The handle of their reserve parachute suddenly snagged on the wing flap, causing it to fully open.
The skydiver was dragged backwards and became caught on the plane’s left horizontal stabiliser, a section of the tail.
This jolted the plane and caused it to suddenly veer upward.
ATSB chief commissioner Angus Mitchell said the pilot was unaware of the situation, or that the skydiver was hanging beneath the plane.
He said the pilot recounted that the plane started vibrating violently and forward pressure and input had to be applied to keep the plane on an even keel.
The pilot issued a mayday signal to Brisbane Centre and notified them they had minimal control of the plane and were prepared to abandon the plane if it became unflyable.
Flapping in the high-altitude winds, the parachutist used a hook knife to slash 11 lines from the reserve parachute in just 50 seconds, before finally releasing it from the tail.
The experienced skydiver, with over 2000 prior jumps, then entered into a freefall, deployed their primary parachute and landed safely, with only minor injuries.
The incident caused minor damage to the tail of the plane.
“In difficult circumstances, the pilot managed to control the aircraft and land safely at Tully Airport,” Mitchell said.
Mitchell also warned that skydivers should keep a keen eye on their parachute handles when preparing to jump.
“Carrying a hook knife, although it is not a regulatory requirement, could be lifesaving in the event of a premature reserve parachute deployment,” he said.
Footage captured during the flight will be used in training materials for future parachutists.
