DH ceiling and minimums CAT II
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Join Date: Jan 2013
Location: Ushuaia - Tierra del Fuego - Argentina
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DH ceiling and minimums CAT II
We had a discussion between colleagues regarding the items in the title. If the weather report is RVR 550 - OVC 001 the airport is CAT I ?? ( DH not less than 200 ) or CAT II ?? ( less than 200 but not les than 100 ). Taking into account just the visibility, the Airport operates in CAT I but with the Ceiling its will remain CAT I or changes to CAT II? are DH and ceiling the same thing? can the ceiling be lower than the DH? is the ceiling a minimum ? FAA stands in the approach plates "CEILING REQUIRED" but what about ICAO? is there any ICAO regulation or document that clarifies this? thanks in advance.
Ground person here, not pilot. Cat I, II or III relates to particular approaches, not to the airport, and is generally related to the ground equipment that is available/working. If the airport has a Cat II/III approach available and the weather drops below that where a Cat I approach is likely to be successfully completed, then the Cat II/III approach will be made available - this is usually notified by the phrase 'Low Visibility Procedures in force' on the ATIS. Nothing much changes as far as ground equipment is concerned (except that back-up generators are usually switched on and may become the primary source of power for some systems), but ground procedures will change to 'protect' the approach guidance signals from interference and to reduce the risk of ground collisions. LVPs will typically be introduced at an airport if the RVR falls below 550 metres or the cloud base is below 200 ft aal, but some airports will have different criteria and may introduce restrictions in phases/stages. In my experience (mainly around Europe), RVR controls whether an approach can be commenced and, sometimes, continued below 1000ft, but at DH the only thing that matters is whether the pilot has the required visual reference. However, if a plate says a particular minimum ceiling is required, then I guess that's the rule - the national authority has the ability to stipulate additional limitations or requirements if it is felt necessary. Don't know if that helps......
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Agreed. At Heathrow we removed the cloud trigger for entering LVP quite a few years ago. We only consider RVR.
If the cloud is, for example, BKN001 then we will be safeguarded and ready to enter LVP immediately, and will do so if aircraft start to struggle to obtain visual reference before 200ft.
If the cloud is, for example, BKN001 then we will be safeguarded and ready to enter LVP immediately, and will do so if aircraft start to struggle to obtain visual reference before 200ft.
Last edited by Gonzo; 29th Jun 2022 at 10:46.
Agreed. At Heathrow we removed the cloud trigger for entering LVP quite a few years ago. We only consider RVR.
If the cloud is, for example, BKN001 then we will be safeguarded and ready to enter LVP immediately, and will do so if aircraft start to struggle to obtain visual reference before 200ft.
If the cloud is, for example, BKN001 then we will be safeguarded and ready to enter LVP immediately, and will do so if aircraft start to struggle to obtain visual reference before 200ft.
Not all flight crews were fully briefed on the change - the following day it was BKN at 150’ and one of the long hauls wouldn’t leave the hold until LVPs were initiated.
Initial refusals were met with the phrase “aren’t you down there to benefit us up here rather than the other way round?”
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’Twas ever thus!
I think we started warning airlines with at least 6 months to go to the change, and this change was originally requested by the airline community too!
Off the top of my head, it was raised at, and briefing packs I wrote were sent out to, the LHR FLOPSC, Heathrow airline station managers, the NERL ops group, the NATS SPA, BALPA, UK Flight Safety Committee, and IATA UK. I spent days at Waterside and T5, and Virgin crew report centre, and shotgun emailed any airline.
There’s only so much one can do. There was certainly no lack of information sent out!
I think we started warning airlines with at least 6 months to go to the change, and this change was originally requested by the airline community too!
Off the top of my head, it was raised at, and briefing packs I wrote were sent out to, the LHR FLOPSC, Heathrow airline station managers, the NERL ops group, the NATS SPA, BALPA, UK Flight Safety Committee, and IATA UK. I spent days at Waterside and T5, and Virgin crew report centre, and shotgun emailed any airline.
There’s only so much one can do. There was certainly no lack of information sent out!
