View Full Version : UK Conspicuity Code Change Over
flipster
28th May 2011, 15:43
For all you ATC historians out there - when did the UK mode 3/A conspicuity code change from 4321 to 7000? I believe it was c1993 but it would settle an argument if one could be more precise.
TVm
ZOOKER
28th May 2011, 22:32
Not the exact date, but '93 sounds close.
It was about the same time tat Manchester changed from flat-top displays to NODE. I can't recall seeing A7000 on a Plessey display. I bet I still have the SI amendment somewhere upstairs.
ATCO Fred
28th May 2011, 23:11
I get all misty eyed when London allocate a 4321 as an ORCAM squawk! I have got the original drawing that illustrated an article in Flyer magazine. The drawing is of parrots in 'plums' of the colours of the European countries (Squawking 7000 & 7001) and the UK Parrot squawking 4321. Also kept a copy of the original magazine article as well – when I find it (just moved house) I'll post a reply!
tori chelli
29th May 2011, 12:36
I validated in '88 using 4321 and moved jobs in '91 using 7000...so I reckon it was around 1990ish
Tori
ATCO Fred
30th May 2011, 23:07
I get all misty eyed when London allocate a 4321 as an ORCAM squawk! I have got the original drawing that illustrated an article in Flyer magazine. The drawing is of parrots in 'plums' of the colours of the European countries (Squawking 7000 & 7001) and the UK Parrot squawking 4321. Also kept a copy of the original magazine article as well – when I find it (just moved house) I'll post a reply!
Found them - just a quick picture!
http://farm6.static.flickr.com/5226/5778508252_f643e67a8e_b.jpg (http://www.flickr.com/photos/61922019@N08/5778508252/)
http://farm6.static.flickr.com/5308/5777964517_39c3e8274c_b.jpg (http://www.flickr.com/photos/61922019@N08/5777964517/)
The flyer article states the change will occur on the 5th March that year. The accompanying articles states preceding years 1990 & 1991. Therefore I conclude that the change took place on 5 March 1992. This would appear to be supported by the article here : level douglas | twin otter | capt speaking | 1992 | 0270 | Flight Archive (http://www.flightglobal.com/pdfarchive/view/1992/1992%20-%200270.html) which is dated February 1992.