What happened
On July 9, 2016, a tandem skydive instructor and a passenger exited an L-410 aircraft at an altitude of approximately 4,000 m AGL near Kolín, Czech Republic. The jump proceeded normally until the instructor activated the main canopy at approximately 1,600 m AGL. During the deployment, twists formed on the suspension lines, causing the HOP 330 canopy to enter an uncontrollable right-hand spiral descent.
The tandem pair descended in a high-speed spiral, completing 38 horizontal rotations over a period of 76 seconds. The instructor attempted to clear the line twists manually rather than immediately executing a main canopy cutaway. During the descent, the passenger's physical positioning likely obstructed the instructor's access to the cutaway handle. The descent ended with a high-velocity impact into trees and vegetation, which partially mitigated the force of the impact. The passenger sustained severe injuries.
The investigation
Investigators from the ÚZPLN examined the tandem equipment, including the HOP 330 main canopy and the VR 360 reserve parachute. Technical inspections confirmed that the equipment was properly maintained, serviced, and packed according to manufacturer specifications. The investigation included a review of video footage captured by a cameraman who was jumping in the same formation.
Physical testing of the tandem system ruled out the possibility that the passenger's limbs prevented the instructor from reaching the cutaway handle. The investigation also focused on the instructor's actions during the emergency, noting that while she was theoretically trained for such scenarios, she had never performed a manual cutaway during a tandem jump in practice.
Findings
- The primary cause of the accident was the instructor's failure to manage the critical situation by performing an immediate cutaway of the malfunctioning main canopy.
- Line twists formed on the suspension lines during the deployment of the main canopy, rendering the parachute uncontrollable.
- High centrifugal forces and intense stress during the spiral descent likely hindered the instructor's ability to locate and operate the cutaway handle.
- The instructor attempted to rectify the line twists manually instead of deploying the reserve parachute immediately.
- The impact was mitigated by the presence of dense vegetation and trees at the landing site.