Does anyone know if there is a GOOD reason

[finfly1]

Yesterday I flew on United into KDCA and listened on ch9 (the ride report channel) and was struck by the overwhelming number of four digit call signs.

With mergers and flight cutbacks, I do not understand why 2 and 3 digit call signs have all but disappeared. If we are slave to puters, could it still not be possible to input 00 at the beginning of a 2 digit flight number?

It would seem to be far easier on controllers (not to mention old people taking three flights in a single day).

[HEATHROW DIRECTOR]

So are you suggesting that some callsigns could start with several zeros? Inputting leading zeros used to be possible but served little use. Often nowadays aircraft callsigns have a mix of numbers and letters, primarily to avoid callsign confusion when two flights occur at the same time with similar callsigns. Having used R/T for most of my working life I don't recall too much difficulty with callsigns whether they had one number or several, e.g. Clipper One through to Air Force 48913..

[DaveReidUK]

I do not understand why 2 and 3 digit call signs have all but disappeared

Actually, the majority of United's own flights are 1-3 digit flight numbers, with the low ones being mainly used on high-profile routes (e.g. UAL5 LHR-IAD). However 4-digit flight numbers are invariably used by commuter carriers operating UAL flights, with each partner having its own range of numbers.

For example on DCA-ORD, UAL's Airbuses fly as UAL207, 265, 287, etc, but on the same route UAL3461, 3463 and so on are United Express (Shuttle America) Embraer 170s.

[LoserGill]

Just as an example, Air Canada has 1-3 digit flight numbers however their feeder airline, Jazz, has 4 digit flight numbers. In my experience, the 4 digit ones of US carries tend to typically be the feeders, not the mother ship.

[cossack]

To aid in reducing callsign confusion with Jazz flights, a couple of years ago, the 8 at the start of the flight number (and if the 8 were followed by a 0, the 0) was removed from the ATC callsign but not the flight number. JZA8029 became JZA29 and JZA8666 became JZA666.

Just have to get to grips with those starting with 7 now:

JZA 7779, 7797, 7739, 7793, 7939 etc.

[obwan]

HD

The mention of Clipper One brings back such great memories of times gone.

[confused atco]

In Europe Eurocontrol from an ATC perspective have a project running to reduce callsign confusion.

The aim is where say an airline with callsigns AIRLINE-113 AIRLINE-123 and AIRLINE-133 all opereate in the same airspace then 2 will be changed.

Also they are looking at situations where AIRLINE1-333 and AIRLINE2-333 are also operating.

they are using a mix of alpha numeric callsigns and 3 or 4 digit to assist decluttering.

regards

[HEATHROW DIRECTOR]

obwan... indeed. I would love to be able to turn the clock back...

[Loki]

Then there was Sagittair zero zero one.

Raffles 1 springs to mind also....but back in those days 4 digit callsigns weren't exactly unknown....a lot of the BEA numbers had 4 IIRC.

[5milesbaby]

Speedbird 1, 2, 3 and 4 doesn't have quite the same thrill as it used to, and similarly Air France 001 and 002.

[scotbill]

Did once suggest that 4 figure callsigns should be pronounced as two numbers - eg "fifty one, fifty three" or "forty four, forty four" but the idea fell on fallow ground.

[Vercingetorix]

Clipper One
The one that got stuck in the mud one evening while taxying to the runway for take off at EGLL!!

[topdrop]

Did once suggest that 4 figure callsigns should be pronounced as two numbers - eg "fifty one, fifty three" or "forty four, forty four" but the idea fell on fallow ground.

Flight Number callsigns in Oz use this format. For 3 numbers e.g. 412, we say four twelve.

[Spitoon]

In Europe Eurocontrol from an ATC perspective have a project running to reduce callsign confusion.

There was some work done in the UK - a good few years ago now - but I think a lot of it is probably still relevant. I think it was published as CAP704.

[LoserGill]

I say that instead of numbers, use names

like this

...

[N90-EWR]

Clipper One memories!