Easy226
The callsigns to which you refer have been discontinued for about two years now.
The UK2MS was formed from part of the flight number and the MS bit was for AMS or Amsterdam. On the way out it would have been something like UK2HX, with the HX part of BHX or Birmingham.
There were obviously quite a lot of combinations and the company found that there were callsign conflicts, ie. where the callsigns of two aircraft could be so similar to cause confusion, ie 2MS or 3MS.
Also, the controllers at Amsterdam started to get a bit smart-arsed about it all and started clearing aircraft to land such as "UK Manchester clear land 19R....Hello UK Edinburgh, you're number two, continue approach..." etc!
It was quite funny at the time but clearly unworkable. These callsigns lasted no more than two months. For the past two years we have used callsigns such as (for Birmingham) UK11M, UK21M, UK82S, UK52S and so on. This appears to be a bit more random and nothing at all to do with the flight numbers (UKA2041,2,3,4 respectively). These have been designed to avoid callsign conflicts with either our own aircraft or those of other operators. It usually works but can fall apart if the flight is delayed and is operated at an unusual time. As the controllers on this forum will I am sure agree, there are a lot of UKA aircraft flying at any one time as all of our flights into and out of AMS are timed to arrive or depart at more or less the same time...the so called 'Wave System,' which is necessary for our customers to transfer onto longhaul flights without four or five hour waits....ninety minutes is typical.
I hope this helps.
By the way, you may hear some slightly different KLM uk callsigns on en route ATC frequencies, such as UK9YL which are a bit more random than the old callsigns and have less conflicts. In this case, if it has two letters it will be a buzz flight, ie. a BAe 146 or a B733. These are operated by KLM uk employees. Unfortunately, you will not get these flights landing at Birmingham.
see
www.buzzaway.com for more information on our low cost airline, buzz.