FROM A CAA ACCIDENT report released on 16 May 2022:
On 28 October 2021, the pilot of a Rand KR-2 two-seat high-performance aircraft with registration ZS-UKU took off on a private flight from Kitty Hawk Aerodrome (FAKT).
Visual meteorological conditions (VMC) prevailed at the time of the flight. According to the first eyewitness, the aircraft entered the aerobatic box situated west of FAKT; thereafter, the pilot executed a few aerobatic-type manoeuvres before flying towards the south.
A second eyewitness saw the aircraft make a high-speed left turn during which the right wing broke off in-flight. As a result, the pilot lost control and crashed approximately 0.57 nautical miles south of FAKT. The aircraft was destroyed and the pilot was fatally injured.
Post-accident examination of the failed right-wing aileron indicated that the right wing separation was triggered by the aileron aerodynamic flutter which was caused by the aileron that was not balanced in accordance with the Rand Robinson Engineering Build Manual.
The KR2 was built small to go fast.
The pilot lost control of the aircraft after the right-wing broke off in-flight due to the aileron aerodynamic flutter.
The aileron was under balanced to the extent of 60 kilograms per millimetre (kg/mm) residual moment.