This wingsuiter deployed at 5,000 feet and opened into some line twists. He wasn’t able to kick out of the line twists, so he cutaway and his reserve was deployed by a Skyhook, which opened into another set of line twists. Balls.
Why did it happen
Wingsuits can be more prone to line twists for a variety of reasons. The most obvious is that their basic nature makes symmetric deployment procedures far more critical. Small asymmetries have a larger effect while flying a wingsuit and even a small difference in the sides of the jumper’s body can cause their wake to become turbulent, resulting in line twists. Furthermore, the larger burble and wake caused by a wingsuit can cause a pilot chute and deployment bag to not clear the jumper as cleanly.
With virtually every line-twist scenario, there is a possibility that it was caused by a bad pack job. There’s no denying that as a potential culprit but it’s also hard to confirm from watching the video.
How could it be prevented
Cleaner Deployment (Maybe?)
Realistically, this jumper did a pretty good job on this deployment. From this video, they appear to continue flying straight, continue flying their body through the whole deployment process, and appear to maintain a (mostly) symmetric body position all the way through the deployment process. When their legs swing forward due to the relatively fast opening, there was some asymmetry but it’s going to be hard to control that factor in this situation. However, we cannot gauge how firmly they threw their pilot chute. If they did a weak toss there is a possibility that their pilot chute and deployment bag may have not deployed cleanly.
On every pack job, jumpers should take their time, not rush and not become complacent. Trying to rush to make a call, not replacing a worn-out stow band, etc., can cause mistakes which can result in line twists or worse.
Line Twist Techniques
Every video featuring line twists brings up a debate about which technique to use to clear them. Some folks say grab the risers, pull them apart, and twist your body in the opposite direction. Some people say bring the risers together to get the twists to come down to you. Ask a dozen jumpers and you’ll get thirteen opinions on which method is preferred. The important part is that you keep working and never give up.