BASE jumping

From Academic Kids

BASE jumping is the sport of using a parachute to jump from fixed objects. "BASE" is an acronym that stands for the four categories of objects from which one can jump; (B)uilding, (A)ntenna (an uninhabited tower such as an aerial mast), (S)pan (a bridge, arch or dome), and (E)arth (a cliff or other natural formation). BASE jumping is much more dangerous than skydiving from aircraft and is currently regarded as a fringe extreme sport.

Contents

History

There are isolated examples of BASE jumps dating from the early 1900s. Frederick Law jumped from the Statue of Liberty in 1912; Michael Pelkey and Brian Schubert jumped the cliff "El Capitan" in Yosemite Valley in 1966; and in 1976, Rick Sylvester jumped Canada's Mt Asgard for the opening sequence of the James Bond movie "The Spy Who Loved Me", giving the wider world its first look at BASE jumping. However, these and other sporadic incidents were one-off experiments, not the systematic pursuit of a new form of parachuting. The acronym "BASE" was coined by film-maker Carl Boenish, who in 1978 filmed the first jumps from El Capitan to be made using ram-air parachutes and freefall tracking technique, which effectively defines modern BASE jumping. These jumps were repeated, not as a publicity exercise or as a movie stunt, but as a true recreational activity. It was this which popularised BASE jumping more widely among parachutists. Boenish continued to publish films and informational magazines on BASE jumping until his 1984 death on a cliff jump in Norway. By this time, the concept had spread among skydivers worldwide, with hundreds of participants making fixed-object jumps.

Equipment and Techniques

BASE jumping grew out of skydiving (recreational parachuting from aircraft). There are three main technical differences between the two. Firstly, BASE jumps are generally made from much lower altitudes than skydives. Secondly, a BASE jump takes place in close proximity to the cliff or tower which provided the jump platform. Thirdly, the BASE jumper generally has a lower airspeed than a skydiver throughout the jump, because a BASE jump starts with zero airspeed, and (due to the limited altitude) a BASE jumper very seldom approaches the terminal velocity (airspeed) of a skydiver. All three factors have significant implications.

Firstly, the BASE parachute system has to be made to open very quickly at low airspeeds. Skydiving parachutes are reefed to slow down the opening and reduce opening shock forces. Secondly, the cliff or tower presents a risk to the BASE jumper if, for example, the parachute opens facing backwards. An off-heading opening is not considered a problem in skydiving, but has caused fatal impact injuries in BASE jumping. Off heading opening resulting in object strike is the leading cause of serious injury and death in BASE jumping.

An experienced skydiver is recommended to deploy their parachute no lower than 2,000 feet (610 m). At that time, if they have already been in freefall for at least 1,000 feet (305 m), the jumper is traveling 120 miles per hour (54 m/s), and is 11 seconds from the ground. Most BASE jumps are made from less than 1,000 feet (305 m). For example, a BASE jump from a 500 foot (152 m) object is about 6 seconds from the ground if the jumper remains in freefall. On such a jump, the parachute must open at about half the airspeed of the skydiver, and more quickly (ie. in a shorter distance fallen). Standard skydiving parachute systems are not designed for this situation. Many BASE jumpers use specially designed harnesses and parachute containers, with extra large pilot chutes, and jump with only one parachute - since, with a total freefall time of 6 seconds, there would be no time to use a reserve parachute. In these systems, the actual parachute canopy should also be specifically manufactured for BASE jumping, however skydiving parachutes with some modifications (primarily the addition of a tail pocket for stowing suspension lines) are occasionally used by those unable to purchase appropriate equipment. The rest of the system is almost always specifically designed for BASE use. Standard skydiving equipment can only be used on relatively high BASE jumps. If modified, by removing the bag and slider, stowing the lines in a tail pocket, and fitting a large pilot chute, standard skydiving gear can be used for lower BASE jumps, but is then prone to kinds of malfunction which are rare in normal skydiving (such as "line-overs" and broken lines).

The vast majority of people who try BASE jumping are those that have already learned to skydive. It is important to know how to safely fly and land a parachute, and this is best learned on airplane skydives, from higher deployment altitudes, over large fields that provide room for error in learning how to land. Most BASE jumping venues have very small areas in which to land. A beginner skydiver, after parachute deployment, may have 3 minutes or more of a parachute ride to the ground. A BASE jump from 500 feet (152 m) will have a parachute ride of about 10 to 15 seconds.

One way to make a parachute open very quickly is to use a static line or direct bag. These devices form an attachment between the parachute and the jump platform, which stretches out the parachute and suspension lines as the jumper falls, before separating and allowing the parachute to inflate. This method enables the very lowest jumps (below 200ft) to be made, although most BASE jumpers are more motivated to make higher jumps involving free fall.

In parachuting, height is safety, and by making lower altitude jumps, BASE jumpers give up the safety margins built into skydiving (such as the option of using a reserve parachute if there are problems deploying the main chute). The lower airspeed of a BASE jump is also a risk factor. Skydivers use the air flow to stabilise their position, allowing the parachute to deploy cleanly. BASE jumpers, falling at lower speeds, have less aerodynamic control, and may tumble. The attitude of the body at the moment of jumping determines the stability of flight in the first few seconds, before sufficient airspeed has built up to enable aerodynamic stability. On low BASE jumps, parachute deployment takes place during this early phase of flight, so if a poor "exit" leads into a tumble, the jumper may not be able to correct this before the opening. If the parachute is deployed while the jumper is tumbling, there is a high risk of entanglement or malfunction. Beginner BASE jumpers often make the error of rotating forwards by jumping with a swimming-pool type of diving motion, leading to an involuntary forward loop. Better technique is to exit without any rotational motion.

On higher BASE jumps, those which allow a free fall of five seconds or more, it may be necessary to use freefall tracking technique to move away from the jump object (especially on cliff jumps). Jump platforms providing an overhang, such as arch bridges or naturally overhung cliffs, are more forgiving in this respect and so are more suitable for beginner BASE jumpers.

Legal issues

In the United States, skydiving from an airplane involves regulations set by the FAA, notably the requirement of an airplane jumper to carry two parachutes. Since BASE jumping does not involve an airplane, the FAA has no jurisdiction.

The legal issues that a BASE jumper must consider concern permissions to use the object that is being jumped, and the area used for landing. The general reluctance of the owners of jumpable objects to allow their object to be used as a platform leads many BASE jumpers to attempt to jump from them covertly. Notable exceptions are a bridge in Idaho, and, once a year, on the third Saturday in October ('Bridge Day') when jumping is legal from the New River Gorge Bridge in Fayetteville, West Virginia. The bridge deck is 876 feet (267 m) above the river. A rock dropped from the deck will hit the water in 8.8 seconds. This annual event attracts about 350 BASE jumpers, and nearly 200,000 spectators. If the conditions are good, in the 6 hours that it is legal, there may be over 800 jumps at Bridge Day. For many skydivers who would like to try BASE jumping, this will be the only fixed object from which they ever jump.

Covert BASE jumps are often made from tall buildings and antenna towers. Jumpers who are caught in the act may face charges of trespass or reckless endangerment. BASE jumping itself is not illegal, however there is a unique situation in US National Parks, because the National Park Service has the authority to ban specific activities, and has done so for BASE jumping as a result of jumping activity in Yosemite. In the early days of BASE jumping, the Service ran a permit scheme under which jumpers could get authorisation to jump El Capitan. This scheme ran for 3 months in 1980 and then collapsed amid allegations of abuse by unauthorised jumpers. Since then, the Service has vigorously enforced a ban, charging jumpers with "aerial delivery into a National Park". One jumper was drowned in the Merced river while being chased by Park Rangers intent on arresting him. Despite this, illegal jumps continue in Yosemite at a rate estimated at a few hundred per year, often at night or dawn. El Capitan, Half Dome and Glacier Point are all used as jump sites.

The legal position is better at other sites and in other countries. For example, in Norway's Lysefjord, BASE jumpers are made welcome. Many sites in the European Alps, near Chamonix and on the Eiger, are open to jumpers.

BASE jumping today

It is not known how many people have tried at least one BASE jump; however, when a jumper completes a jump from each of the four categories of objects, they may choose to apply for a "BASE number". These are awarded sequentially. In 1981, Phil Smith of Houston, Texas, was awarded BASE-1. In March 2005 the 1000th application for a BASE number had been filed.

BASE jumping is often featured in action movies, like the 2002 Vin Diesel film xXx where Diesel's character catapults himself off a bridge in an open-topped car, landing safely as the car crashes on the ground. After the 1976 Mt Asgard jump, the James Bond movies continued to feature BASE jumps, including one from the Eiffel Tower in 1985's A View to a Kill, the Rock of Gibraltar in 1987's The Living Daylights, and in Die Another Day, 2002, Pierce Brosnan as James Bond jumps from a melting iceberg. Of the James Bond jumps, though, only the Mt Asgard and Eiffel Tower jumps were filmed in reality; the rest were special effects.

The 1990s surge of interest in extreme sports saw many developments in BASE jumping and increasing acceptance of it generally, although it is still widely seen as a daredevil stunt rather than a sport. Although it is a highly skilled activity, the lack of an objective way to measure skill as the basis for records and competitions, hinders acceptance as a true sport; and it remains as dangerous as it looks, prompting some, with typically black humor, to say that BASE stands for "Bones And Shit Everywhere". Although probably safer today than in the early days, through the availability of specialised equipment and wider knowledge of techniques, the occasional fatalities and injuries provide sensational press coverage. Although deaths through ground impact in freefall or object strike do occur, most incidents are due to hazardous landing sites or other problems which develop after the parachute is open. Because of the covert nature of much BASE jumping, no reliable figures are available to assess the statistical risks of BASE jumping.

The Guinness Book of Records first listed a BASE jumping record with Carl Boenish's 1984 leap from Trollveggen (Troll Wall) in Norway (the jump being made two days before his death at the same site) being described as the highest BASE jump. This record category is still in the Guinness book and is currently held by Nic Feteris and Glenn Singleman with a jump from the 19,000ft Trango cliff in Pakistan, which seems unlikely to be beaten. However, the sheer variety of the nature of the challenge at different jump sites means that direct comparisons of different jumps are often meaningless. As a result, some of the claimed records in the field may be seen as spurious. There is another Guinness entry for "oldest BASE jumper" which is clearly nothing to do with sporting skill. Even more contentious are claims sometimes made (although not recognised by Guinness) for the lowest jump. Given that a static-lined parachute can be made to open in little more than the length of its suspension lines, jumps can actually be performed at practically any altitude right down to the point at which a parachute is not necessary for survival. BASE competitions have been held since the early 1980s, with accurate landings or freefall aerobatics used as the judging criteria. Recent years have seen a formal competition held at the 1300ft Petronas Towers building in Malaysia, judged on landing accuracy, but it is a long way from joining the Olympics. However, an increasing number of BASE devotees take their sport seriously as a skilled athletic pursuit, and it is moving steadily towards the crossover point at which it will be taken seriously by everyone, as a minority, but genuine, sport.

For now, BASE jumpers are mostly focused on the challenges of public acceptance and understanding of a sport so obviously extreme and so highly dangerous; and on the development of equipment and techniques. Searching for new, and preferably legal, jump sites has also been a fruitful activity for many devotees.

External links

fr:Base jump nl:BASE-jumpen pl:BASE jumping

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