Misplaced Pages

#146853

63-413: A dust devil is a strong, well-formed, and relatively long-lived whirlwind. Dust devil may also refer to: Dust devil They are comparable to tornadoes in that both are a weather phenomenon involving a vertically oriented rotating column of wind. Most tornadoes are associated with a larger parent circulation, the mesocyclone on the back of a supercell thunderstorm . Dust devils form as

126-443: A drogue , catching air and pulling out the main parachute or the main canopy. There are two principal systems in use: the "throw-out", where the skydiver pulls a toggle attached to the top of the pilot-chute stowed in a small pocket outside the main container: and the "pull-out", where the skydiver pulls a small pad attached to the pilot-chute which is stowed inside the container. Throw-out pilot-chute pouches are usually positioned at

189-481: A snow whirlwind , snow devil , or sometimes referred to as a "snownado", although differential heating is more difficult in snow-covered areas. Steam devils are a small vortex column of saturated air of varying height but small diameter forming when cold air lies over a much warmer body of water or saturated surface. They are also often observed in the steam rising from power plants . Skydiving Parachuting and skydiving are methods of descending from

252-470: A 4-man star formation, photographed by Bob Buquor. This discipline was formerly referred to in the skydiving community as Relative Work, often abbreviated to RW, Relly or Rel. Style can be considered as the sprint of parachuting. This individual discipline is played in free fall. The idea is to take maximum speed and complete a pre-designated series of maneuvers as fast and cleanly as possible (speed can exceed 400 km/h/250 mph). Jumps are filmed using

315-426: A diameter of up to 300 feet (90 m) with winds in excess of 60 mph (100 km/h+) and can last for upwards of 20 minutes before dissipating. Because of their small diameter, Coriolis force is not significant in the dust devil itself so dust devils with anticyclonic rotation do occur. Dust devils typically do not cause injuries, but rare, severe dust devils have caused damage and even deaths in

378-468: A dust devil and lifted over 10 feet (3 m), travelling over a fence and landing in a backyard three houses away. In Commerce City, Colorado in 2018, a powerful dust devil hurtled two porta-potties into the air; no one was injured. In 2019, a large dust devil in Yucheng county, Henan province, China killed 2 children and injured 18 children and 2 adults when an inflatable jump house was lifted into

441-578: 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 732 m. 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

504-414: A forward momentum. The dust devil may be sustained if it moves over nearby sources of hot surface air. As available hot air near the surface is channelled up the dust devil, eventually surrounding cooler air will be sucked in. Once it occurs, the effect is dramatic, and the dust devil dissipates in seconds. Usually it occurs when the dust devil is moving slowly (depletion) or begins to enter a terrain where

567-436: A ground-based camera (with an exceptional lens to record the performance). Performance is timed (from the start of the manoeuvre until its completion) and then judged in public at the end of the jump. Competition includes 4 qualifying rounds and a final for the top 8. Competitors jump from a height of 2200 m to 2500 m. They rush into an acceleration stage for 15 to 20 seconds and then run their series of manoeuvres benefiting to

630-449: 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 (the skydiving segment), 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

693-596: 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" (in Canada DSO – Drop Zone Safety Officer; in the U.S. S&TA – Safety and Training Advisor) who is responsible for dealing with jumpers who violate rules, regulations, or otherwise act in

SECTION 10

#1732784032147

756-410: A higher terminal velocity than normal. In AFF, one (or sometimes two) instructor(s) are dedicated to just one student, causing this method of training to be more expensive than static line progression, where one instructor can dispatch multiple students per load, initially from a lower altitude. At a sport skydiver's deployment altitude, the individual manually deploys a small pilot-chute which acts as

819-492: A magnetic field that fluctuates between 3 and 30 times each second. These electric fields may assist the vortices in lifting material off the ground and into the atmosphere. Field experiments indicate that a dust devil can lift 1 gram of dust per second from each square metre (10 lb/s from each acre) of ground over which it passes. A large dust devil measuring about 100 metres (330 ft) across at its base can lift about 15 metric tonnes (17 short tons) of dust into

882-411: 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

945-730: A manual release could. Whichever method is used, a spring-loaded pilot-chute then extracts the reserve parachute from the upper half of the container. World Championships are held every two years both Indoor and Outdoor in the competition disciplines Artistic Events (Freestyle and Freefly, indoor and outdoor), Canopy Formation (outdoor only), Canopy Piloting (outdoor only), Dynamic (indoor only), Formation Skydiving (indoor and outdoor), Paraski (outdoor only), Style & Accuracy Landing (outdoor only) and Wingsuit Flying (outdoor only). Continental Championships and World Cups can be held in alternate years. There are now two competitive Artistic Events, Freestyle and Freefly. Freestyle teams consist of

1008-402: 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 (whether used or not) by a certified parachute rigger (in the US, an FAA certificated parachute rigger every 180 days). Many skydivers use an automatic activation device (AAD) that opens the reserve parachute at

1071-531: 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. As parachuting is an aviation activity under the visual flight rules , it

1134-402: 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. The first parachute jump in history

1197-403: A performer and a videographer, Freefly teams have two performers and a videographer. Skysurfing is no longer a competitive event after insufficient competitors entered in two successive World Championships. The history of these events is on this Freeflying page. Often called "Classic accuracy", this is an individual or team contest performed under an open parachute. The aim is to touch down on

1260-399: A pouch (e.g., B.O.C pouch). Activation begins when the pilot-chute is thrown out. It inflates and creates drag, pulling the pin out of the closing loop and allowing the pilot-chute to pull the deployment bag from the container. The parachute lines are pulled loose from the rubber bands and extend as the canopy starts to open. A rectangular piece of fabric called the " slider " (which separates

1323-409: 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. Injuries and fatalities occurring under a fully functional parachute usually happen because

SECTION 20

#1732784032147

1386-581: A sudden collapse (deflation) of one or more of the involved parachutes. When this occurs, the jumpers often must quickly perform emergency procedures (if there is sufficient altitude to do so) to "cut-away" (jettison) 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 may contribute to fatalities and injuries. Approximately one in 750 deployments of

1449-403: A swirling updraft under sunny conditions during fair weather, rarely coming close to the intensity of a tornado. Dust devils form when a pocket of hot air near the surface rises quickly through cooler air above it, forming an updraft. If conditions are just right, the updraft may begin to rotate. As the air rapidly rises, the column of hot air is stretched vertically, thereby moving mass closer to

1512-423: A target whose center is 2 cm in diameter. The target can be a deep foam mattress or an air-filled landing pad. An electronic recording pad of 32 cm in diameter is set in the middle. It measures score in 1 cm increments up to 16 cm and displays result just after landing. The first part of any competition takes place over 8 rounds. Then in the individual competition, after these 8 selective rounds,

1575-469: A very important part. So classic accuracy requires high adaptability to aerology and excellent steering control. It is also the most interesting discipline for spectators due to the closeness of action (a few meters) and the possibility to be practiced everywhere (sport ground, stadium, urban place...). Today, classic accuracy is the most practiced (in competition) discipline of skydiving in the world. Previously called Canopy Relative Work, or CREW for short,

1638-415: A wildfire that possibly extended from 10,000 to 50,000 hectares or more. Dust devils, even small ones, can produce radio noise and electrical fields greater than 10,000 volts per meter. A dust devil picks up small dirt and dust particles. As the particles whirl around, they become electrically charged through contact or frictional charging ( triboelectrification ). The whirling charged particles also create

1701-429: Is a fixed cord attached to a large, stable object. It is used to open parachutes automatically for paratroopers and novice parachutists . Instructor-assisted deployment (IAD) is a parachute deployment program most adequately similar to static line. The main difference is that instead of being deployed by a static line, the student's jumpmaster (who is in the plane with them) deploys the student's parachute by throwing

1764-430: Is a funnel-like chimney through which hot air moves, both upwards and in a circle. As the hot air rises, it cools, loses its buoyancy and eventually ceases to rise. As it rises, it displaces air which descends outside the core of the vortex. This cool air returning acts as a balance against the spinning hot-air outer wall and keeps the system stable. The spinning effect, along with surface friction , usually will produce

1827-421: Is a skydive where the participants open their parachutes very quickly after leaving the aircraft with the intention of flying in close proximity to each other. The goal is to create various formations by "docking" with other parachutists on the jump. The dock is often accomplished by placing one's feet into the lines of another person's parachute. Formations require at least 2 people, but can have many more. Due to

1890-589: 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. Skydiving can be practised without jumping. Vertical wind tunnels are used to practise for free fall ("indoor skydiving" or "bodyflight"), while virtual reality parachute simulators are used to practise parachute control. Beginning skydivers seeking training have

1953-415: Is a vortex-shaped formation of burning gases being released from the combustible material. The genesis of the vortex is probably similar to a dust devil's. As distinct from the dust devil, it is improbable that the height reached by the fire gas vortex is greater than the visible height of the vertical flames because of turbulence in the surrounding gases that inhibit creation of a stable boundary layer between

Dust devil (disambiguation) - Misplaced Pages Continue

2016-560: Is equivalent to an EF0 tornado. On May 19, 2003, a dust devil lifted the roof off a two-story building in Lebanon, Maine , causing it to collapse and kill a man inside. On June 18, 2008, a woman near Casper, Wyoming was killed when a dust devil caused a small scorer's shed at a youth baseball field to flip on top of her. She had been trying to shelter from the dust devil by going behind the shed. At East El Paso, Texas in 2010, three children in an inflatable jump house were picked up by

2079-495: Is generally illegal to jump in or through clouds, according to the relevant rules governing the airspace, such as FAR 105 in the US or Faldskærmsbestemmelser ( Parachuting Ordinances ) 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. A collision with another canopy

2142-488: 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

2205-576: The 186 injured in a 110,000 parachute jump study. Due to the possibility of fractures (commonly occurring on the tibia and the ankle mortise), 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. Parachuting in poor weather, especially with thunderstorms, high winds, and dust devils can be

2268-539: 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 (roughly 7.5 fatalities per one million jumps). In 2017, members of one organization, the United States Parachute Association (USPA) reported 2,585 skydiving injuries sufficiently severe to require resort to

2331-534: The air in 30 minutes. Giant dust storms that sweep across the world's deserts contribute 8% of the mineral dust in the atmosphere each year during the handful of storms that occur. In comparison, the significantly smaller dust devils that twist across the deserts during the summer lift about three times as much dust, thus having a greater combined impact on the dust content of the atmosphere. When this occurs, they are often called sand pillars . Martian dust devils are convective atmospheric vortices that occur on

2394-411: The air. Dust devils have been implicated in around 100 aircraft accidents. While many incidents have been simple taxiing problems, a few have had fatal consequences. Dust devils are also considered major hazards among skydivers and paragliding pilots as they can cause a parachute or a paraglider to collapse with little to no warning, at altitudes considered too low to cut away , and contribute to

2457-432: The axis of rotation, which causes intensification of the spinning effect by conservation of angular momentum . The secondary flow in the dust devil causes other hot air to speed horizontally inward to the bottom of the newly forming vortex. As more hot air rushes in toward the developing vortex to replace the air that is rising, the spinning effect becomes further intensified and self-sustaining. A dust devil, fully formed,

2520-406: The bottom of the container – the B.O.C. deployment system – but older harnesses often have leg-mounted pouches. The latter are safe for flat-flying, but often unsuitable for freestyle or head-down flying. In a typical civilian sport parachute system, the pilot-chute is connected to a line known as the "bridle", which in turn is attached to a small deployment bag that contains the folded parachute and

2583-412: The canopy suspension lines, which are stowed with rubber bands. At the bottom of the container that holds the deployment bag is a closing loop which, during packing, is fed through the grommets of the four flaps that are used to close the container. At that point, a curved pin that is attached to the bridle is inserted through the closing loop. The next step involves folding the pilot-chute and placing it in

Dust devil (disambiguation) - Misplaced Pages Continue

2646-458: 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

2709-399: The chest) which will release the main canopy from the harness/container. Once free from the malfunctioning main canopy, the reserve canopy can be activated manually by pulling a second handle on the front left harness. Some containers are fitted with a connecting line from the main to reserve parachutes – known as a reserve static line (RSL) – which pulls open the reserve container faster than

2772-581: The close proximity of the canopies, care has to be taken by all participants to ensure the safety of the jump. It is common for a CREW jumper to carry a hook knife to use in case they become entangled in another jumper's lines. Formation Skydiving (FS) was born in California, USA during the 1960s. The first documented skydiving formation occurred over Arvin, California in March 1964 when Mitch Poteet, Don Henderson, Andy Keech and Lou Paproski successfully formed

2835-700: The darker color of the ash may create dust devils that are visible hundreds of feet into the air. Ash devils form similar to dust devils and are often seen on unstable days in burn scar areas of recent fires. Coal devils are common at the coal town of Tsagaan Khad in South Gobi Province , Mongolia . They occur when dust devils pick up large amounts of stockpiled coal. Their dark color makes them resemble some tornadoes. Fire whirls or swirls, sometimes called fire devils or fire tornadoes, can be seen during intense fires in combustible building structures or, more commonly, in forest or bush fires. A fire whirl

2898-690: 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 (especially military aviators and aircrew ) and passengers to escape an aircraft that could not otherwise land safely. While this method of escape

2961-400: The following options: Tandem skydiving or tandem parachuting refers to a type of skydiving where a student skydiver is connected to an instructor via a harness. The instructor guides the student through the whole jump from exit through freefall , piloting the canopy , and landing. The student needs only minimal instruction before making a tandem jump with the instructor. A static line

3024-432: The jumper. During a normal deployment, a skydiver will generally experience a few seconds of intense deceleration, in the realm of 3 to 4 g, while the parachute slows the descent from 190 km/h (120 mph) to approximately 28 km/h (17 mph). If a skydiver experiences a malfunction of their main parachute which they cannot correct, they pull a "cut-away" handle on the front right-hand side of their harness (on

3087-679: The majority of parachute injuries occur upon landing (approximately 85%), the greatest emphasis within ground training is usually on the proper parachute landing fall (PLF), which seeks to orient the body so as to evenly disperse the impact through flexion of several large, insulating muscles (such as the medial gastrocnemius , tibialis anterior , rectus femoris , vastus medialis , biceps femoris , and semitendinosus), 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

3150-494: The maximum of the stored speed. Those series consist of Turns and Back-Loops to achieve in a pre-designated order. The incorrect performance of the manoeuvres gives rise to penalties that are added at run time. The performance of the athlete is defined in seconds and hundredths of a second. The competitor with the lowest cumulative time is declared the winner. Notice the complete sequence is performed by leading international experts in just over 6 seconds, penalties included. Using

3213-489: 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. The slider slows and controls the deployment of the parachute. Without a slider, the parachute would inflate fast, potentially damaging the parachute fabric and/or suspension lines, as well as causing discomfort, injury or even death of

SECTION 50

#1732784032147

3276-455: 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. 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

3339-579: The past. One such dust devil struck the Coconino County Fairgrounds in Flagstaff, Arizona , on September 14, 2000, causing extensive damage to several temporary tents, stands and booths, as well as some permanent fairgrounds structures. Several injuries were reported, but there were no fatalities. Based on the degree of damage left behind, it is estimated that the dust devil produced winds as high as 75 mph (120 km/h), which

3402-533: The pilot chute downward and clear of the door as the student exits. Accelerated freefall (AFF) (known in Canada as progressive freefall, and in Finland as Nova (NOpeutettu VApaapudotus, a literal translation) is a method of training for skydiving, called accelerated because the progression is the fastest way to experience solo freefall, normally from 10,000 to 15,000 feet above ground level (AGL), allowing one to reach

3465-493: 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. Parachuting disciplines such as BASE jumping or those that involve equipment such as wingsuit flying and sky surfing have

3528-405: The rotating/rising gases relative to the surrounding gases. A "hay devil" is a gentle whirlwind that forms in the warm air above fields of freshly-cut hay . A vortex forms from a column of hot air rising from the ground on calm, sunny days, tossing and swirling stalks and clumps of hay harmlessly through the air, often to the delight of children and onlookers. The same conditions can produce

3591-404: 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. In the U.S. during the 1970s, the sport averaged 42.5 fatalities annually. In

3654-463: The serious injury or death of parachutists. Such was the case on June 1, 1996, when a dust devil caused a skydiver's parachute to collapse about 30 feet (9.1 m) above the ground. He later died from the injuries he sustained. Dust devils can also contribute to wildfires. One case occurred in Engebæk , Billund Municipality , Denmark in 1868 where a dust devil tossed tuft into a heater, causing

3717-509: 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. Changing wind conditions are another risk factor. In conditions of strong winds and turbulence during hot days,

3780-464: The surface of Mars . They were discovered from data reported by NASA 's Viking probes , and have been photographed by orbiting satellites and surface rovers in subsequent missions. In Australia, a dust devil is more commonly known as "Willy willy". In Ireland, dust devils are known as "sí gaoithe" or "fairy wind". Hot cinders underneath freshly deposited ash in recently burned areas may sometimes generate numerous dust devils. The lighter weight and

3843-424: The surface temperatures are cooler. Certain conditions increase the likelihood of dust devil formation. Many dust devils are usually small and weak, often less than 3 feet (0.9 m) in diameter with maximum winds averaging about 45 miles per hour (70 km/h), and they often dissipate less than a minute after forming. On rare occasions, a dust devil can grow very large and intense, sometimes reaching

SECTION 60

#1732784032147

3906-431: The top 25% jump a semi-final round. After the semi-final round, the top 50% are selected for the final round. The competitor with the lowest cumulative score is declared the winner. Competitors jump in teams of 5 maximum, exiting the aircraft at 1,000 or 1,200 meters and opening their parachutes sequentially to allow each competitor a clear approach to the target. This sport is unpredictable because weather conditions play

3969-433: 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 (910 m) from a hot air balloon. 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

#146853