Parachute Deployment - Technical Library - Blue Sky Adventures Skydiving
At a skydiver's designated deployment-altitude; the individual throws the pilotchute from a pocket at the bottom of the rig (the backpack-like container holding both parachutes a.k.a., canopies). This is known as a bottom of container (B.O.C.) deployment system. This small parachute is connected to the main parachute by a cord known as the "bridle" which feeds through a grommet on a small black bag which has the carefully folded parachute inside and the lines stowed through rubber bands across the top. At the bottom of the container's tray which holds the main parachute is a loop which, in the closing sequence of the parachute system, is fed through grommets on each of four flaps that closes the container.
Attached to the bridle is a curved pin which is inserted through the closing loop after it has been fed through each of these grommets. When the pilotchute is thrown out, it catches the wind and pulls the pin out of the closing loop, releasing the black bag off the back of the individual (who is in the stable belly-towards-earth arched position). The parachute lines are pulled loose from rubber bands, through which they were stored during packing, and extend as the canopy starts to open. To reduce the risk of injury, A rectangular piece of fabric called the "slider" (which separates the parachute lines into four main groups fed through grommets in the four respective corners of the slider) slows the opening of the parachute and works its way down until the canopy is fully open and the slider is just above the head of the skydiver. During a normal deployment, a skydiver will generally experience a few seconds of intense deceleration, in the realm of 3 to 4 G's, while the parachute slows the descent from 120 mph to approximately 12 mph.
If a skydiver experiences a malfunction with their main parachute which they cannot correct, they have a "cut-away" handle on the front right-hand side of their container (on the chest) which will release the main canopy from the container. Once free from the malfunctioning main canopy, the reserve canopy can be activated by pulling a second handle on the front left (sometimes triggered by a Reserve Static Line (RSL) which, if present, will deploy the spring loaded Reserve Canopy located in the top of the container immediately after the main is cut away). A new type of RSL has been developed called the Skyhook. This new system uses the "cut-away" canopy to act as a very large pilot chute to more quickly extract the reserve canopy. The Skyhook is an incredibly fast system that has the jumper under the reserve canopy and flying within 2 seconds (compared to the 5-10 seconds of the old system).
