Rolladen Schneider LS3A, VH-IUB, 16 km north-north-east of Parkes, New South Wales, on 1 October 1990

Circumstances:

The aircraft departed Narromine in company with three other gliders for a cross-country flight Narromine - Parkes - Condobolin - Narromine. Weather conditions were fine with good visibility but were otherwise difficult with weak and well-separated thermals being the only sources of lift. North of Parkes all four aircraft had descended to a low altitude. The other three pilots were able to use the weak lift to continue the flight but the pilot of VH-IUB decided that he was unable to continue and informed the other pilots by radio that he would land in a paddock. A south westerly wind of about five knots was blowing on the surface. The aircraft approached the paddock from the south west. In the latter part of the approach, at very low altitude, the pilot initiated a left turn to track away from trees at the edge of the paddock. During the turn the left wingtip struck the ground initiating a cartwheel motion. The fuselage impacted heavily in a steep nose-down attitude. The aircraft was destroyed and the pilot received fatal injuries. The pilot was a qualified glider pilot who had begun gliding ten years previously. However, he had only recently purchased the glider and resumed gliding after a layoff of several years. Stress and fatigue were possible factors in the accident, potential sources being a. the workload required to fly a cross-country route in conditions of poor lift; b. concern about the loss of an important horse sale; c. about sixteen hours driving, including caravan and glider trailer towing, in the 72 hours prior to the accident; and d. pressure to launch on the flight. Before DEPARTURE from Narromine the aircraft altimeters were set to read zero (QFE). Narromine Aerodrome is 782 feet Above Mean Sea Level (AMSL) and Parkes Aerodrome is 1069 feet AMSL. Consequently, an aircraft operating in the Parkes area, with Narromine QFE set on the altimeter subscale, would have approximately 300 feet less terrain clearance than at Narromine. A pilot lacking in currency, under a high workload, and possibly suffering from stress and fatigue, could fail to take this difference into account when considering the minimum altitude required for a safe outlanding. Examination of the wreckage did not reveal any defect that may have contributed to the accident. In March 1988, the wings were reprofiled from the original Wortmann FX67 airfoil sections to modified sections developed from research in USA. There is no evidence to indicate that the wing reprofiling resulted in the need for enhanced pilot skills for safe operation. The pilot was aware of the reprofiled airfoils.

Significant Factors:

The following factors were considered relevant to the development of the accident:

1. The pilot lacked recent experience.

2. The pilot could have been suffering the effects of stress and fatigue.

3. The pilot misjudged the altitude required and the approach direction during an outlanding.