Skip to Content

Skydiving: safety: Students: Skydiving Glossary

Skydiving Glossary

By Bryan Burke on 2003-08-22

This glossary of skydiving terms accompanies the Student Skydiver's Handbook, by Bryan Burke.

Click on the letter corresponding to the first letter of the word you are looking for:


Use the "Back" button on your brower to return to the top of the Glossary to search for more words.

The Letter A

AAD. Automatic Activation Device. A device that senses rate of descent and altitude and which will attempts to mechanically activate the reserve parachute if the skydiver passes below a set altitude at a high rate of descent.

A/C. Aircraft.

Accuracy. Also known as Precision Landing, this is a competition discipline in which the skydiver attempts to land on an established target. At the National level the target is 3 cm in diameter, about the size of a quarter. Accuracy landings of various difficulty, from 20 meters to 2 meters, are required for USPA licenses. See the SIM for details.

AFF. Accelerated Free Fall. An AFF student receives training on freefall jumps of 40 seconds or longer, accompanied by a qualified jumpmaster, as opposed to Static Line training which does not involve long freefall in the initial training phase.

AGL. Above Ground Level. Altitudes are in reference either to Ground Level of Sea Level (see MSL). Skydivers always use AGL when referring to altitude.

Airspeed. The speed of a flying object through the air, commonly used in reference to aircraft or canopies.

Altimeter. A device indicating altitude.

Angle of attack. The angle at which the wing is presented to the apparent wind. With square parachutes this changes when the brakes are applied.

Angle of incidence. The angle at which a canopy is trimmed to glide through the air.

Apparent wind. The wind perceived by an observer. See relative wind.

ASP. Skydive Arizona's version of AFF, the Accelerated Skydiving Program includes two tandem jumps and an enhanced version of the AFF syllabus.

ASTRA. An AAD made by FXC Corporation.

Aspect ratio. The ratio of a canopys width (side to side) to breadth (front to back). Seven cell canopies typically have an aspect ratio of about 2.2 to one, while nine cell canopies are usually between 2.8 and 3.0 to one.

The Letter B

Backslide. To move backward in freefall relative to a neutral reference. Usually unintentional and undesirable, caused by poor body position.

Bag. The deployment bag in which the canopy is packed.

Base. The core around which a formation skydive is built. Can be a single person or a group of people, depending on the number of skydivers involved.

BASE jump. A jump made from a fixed object rather than an aircraft. BASE is an acronym for building, antennae, spans (bridges) and earth (cliff).

Beech. Short for Beechcraft, an aircraft manufacturer. Usually used in reference to a Beech D-18, a.k.a. Twin Beech. At one time these were common skydiving planes, but they are becoming obsolete.

BOC. Bottom of Container. Refers to the location of the pilot chute. An increasingly common position for main deployment devices, as opposed to belly or leg mounted.

Body position. Ones freefall body posture. Variations in body position are what make a wide range of freefall maneuvers possible.

Boogie. A gathering of skydivers, usually focused on fun rather than competition. Big drop zones host several boogies a year, often on long holiday weekends.

Bounce. To land at unsurvivable speed. Also to frap, or go in.

Box man. A neutral, face to earth body position in which the arms form right angles at shoulder and elbow, and the legs are spread at about 45 degrees from the long axis and bent 45 degrees at the knees. Generally considered the ideal position for Formation Skydiving.

Brakes. The brake lines of the canopy are synonymous with steering lines. Used together, they slow the parachute. Used independently they result in a turn.

Break off. To cease formation skydiving by tracking away from the formation prior to deployment.

Bridle. The thin webbing strap from the pilot chute to the top of the canopy. Part of the deployment system which consists of pilot chute, bag and bridle.

BSR. Basic Safety Requirements. BSRs are USPA guidelines. They do not have force of law but are generally regarded as excellent minimum safety standards.

Burble. The area of turbulence behind an object going through the air, whether a person in freefall or a canopy in flight.

The Letter C

Call. The time remaining until you are to board the aircraft. For example, a fifteen minute call means you will board in fifteen minutes.

Canopy. The construction of fabric and lines used to land safely after a freefall. Usually used in conjunction with a type reference (round, square, zero-p, main or reserve).

Cascade. The point where two lines join together so they run smoothly into one. Cascading the suspension lines results in reduced bulk and drag.

Cell. Square canopies are made up of pressurized cells, usually seven or nine. Each cell consists of a load bearing rib at each side to which the suspension lines are attached. A third, non load bearing rib runs down the middle of the cell. The cell is pressurized through the open mouth at the front and also through cross ports in the ribs. Adjacent cells share load bearing ribs.

Center point. The point around which movement takes place. In an individual the center point is considered to be in the middle of the torso. In a group, it is the point that the formation centers around.

Cessna. An aircraft manufacturer. Single engined Cessnas such as 180s, 182s and 206s are the workhorse of smaller drop zones, carrying four to six jumpers.

Chute assis. French for sit flying, or freefalling with one's seat presented to the relative wind.

Closing loop. The small loop that holds the flaps of the container closed once the pin has been guided through the loop.

Coach. A skydiver with some formal training in the art of instructing freefall technique.

Container. The element of the parachute that houses the canopies. Technically, the Harness/Container but usually just referred to as the container.

Crabbing. A canopy is crabbing when it is flown at an angle sideways to the ambient wind, resulting in a path across the ground that is sideways as well as forwards.

Creep. To creep is to practice formation skydiving sequences while laying prone on a creeper.

Creeper. A board equipped with wheels on which a skydiver lays to simulate freefall maneuvers.

Cross ports. Holes in the ribs of a cell that allow air to flow from one cell to another.

Current. To "be current" is to have jumped recently enough to retain proficiency in the sport. Uncurrent skydivers, depending on their experience, must be supervised to some degree when they resume jumping. See the SIM.

Cut away. To release the main parachute, cutting away is a standard emergency procedure prior to deploying the reserve. More properly known as a breakaway, the technique did involve using a simple release system activated by pulling a handle.

CRW. Canopy Relative Work, now officially known as Canopy Formations. CRW involves flying open canopies in close formation, where the pilots actually take grips on each other's parachutes.

CYPRES. A type of AAD. Made by AirTech of Germany, this is the most common type of AAD and the first modern design to be widely adopted by expert skydivers.

The Letter D

DC-3. A type of aircraft, the Douglas DC-3 is a large, twin engined airplane capable of carrying over 40 jumpers. Like the Twin Beech, DC-3s are being rapidly replaced by more modern turbine engined aircraft.

De-arch. To flatten out or reverse one's body position from the normal arched box man. A de-arch results in a slower fall rate than an arch.

Dacron. A common construction material for canopy suspension lines. Dacron lines are thicker and softer than so called "microlines".

Data card. Every parachute carries a data card with information on the reserve parachute, including type, last date packed, owner, serial number, etc.

Dead spider. Slang for de-arch.

Decision altitude. The altitude at which a skydiver is trained to begin execution of emergency procedures. Usually 2,500 feet AGL for students, and 1,800 feet for expert skydivers.

Deployment system. The components of the parachute that control deployment of the canopy. Includes pilot chute, bridle and bag.

Dirt dive. To rehearse a skydive on the ground.

Dive floater. A dive floater is a skydiver who is inside the airplane in the exit line up, but leaving prior to the base. This configuration only occurs on large formations.

Dive loops. Many advanced skydivers have loops or "blocks" on their front risers to make it easy to grip the front risers for steering purposes. Also called front riser loops.

Diver. Anyone diving out of the plane during a formation skydiving exit.

Door jam. To practice an exit in the aircraft door of a mock up of it prior to the skydive.

DOS - Double or Dual Action System

Down plane. A CRW formation with two canopies, both pointed toward the ground. This can also occur to a single skydiver with both main and reserve deployed.

Drop zone. Common slang for a skydiving center, also DZ.

Dytter. A brand of audible altimeter.

The Letter E

Elliptical. A wing shape characterized by a tapering leading and trailing edge so that the middle of the canopy is wider, front to back, than the ends. This configuration is typical of many high performance canopies.

End cell. The cell furthers out on a canopy.

Exit weight. The total weight of the jumper and all equipment and clothing.

The Letter F

F-111. A fabric common in mid range canopies, F-111 is slightly permeable to air and wears faster than zero-p fabric. Pronounced "F one eleven".

FAA. The Federal Aviation Administration is the agency of the US government that regulates aviation activity, including skydiving.

FAI. Federation Aeronautique International. The international organization governing air sports.

FARs. Federal Aviation Regulations, the laws governing aviation.

Fall rate. The speed at which a skydiver falls. Matching fall rate is essential to successful formation skydiving. This is done with jumpsuits, weights and body position.

Finger trap. A method of installing a loop in a brake line without producing rough spots on the lines, the finger trap is accomplished by sliding one line into the other. The loop serves as a method of setting brakes in the desired position for the parachutes deployment.

Flare. The act of pulling down the brakes of the canopy in order to slow it down, resulting in an increased angle of attack and reduced descent rate.

Floater. Skydivers who leave the airplane before the base are called floaters since they must use a slow fall rate to get up to the base. Floating also refers to an exit position outside the airplane.

Freestyle. A type of skydiving characterized by acrobatic individual flying, reminiscent of gymnastics.

FS. Formation Skydiving, formerly known as relative work. In FS, skydivers attempt to go through a predetermined sequence of freefall formations.

Formation. 1) A freefall skydiving formation of more than one jumper. 2) A flight of more than one jump plane.

Funnel. A funnel occurs when one or more skydivers find themselves in an unstable body position and end up in a skydivers burble. The resulting loss of stability for the other skydivers usually causes the formation to break up.

FXC. A company manufacturing AADs. One FXC design is common on students but considered by many to be unsuitable for expert skydivers. A new FXC design, the ASTRA, went on the market in the spring of 1996 and is relatively unknown.

The Letter G

Glide ratio. The distance a canopy flies forward compared to down. A canopy with a 3:1 glide ratio flies three feet forward for every foot of vertical descent.

GPS. Global Positioning System. By picking up signals from satellites, a GPS receiver can tell the user position over the ground. Used in skydiving aircraft to spot the exit.

Grips. Using the hands to hold onto another skydiver in freefall or during the aircraft exits. In formation skydiving, the formations are scored as complete when every skydiver has taken the correct grips.

Grippers. Hand holds built onto formation skydiving jumpsuits to make it easier to take grips.

Ground speed. The speed of an airplane or skydiver over the ground, as opposed to through the air.

The Letter H

Hand deploy. To activate the parachute by manually deploying the pilot chute as opposed to pulling a ripcord.

Harness/container. The webbing and fabric holding the main and reserve canopies to the skydiver.

Heading. The direction an aircraft, skydiver, or parachute is facing. The ability to recognize and maintain heading is crucial to jumping with others successfully. "On" or "off" heading are terms commonly used to describe exits and deployments.

Holding. When a parachute is flying directly into the ambient wind, it is said holding. See running and crabbing.

Hook knife. A small knife carried in the jumpsuit or on the parachute harness, the hook knife is designed to cut lines or webbing. A small razor blade is recessed in a hook shaped handle to prevent unintentional cuts.

Hook turn. A turn of 90 degrees or more executed close to the ground. Because of the high risk associated with this maneuver, hook turns have an unfavorable connotation.

Hot fuel. When the airplane does not shut down during fueling. Do not board the aircraft while fueling is in progress.

The Letter I

In date. A reserve packed within the previous 120 days is said to be "in date". If more than 120 days have elapsed since the reserve was packed it is"out of date" and illegal to use.

Instructor. Someone who has held a USPA jumpmaster rating for at least one year and passed an Instructor Certification Course.

IPC. The International Parachuting Commission oversees sport parachuting. It is a committee of the FAI.

The Letter J

Jump run. The flight path taken by the jump plane to put the skydivers in position over the airport.

Jumpsuit. A cover all type garment designed for specific skydiving applications such as FS, freestyle or accuracy.

Jumpmaster. Someone who has successfully attended a USPA Jumpmaster Certification Course. A jumpmaster has all of the privileges of an Instructor except that they cannot supervise a first jump course, sign off licenses, or manage a student program without an instructor's supervision.

The Letter K

Key. A signal to move on to the next step in a skydive.

King Air. A turbine aircraft made by Beechcraft and common in medium sized drop zones.

The Letter L

Line of flight. An imaginary line corresponding to the jump plane's path over the ground, the line of flight is a useful reference line on larger formation skydives. Also, during the jump run the skydivers will be distributed along this line of flight.

Log book. Like pilots or sailors, skydivers log their activity and achievements in order to document their experience.

LORAN. A navigational system similar to GPS except based on ground transmitters, LORAN is relatively obsolete.

The Letter M

MSL. Mean sea level. Used by pilots when defining altitude, MSL refers to feet above sea level as opposed to above the ground. Pilots always use MSL when referring to altitude.

Main. The primary parachute.

Manifest. 1) The list of skydivers on the jump plane. 2) The act of going to the office where this list is maintained to put yourself on a plane. 3) The location where manifesting takes place.

MARDS - Main Activated Reserve Deployment System

Microline. A modern type of suspension line considerably smaller than dacron line.

The Letter N

The Letter O

Organizer. Someone with leadership skills and skydiving expertise who plans formation skydives.

Otter. The DeHavilland Twin Otter, a very popular turbine jump ship carrying up to 23 jumpers.

Out landing. Landing off target.

Out of date. See in date.

The Letter P

Packing data card. See data card.

Peas. Pea gravel, used in the landing area as a target reference and because it is forgiving of hard landings.

Pin. 1) The skydiver who first gets to the base. Base/pin are the two people around which many formations are built. 2) The act of docking on the base. 3) The closing pin of the main or reserve container, which should both be checked prior to jumping.

Pit. The pea gravel area.

Pilot chute. A small, round parachute that acts as a drogue to extract the main parachute from the container and deploy it.

PLF. Parachute landing fall. A technique used to minimize injury during rough landings, a PLF distributes the landing shock along feet, calves, thighs, hip and shoulder.

Porter. A single engined turbine aircraft carrying up to ten jumpers.

Post dive. Review of a skydive after everyone has landed.

PRO rating. A USPA rating indicating competence to perform difficult demonstration jumps.

Pull out. A type of hand deploy pilot chute where the pilot chute is packed inside the container and pulled out using a handle with a lanyard to the pilot chute.

Pull up cord. A piece of cord or line used to pull the closing loop through the grommets of the container.

Pud. Slang for the handle on a pull out pilot chute system.

The Letter Q

The Letter R

RSL. Reserve static line. This is a line from the main risers to the reserve cable. In the event the main is cut away, it may pull the reserve pin. Note: this system is only effective in malfunctions where the main is at least partially deployed.

RW. Relative work, the term used to describe formation skydiving until a change in nomenclature made by the International Parachuting Commission in the early 90s.

Relative wind. The apparent wind felt by a jumper in freefall, relative wind is the result of the skydiver's speed through the air.

Reserve. The auxiliary parachute carried on every intentional parachute jump.

Rip cord. The deployment system on all reserves and most student parachutes. The ripcord is a piece of cable with a handle at one end and a pin at the other. When pulled, the pin comes out of the closing loop holding the container shut, and the pilot chute is released.

Rig. Skydiver slang for the entire parachute, including main and reserve canopies and the harness/container.

Rigger. Someone with a certificate from the FAA stating they have successfully met the requirements to be a parachute rigger.

Rigger's certificate. The certificate possessed by a rigger as proof of competence. Senior riggers may make minor repairs and pack reserve and main parachutes. Master riggers may make major repairs and alterations as well as packing parachutes.

Risers. The webbing that connects the harness to the suspension lines. At the bottom of the risers will be a mechanism for attaching and releasing the risers and harness, usually in the form of a three ring release. On the rear risers are the brakes/steering lines. The suspension lines attach to the top of the risers with connector links, also known as rapid links.

Round. 1) A formation where each skydiver has grips on the arms of those next to him, also known as a star. 2) A round parachute, as opposed to a modern ram-air "square" parachute.

Running. When a canopy is flying with the ambient wind it is said to be running. This produces the greatest possible ground speed.

The Letter S

S&TA. Safety and Training Advisor. The S&TA is a volunteer representative of USPA who attempts to disseminate information about safety and act as a liaison between the DZ and USPA. Most S&TAs hold instructor ratings.

SCR. The oldest award for formation skydiving achievement, for those who have been in a star of at least eight people in which each person left the aircraft separately and flew to the formation.

SIM. Skydiver's Information Manual. Published by the USPA, the SIM is a comprehensive manual on USPA policies and training methods. It also includes FARs pertinent to skydiving.

SOS. Single Operation System. This system simplifies emergency procedures by combining the functions of the cut away and reserve handles in a single handle.

Seal. Reserve parachutes have a small lead seal on a piece of red thread around the closing pin. This seal indicates the reserve has not been opened since it left the riggers hands.

Sentinel. A type of AAD.

Single operation system. See SOS.

Skygod. Although on the surface this term refers to a superior skydiver, in drop zone use skygod is a derogatory term for a skydiver whose ego has grown faster than his skydiving ability.

Slider. A rectangular piece of nylon fabric with a grommet at each corner through which the canopy's suspension lines are routed. Packed at the top of the lines, the slider controls the opening of the canopy by preventing the parachute from expanding too rapidly.

Slot. A position in the skydive or on the plane. Uses: "dock in your slot", or "two slots left on the next Otter".

Spectra. A material from which microline is made.

Spot. The position of the aircraft when the jumpers exit. Spotting duties (selecting the spot) can be done by a skydiver or the pilot.

Square. A ram air parachute as opposed to a round parachute.

Stabilizer. The vertical strips of cloth depending from the end cells of the canopy. Stabilizers improve the canopy's ability to fly straight ahead and enhance efficiency by reducing tip vortices.

Stall. When the angle of attack of a wing becomes too high to sustain lift, the wing is said to be stalled.

Static line. In static line deployments the parachute deployment system is attached to the airplane, with a cord ten to fifteen feet long, resulting in deployment immediately after exit.

Steering lines. The lines that run from the steering toggles on the rear risers to the trailing edge of the parachute.

Steering toggles. Handles attached to the end of the steering lines to facilitate their use. Toggles and lines are configured so they can be stowed in a partially down position to enhance the opening of the parachute.

Stow. To neatly arrange suspension lines on the deployment bag or steering toggles in their keepers.

Style. A type of freefall competition where an individual skydiver attempts to execute a predetermined sequence of maneuvers in the shortest possible time.

Suspension lines. The lines from the risers to the canopy. They are normally in four groups, labeled from front to back as A, B, C and D. They can be further divided into right and left or front and back riser groups, and by type of material.

Swoop. 1) To dive down to a formation or individual in freefall. 2) To aggressively approach the landing area in order to produce a long, flat flare and an exciting landing.

The Letter T

TAF - Tandem Accelerated Freefall where the 1st 3 or 4 stages are done on tandem and then the AFF one on one jumps are done as per the standard AFF program.

Tandem. Parachute jumps in which two skydivers, usually an instructor and student, share one parachute system. The student is in a separate harness that attaches to the front of the instructor's harness.

Terminal velocity. The speed at which drag matches the pull of gravity, resulting in a constant fall rate. Typical terminal velocity for formation skydiving is in the 120 to 135 mile per hour range, but speeds as high as 300 miles per hour have been reached.

Three ring. A parachute release mechanism that utilizes three rings of separate size in a mechanical advantage system. Invented by Bill Booth in the late 70s, the three ring release is almost universally considered the best cut away system available.

Throw out. A deployment method in which the pilot chute is stowed in a pouch on the belly, leg of bottom of container.

Toggles. Handles on the steering lines.

Track. To assume a body position that creates a high forward speed. Used to approach or depart from other skydivers in freefall.

TSO. Technical Standard Order. A technical standard that all American parachutes must meet before they can be marketed. Unless specifically exempted by the FAA, a parachute must have a TSO placard to be legal.

Turn around load. When the aircraft does not shut down between loads, but lands and picks up skydivers for immediate departure.

The Letters UV

Uppers. The upper winds, or winds at exit altitude. The "uppers" are often much stronger and occasionally from a different direction than ground winds.

USPA. The United States Parachute Association is a non profit skydiver's organization. USPA offers guidance and assistance to skydivers in training, government relations, competition, and many other fields. Most drop zones require USPA membership of individual skydivers because such membership includes third party liability insurance.

The Letter W

Wave off. Prior to deployment a skydiver should make a clearly defined arm motion to indicate to others nearby that he is about to open his parachute. A good wave off is essential to the avoidance of deployment collisions.

WDI. Wind drift indicator. A paper streamer thrown from the jump plane to estimate winds under canopy and determine the spot.

Weights. Many lighter skydivers wear a weight vest to allow them to maintain a fast fall rate.

Wuffo. Skydiver slang for people who don't jump, from "Wuffo you jump out of them planes?"

Wind line. An imaginary line from the desired landing area, extending directly along the direction the wind is blowing.

Winds aloft. See uppers.

Wing loading. The ratio of weight born by a wing to its surface area. In the US, divide your exit weight in pounds by the square footage of the canopy.

The Letter XYZ

Zero-p. Common slang for a type of fabric relatively impermeable to air. The less air that flows through the fabric wing of a ram air parachute, the more efficiently it flies.

By Bryan Burke on 2003-08-22 | Last Modified on 2012-04-18

Rating: 12345   Go Login to rate this article.  | Votes: 0 | Comments: 0 | Views: 7145

More articles in this category: