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XC League Rules - 2024
The rules and changes for the current year.

4 Flight Evidence

4.1 General

The onus is on the pilot to produce irrefutable evidence that the flight they are claiming took place, if challenged. The XC League is policed to ensure that no unfair play takes place, although in essence it is largely based on trust and relies on pilots entering data accurately and honestly. However, pilots should be careful to abide by the rules and provide all the necessary proof to validate their flights.

If flights have been checked against airspace and any declaration they will be marked as Validated in the XC League and this can happen at any point up until the end of November. Any flights found to be infringing airspace or without the appropriate evidence to substantiate the flight may be removed at any time. Any flights of the top 10 scoring pilots at any one time and any flights scoring over 100km will be checked in a fair and timely manner. Other flights will be checked as and when resources allow.

4.2 IGC Tracklogs

Primary evidence is a continuously recorded IGC tracklog containing altitude data. Your tracklog must also contain your pilot name and must include a security signature (a G record, automatically added by conforming software) which will be checked later to ensure that the data has not been altered.

A continuously recorded tracklog must have at least one position recorded every 20 seconds, although it is recommended that the recording interval be set between 5 and 15 seconds. Please note that tracklogs that are recorded at sub-second intervals cannot be accepted.

The tracklog must provide unequivocal evidence that no intermediate landing was made and must generally substantiate the flight. Your tracklog should contain your takeoff and landing, to allow us to calibrate the tracklog altitude trace. If both of these are missing we will be unable to check your altitude and your flight will not be accepted. A tracklog that includes the landing is always preferable as a tracklog that ends at altitude as you are approaching airspace may not be accepted.

4.3 Track Breaks

Interruptions in the tracklog will not invalidate the flight, provided the gaps:

  • Do not bring into question the continuity of the flight.
  • Are not within 2000ft vertically or 1 km horizontally of airspace that must be avoided.

The system will reject tracklogs with breaks greater than 10 minutes, or more than two 20-second breaks. In this case the pilot must email their flight details to be checked and entered by an administrator.

If your instrument has recorded multiple tracks, we will stitch them together provided they are from a single instrument and that the above rules apply.

4.4 Supported Instruments

The XC League endeavours to support most of the instruments and software listed on the Open Validation Server, with the following exceptions:

  • Software that has been assigned the XXX indentifier.
  • Software that publishes the security signature code (XCSoar, LK8000, Tophat etc).
  • Live tracking software.

If the system rejects your tracklog as unsupported software, email the flight details and we will see if we can support it. This may happen because new software is regularly added and we like to check the IGC files first.

We do this to protect the interests of pilots, because the Open Validation Server project does not check if new instruments output the correct IGC data, and unusable implementations occasionally get listed. In such cases we will work with the developers to correct any issues.