Gemini Thruster, AUF 25-0046, Wellington, New South Wales, on 29 July 1990

Circumstances:

The aircraft was engaged in circuit training in the 05 direction. Wind conditions were reported to be 030/5 to 8 knots and gusty. A number of normal take offs and landings were safely executed before the instructor attempted a downwind take-off in the 23 direction. The aircraft was observed to take a longer than normal ground roll. When it reached a height of about 50 feet the left wing dropped, and the aircraft commenced to rotate to the left before striking the ground in a steep nose down attitude on a heading of about 050 degrees. A witness who was standing near the north eastern end of the strip said the wind gusted to about 15 knots from the north east immediately prior to the accident. It would appear that during a critical stage of the take-off, the aircraft stalled after suffering a sudden a loss of airspeed associated with a significant wind shear. This accident highlights the dangers of attempting downwind take-offs in ultra-light aircraft.

Recommendations:

It is recommended the AUF publicise the circumstances of this accident to highlight the dangers associated with downwind take offs in ultra-light aircraft.