Primarily for general aviation discussion, but other aviation topics are also welcome.
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By JonathanB
FLYER Club Member  FLYER Club Member
#1895106
I’ve been looking into the status of the Holyhead CTAs 19, 20 and 21 which are off the West coast of Wales, near the Lleyn peninsular.

They have bases of FL55, FL85 and FL145 respectively from West to East (in the order of the numbering) and are Class C airspace.

In the AIP there is a note which gives hours of promulgation to be basically 1800-0900 local, plus Weekends and Bank Holidays, but also says “during periods of availability of ATS Route L18 as detailed in the AUP/UUP.”

I know this won’t really affect GA much, but my questions are thus:
  • If you were flying this way to Ireland during the day, midweek would you consider the airspace to exist or not?
  • Can you plot a route using Skydemon from MEDOG to LIPGO for Monday lunchtime at FL150 and show me what it reports?
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By Iceman
FLYER Club Member  FLYER Club Member
#1895108
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I would certainly assume that the indicated Class C existed for any such flight.

Iceman 8)
Last edited by Iceman on Sun Jan 23, 2022 10:42 am, edited 1 time in total.
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By JonathanB
FLYER Club Member  FLYER Club Member
#1895113
Thanks, that at least suggests that SD treats it as permanently there!
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By James Chan
FLYER Club Member  FLYER Club Member
#1895189
They have bases of FL55, FL85 … I know this won’t really affect GA much


Those levels definitely affect GA. But I’ve transited through there before and Dublin are very accommodating.
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By JonathanB
FLYER Club Member  FLYER Club Member
#1895229
Thanks Cub, the bit we’re confused about (sort of) is the tactical use outside the times listed. I’m trying to work out if the airspace always exists or if it needs promulgation through the AUP/UUP process.
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By Cub
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#1895238
JonathanB wrote:Thanks Cub, the bit we’re confused about (sort of) is the tactical use outside the times listed. I’m trying to work out if the airspace always exists or if it needs promulgation through the AUP/UUP process.


I think you may be convoluting an airspace structure, it’s activation times and method of activation.

An airspace structure will be specified in the AIP and generally represented on a paper chart, obviously permanently, in that you can’t rub it off the chart during periods of deactivation. Of course, with the advent of electronic graphical depiction of airspace, that does offer the opportunity to not display a volume of airspace when it is not active, however, caution is generally advised in doing this when the activation method and timings may very from a published cycle.

So, in answer to your question, the airspace structure, as detailed in the UK AIP always exist but is activated and de-activated via the published timings or additionally through the AUP/UUP process. When deactivated the encompassed airspace of course, reverts back to it’s background classification of Class G.

Maybe easier to think of another example such as the Southampton CTR which is deactivated every night unless varied by NOTAM but the structure remains textually described in the AIP and graphically depicted on the paper chart H24 (obviously!) but also continues to be depicted graphically in electronic airspace depictions in various applications regardless of its activation state.

Finally, with reference to the Holyhead CTAs you mention, some process AUP/UUP or other, must generate a NOTAM to support additional activation outside of the published hours in order to safely activate the airspace.

I am sure your MATS Part 2 must contain a procedure to safely and robustly achieve this? ;-)