PPRuNe Forums - UK Conspicuity Code Change Over

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UK Conspicuity Code Change Over

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

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.

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!

I validated in '88 using 4321 and moved jobs in '91 using 7000...so I reckon it was around 1990ish

Tori

Quote:

Found them - just a quick picture!

[IMG]http://farm6.static.flickr.com/5226/...43e67a8e_b.jpg[/IMG]

[IMG]http://farm6.static.flickr.com/5308/...c3e8274c_b.jpg[/IMG]

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 which is dated February 1992.