Australian authorities on Thursday released footage from a September incident that shows a skydiver dangling thousands of metres in the air after their reserve parachute became caught on the tail of an aircraft.

The group had planned a 16 way formation jump from about 15,000 feet south of Cairns. Seconds after the first jumper moved towards the exit, the situation turned dangerous.

Video of the incident shows the jumper’s reserve chute opening by mistake after its handle snagged on the aircraft’s wing flap, pulling the skydiver backwards.

The skydiver’s orange reserve canopy wrapped around the tail of the plane and left him hanging over empty air.

For a brief moment, the skydiver appeared frozen with hands on their helmet while trying to comprehend what had happened.

He then used a hook knife they were carrying to cut the tangled reserve lines and free themselves. After releasing the reserve, he deployed the main parachute and landed safely.

The Australian Transport Safety Bureau said carrying a hook knife is not mandatory but can be vital in emergencies.

"Carrying a hook knife, although it is not a regulatory requirement, could be lifesaving in the event of a premature reserve parachute deployment," said the bureau's chief commissioner Angus Mitchell, as quoted by news agency AFP.

The aircraft’s tail suffered damage from the impact, reported AFP. The pilot briefly lost control and issued a mayday call but managed to land the plane safely.