What happened
On 6 October 2018, a Windlass Aquilla microlight, registration ZU-CBR, departed the Mlala Game Farm private airstrip in Limpopo Province for a scenic flight. The flight, which included a pilot and one passenger, proceeded without incident for approximately 30 minutes.
As the aircraft approached the airstrip for landing, an eyewitness observed the aircraft at an altitude of roughly 500 feet. A sudden, unusual noise was heard, followed by the visible separation of the aircraft's wing from its main body. The fuselage underwent three longitudinal rotations before impacting the ground, while the wing settled in a nearby tree. The impact was so severe that the occupants were ejected from the aircraft after their safety harnesses failed. Both the pilot and the passenger sustained fatal injuries.
The investigation
SACAA AIID investigators examined the wreckage and analyzed data from a Garmin watch worn by the pilot. The investigation focused on the flight maneuvers performed immediately prior to the accident. Technical analysis of the aircraft's components, including bent battens, confirmed that the structural failure was a result of extreme aerodynamic forces rather than a pre-existing mechanical defect. The investigation also confirmed that the aircraft was within its mass and balance limits and that the weather conditions were clear and favorable.
Findings
- The pilot successfully completed an initial stall maneuver without incident.
- During a subsequent stall exercise, the pilot pushed the base bar forward, causing a steep climb that exceeded the aircraft's critical angle of attack.
- This maneuver induced a whip stall, a high-energy aerodynamic state from which the pilot could not recover.
- The resulting tumbling motion created a pendulum effect that caused the airframe to break apart, leading to the separation of the wing from the fuselage.
- The failure of the safety harnesses during the sequence resulted in the occupants being thrown from the aircraft.