Grob Astir CS 77, VH-IKJ, 2.5 km south-south-west of Waikerie, South Australia

Factual information

The glider was launched by aerotow for a local flight and at about 2,000 ft it was observed by the tug pilot to release and to fly straight and level.

Sometime later, the pilot a of glider flying in the Waikerie circuit area reported that there was a damaged glider in a field about 3 km south of the airfield. The tug pilot immediately commenced an aerial search and on locating the severely damaged glider, alerted emergency services. The pilot had not survived the impact.

On-site examination of the wreckage indicated that the glider had impacted the flat, grass covered terrain at high speed in a vertical, or near vertical dive. There was no evidence that the aircraft had been rotating immediately at impact and all aircraft components were located at the site except for the radio battery. Impact forces had destroyed the cockpit area, partially detached both wings, and broken the fuselage near the wing trailing edge.

The wreckage was recovered to a hangar at the airfield and inspected by engineers. Despite the extreme disruption of the airframe, all primary control system components were identified and examined. Many components had fractured during impact, however, it was determined that the control systems were all correctly connected prior to impact. The damage to componentry precluded a conclusive examination for jamming or obstruction of the control systems. The radio battery location was in an area of the aircraft well away from the control systems. The battery to electrical system connector wiring was found torn apart, consistent with separation of the battery from the aircraft at impact.

The glider had a valid maintenance release, and no maintenance deficiencies were identified. No evidence was found to suggest that a pre-existing failure of an aircraft component contributed to the accident.

The pilot was one of a group of foreign glider pilots visiting Waikerie for a period of intensive flying. He was correctly licensed and endorsed on the type. Prior to being approved to conduct solo flights at Waikerie, he was given flight instruction which included stall and spin recovery techniques.

A witness reported that on the day before the accident, a similar glider flown by the same pilot had pitched steeply nose-down and lost height immediately after release from the aero-tow.  The pilot was severely shaken, and he was subsequently debriefed by instructional staff before undertaking further flying.

The tow had appeared normal to the tug pilot who also briefly observed the glider in straight and level flight following the release. The descent was apparently not observed; however, in the light of the witness report of the previous day's incident, the possibility that the pilot lost control of the glider cannot be discounted.

The reason for the dive and the inability of the pilot to regain control of the glider could not be determined.