What happened
On May 31, 2011, a Pilatus Porter PC6-B2H4, registration F-HDEY, operated by Revolution’Air, was conducting a private skydiving session near Saint-Vaast de Longmont, France. The aircraft was carrying a pilot and five skydivers. While flying at 500 meters, the pilot maintained a speed of 70 knots to drop a wind indicator.
As the skydiver responsible for the drop opened the aircraft door, the airflow entered the cabin and caught the hand deploy device. This triggered the premature deployment of the main parachute. The force of the deployment pulled the skydaries out of the aircraft. During the inflation process, the 239 ft² main canopy struck the right side of the aircraft's horizontal stabilizer, causing the fabric to tear on the upper surface. The skydiver successfully deployed a reserve parachute and landed safely.
Although the pilot did not immediately notice a significant impact and continued the flight to complete the remaining jumps, the aircraft exhibited abnormal handling during the return to Compiègne. The pilot noted difficulty controlling the aircraft's pitch and noticed unusual behavior when using the trim controls. Upon landing, a ground inspection revealed that the adjustable horizontal stabilizer was deformed and had rotated 15 degrees to the right, causing interference with the airframe.
The investigation
The investigation focused on how the hand deploy device was activated. The skydiver involved was a highly experienced professional with over 10,000 jumps. Investigators examined the parachute and found no technical malfunctions that would cause the hand deploy to exit its storage pouch on its own. However, they noted that the device's handle protrudes slightly from the pouch.
To drop the wind indicator, the skydiver must move into a kneeling position. The investigation established that the physical act of opening the sliding door could cause the door to rub against the parachute or the door handle to snag the hand deploy handle. This movement could partially pull the device from its pouch, making it vulnerable to the high-velocity airflow entering the cabin, which then provided enough force to initiate deployment.