Flights with no heading of direction in SkyAware

[dvsvejk]

I occasionally see Air France flights (always Air France) which display no heading in the data table of SkyAware. The flight does track correctly on my local SkyAware map albeit with the amusing sight of a bolt upright plane icon dancing across the screen (see pic). Checking concurrently on the Flightaware web site shows the plane tracking normally. In the past even my own data has been used by FA to track such a flight despite my local view showing no heading. Any ideas on what is going on and why just Air France?

[geckoVN]

The icon does point north if it has a location, but no heading (this is normal). It just means you are not getting all the messages.

[dvsvejk]

The issue I have is I never get a heading for these flights. In the example I posted I saw the inbound leg of this flight and it was the same behaviour - no heading whatsoever from start of acquisition until I lost contact. There is a subset of AF aircraft that display this issue. Guess I wait until I catch another one in the act and take a closer look at it.

Edit: After some searching I found the aircraft in question (F-GKXI/392AE8) appears to be equipped with an old, first-generation ADS-B transponder - DO-260/version 0. Current iteration is DO-260B/version 2 and is a mandate in many locations. Again I will have to wait for another such AF flight to pass by to confirm. I’m guessing Flightaware can’t provide me a local real-time heading based on the data from the older version, but it is something they can do on their back-end servers for their web site.

[wiedehopf]

utcTime: 15:01:00.565 epoch: 1651158059.565
DF:17 AA:392AE8 CA:5 ME:991021C6A00426
 Extended Squitter Airborne velocity over ground, subsonic (19/1)
  ICAO Address:  392AE8 (adsb_icao)
  Air/Ground:    airborne
  Geom - baro:   925 ft
  Ground track   176.8
  Groundspeed:   564.9 kt
  Geom rate:     0 ft/min
  NACv:          2

Seems to be sending ground track just fine to me.

FA could be just calculating the track from the positions or something?
Not certain.

Edit: Now that’s funny, the transponder on that plane was fixed yesterday.
First leg of the 27th, track is not available (n/a):
https://globe.adsbexchange.com/?icao=392ae8&lat=52.921&lon=1.108&zoom=5.0&showTrace=2022-04-27&leg=1&trackLabels&timestamp=1651037307
3rd leg of the 27th, it works:
https://globe.adsbexchange.com/?icao=392ae8&lat=51.554&lon=0.986&zoom=7.0&showTrace=2022-04-27&leg=3&trackLabels&timestamp=1651055736

Could be they’re using the a 2nd transponder until the first one is fixed?
It was sending erratic values for some stuff on the way to Manchester.

Anyhow it’s an issue with that transponder.

[dvsvejk]

I’ve only been feeding since September 2021, but this scenario with AF flights has been something I have noted since then. A similar thing happened a few days before the example in my post. I did a backwards search on F-GKXI but it was not in my area at the time, so it was another AF aircraft.

Your theory about a broken transponder may be right. As I am writing this I see F-GKXC/392AE2 coming in to land at Arlanda. It too has a version 0 transponder, but heading is being displayed fine in SkyAware. Seeing as these two aircraft are 19 and 21 years old and running the original type of transponder, things breaking is probably a to be expected occurrence. Thanks for your research.

I see there is a EU mandate of 7 June 2023 for “ADS-B out” and upgrading of transponders. I wonder if AF and/or the aircraft lessor are simply milking these assets (repairing and not upgrading the transponders) and will put these aircraft out to pasture next year.

[dvsvejk]

Ha! I spoke too soon. F-GKXC just took off for the return leg to Paris and again no heading in SkyAware. Something is not quite right with these older AF aircraft.

[dvsvejk]

I’ve resolved this to my own satisfaction by narrowing the behaviour down to nine A320 delivered to Air France between 2001 and 2003 : F-GKXC to F-GKXK. (Some of these planes are currently parked and one flown by Czech Airlines). They all seem to have the old version 0 transponder type. Whenever one shows up in my area it is a toss up if the plane will show a correct heading or not in my local SkyAware view.

[wiedehopf]

@dvsvejk

They all seem to have the old version 0 transponder type.

Yeah but it’s not so much the ADS-B version but rather that their specific transponer model seems completely broken.
Seen plenty of v0 transponders that work nicely.