What happened
On 28 October 2006, a Thunderbird MK II aircraft, registration ZU-DUW, was involved in a runway excursion during a private flight near Groblersdal. The aircraft departed from a private aerodrome located on a farm in the area, with the intention of returning to the same location. During the takeoff roll on Runway 27, the aircraft encountered wind shear, which caused a sudden loss of lift. This aerodynamic disturbance forced the aircraft to land heavily back on the runway surface, subsequently leading to an overrun at the end of the runway.
Both the pilot and one passenger were on board at the time of the incident. There were no injuries reported following the event.
The investigation
SACAA AIID investigators reviewed the circumstances surrounding the takeoff and the mechanical state of the aircraft. The investigation confirmed that the Thunderbird MK II was operating under a valid Authority to Fly, which had been issued in July 2006 and was set to expire in July 2007. Records indicated that the aircraft's last annual inspection was completed on 7 July 2006, with only 7.3 flight hours accumulated since that certification.
Upon inspection of the aircraft, it was noted that the impact caused damage to the nose and the main landing gear. Meteorological data at the time of the incident indicated good visibility, with a light wind of 5 knots from 040° and a temperature of 16°C.
Findings
- The primary cause of the incident was the occurrence of wind shear during the takeoff phase.
- The wind shear resulted in a sudden loss of lift, causing the aircraft to settle heavily onto the runway.
- The momentum of the heavy landing contributed to the aircraft overrunning the end of Runway 27.
- The aircraft sustained structural damage to the nose and main landing gear.