of the S91 dirt road as a suitable landing site. During the forced landing, the aircraft's left wheel struck a muddy depression, causing the plane to veer off the road. The impact resulted in the collapse of the nose gear and the propeller striking the ground. While the aircraft sustained substantial damage, there were no injuries to the pilot or the two passengers on board.
The investigation
Investigators examined the aircraft's fuel state and maintenance history. At the time of the accident, the aircraft had been flying for 2.1 hours since its last refueling, which had provided 190 litres of AVGAS. Post-accident analysis by a maintenance engineer revealed that approximately 80 litres of fuel remained in the right tank, while only about 10 litres remained in the left tank.
Technical inspections of the fuel system also identified that the left fuel tank vent was obstructed by insect nest deposits, which the engineer subsequently cleared using compressed air. The investigation focused on the timing of the fuel tank switch relative to the remaining fuel levels.