Suffix flight numbers

[Spitfire boy]

Help please from ATC ppruners about use of suffix flight numbers?

I note a recent posting on another pprune forum about what letters mean, for example P for a positioning flight. From an IT systems perspective I would like to better understand how common use of suffix flight numbers are as opposed to airlines using numeric flight numbers in an agreed sequence perhaps solely for positioning, training, air tests? For example Flight number XX123P v XX8000

Some airlines seem to make extensive use of suffix flight numbers whilst others may not need them. Is use of suffix flight numbers a mandatory industry requirement or do airlines do their own thing?

[FinDir]

I think there are some standard letters like the one you mentioned e.g.
P = positional
T = training
and in the case of Police flights
A / B = cat A / B high priority

Other airlines use them to differentiate between callsigns that otherwise may have been confusing e.g.
xxx879
xxx897Q

In the old days, Britannia used to have A for the outbound flight and B for the inbound flight. So there are many reasons, and not really any rules about it. But just because there may be a P, doesn't necessarily mean it is a positioner!

[timelapse]

D is often used for "Delayed" on scheduled flights if they are delayed by enough time that could cause the next day's flight of the same callsign to conflict.

[Reimers]

Operators use flight numbers to organize data for a great number of flights. Not all these numbers may refer to actual flights, there may be codeshare operations, train/coach or trucks running on a flight number.
Often, similar services may receive consecutive numbers, so that at first glance it becomes clear to an insider what the numers refers to. Also, in the past the flight number has been used as an ATC call sign.

This created the unfortunate situation that similar callsigns confused everyone on the airwaves, and as airlines operated more and more flights, the four digit spectrum availabe was used up entirely. Therefore, airlines started callsigns that no longer had anything to do with their flight number.
Of course, the software at airports had to be changed so that the display boards could recognize which flight the ATC data refered to when displaying ETA and such.

Flight numbers still tend to be numerical, as opposed to the alphanumerical callsigns. However, as you noticed, suffixes (spelling?) exist. They tend to be suffixed to diverted flights, positionings, additional services and so on. These flights receive suffixes so that both flights can later be recognized as belonging together. When they calculate whether a flight makes money, they can easily include the price of all the diversions as extra flights still have the same flight number.

[thorisgod]

I work in Shannon and every night at about 4 or 5 AM (when body and mind are in lowest ebb) during the busiest part of our day we used to get KLM602, KLM612, 622, 632, 642, etc.... all through the airspace within an hour of eachother, all trying to get to EHAM in the morning. It took about 2 years of petitioning KLM to get their callsigns changed. But it works.

Thorisgod

[Waterfall]

Same stuff with AFR342 AFR243 AFR432 :confused::\ And not only us but they confuse themselves-do they not realize that?:ugh:
On the other hand if u have BAW67AG /BAW5BW or similar callsign -try to say that guickly and several times....:rolleyes:

[chiglet]

On an everyday basis, the suffix "P" [Positioning] no longer exists. EG TOMxxP from Doncaster...and I have seen a "T" or two. On hols at the mo, but these are ok AFAIK :ok: