Are we getting full ADS-B Data??


#1

In light of the recent Germanwings crash I’m curious as to whether we are receiving all the ADS-B data that’s available.

Aviation Week had an article showing what the Germanwings A320 was sending out in regards to what was selected in the FCU/Mode Control panel in the cockpit.

It showed the deliberate selection of lower altitudes to command the auto flight system to descend into the mountains, with the last altitude selected to 100’ in terrain of 6000’ mountains.

Just curious if it’s possible to receive the ‘extra’ data.


#2

Yes it’s possible. Not all aircraft transmit the same data though, and it depends what software you are using as to whether you can see it or not.

For example, in the map display of modesmixer2, if you select a flight you get a pop up window that gives all the available data. Looking at an Easyjet A319 flight, I can see the following data:

ICAO, Squawk, Track, Altitude, Speed, VSpeed, Lat/Lon, True Airspeed, Indicated airspeed, Mach number, Ground speed, Magnetic heading, Altimeter pressure setting, and FCU set altitude (this is the one referred to in the Germanwings flight). There is also weather data such as wind speed and direction and the temperature.

There are several other fields for parameters relating to the flight management system, but for most planes they appear blank. The exact parameters transmitted seems to vary between aircraft types and airlines.

I’m not sure what other software lets you see that data - Virtual Radar Server has quite a lot of fields you can add to the detail panel, but it doesn’t seem to include all those given in modesmixer2.


#3

Part of the difficulty is that much of that data is not spontaneously broadcast as part of an extended squitter; it is only sent in response to a ground query (a Comm-B response).
And the response data does not explicitly identify what type of data the response carries (after all, the ground station sending the query knows that).

So it’s quite dependent on what your local ATC happens to be querying, and whether it’s possible to guess the type of response from its format.

(This is one reason why you will sometimes see garbled callsigns from dump1090, FWIW - it is dump1090 interpreting something that looks like a response to a query for the transponder register that holds the callsign, but it’s actually some other message entirely that just happens to look similar)


#4

OBJ is correct. It generally varies among different ANSPs and locations and is also dependent on the operator. However, it’s definitely on the roadmap for FlightAware to add all available “extra” data to the flight pages, track logs, etc.


#5

i wonder if they also send transponder freq where they comunicate to the ground.