Guesstimates vs actual ADS-B Tracks


#1

I’ve noticed that over the oceans, where there isn’t an ADS-B receiver to pinpoint a position and FlightAware needs to use estimates, it doesn’t then “correct” the track so far when an actual position is available over land. The estimated ETA then doesn’t take account of where the aircraft actually is but seems to rely on the original guesstimate from the flight plan

I’m tracking a flight from Dubai to Australia, the track on another ADS-B website runs out over the Indian Ocean but re-appears over Male in the Maldives but by then the FlightAware track is hundreds of miles adrift from the actual. Is it not possible to apply corrections, much as pilots would have corrected for guesstimates from dead reckoning or early inertial navigation systems. Or am I missing something ?


#2

lmgtfy.com/?q=flightaware+service+area


#3

Thanks, I had of course read the FAQs, so I guess the answer to my specific question is that the range of ADS-B receivers available to FlightAware differs from those used by Flightradar24.com for example as the flight I was tracking was accurately tracked over the Maldives by the latter but not by the former.


#4

flightaware.com/adsb/coverage


#5

Hi

The probable reason for what you saw is that in the Maldives someone is feeding ADS-B info to FlightRadar24 but not to FlightAware…

Gary


#6

Hi Gary, that was partly my point but I was more curious to understand what efforts FlightAware goes to (none it seems) to correct its displayed ETA data once it gets an accurate position fix.

In my example, it’s a bit unhelpful, even silly, to display “4 minutes” to go when it also knows the aircraft is still “150 statute miles” from its destination, needing an average speed of 1000mph. FlightAware got its 4 minutes simply from the initially estimated flight duration minus time flown so far, rather than estimating actual flying time left, not that difficult really. But I now understand that the ETA info displayed is really all about simplistically following the flight plan rather than estimating a time from reality.

Despite Australia being a “primary service area” FlightAware sometimes had the aircraft 150-200nm away from its actual position, even over land and within its tracking network, and its displayed arrival time was 20 minutes earlier than reality. The simplistic FAQ explanation of “arriving shortly” that the data is “delayed” is unhelpful and incorrect really but never mind it has lots of other useful features.

Thanks for your reply, Mike