With the advent of satellite navigation equipment at an affordable price, glider pilots can provide precise evidence of position without using either ground-based observers or photography. There is a Technical Specification for IGC-approved Flight Recorders, which includes the provision of a pressure altitude sensor in addition to a GNSS (Global Navigation Satellite System) receiver. Functions such as Pilot Event (PEV), task declaration and navigation to turn points, may also be incorporated. The pressure altitude system in an IGC-approved FR is a barograph in its own right, and is subject to normal barograph rules (such as on accuracy and calibration). Most IGC-approved GNSS FRs are units which integrate the GPS and other functions all in one sealed case, although for badge flights up to and including diamonds, FRs have been approved which connect by cable to a separate proprietary GPS unit such as named Garmin models.
GNSS and pressure altitude data is recorded in the form of regular fixes, the fix interval being governed by pilot's setup of the Flight Recorder. The maximum fix interval set on the FR and allowed for a flight to be validated to IGC rules is one minute, and pilots approaching the Observation Zones for Turn Points often set short fix intervals as low as 1 second (if the FR allows such a fix interval), in order to spend the minimum possible time in the Observation Zone.
OBSERVATION ZONE VALIDATION At least one valid fix must be in the Observation Zone (OZ), or a straight line joining two consecutive valid fixes must pass through the OZ.
Flight data is stored in the FR memory, and after flight is downloaded from the FR either to a PC, memory card or USB memory stick (depending on the characteristics of the Recorder).
For download to a PC and validation of the electronic flight data, free files are available through this web site. The MS Windows-based IGC Shell Program works with each manufacturer's DLL file. For older recorders there are short program files for transfer of the flight data (DATA.EXE), conversion to the IGC data file format (CONV.EXE), and for validation of electronic security (VALI-EXE) using standard electronic security systems such as RSA. For current recorders these functions are part of the IGC Shell program and the manufacturers' DLL files.
Where downloading of the IGC file is direct to a memory card or USB memory stick, the Validation function of the IGC Shell program must be used to check the integrity of the data in the IGC file.
There are also programs for analysis of the IGC data file format. Some analysis programs are incorporated in the FR manufacturer's full software programs, and some are independent of FR manufacturers' programs. There is no obligation for a FR manufacturer to have a proprietary program for data transfer and analysis, as the short program files and independent analysis programs, provide these functions.
For all FAI/IGC badge flights, and record flights to IGC criteria, rules for GNSS Flight Recorders may be found in the following documents. Rules for competitions are decided by the competition organisers, who may choose to use IGC rules, variants of them, or local rules of their own.
The IGC set up a "GNSS FR Approval Committee" (GFAC) whose task it is to test FRs for their suitability for documenting badge and record flights according to the IGC rules. The Terms of Reference of GFAC are in Annex B to the Code. The following documents and software are made available on the IGC web site by GFAC on behalf of IGC:
Each manufacturer is allocated a three-letter code by IGC that is included in the title of the DLL and DOS files, so that these files can be specific to the protocols used by that manufacturer. The three-letter code is normally the first three letters of the name of the organisation, or in some cases its initials. Codes are allocated by the GFA Committee and are given in the IGC Specification document, Appendix 1, para 2.5.6. Allocations are made when necessary between publication of amendments.
The DLL file names have the form IGC-XXX.DLL where XXX is the manufacturer=s IGC three-letter code and fulfil transfer, conversion and validation functions. The DOS short program files are DATA-XXX.EXE for data transfer, CONV-XXX.exe for conversion to IGC format, and VALI-XXX.EXE validation of electronic security.
Gliding organisations are encouraged to take copies of the freeware files so that pilots needing an Official Observer to take and store the flight data, can do so as soon as possible after the flight as required by IGC rules and procedures.
Are you thinking of developing a flight recorder? If so, please read this important notice.
Download the format document as PDF file suitable for browsing on line (113 KB).
Download a ZIP file containing the above file in a form suitable for printing (A4 paper).
Introduction by President IGC:
The International Gliding Commission of FAI hereby announces its approved IGC Waypoint Format.
This initiative was started by the IGC Sub-Committee which handles the championships rules. Organizers of championships found that they had to handle a larger and larger number of waypoint formats in their analysis of flights. One common standard was seen as being an immense help to championship organizers, and pilots and Official Observers in the field.
Agreement has now been reached after 11 drafts, with a common-sense compromise which we believe will fulfil the objectives of the initiative.
We must recognize the considerable amount of work which has been done to bring this to an approved standard. Thanks to the GNSS and GFAC Sub-Committees and their advisors, and particularly to Ian Strachan who acted as co-ordinator for the drafts, for the great work done by all who participated in that effort!
Tor Johannessen
President IGC
May 2000
Introduction by Chairman IGC GNSS subcommittee:
This is the approved IGC format for WayPoint lists, which is the name adopted to cover Turnpoints, Startpoints, Finishpoints, and may even be used to delineate the 'corners' of straight-lined airspace areas, such as TMAs, prohibited areas, restricted areas, etc.
This format is not mandatory at this time. However, it is possible that some may require it for certain activities.
Yes, the format may seem complicated at first look, because it will do many things. But, most everything is optional. There is only one requirement:
CCCCCC | NN | DD MM.mmmN/S | DDD MM.mmmE/W
and part of it is also optional:
It gives you the W/P name (CCCCCC), or code for it if the name is longer than six characters, the nation (NN), and the Latitude/Longitude in degrees, minutes and thousandths of minutes (DD MM.mmmN/S | DDD MM.mmmE/W).
You don't need to use the nation indicator if your list is all in one nation. - You may omit the hemisphere designators if your country is not divided by the 0/180 meridian or equator. - If your lat/long is less than 3 numbers (e.g. 001), the leading zeros need not be repeated. However, there must be a key for the waypoint list showing the method being used for omitting such data.
However, even the full CCCCCC | NN | DD MM.mmmN/S | DDD MM.mmmE/W won't tell very much about the point, although it does describe it uniquely. That is essential for entering into an IGC-approved GNSS FR (Flight Recorder).
The rest of the material in the standard format provides for definitive names of the W/P which many will find they want to use because they give all the distinguishing information to describe the point, particularly necessary for those not using GNSS for flight verification. There are still a lot of camera/baro users out there. Hard copy of a W/P listing can look as bare as you want with only CCCCCC | NN | DD MM.mmmN/S | DDD MM.mmmE/W or as fully definitive as using all the provisions would provide. It's hard to imagine one would not provide pilots something morethan the bare minimum, but we have allowed for that if so desired.
The introductory material (Sections 1-4) is designed to assist your understanding of how the format can be used for lists.
Please do not be put off by section 4 regarding accuracy responsibility. That lies ultimately on whomever produces the particular list. There may be one for a country covering all waypoints, or many for a country, each one covering different areas, produced by a different person.
Bernald S. Smith
Chairman, IGC GNSS subcommittee