What happened
On 30 June 2012, during an aerobatic display at Klerksdorp Aerodrome in the North-West province, a formation of two L-39C aircraft was performing maneuvers for an air show. The flight began successfully with both aircraft departing Runway 36 and completing an initial loop in close formation. However, as the flight transitioned into a second loop, the lead aircraft executed a steep, descending left turn. This maneuver caused the following aircraft, registration ZU-HIT, to drop into a line-astern position.
During this maneuver, the pilot of ZU-HIT inadvertently flew into the slipstream and wake turbulence left by the lead aircraft. This encounter triggered a high-speed stall, causing the aircraft's nose to pitch up and the plane to roll to the right. The aircraft subsequently entered a steep, inverted dive. Due to the low altitude and the rapid nature of the descent, the pilot was unable to recover the aircraft or utilize the ejection system before impacting the ground. The impact resulted in one fatality.
The investigation
An investigation by the SACAA AIID examined the aircraft, the pilot's credentials, and the sequence of events using video footage captured by an onlooker. The investigation confirmed that the pilot held a valid Airline Transport Pilot License and the necessary aerobatic ratings. Mechanical inspections of the engine and airframe revealed no pre-impact failures, and the engine was found to have been producing sufficient power throughout the flight sequence.
The investigation also noted that the aircraft was properly maintained and possessed a valid Authority to Fly. While the aircraft was equipped with a functional automated ejection system, the extreme forces of the impact and the limited time available prevented a successful escape.