Glossary

Canopy, swooping and data terms in plain language. Want to go deeper? See the Swoop Academy and cheat sheets.

AGL: Above ground level: height above the landing area, as opposed to MSL (above mean sea level).
AGL — above ground level: DERIVED. Height above the ground where you landed. How calculated: FlySight's GPS height above sea level (MSL) minus the MSL height at your touchdown point. Shown in feet with metres alongside.
Airspeed: How fast the canopy moves through the air. It makes the lift — your flare power — and it is the same whichever way the wind blows. Ground speed is airspeed plus or minus the wind.
Altitude vs rotation: Each line is one jump's landing turn: across = degrees turned, up = height used since the turn started. A steeper line used more height for the same rotation. Lines that overlap closely = repeatable turns.
Angle of attack: The angle between the wing and the air flowing past it. Toggles and rear risers raise it (slower, flatter, closer to a stall); front risers lower it (faster, steeper).
Canopy piloting: Swooping as a competitive sport: speed, distance, zone accuracy and freestyle courses over a pond, under FAI rules.
Confidence: How much to trust the numbers: high = clean GPS and a clear turn; medium = shorter section or weaker GPS; low = noisy heading (slow ground speed) or GPS spikes — treat with caution.
Consistency score: 0–100, compared only with YOUR own jumps: landing close to your usual spot (35%), a steady heading on final (30%), and descent rate and final-leg time similar to your norm (35%). It is not a safety rating and not a grade of the turn.
Cross-braced: A canopy with diagonal internal ribs that keep it stiffer and flatter — a different class of wing from a conventional 7- or 9-cell.
Data quality: Three states per check: High confidence, Limited confidence, Unavailable. Checks: sampling continuity, final 1,500 ft available, landing detected, altitude vs vertical speed agreement, vertical-speed spikes, turn, weather, canopy. Limited or unavailable data is excluded from your averages — never replaced with guesses.
Density altitude: How thin the air is, expressed as an altitude. Hot or high air is thinner, so canopies fly faster over the ground and need the same airspeed to flare.
Exit weight: You plus everything you jump with — container, both canopies, clothes, helmet, instruments, camera. Divided by canopy size it gives wing loading.
Final heading: Compass direction you were flying on final after the turn (0° = north, 90° = east…).
Flare: Pulling both toggles (or rears) to turn speed into lift and level out for touchdown. Its power comes from airspeed — braking before the flare spends it.
FlySight: A GPS logger worn by skydivers that records position, height and speed several times a second — the data this site analyses.
Front risers: Pulling the front risers shortens the front lines: the nose goes down, the wing speeds up and descends steeply. Height is traded for speed; the recovery needs height. A coached skill.
Gates: Heights where the turn passed 45°, 90°, 180° and 270° of rotation.
Glide polar: A chart of airspeed against descent rate for the whole range of an input. A line from the corner to a point shows the glide at that setting: steeper line, steeper path.
Glide ratio: DERIVED: horizontal distance covered ÷ height lost over the same stretch of track (from GNSS positions and heights). Ground-referenced, so wind changes it.
Glide ratio, last 70 ft: Distance covered over the ground for every foot of height lost during the last 70 ft before touchdown (the plane-out and landing). 3:1 means 3 ft forward per 1 ft down. Wind changes it a lot.
GNSS points: GNSS = satellite positioning (GPS plus Galileo, GLONASS…). Your FlySight records your position, height and speed several times a second — each record is one 'point'. More points = a longer or more detailed recording, not a better jump.
Ground speed: MEASURED by GNSS (horizontal velocity north/east). Speed over the ground, so wind is included: into a headwind it is lower than airspeed, downwind higher. Shown in km/h and mph.
Harness turn: Turning by shifting weight in the harness instead of pulling a toggle: smooth and keeps the wing's shape. The turn tightens the longer you hold it.
Head / tail and cross wind: DERIVED from stored weather (never measured by FlySight). Headwind = wind speed × cos(wind-from − landing heading); crosswind = wind speed × sin(…), positive from the right. Contextual unless an on-site wind was entered.
Hop-and-pop: A jump where the canopy is opened soon after exit — often used for dedicated canopy practice.
Landing offset: How far you landed from your target at that drop zone (or, if you haven't set a target there, from your usual landing spot at that drop zone).
Landing pattern: The planned downwind, base and final legs flown before landing, so everyone in the air is predictable.
Landing scatter: Each dot is where one jump landed, relative to your target (blue ✕) at that drop zone. Up = north, right = east, in metres. Dots close together = consistent landings.
Long spot: Opening further from the landing area than usual, so getting back depends on wind and on how you fly: full flight, rear risers or brakes.
Loss per 90°: Height used in each quarter of the turn (start→90°, 90°→180°, …). Shows where in the turn most height went.
Max AGL: Highest point of the recording above the ground where you landed (AGL = above ground level). Usually your exit altitude.
MSL — mean sea level: MEASURED by FlySight's GNSS receiver: height above the WGS-84 reference (approximately sea level). Used only to work out AGL; it changes with the drop zone's elevation.
Peak descent (rollout start): DERIVED: the moment of maximum descent rate after the turn started — the dive peak. Recovery (plane-out) begins here and, by the gSwoop convention, so does the rollout phase. It is a different event from the turn end (when the heading stops turning) and can happen before it. Not a height recommendation.
Plane-out: After the dive of a turn, the wing swings back over your head and levels out, carrying the extra speed along the ground before the flare.
Planform: The canopy's shape seen from above: rectangular, semi-elliptical (tapered) or elliptical. More taper generally means more roll response.
PLF: Parachute landing fall: feet and knees together, knees bent, rolling along the side of the body (feet, calf, thigh, hip, back) to spread the impact.
Rear risers: Pulling the rear risers shortens the back lines: the whole wing pitches up with its shape intact — speed mostly kept, glide flatter, and a short range before an abrupt stall.
Recovery: Time from the end of the turn to a steady final. 'Already steady' means the heading was settled the moment the turn ended.
Recovery arc: DERIVED: the path from the peak descent (dive peak) to a stable final — descent rate easing, heading and ground speed settling. Shown as a side profile (distance vs height). Compared only with your own jumps of the same turn type.
Red mist: The urge to swoop no matter what — ignoring traffic, wind or a bad setup. Recognising it and choosing a straight-in landing is a skill.
Reference jump: The jump that is most consistent with your own usual flying — a personal example to compare other jumps with. Not a 'best' jump and not a recommendation.
S&TA: Safety & Training Advisor — the person appointed at a drop zone (USPA term) to oversee safety and training.
Sight picture: Your visual sense of height, speed and where the turn or flare has to happen. It is built over many jumps and fades quickly when you are not current.
Stable final: Height where your heading had settled on final and stayed steady for at least 1.5 s.
Stall: The wing stops flying normally because the angle of attack is too high — the air no longer flows smoothly over the top skin. It is about angle, not speed: on rear risers a wing can stall while still fast.
Stall point: Where in the travel of the toggles or rear risers the wing reaches its stall. It comes much earlier on rear risers than on toggles, earlier with more wing loading, and front risers have none.
Sweet spot: The toggle depth where the canopy levels out: in a flare from full flight the horizon stops rising and the descent nearly stops for a moment. Where it sits depends on your canopy, size, wing loading and brake-line setting — find it up high.
Swoop / standard: 'Swoop' means a landing turn of about 200° or more was found in the last part of the flight; 'standard' means a normal landing without one. The number is the total degrees turned.
Total rotation: How many degrees the canopy turned in the landing turn, measured from GPS heading: about 90 = quarter turn, 180 = half, 270 = three-quarter, 360 = full circle, 450 = one and a quarter.
Trim (full flight): Hands up, no input: the speed and glide the manufacturer built the wing to fly.
Turbulence / rotor: Rolling, uneven air downwind of buildings, hangars and trees. It can reach many times the obstacle's height downwind and can take pressure and airspeed from the wing.
Turn end: DERIVED: where the heading stopped turning — rotation below 8°/s for 1.5 s. Slow rotation after the last gate keeps the turn open, so the turn end can be lower than where you felt you rolled out.
Turn rate: DERIVED: change in GPS ground-track heading per second (°/s), lightly smoothed. At low ground speed the heading is noisy, which lowers confidence.
Turn start: Height where the heading started changing steadily in the turn direction.
Vertical speed / descent rate: MEASURED by GNSS (vertical velocity). Negative = descending. Descent rate is shown as a positive number. Brief spikes can be GPS noise — see Data quality.
Wind gradient: Wind is usually weaker close to the ground. Descending into a headwind through it, the wing briefly loses airspeed (it can sink); with a weakening tailwind it briefly gains some.
Wing loading: Exit weight in pounds divided by canopy area in square feet (lb/ft²). × 4.88 gives kg/m². Manufacturers publish model-specific charts.
Wing loading (WL): DERIVED from what you enter, not from GPS. How calculated: exit weight in pounds (you + all gear) ÷ canopy size in square feet. Also shown in kg/m² (×4.882). Information only — not approval to fly a size.

Safety notice: This tool is for data review only. It does not replace canopy coaching, DZ rules, traffic awareness, S&TA guidance, or manufacturer guidance. Everything here is information for learning — not advice or a recommendation about any canopy, wing loading, turn or decision. Your decisions are your own. See the Terms of Service.