Flightradar24 doesn’t care about ATC. It receives signals on 1090 MHz and displays them.
Unless they have a link to the FAA which is probably likely.
Dimme wrote:
Flightradar24 doesn’t care about ATC. It receives signals on 1090 MHz and displays them.
No way for mode A/C transponders, there is no identification other than the transponder code which is not unique. Mode S can be detected by MLAT or ADS-B can be detected on 1090 MHz if the aircraft is equipped. About 25% of US aircraft don’t have ADS-B of any sort and of the remaining aircraft that are ADS-B equipped, about 20% use 978 MHz. ATC provides radar feeds if the vendor agrees not to provide tracking information for blocked aircraft.
Many thanks NCyankee for looking into it.
Would FR24 really have a link to the FAA, rather than picking up just radiated signals?
FlightAware and other competitors have a link to the FAA, that is where they get the flight plan route information from and radar data from. ForeFlight uses FlightAware for its traffic feed. To use the traffic data, one has to agree not to display information on FAA blocked tail numbers. Without the FAA traffic feet, one will miss a significant number of flights. ADS-B Out equipage is roughly 75% of the fleet (90% of which is compliant), about 10% of the fleet are only primary targets, no transponder and no ADS-B Out, The remaining 15% is transponder equipped, but almost all Mode A/C. ADS-B Out or a transponder is not required, even for IFR flight, as long as one remains below 10000 MSL and outside of B and C airspace.
NCYankee wrote:
ADS-B Out or a transponder is not required, even for IFR flight, as long as one remains below 10000 MSL and outside of B and C airspace.
Below 10,000 feet and outside of rule airspace, which for Class B has a volume several times larger than the lettered airspace it surrounds. For those of us operating around Class B the distinction continues to matter – it cost me $3K or so.
I suspect that the 75% ADS-B OUT equipped number quoted above for the US must apply to flights on a flight plan, flights using flight following, planes on FAA radar or some other subset of all the aircraft extant in the US. It’s certainty a high number that the FAA would like to promote but there are airports by my observation where likely not one aircraft is equipped, or perhaps just one. It’s a big country and most of the planes never go anywhere near rule airspace. On the other hand, it has become fairly easy to equip if the plane has a Mode C transponder – with a skyBeacon, a logbook entry, a test flight, an FAA performance report via the website, another logbook entry and submission of an A&P IA signed form 337.
Silvaire wrote:
I suspect that the 75% ADS-B OUT equipped number quoted above for the US must apply to flights on a flight plan,
That is my number estimate. I assume there are 200,000 aircraft of US registry. The latest data from the FAA shows that 147414 aircraft have been equipped, 147414/200000 = 74%. The FAA monitors the ADS-B broadcasts and that is where they get their numbers from, not flight plans. 14059/147414 or 10% of the aircraft that are installed are not yet compliant with the rule. Most of these are installation setup issues or non compliant position sources. These pilots get letters from the FAA to get their equipment fixed.
