On May 26, 1996, at 1400 eastern daylight time (edt), a Cessna P206, N2625X, piloted by a commercially certificated pilot, was substantially damaged when the shroud lines of a parachutist's reserve parachute collided with the airplane's right horizontal stabilizer following an inadvertent deployment. The 14 CFR Part 91 parachute jump flight was not operating on a flight plan. Visual meteorological conditions prevailed at the time of the accident. The pilot and 6 passengers reported no injuries. The flight departed Goshen, Indiana, at 1345 edt. According to the jumpmaster, two parachutists were standing on the airplane's jump step. One of the two parachutists began the cadence used to jump from the step. The jumpmaster said the parachutist doing the cadence rocked back and forth in an "exaggerated" manner. During this motion his reserve parachute's ripcord pin protective flap brushed against the airplane's open door. The jumpmaster continued, "...the reserve ripcord was snagged and dislodged from the cloth closing loop resulting in an open reserve container. The reserve pilot chute entered the airflow past the airplane and pulled the reserve from the container." As the parachutists jumped from the step the parachute began to inflate. One of the steering lines struck the right horizontal stabilizer, bending it downward. According to the jumpmaster, the reserve container of the parachutist's whose reserve parachute deployed was loose. He said the pilot chute was "...slightly tilted inside the container." After the accident the jumpmaster spoke with the parachutist whose reserve parachute had opened prematurely. He said the parachutist told him his reserve parachute's ripcord protective flap would come lose quite often. He said this was due to a worn or weak velcro fastener. The pilot said he was not aware of what took place until after the parachutists had jumped. He said he was concentrating on flying the airplane. The outboard half of the right horizontal stabilizer was bent downward about 8 inches. The pilot said the airplane "...displayed no adverse flight characteristics..." after the event. His written statement confirms the jumpmaster's recall of the events.