Each type of IGC Flight Recorder has an IGC-approval document that gives details of the Recorder, its hardware, internal and external software and what devices can be connected to it such as displays. Each document has a standard format, a main body followed by Annex A for pilots and owners, then Annex B for Official Observers and National Airsport Control (NAC) organisations such as the National Gliding body. Pilots and owners of IGC FRs are advised to copy the relevant IGC-approval document and read it closely before using the FR for a flight that requires official Validation.
There are three IGC-approval levels for Flight Recorders (see Annex B to the Sporting Code for Gliding (SC3B), parA 4.1.1. Briefly these are (1) All Flights (including World Records); (2) All IGC Badge and Distance Diploma Flights (excluding Records); and (3) Silver and Gold Badge Flights.
The Technical Specification for IGC-approved Flight Recorders requires a pressure altitude sensor in addition to a Global Navigation Satellite System (GNSS) receiver. A Pilot Event (PEV) system allows pilots to mark particular times during a flight, such when inside a Turn Point Observation Zone (TP OZ), and the Pilot Event is followed by a series of fixes at a small time interval, commonly 30 fixes at one second intervals. A longer fix interval can be set before flight for cruising flight between Turn Points, so that the IGC file is not too large for a very long flight. 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).
Flight data in the form of fixes and other data is stored in the FR memory, and after flight is downloaded from the FR either to a PC, memory card (typically an SD card) or USB memory stick (depending on the characteristics of the Recorder).
For download to a PC and electronic Validation of the structure of the IGC file, free files are available through this web site. The MS Windows-based IGC Shell Program works with each manufacturer's DLL file. Where FR manufacturers have not produced DLL files, the previous generation of EXE files are used. These are DATA-XXX.EXE, CONV-XXX.EXE and VALI-XXX-EXE where XXX is the FR manufacturer's three letter code tht is allocated by IGC.. The DATA file is for downloading from the FR to a PC, CONV for converting binary files (where produced by a particular FR type) and VALI for electronic Validation of the structure of the IGC file and checking that it has originated correctly from an IGC-approved type of FR.
The IGC GNSS FR Approval Committee (GFAC) tests FRs and issues IGC-approval documents on behalf of IGC.