About
IGC Viewer is a lightweight, open-access web application tailored for the gliding community, allowing pilots to load and inspect IGC-format flight recordings directly in their browser. Built by Alistair Malcolm Green and Richard Brisbourne, with OpenStreetMap integration by Chris Fox, the tool covers the full spectrum of post-flight analysis needs. Pilots can upload an IGC file and instantly see their flight path overlaid on a map, with zoom controls and track-height coloring for quick visual assessment. The integrated barogram displays altitude and climb rate over time, with adjustable altitude references including QFE, QNH, GPS, and standard pressure (STD). An AGL (above ground level) height view adds terrain awareness to the analysis. Task planning and review are core features: users can define a soaring task using BGA trigraphs, Welt2000 waypoints, or lat/long coordinates, then evaluate performance against traditional or AAT sector geometries. Sector radii, observation zone types, and timing windows are all configurable. Thermal detail mode summarises each detected thermal—entry/exit time, net gain, average climb rate, and estimated wind—giving pilots actionable feedback for debriefs. Engine detection (ENL/MoP) is also supported, helping competition officials and coaches verify unpowered flight. The tool is entirely free to use, runs in any modern browser, and stores user preferences locally. It is ideal for club pilots, competition flyers, coaches, and soaring enthusiasts who need quick, reliable IGC flight analysis without installing dedicated software.
Key Features
- Interactive Flight Track Map: Renders the full IGC flight path on OpenStreetMap with zoom controls and color-coded altitude or AGL height visualization.
- Barograph & Altitude Analysis: Displays altitude over time with selectable references (QFE, QNH, GPS, STD 1013.25 mb), climb rate, and cruise speed in configurable units.
- Soaring Task Definition & Analysis: Supports traditional and AAT task sectors using BGA trigraphs, Welt2000 waypoints, or lat/long coordinates, with configurable radii and timing windows.
- Thermal Detail Mode: Breaks down each thermal climbed during the flight, showing entry/exit times, net altitude gain, average climb rate, and estimated wind direction.
- Engine Detection (ENL/MoP): Detects and flags engine use during flight using configurable ENL or MoP threshold values, supporting competition verification and coaching.
Use Cases
- Glider pilots reviewing their post-flight track, altitude profile, and thermal performance after a cross-country flight.
- Soaring coaches debriefing students by examining thermal entry/exit data and task sector execution.
- Competition officials verifying that a declared task was correctly flown and checking for unauthorized engine use via ENL/MoP data.
- Club members comparing barograph traces and task speeds from a competition day without specialist desktop software.
- Aviation enthusiasts and flight recorders analyzing IGC logs from motorgliders or other aircraft fitted with IGC-approved loggers.
Pros
- Completely Free & No Install: Runs entirely in the browser at no cost, with no account creation or software download required.
- Comprehensive Flight Analysis: Covers tracks, barogram, thermals, task sectors, AGL height, and engine detection in a single unified interface.
- Flexible Unit & Configuration Support: Supports feet/metres, knots/m/s/ft-min, km/h/mph, and multiple altitude references, with preferences saved locally.
Cons
- Airspace Data Not Navigation-Valid: The tool explicitly warns that its airspace overlay is not suitable for flight planning or navigation — official publications must be consulted separately.
- No Cloud Storage or Account Features: Flights cannot be saved to an account or shared via a permalink; each session requires re-uploading the IGC file.
- Niche Audience: Designed specifically for the gliding/soaring community and has limited utility outside of IGC-format flight log analysis.
Frequently Asked Questions
What file format does IGC Viewer support?
IGC Viewer supports the standard IGC (International Gliding Commission) file format produced by most soaring flight loggers and GPS variometers.
Is IGC Viewer free to use?
Yes, IGC Viewer is completely free. No registration, subscription, or payment is required.
How do I define a soaring task in IGC Viewer?
You can enter task waypoints using BGA trigraphs, six-character Welt2000 codes, or lat/long in dd:mm.mmm or dd:mm:ss format. Start and finish are required; up to four turning points are supported.
Can IGC Viewer detect engine use during a flight?
Yes. Engine detection can be enabled using ENL (Engine Noise Level) or MoP (Means of Propulsion) sensor data embedded in the IGC file, with configurable thresholds and minimum-time filters.
What altitude references are available?
IGC Viewer supports Standard pressure (1013.25 mb), QFE (take-off reference), QNH (sea-level reference), and raw GPS altitude, selectable in the preferences panel.
