Originally Posted by
TheOddOne
I'm sure we all understand how the code is used. A few pilots I've spoken to mistakenly think that because they're being allocated a code, they're getting a radar service, which of course they're not!
I think what Sam is asking is why 1177 was chosen, against any of a range of other possibilities. The real question here, is there a clever scheme working in the background where 1177 is a better choice for some reason or is it rather a random choice by a clerk just picking a spare code that has no more or less significance than, say, using 0013 for the Luton conspicuity code or down our way, Newquay having 17XX, Exeter 04XX and Culdrose 40XX? My guess is that there is no clever system, it's just random. It probably represents a convenient random gap in the groups of codes allocated to different ATC units.
Sam, we'll probably never know unless the person working in the office that allocates codes is reading this - odds against, I'd say!
It'll all get washed away when the UK mandates ADS-B OUT and IN - bring it on, I say.
TOO
Code assignments aren't done on a random basis, they have to be carefully chosen so that 2 different units operating (say) 50 miles apart don't get the same code block thus leading to confusion for other units as to who is working what aircraft. This applies to radar units operating either side of international boundaries too.