How Track Validity Checks Work

Sometimes the wrong file gets uploaded — a flight from another day, or another site. It is an easy mistake and a hard one to spot: the file is valid IGC, it opens, and it looks like flying.

Scoring cannot catch it. Tasks often run across UTC midnight, so GlideComp resolves start gates and deadlines relative to the flight being scored rather than to a fixed date. A tracklog from another day therefore carries the whole task onto its own day and scores as though nothing were wrong.

FAI S7A §4.4.2 makes this the software's job: the points used to verify a flight must have "occurred at reasonable times (e.g. on the day in question)".

Both ask one question — is this file this flight? — with margins no honest entry can reach.

A track failing either is kept out of scoring and out of the field analysis, where its clock and its air would distort the day's statistics for everyone else.

These describe the flying, not the file. Each one fires on legitimate flights too, so they are shown for a human to judge and never affect a score.

• Never left the take-off cylinder. What a pilot who launches and sinks straight back looks like — correctly scored the minimum distance — and also what a recorder left running on launch looks like.
• No sign of flight. No sustained climb (1.5 m/s for two minutes) and no sustained glide (90 seconds descending at 0.8 m/s, never below 4 m/s over the ground, roughly straight). This is what catches a vario recording the drive up to launch — speed alone cannot, since a retrieve vehicle outpaces a paraglider.
• Implausible speed. Ground speed held for a full minute above about 119 km/h for paragliders or 162 km/h for hang gliders, tailwind included. The minute-long window keeps GPS jitter out. It is looking for something that is not a glider at all.

A pilot who launches and lands short is scored the minimum distance, about 5 km. That is unchanged — a short, unlucky flight still earns it.

A withheld tracklog is different: it is not evidence the pilot flew this task. Those pilots keep their place in the results with zero points and the reasons beside their name. They are never dropped from the standings.

Nobody else's score moves. The pilot is left out of the launch-validity count ( S7F §9.1 ) rather than counted as having flown, so a wrong verdict can only ever cost that one pilot.

Under S7A §4.4.6 rejecting a track log is the organiser's call, not the software's. A scorekeeper can accept a flagged tracklog in one action: it is then scored normally, its findings stay visible, and the decision goes into the competition's public audit log.

If your track was withheld, the fix is usually to upload the right file. If it is the right file, ask the scorekeeper.

Wrongly zeroing a pilot is worse than missing a bad file, so the thresholds come from real competition data.

Across 4,762 archived tracks, the typical flight passes within 70 m of a turnpoint, and the furthest any honest track stayed from every turnpoint was 45 km. The 100 km threshold is more than twice that.

The one-day grace has the same origin. One archived task has three pilots (of eighty) whose recorders were stamped a day late; all three flew the task and were scored normally, one finishing fourth, in goal. Treating a one-day offset as disqualifying would have zeroed a podium flight.

Over all 5,112 tracks GlideComp holds, the checks withhold exactly one: a New Zealand flight submitted to a Victorian task ten days later.

When a check fires, the pilot's score page names it, shows the numbers behind it, and says what to do next. A withheld track is labelled in the results table too, so a zero never looks like a bug.

Same rule as track data cleaning: anything the system did on the way to a score must be visible.