AC-5M loses its right wing in a spiral-dive recovery on a first flight on type

The pilot of an AC-5M was seriously injured, and the glider substantially damaged, when its right wing separated near North Plains on his first flight on the type. He had been aerotowed to about 945 m MSL to fly the manoeuvres his insurer required. At about 760 m MSL a right turn, possibly flown too slowly, dropped the glider into a very tight spiral dive; he stopped the rotation after several turns but was left fast and shaking, and as he eased back on the stick the wing came away with a bang. He bailed out, and his parachute opened below 150 m. The spar had broken in overstress well below the load the design should have carried.

1. First flight on a newly bought type: Assembled at North Plains that day, the glider was aerotowed and released at about 945 m MSL. The pilot, who had no time on the type, began the manoeuvres his insurer required.
2. Right turn goes into a spiral dive: At about 760 m MSL the pilot began a 30 to 45° right turn, possibly too slow. The glider dropped straight into a very tight clockwise spiral dive.
3. Rotation stopped, speed high: He neutralised the stick and applied left rudder. After several turns the rotation stopped and the wings came level, but the glider was fast and shaking.
4. Right wing separates on the pull-out: As the pilot eased back on the stick there was a bang and the right wing came away from the fuselage.
5. Bail-out below 150 m: He jettisoned the canopy and left the glider, his parachute opening below 150 m AGL. The landing was hard and he was seriously injured; the glider fell to the ground nearby.