What happened
On 9 October 2021, a flight of three gyrocopters was conducting a navigation mission from Van Wyk Vlei toward Calvinia in the Northern Cape. The aircraft, an Autogyrocopter MT03 with registration ZU-ETK, was flying at approximately 1,000 feet above ground level as part of a formation.
As the flight approached a rising hill, the pilot of ZU-ETK encountered a sudden, powerful wind that forced the aircraft downward. The pilot was unable to maintain altitude or counteract the downward force, leading to a hard impact with an uneven, rocky surface. The impact caused the oil cooler to fail, leaking oil onto hot engine components and triggering an intense fire. Although the pilot successfully evacuated the aircraft and attempted to use an onboard fire extinguisher, the flames were too intense to suppress. The aircraft was destroyed by the fire. The pilot escaped the wreckage with 0 fatalities and no injuries.
The investigation
SACAA AIID examined the flight data and environmental conditions surrounding the crash. The investigation confirmed that while the pilot's indicated airspeed was 81 mph, the ground speed had dropped significantly to 50 mph, as recorded by the onboard GPS. This discrepancy indicated a substantial headwind or atmospheric resistance. Weather reports from the South African Weather Service for the day of the accident showed winds originating from the south, which, when interacting with the local terrain, contributed to the hazardous conditions.
Findings
- The primary cause of the accident was the encounter with a strong downdraught that prevented the pilot from recovering altitude.
- The aircraft struck rocky terrain, which led to the mechanical failure of the oil cooler.
- The subsequent fire was fueled by oil contacting hot engine parts and was too intense for the onboard extinguisher to manage.
- The other two aircraft in the formation were able to successfully climb and avoid the same atmospheric disturbance.