Cat iiia and iiib usage in UK
 

Just looking for clarity as a very experienced guy was trying to tell me that iiia and iiib are no longer valid terms in the UK (as in the USA). Our ops specs and the CAA AWOPS approval however still quote iiia ( unlike other established Boeing operators, we do not have iiib approval yet).

His view was that if the aircraft is ASA indicates land 3 then our visual reference requirement was only one light (my understanding is that this would only be the case if we were iiib approved) and, as we are not, require a visual reference of three lights even if the aircraft is fail operational?

I thought you needed 1 light if you had a DH <50' and no lights with no DH?

I have just learned that a/b is not a thing anymore (mere ppl here).

So do I, and as our ops spec sates cat iiia I don’t understand why he believes if we are fail operational with 50’ decision we need one light (irrespective of whether the UK CAA has abandoned cat iii a / iii b (which I don’t believe they have).

I guess if you have a DH then you need something on which to base a decision. Does anywhere still have 3B with a DH? If so it'll prob be in France.

I was only involved with autoland development and never with operation approval. The change in definitions came much later than my involvement but I did find this reference interesting -

https://www.regulations.gov/document...2009-0092-0242

Sorry wasn’t clear. Should have read “why ONLY needs one light”, I really believe we should be looking at three lights when the ops spec limits us to cat iii a with a 50’ decision.

Thanks, do you have another link that one has no content.👍

it has content to me

Cat 3a/b have been superceded by Cat 3 with/without DH. In addition, the RVR for Cat 3 with DH has been reduced to 175m from 200m. So your friend is correct. The required visual criteria at minima remain unchanged.

Can the approach be continued for a manual landing if the autopilot disconnects below DH in 'Cat 3 with DH' operations?

If so, then the lowered RVR requirements appear challenging compared with previous visual segment (distance seen) requirements - or are they retained - which accounted for different aircraft types - cockpit cutoff etc.