I had a look at my last flight on FR24 and noticed the altitude seems to be off by quite a bit (on the low side), I suspect it is recording the pressure altitude rather than correcting it for barometric altitude. This would obviously need to be taken into account as pressure vs baro can be a few hundred feet apart, and in high pressure will suggest the aircraft was flying lower than it really was.
@Malibuflyer
I am confident that accident investigators don‘t rely on Flightradar24 e.a.
They get their stuff first hand from the respective ATC units.
Looking at how many accident threads we have had, and what info FR24 etc has brough to them, I would say they are extremely useful.
Otherwise, you just get some local news (which is usually useless) and a year or two later, after almost everybody has forgotten about it, is the accident report, whose value depends on a lot of things and which is also often useless.
172driver wrote:
I’m not too sure about ADS-B close to the ground.
ADS-B is as accurate close to the ground as it is high up. The challenge is that (like any radio signal) the signal range gets smaller close to the ground. So if you don’t have an ads-b reception station at the destination airport, the next station will at some point in time loose the signal.
All flight tracking sites I know do some kind of interpolation if they don’t have real data – what you see as “imprecise” is in reality missing data that is filled by made up data of FlightAware.
The operator of Fligthaware, however, knows which data was actually received and which was made up – and therefore they can clearly mark that when handing over this tracking data to accident investigators…,
I’m not too sure about ADS-B close to the ground. We track our club aircraft (all ADS-B in/out compliant) and very often the track starts a few hundred feet AGL and also stops before landing and/or gets imprecise. I have no idea why that would be the case, but as I look at our tracks every day, it’s certainly there. We use FlightAware.
Airborne_Again wrote:
As good as the GPS position accuracy, i.e. very.
Only as long as someone picks up the signal, and does so at a reasonable rate. Anyway, there is no mandatory ADS-B in Europe, so it is a moot point. We have Mode-S, at best (not mandatory in Norway for instance). The accuracy, or lack of, will always be the main factor.
Going forward it will only get more accurate.
Also with starlink up and running, I think it will be the medium used to help low cost anti collision systems
LeSving wrote:
ADS-B would probably be a bit better, but by how much?
As good as the GPS position accuracy, i.e. very.
Airborne_Again wrote:
FR24 accurately shows ADS-B out equipped aircraft taxying
That isn’t very useful in a crash investigation. IMO the problem is always the path of the aircraft in difficult terrain and far away (from people) places. ADS-B would probably be a bit better, but by how much?
LeSving wrote:
There is the inaccuracy of these tracking sites. All they really show is an approximate path until some minutes before the crash. The don’t seem to improve certainty. A tiny little GPS/G-force logger tucked away at some survivable point would probably do a better job.
If the aircraft has ADS-B out, the tracking is very accurate. FR24 accurately shows ADS-B out equipped aircraft taxying.
