What happened
On 22 September 2006, a Thunderbird MKII micro-light, registration ZU-ASS, was conducting a private flight near Farm Panqua in the Karoo. The aircraft, carrying a pilot and one passenger, was flying a local route when the engine ceased operation at an altitude of approximately 1,000 feet. The pilot identified a dirt road and attempted an emergency landing on the track.
During the landing sequence, the aircraft's nose wheel struck a mound of sand, causing the plane to veer left off the road. The momentum led to a ground loop, during which the aircraft struck another sand mound sideways. The impact caused the aircraft to roll over and come to rest in an inverted position. There were 0 fatalities and 0 injuries as both occupants were able to exit the wreckage safely.
The investigation
Investigators examined the fuel management and the mechanical state of the aircraft. The pilot reported that the engine failed after 2.25 hours of flight time. While the aircraft's fuel capacity is 50 litres, the pilot had departed with an estimated 45 litres. Based on an average consumption rate of 20 litres per hour, the fuel supply would have been depleted by the time the engine failed.
The investigation also looked into the pilot's reliance on the cockpit fuel gauge, which incorrectly indicated that one-quarter of the tank remained. The pilot noted that the plastic fuel tank was difficult to visually inspect due to severe discoloration. The aircraft's maintenance records showed a valid Authority to Fly and a recent annual inspection completed in November 2005.
Findings
- The primary cause of the engine failure was fuel exhaustion resulting from improper fuel management.
- The pilot relied on an unreliable fuel gauge reading rather than calculating remaining endurance based on known consumption rates.
- The subsequent rollover was caused by the aircraft encountering sand mounds during the forced landing attempt.