What happened
On 03 September 2010, a GS-2 Sportsman, registration ZU-FEZ, was performing a private VFR flight from Knysna to a farm airstrip in the Jakalskraal district near Plettenberg Bay. The flight was routine until the final moments of the approach. As the pilot attempted to flare the aircraft approximately two meters above the runway, the flight controls failed to respond as expected. The pilot discovered that the control stick was stuck and could not be moved backward.
Because the aircraft could not be flared, it struck the runway with excessive force and bounced. This unstable landing sequence caused the nose landing gear to collapse and break away. The momentum of the impact caused the aircraft to flip over, eventually coming to rest upside down on the runway. While the aircraft suffered substantial structural damage, the pilot escaped the wreckage without any injuries.
The investigation
SACAA AIID investigators examined the wreckage and the primary flight control systems to identify why the controls had locked. While the control system was functioning normally when the seats were in their upright positions, investigators discovered that folding the passenger seat backrest forward created a physical barrier. This barrier prevented the control stick from reaching its full rearward travel stop.
Testing confirmed that when the seat was folded, the elevator's upward deflection was reduced from the required 23 degrees to just 13 degrees. Furthermore, the investigation found that the seat backrests lacked a latching mechanism to prevent them from shifting forward during flight. Inspections of other GS-2 Sportsman aircraft assembled by the same local organization revealed that this design vulnerability was present in multiple aircraft.