The question of sourcing accurate positional and flight track data from onboard avionics versus third-party ADS-B aggregators reflects a practical challenge that arises frequently in general aviation and business aviation contexts — whether for incident review, insurance documentation, legal proceedings, or simply flight analysis. The Garmin GTN 375 is a touchscreen GPS navigator capable of logging flight track data internally, and that onboard record is categorically more accurate than what FlightAware or ADS-B Exchange can reconstruct. Those services depend on a distributed network of ground-based ADS-B receivers maintained by volunteers, government agencies, and commercial partners. Coverage gaps — particularly at low altitudes, in mountainous terrain, or in sparsely populated regions — can result in missing data segments, interpolated position points, and timestamp inconsistencies that make the reconstructed track an approximation rather than an authoritative record.
The GTN 375 logs GPS track data to the SD data card installed in the unit, which also carries the aviation database. This log is typically stored in a proprietary Garmin format but can be read and exported using Garmin's PC-based tools, including Garmin BaseCamp or the Flight Data Logger function accessible through the unit's own interface. The track data recorded directly by the GPS receiver reflects the unit's own computed position solution — typically accurate to within a few meters under WAAS conditions — and is not subject to the reception quality, receiver density, or network latency issues that affect ADS-B aggregators. Pilots or operators seeking the most accurate positional record of a specific flight should pull the data card from the unit as soon as possible after the flight and archive the log files before subsequent flights overwrite them, as storage capacity is finite.
For operators functioning under Part 135 or Part 91K, where flight records and operational data may be subject to audit or subpoena, the distinction between onboard GPS logs and third-party aggregated data carries legal and regulatory weight. ADS-B Exchange and FlightAware data can serve as useful corroborating references, but they are not primary records. In accident or incident investigations, the NTSB and FAA treat onboard avionics data — including GPS track logs, engine data monitors, and glass cockpit data card exports — as primary sources, precisely because they are direct outputs of certified equipment rather than reconstructions from secondary receivers. Any operator who anticipates needing precise flight data for compliance, insurance, or safety purposes should develop a habit of exporting and archiving avionics logs routinely, not retroactively.
The broader trend here points toward increasing reliance on onboard data ecosystems rather than external aggregation. Modern avionics platforms — including Garmin's G3X, G500/G600, and GTN series — produce rich data outputs that, when properly archived, rival the kind of FOQA data that major airlines have collected for decades. For Part 91 operators and business aviation flight departments, tools like Garmin Pilot's logbook sync, SureSafe, and dedicated FOQA platforms from companies like Teledyne Controls and Appareo are making structured flight data capture accessible well below the airline tier. The GTN 375's onboard log is a starting point, not a ceiling, and pilots who understand how to extract and interpret that data gain a significant advantage in both safety management and operational accountability.