What happened
On July 6, 2019, during student and tandem skydiving operations at Chrcynno Airport (EPNC), a serious incident occurred involving a reserve parachute system equipped with a Vigil Cuatro automatic activation device (AAD). During a flight involving fifteen skydivers, deteriorating weather conditions led the jump coordinator to order a return to the ground. To prevent the AADs from triggering due to high descent rates, the pilot had been maintaining a descent rate below 2,000 ft/min.
At an altitude of 1,500 m, an instructor decided to manually deactivate the AADs in the student and instructor parachutes. Following this, the pilot increased the descent rate to approximately 2,500 ft/min. It is believed that the deactivation procedure for one of the parachutes was not completed fully. As a result, the Vigil Cuatro AAD triggered during the descent. Although the cutter functioned, the reserve parachute container flaps did not open, and the pilot chute failed to deploy the reserve canopy.
After landing, the parachutes were placed on racks, and the triggered state of the AAD went unnoticed. When the same equipment was prepared for subsequent jumps, the instructor discovered a "cutter error" message on the AAD display, indicating the closing loop had been severed. Upon pressing the container flaps, the pilot chute successfully separated from the container.
The investigation
The PKBWL examined the specific AAD involved using CT scanning, which revealed no structural defects in the cutter. The investigation also included low-pressure chamber testing using three different parachute sets, including two with Vigil Cuatro units. The tests simulated high-speed descents of approximately 10,433 ft/min. The results showed that the AADs functioned correctly, successfully cutting the loops and initiating the deployment process in all tested configurations.
Findings
- The AAD triggered because the deactivation procedure for one parachute was likely incomplete.
- The increased descent rate following the deactivation attempt caused the AAD to reach its activation threshold.
- While the cutter successfully severed the loop, the reserve parachute failed to deploy because the container flaps had not opened.
- The investigation found no mechanical or design flaws in the Vigil Cuatro AAD or its cutter.