What makes parachuting dangerous? It might be thought that it is the risk that the parachute won’t open, but in a dissertation he is defending at Umeå University in Sweden on March 27, Anton Westman shows that carelessness or lack of skill in controlling your body or your parachute through the air is considerably more dangerous.

In both skydiving (jumping from aircraft) and BASE jumping (from stationary objects), instability in free fall is a fatal risk factor. Jumping from an airplane into the wind rushing by feels roughly like diving into a swift current of water, and there is a risk that beginners will lose control and start tumbling around in the new environment, which can lead to unstable activation of the parachute with subsequent tangling of its lines and even late parachute activation.

When you jump from the ledge of a cliff, it’s not as windy, but this can in fact be a danger, since for the first few seconds you don’t get any help from rushing wind to control your body and straighten up if you should fall forward and start tumbling around. Just as in skydiving, there is a risk of unstable or late parachute activation. An extra risk factor in BASE jumping is that a wing parachute can open in such a way that it steers you toward the object you jumped from.

The fatality risk in Swedish skydiving between 1994 and 2003 was roughly one death per one hundred thousand jumps. The fatality risk in BASE jumping appears to be about 60-90 times as great as in skydiving, and the dissertation urges jumpers to be cautious in pursuing this activity.

Wing parachutes are formed in different ways for different types of parachuting. BASE parachutes are constructed for landing at low speeds in difficult terrain, whereas certain types of wing parachutes for skydiving are designed for opposite reasons, for flying and landing at speeds of over 100 km per hour, roughly like small sailplanes made of cloth. They place great demands on the judgment and skill of the parachutist. The dissertation shows that many injuries are a result of “pilot error” on the part of the jumper. Besides miscalculated landings, collisions between wing parachutes have also led to injuries and deaths.

Further fatal and non-fatal risks are described in the dissertation, with suggestions for dealing with each. Injury prone body parts include legs, feet, the spine, and shoulder joints. Beginners run a greater risk of getting hurt, but the most serious injuries are described among the most experienced jumpers. An interview study describes the views of a number of parachutists regarding the risk of injury and their motives for pursuing the sport. What stand out are depictions of its recreational value, of “having fun,” as a main reason.