Four experienced parachutists intended to carry out a group descent from 5000 feet agl. To facilitate the procedure, all four were to exit the cabin and hold onto the aircraft structure before releasing at the appropriate moment. As the second parachutist moved to take up his parachute pack evidently snagged on the door opening, and the parachute deployed. The lines passed around the lift strut and under the gear leg. The parachutist was pulled off his seat but managed to throw his arms back and around the strut. The pilot felt the aircraft slow dramatically as the parachute opened, and he applied full forward movement of the control column. One of the other parachutists activated the cut away on the deployed parachute and assisted the parachutist to return to the cabin. The aircraft lost 3200 feet of altitude during the occurrence. During the descent to land it was noticed that the wing strut was flexing. After landing it was found that the strut was partly fractured. Had it failed in flight the wing would have been free to pivot upwards, with consequent loss of aircraft control.
