Track log - Altitude on ADS-B reports

FlightAware General
1

Could someone explain to me where the altitude field gets it’s data in track logs that are mostly flightaware ADS-B reports? Is this mode C, ADS-B GPS or some special blend?

I ask because I’m investigating a problem with an aircraft that the FAA insists is breaking altitude by 170 to 200 feet or more, yet shows on FlightAware as consistently 25-50 feet below the filed target altitude. I assume, from the 25 foot increments, that the track log shows the ADS-B GPS altitude solution. Is that correct?

2

It’s uncorrected pressure altitude, from any of Mode 3/C, Mode S, or ADS-B squitters.

1 Like
3

Thanks. Not what I’d hoped to hear, but important regardless.