FR24 vs FlightAware
I've been following this thread throughout the day and much has been made of differing position reports being quoted so thought I'd clarify a couple of things, as speculation continues a day after the event.
As far as I'm aware:
- both these systems rely on users/enthusiasts uploading ADS-B data but they have different users/sources so don't cover the whole globe equally.
- my experience of FR24, living under several airways and Gatwick/Heathrow arrival and departure routes, is that it is very accurate for say 99% of time
- when FR24 has no data in a region, it just doesn't show any aircraft
- as we have several aircraft tracks from FR24 in the general vicinity before and after this incident we can assume MAS370 was more or less where it was displayed as being while at FL350, with the likely exception of the last few miles when the ADS-B was probably transmitting garbage or nothing at all
- when FlightAware has no data it uses the filed flight plans to guesstimate where aircraft may be. The track lines are dashed in those cases whereas they're solid lines if they have ADS-B input. It's not unusual for the guesstimate to be several hundred miles away from where FR24 is showing an aircraft to be. Indeed FlightAware may still say that an aircraft is hundreds of miles and hours from landing when it's on final approach because it lacks the ADS-B data available to FR24 !
That said, all ADS-B transmissions are from the aircraft themselves calculating where they are and this may or may not be exact, indeed many an FR24 aircraft has "landed" several miles from its target airport after a long flight because of these estimates - the A40 north of Heathrow is very popular. This can also be from conflicting data received from several users I believe.
Finally and a comment on this thread, I lost a good friend in a flying incident last year and appreciate all the good efforts to shed light on what will be a devastating day for those involved today. Rumour, supposition, insight, speculation and deduction are what makes PPrune so popular but please let's just try to keep the sniping at bay.
Last edited by Golf-Mike-Mike; 8th Mar 2014 at 20:12.