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How Skydiving Works

Skydiving Equipment

A parachute rig used by any sport skydiver today has six basic parts:

  • There is the parachute itself, also known as the main canopy.
  • There is the pilot chute -- a small (12 to 18-inch / 30 to 45-centimeter diameter) parachute that the skydiver uses to pull out and open the main canopy. The skydiver throws out the pilot. It catches the wind and pulls on a 7 to 10-foot (2 to 3-meter) long piece of nylon webbing (known as the bridle). The bridle pulls the main canopy out of the container so that it can inflate.
  • There is a second parachute, known as the reserve, that is available in case the main canopy fails for some reason. The main canopy might not come out of its container, it might not inflate properly, it might get tangled in its lines, and so on. If it fails, the skydiver can cut it away and deploy the reserve.
  • There is the container, which is a backpack that holds the main chute and the reserve chute. The container also includes thick shoulder and leg straps that keep the container firmly attached to the skydiver.
  • There are the lines, which run from the parachute to the container through a pair of thick straps called the risers. Most modern parachutes have five sets of lines called the A-lines, B-lines, C-lines, D-lines and brake lines.
  • There is the AAD, also known as the automatic activation device. If something goes wrong -- for example, the skydiver passes out or gets distracted -- the AAD will automatically release the reserve parachute at about 750 feet (230 meters).

Just about everyone today uses ram-air canopies. This type of parachute is square or rectangular and is made completely out of lightweight nylon. There is a top and bottom sheet of nylon, and then a set of fabric ribs between them. The ribs divide the parachute into a set of individual cells. Air enters, or rams, into the front of the canopy to inflate the cells and give the parachute an airfoil shape. This shape makes the parachute act like a wing (see How Airplanes Work for a description of wings). Instead of coming straight down like you would with a round parachute, you actually glide in with a ram-air chute.

You also have a lot of control with a ram-air chute. You have two sets of lines connecting to the rear edge of the parachute on the left and right sides. You control these lines with two handles called toggles. When you pull on the left toggle, you lower the back part of the left side of the wing. This causes the left side of the parachute to slow down, so you turn to the left. You can turn to the right in the same way. If you pull both the left and right toggles together, it slows the whole wing down and acts like a brake. This allows you to flare to a stop during landing. This level of control makes extremely precise landings possible.

Next, we'll look at how a parachute is packed.