Incident Overview
A sport parachute flight operating in a cargo configuration carried 24 parachutists to an altitude of 12,500 feet over a designated drop zone for a mass jump. The aircraft had no passenger seats except for one jump seat, and 24 seat belts were attached to the floor of the cargo area. The cabin door had been removed, and an unapproved step along with four handholds were installed outside and forward of the cabin door for the use of parachutists.
Jump Run Procedure
The usual jump-run procedure involved slowing the aircraft to 95 to 100 knots, extending the landing gear and approach flaps, and reducing power on the left engine. Parachutists remained in position without using seat belts until approaching the drop zone. At that point, two jumpers moved outside the aircraft while others moved close to the doorway.
Accident Sequence
The first jumpers were unaware of any problem but subsequently observed the aircraft enter a steep bank, roll over, and spiral nose-down. Sixteen jumpers exited the aircraft, but three of them struck the stabilizer during their exit. The aircraft crashed in a near-vertical descent.
Investigation Findings
Investigation revealed that the aircraft's center of gravity was behind the aft limit for both takeoff and the jump. Additionally, the elevator trim actuator was found in a position corresponding to full nose-up trim.
Conclusion
These findings were documented as part of the official investigation into the accident.