What happened
On the afternoon of 15 April 2022, a De Havilland Tiger Moth, registration ZS-BGL, was conducting a private circuit flight at Brakpan Aerodrome in Gauteng Province. The pilot intended to land on the grass runway (Runway 03) to take advantage of the surface for easier braking. After climbing to approximately 500 feet, the pilot began a maneuver to approach the grass runway.
While flying at roughly 100 feet above the ground, the engine suddenly stopped without warning. The pilot attempted to turn left to reach Runway 3 and land safely, but was unable to reach the strip. The aircraft subsequently landed hard on the grass area situated between the thresholds of Runway 03 and Runway 36. The impact caused the right landing gear to fail and the right wing to strike the ground, resulting in the aircraft skidding for about 20 meters. There were no fatalities and no injuries to the pilot or the passenger, though the aircraft sustained substantial damage.
The investigation
SACAA AIID examined the aircraft's maintenance history and mechanical condition following the accident. The aircraft had undergone its annual inspection approximately 18 hours prior to the event, and no outstanding defects were recorded in the flight logs. Post-accident inspections by an approved person found that the fuel supply was adequate, the fuel filter was clean, and there were no visible defects in the magnetos. While a slight drop in RPM was noted on the left magneto, it was not considered sufficient to cause a total engine failure.
Meteorological data from the day indicated a temperature of 17°C with a dew point of 8°C. Based on the dew point depression, the probability of carburettor icing was classified as serious during descent power.
Findings
- The primary cause of the engine failure was ice formation within the carburettor, which blocked the flow of fuel to the engine.
- The aircraft was operating in atmospheric conditions conducive to significant icing risk during the descent phase.
- The pilot's attempt at a forced landing was unsuccessful, leading to the structural damage of the landing gear and wing.