What happened
On 27 May 2001, a private flight involving an ASH 25E glider, registration ZS-GRY, was conducting a takeoff from Uitsig aerodrome (Hennenman). The pilot was accompanied by one passenger. During the takeoff roll, the sustainer engine, mounted in a pod behind the cockpit, was active to assist with the winch-launch procedure.
As the aircraft approached the point of becoming airborne, the winch mechanism suddenly stalled and ceased operation. This mechanical failure caused the winch cable to lose tension and become slack. Consequently, the glider moved ahead of the drogue chute attached to the end of the cable.
The investigation
SACAA AIID investigators examined the sequence of events leading to the contact between the aircraft and the winch equipment. The investigation established that the loss of tension in the cable allowed the aircraft to overtake the drogue chute. The investigation further determined that the chute was pulled upward, making contact with the aircraft's canopy and the propeller of the sustainer engine.
Findings
- The primary cause of the incident was a winch failure that led to the slackening of the cable.
- The sudden loss of tension allowed the aircraft to overtake the drogue chute.
- The upward movement of the drogue chute resulted in damage to the propeller of the sustainer engine and the cockpit canopy.
- Minor damage was also sustained by the left-hand wing.
- There were no injuries to the pilot or the passenger.