What happened
On the afternoon of 7 December 2021, an Evektor SportStar, registration ZU-EIJ, departed Springs Aerodrome for a private flight. The pilot intended to fly over the Bronkhorstspruit Dam before returning to the departure airfield. The flight was conducted in formation with another light aircraft, a Zenair Zodiac 601HD, registration ZU-AZY.
While traversing the dam, witnesses observed a blue object detach from the fuselage of the ZU-EIJ. Following this structural separation, the aircraft entered a rapid descent, spinning through the sky before impacting an open field near the southern edge of the dam. The impact resulted in the destruction of the aircraft and one fatality.
The investigation
SACAA AIID investigators examined the wreckage and recovered the entire left wing for metallurgical analysis. The investigation also reviewed GPS data from the aircraft and interviewed witnesses and the pilot of the accompanying aircraft. Meteorological data and radar imagery were analyzed to reconstruct the atmospheric conditions at the time of the accident.
Findings
- The primary cause of the accident was the structural failure of the outer left-wing main spar, located 125cm from the wing tip.
- This failure was triggered by exceedingly high wing loads resulting from severe turbulence caused by the outflow of a nearby thunderstorm cell.
- The pilot was flying with 333.8 total hours, including 48.1 hours on this specific aircraft type.
- Eyewitnesses reported gale-force winds in the area during the incident.
- The accompanying pilot encountered such intense turbulence that they were unable to orbit the crash site and were forced to divert to Kitty Hawk Aerodrome.
Safety action
- It is recommended that flight crews receive enhanced training regarding the proper understanding of the flight envelope for their specific aircraft types.
- Pilots are urged to maintain a strict awareness of their personal and aircraft limitations when operating in challenging environments.