Low visibility procedures

[static]

Can anyone tell me what the term "low visibility procedures" exactly means.
Does anyone have any ICAO references to the subject?

[Muppit]

LVP's is the combination of CAT II/III operations (BKN/OVC 200ft or below, or sky obscured, or IRVR below 600m) and runway safeguarding.

We can be in CAT II/III conditions, but if the runway is not safeguarded, then we're not in ATC LVP's.

I try to have as little to do with ICAO as possible, so can't help with an official definition....sorry

<img src="tongue.gif" border="0">

[Lew Ton]

Low Visibility Procedures are a set of procedures agreed between an aerodrome operator and ATC to support a desired movement rate in order that operations can continue safely. The procedures are then agreed with the Aerodrome Inspector (in the UK CAA SRG).

Although normally associated with Cat II/III they are not necessarily so. Basically the procedures are there to prevent unauthorised entry to the movement area, and in particular, inadvertent runway incursions.

I don't know about ICAO (it will be in Annex 14)but the UK procedures, in general, are in CAP168 Licensing of Aerodromes which is available here:

<a href="http://www.srg.caa.co.uk/pub/pub_publication.asp?Action=Cat&type=AED" target="_blank">http://www.srg.caa.co.uk/pub/pub_publication.asp?Action=Cat&type=AED</a>

It's a 2.8M file, I afraid. It's Appendix 2B you want.

HTH

[static]

Thanks, guys.
The reason I`m asking is that I`m in a bit of an argument with an ATCO in my homefield, who seems to be of the opinion that you cannot have low visibility procedures in operation without actually having an RVR below cat 1 limits.

I still would appreciate any reference to an ICAO annex about this. Especially the definition af the terminology "low visibility procedures" as used in R/T.

[NextLeftAndCallGround]

You'll find ICAO calls them Low Visibility Operations (LVOs), I think. There's also a manual - it's got an imaginate title, something like Manual of Low Visibility Operations.

LVOs/LVPs vary widely in detail around the world but, in the UK, are introduced to protect aircraft operations in conditions where either the controllers or pilots cannot see enough to ensure aircraft safety. As Lew says, it's not just for Cat II/III - at aerodromes without an ILS aircraft can usually depart in visibilities as low as 400m (it depends on runway markings and lighting facilities). When you get to visibilities where ATC or pilots can't see much it is inevitable that you'll be into Cat II/III ops if they are available so it is easy to blur the distinction between the two.


As I say, this is what happens in the UK - I don't think the ICAO manual is very specific and leaves a lot of the detail up to the State.

[Cryolosophorous]

STATIC.. you can go into LVP's if the official met. visibility falls below 1500m typically.Most RVR set ups ensure that the system commences reporting RVR's at 1100m or less. You can go into lvp's also if the cloud ceiling is 200' or less. This is an " AND" "OR" situation. ie you could theoretically have 5km of vis. but a cloud ceiling of 150'. Highly unlikely but possible. Does this help with your local tiff?

[Lew Ton]

It's a popular misconception that LVPs are only associated with Cat II/III. At Luton we didn't have LVP as such until we introduced Cat II/III (Oct 92) but once we wrote the procedures we always went into LVP before we got near Cat II/II limits. Now we have to be in LVP and the runway safeguarded by the time the IRVR has reached 800m, in practice we start this at 1500m or more, depending how quickly the vis is dropping. Or the cloud has reached 200ft. . . .

As afterthelanding says, you may need to be in LVP because the cloud has lowered to 200ft or below, yet the vis is still good below it. This is why at Luton we introduced a half-way house we know as Vis 2. We use the Cat II/III holds but all the taxiway cl lights are on up to those holds. We only start full twy routeing when the vis drops to 400m or less (what we call Vis 3.) [Vis 2/3 does not equate with Cat II/III.]

I haven't got an Annex 14 at home but I'll try and dig one out at work and see what it says.

[ 15 January 2002: Message edited by: Lew Ton ]</p>

[static]

Thanks again, this does help a lot.
There seems to be a lot of confusion in my discussion between LVP`s and Cat 2/3 operations.