Flight ID Number - What to set.
 

Hi, I am looking for some advice from those that will know....

Apologies if this has been covered before, but I couldn't find it using search.

We have recently had mode S transponders fitted on our fleet. There seems to be some debate as what to set in the Flight Identification window.

When the flight number and callsign are the same, it is no problem, we set XYZ7285. (Where XYZ is the 3 letter designator for our company, and 7285 is the flight number).

This in accordance with the ICAO statement:

Aircraft Identification, not exceeding 7 characters is to be entered in
item 7 of the flight plan and set in the aircraft as follows:

a) The ICAO three-letter designator for the aircraft operating
agency followed by the flight identification (e.g. KLM511,
BAW213, JTR25), when:
in radiotelephony the callsign used consists of the ICAO
telephony designator for the operating agency followed by
the flight identification (e.g. KLM 511, SPEEDBIRD 213,
HERBIE 25).

However on some flights, like most operators these days, we sometimes use alpha numeric callsigns.

In this case, we are currently instructed to enter the flight number in the FID window, even though this is NOT what we will be know as on the RT.

So in the above example: I am operating the 7285, but my callsign is XYZ 36Romeo, and I have XYZ7285 as my flight ID.

Is this correct?

So in summary, what is the correct way to set up a mode S transponder if you callsign and flight number are not the same.

How does FID appear on the radar display, and what is it used for?

Many thanks in advance,

Brisbane.

You have to set the FID on the Mode-S transponder to exactly the same ID as indicated in the flightplan. Otherwise a match between the flight plan data and the Mode-S radar target is not possible for ATC. This is what the ICAO rules say. The commercial flight number is of no use for ATC.

There is a supervision unit operating in Maastricht that reports Mode-S faulty IDs to the European airlines (via the local authority) and asks to stop that. Around 20-30% of all FID transmitted by Mode-S transponders do not correspond to the flight plan ID these days.

Among the most popular missettings are:

Set the IATA airline code instead of the ICAO code, but with the correct flight id to follow
Set the correct airline code but a commercial flight number iso of a differing callsign
Set no airline code, but only a flight id
Set no ID at all
Leave the last flight's ID in place
Set the registration iso of full flightplan ID
Set some mix of aircraft type, registration (popular for business jets)
Set some awkward alpha crap

It's just to take your flight plan printout and transfer the few characters to the FID window one by one and ATC will be happy.

Threemiles,

Thank-you very much for your informative reply. Everything is much clearer now.

Cheers, Brisbane.