The student was making a practice glide approach to land, with the throttle in the closed position. Sink developed late on the approach with the airspeed reducing, and full power was applied. The aircraft touched down about two metres short of the sealed surface in a soft area. As the aircraft rolled forward the wheels contacted a 'step' at the start of the sealed area. The contact with the 'step' collapsed the maingear legs and the aircraft slid to a stop. Significant Factors The following factors were considered relevant to the development of the accident: 1. The pilot under supervision misjudged the approach. 2. The instructor was late in assessing the situation and did not ensure power was applied in time to correct the sink rate and descent path.