Parachuting
Parachuting and skydiving are methods of descending from a high point in an atmosphere to the ground or ocean surface with the aid of gravity, involving the control of speed during the descent using a parachute or multiple parachutes.
For human skydiving, there is often a phase of free fall, where the parachute has not yet been deployed and the body gradually accelerates to terminal velocity.
In cargo parachuting, the parachute descent may begin immediately, such as a parachute-airdrop in the lower atmosphere of Earth, or it may be significantly delayed. For example, in a planetary atmosphere, where an object is descending "under parachute" following atmospheric entry from space, may occur only after the hypersonic entry phase and initial deceleration that occurs due to friction with the thin upper atmosphere.
History
The first parachute jump in history was made on 22 October 1797 by Frenchman André-Jacques Garnerin above Parc Monceau, Paris. He used a silk parachute to descend approximately 3,000 feet from a hot air balloon.Common uses
Parachuting is performed as a recreational activity and a competitive sport, and is widely considered an extreme sport due to the risks involved. In 2018, there were 3.3 million jumps in the US. Modern militaries utilize parachuting for the deployment of airborne forces and supplies. Special operations forces commonly employ parachuting, especially free-fall parachuting, as a method of insertion. Occasionally, forest firefighters, known as "smokejumpers" in the United States, use parachuting as a means of rapidly inserting themselves near forest fires in especially remote or otherwise inaccessible areas.Manually exiting an aircraft and parachuting to safety has been widely used by aviators and passengers to escape an aircraft that could not otherwise land safely. While this method of escape is relatively rare in modern times, it was occasionally used in World War I by German military aviators, and utilized extensively throughout the air wars of World War II. In modern times, the most common means of escape from an aircraft in distress is via an ejection seat. Said system is usually operated by the pilot, aircrew member, or passenger by engaging an activation device manually. In most designs, this will lead to the seat being propelled out of and away from the aircraft, carrying the occupant with it, by means of either an explosive charge or a rocket propulsion system. Once clear of the aircraft, the ejection seat will deploy a parachute, although some older models entrusted this step to manual activation by the seat's occupant.
Safety
In the U.S. during the 1970s, the sport averaged 42.5 fatalities annually. In the 1980s, the average dropped to 34.1, and in the 1990s, the average decreased to 32.3 deaths per year. Between 2000 and 2009, the average dropped to 25.8 and over the eight years after 2009, the annual average declined to 22.4 fatalities. In 2017, members of one organization, the United States Parachute Association reported 2,585 skydiving injuries sufficiently severe to require resort to a medical care facility.In the US and in most of the western world, skydivers are required to wear two parachutes. The reserve parachute must be periodically inspected and repacked by a certified parachute rigger. Many skydivers use an automatic activation device that opens the reserve parachute at a predetermined altitude if it detects that the skydiver is still in free fall. Depending on the country, AADs are often mandatory for new jumpers, and/or required for all jumpers regardless of their experience level. Some skydivers wear a visual altimeter, and some use audible altimeters fitted to their helmets.
Unsafe maneuvers
Injuries and fatalities occurring under a fully functional parachute usually happen because the skydiver performed unsafe maneuvers or made an error in judgement while flying their canopy, typically resulting in a high-speed impact with the ground or other hazards on the ground. One of the most common sources of injury is a low turn under a high-performance canopy and while swooping. Swooping is the advanced discipline of gliding at high-speed parallel to the ground during landing.Winds
Changing wind conditions are another risk factor. In conditions of strong winds and turbulence during hot days, the parachutist can be caught in downdrafts close to the ground. Shifting winds can cause a crosswind or downwind landing which have a higher potential for injury due to the wind speed adding to the landing speed.Canopy collisions
Another risk factor is that of "canopy collisions", or collisions between two or more skydivers under fully inflated parachutes. Canopy collisions can cause the jumpers' inflated parachutes to entangle with each other, often resulting in a sudden collapse of one or more of the involved parachutes. When this occurs, the jumpers often must quickly perform emergency procedures to "cut-away" from their main canopies and deploy their reserve canopies. Canopy collisions are particularly dangerous when occurring at altitudes too low to allow the jumpers adequate time to safely jettison their main parachutes and fully deploy their reserve parachutes.Equipment failure
Equipment failure may contribute to fatalities and injuries. Approximately one in 750 deployments of a main parachute result in a malfunction. Ram-air parachutes typically spin uncontrollably when malfunctioning, and must be jettisoned before deploying the reserve parachute. Reserve parachutes are packed and deployed differently; they are also designed more conservatively and built and tested to more exacting standards so they are more reliable than main parachutes, but the real safety advantage comes from the probability of an unlikely main malfunction multiplied by the even less likely probability of a reserve malfunction. This yields an even smaller probability of a double malfunction although the possibility of a main malfunction that cannot be cut away causing a reserve malfunction is a very real risk. Static line failures pose risks of towed paratroopers.Base jumping
Parachuting disciplines such as BASE jumping or those that involve equipment such as wingsuit flying and sky surfing have a higher risk factor due to the lower mobility of the jumper and the greater risk of entanglement. For this reason, these disciplines are generally practised by experienced jumpers.USPA member drop zones in the US and Canada are required to have an experienced jumper act as a "safety officer" who is responsible for dealing with jumpers who violate rules, regulations, or otherwise act in a fashion deemed unsafe by the appointed individual.
In many countries, either the local regulations or the liability-conscious prudence of the drop zone owners require that parachutists must have attained the age of majority before engaging in the sport.
The first skydive performed without a parachute was by stuntman Gary Connery on 23 May 2012 at.
Most common injuries
Due to the hazardous nature of skydiving, precautions are taken to avoid parachuting injuries and death. For first-time solo-parachutists, this includes anywhere from 4 to 8 hours of ground instruction. Since the majority of parachute injuries occur upon landing, the greatest emphasis within ground training is usually on the proper parachute landing fall, which seeks to orient the body so as to evenly disperse the impact through flexion of several large, insulating muscles, as opposed to individual bones, tendons, and ligaments which break and tear more easily.Parachutists, especially those flying smaller sport canopies, often land with dangerous amounts of kinetic energy, and for this reason, improper landings are the cause of more than 30% of all skydiving-related injuries and deaths. Often, injuries sustained during parachute landing are caused when a single outstretched limb, such as a hand or foot, is extended separately from the rest of the body, causing it to sustain forces disproportional to the support structures within. This tendency is displayed in the accompanying chart, which shows the significantly higher proportion of wrist and ankle injuries among the 186 injured in a 110,000 parachute jump study.
Due to the possibility of fractures, it is recommended that parachutists wear supportive footwear. Supportive footwear prevents inward and outward ankle rolling, allowing the PLF to safely transfer impact energy through the true ankle joint, and dissipate it via the medial gastrocnemius and tibialis anterior muscles.
Weather
Parachuting in poor weather, especially with thunderstorms, high winds, and dust devils can be a more dangerous activity. Reputable drop zones will suspend normal operations during inclement weather. In the United States, the USPA's Basic Safety Requirements prohibit solo student skydivers from jumping in winds exceeding 14 mph while using ram-air equipment. However, maximum ground winds are unlimited for licensed skydivers.Visibility
As parachuting is an aviation activity under the visual flight rules, it is generally illegal to jump in or through clouds, according to the relevant rules governing the airspace, such as FAR105 in the US or Faldskærmsbestemmelser in Denmark. Jumpers and pilots of the dropping aircraft similarly bear responsibility of following the other VFR elements, in particular ensuring that the air traffic at the moment of jump does not create a hazard.Canopy collisions
A collision with another canopy is a statistical hazard, and may be avoided by observing simple principles, including knowing upper wind speeds, the number of party members and exit groups, and having sufficient exit separation between jumpers. In 2013, 17% of all skydiving fatalities in the United States resulted from mid-air collisions.Training
Skydiving can be practised without jumping. Vertical wind tunnels are used to practise for free fall, while virtual reality parachute simulators are used to practise parachute control.Beginning skydivers seeking training have the following options: