Requesting CAT II approach in CAT I Wx
 

I am new to this CATII/III stuff. We had a ceiling at 200 feet the other day on a CAT I approach at a slow arrival time of day. Landed O.K. but I was wondering if ATC minds if you request a CAT II approach to make more of a guarantee of getting in or does it create a bunch of difficulties for them due to extra procedures.

Maybe it is different at various airports or how busy it is.

Hi JammedStab;

CAT II/III have specific requirements which are different from "normal" ILS approaches, (ie, CAT I). Differences may include an ATC announcement that "Category two (or three) approaches are in progress", ILS LOC/GS transmission standards being assured to be CAT II, standby airport power is operational, airport traffic at/near the approach runway, in-trail distances for aircraft on approach etc. Likely ATC would not issue you a clearance for a CAT II approach if the weather does not require them and the airport is not deemed to be conducting such approaches.

You can practice CAT II procedures on any day on any normal ILS providing you're prepared to take over immediately if the autopilot isn't doing what is expected - there is the possibility the autopilot may do this due to the above standards not being adhered to if CAT II ops aren't in progress. Some OpsSpecs are silent on an autoland off an ordinary ILS but I would not encourage it as the guidance may not be suitable for autoland. However, it is good to practice CATII procedures as you may not see them for years. In 35 years I've done around five or six of them in various types for real and it is a remarkable process each time - I can recall brilliant sunshine until we entered the fog at around 100ft. The RVR was < 600ft, the autoland, (CAT IIIb) was on an A330...(the RVR equipment couldn't measure lower). It really reinforces trust in the autoflight/autothrust/autobrake systems. The trick was in finding one's terminal...

Here's one reference that may be useful: http://www.tc.gc.ca/media/documents/...ns/TP1490E.pdf

If Your company allows the use of monitored approaches, the situation You outlined (marginal Cat I weather with no LVP) would be a classic case for such a procedure: it is a Cat I approach to a Cat I minimum but offers a higher chance of completing the approach. In my company, the RP flies the approach to the minimum and challenges the LP at 100ft above it and again at the minimum - if the LP sees the required lights/other ground features at that point, he takes the controls and lands; if not, either he or in case of no response the RP calls a go around and RP keeps on the controls (except in some rare cases). This procedure allows the LP to adjust his eyes to the outside conditions and gives a higher chance of finding the required ground features.

Thanks,

The odd thing was that the aircraft ahead of us was cleared for a CAT II approach while we did a CAT I. But he was far enough ahead that I did not hear if they had specifically requested that approach.

If Low Visibility Procedures are in force at the airport (and they had to be, if the preceding a/c was cleared for cat II), you can do whatever category you are authorized for at that particular airport. You don't need specific clearance from the ATC for CAT I, II, or III

Requesting a CAT 2/3 due your assessment of the Wx is always an option. Most major airports in EU, certainly UK, will go LVO when cloud base or vis starts getting low. For UK I believe the standard is <300' or <1100m. Correct me if wrong. It makes commercial sense for ATC to avoid G.A's. If you are CAT 3 authorised why stop at CAT 2? It could be a/c type. What irritated me in Germany is when the Wx went 200' or 350m regional ATC declared the airport CAT 2. I asked if there was a problem with our destination, as it was a CAT 3 airfield. The reply was the Wx was only CAT 2 and so that was the status. Of course, when we asked the TWR for CAT 3 it was no problem as the protected area is the same. They had no method for downgrading CAT 1 to only CAT 2. It was CAT 1 or CAT 3. Just confusing pedantics for area control.
In my experience if the weather gets DH +100' or VIS = 150% RVR and CAT 2/3 is available why not request it. ATC have no reason not to allow it if traffic and airfield configuration allow time to organise it. Therein lies the rub. If possible call the airfield 15mins in advance.

You don't have to request anything.

If the wx requires LVP then the Airport ATC will activate it.

If you wish to do an Autoland in CAVOK then go right ahead remembering that the protected areas are not protected and its up to you to be ready to takeover as needed.

Some operators won't allow this practice ( stupid ) and some operators insist you advise ATC.

Whatever, it doesn't matter.

My company allows it to Runways that we have approved for Autoland.

In this case, there was nothing on the ATIS about CAT II or low vis procedures and we were never advised that this was in effect. But the preceding aircraft was cleared for a CAT II while we were cleared for an ILS approach.

If I understand correctly from the above posts, if the weather is a bit low such as at CAT I minimums, we are free to go ahead and use CAT II minimums but advise ATC about autolanding.

But DO remember that you only get the protection for the ILS if Low Vis Procedures haves been declared. As previous, you may get some very peculiar autopilot responses if a vehicle or another aircraft goes through the localiser or glide path beam.

I had our MD80 diving down showing above glide slope but looking at the DME and subtracting the 2 miles knew we were low so had my FO level off at DFW. We were on a Cat 1 approach so told them the problem and they said they didn't have to protect the approach until it got below 800 ft and 2 miles or so. I told them guess we need the localizer approach if that is the case from now on. A 747 parked next to the glide slope antenna and screwed up the glide slope signal. Of course I wouldn't do a localizer approach but how can the FAA authorize an ILS with bogus ILS transmitters?

No no no.

If the weather requires LVP then ATC "should" activate LVP proceedures and you go ahead and shoot whatever approach your company allows.

You cannot do a real CAT2 or 3 or 3B approach below CAT 1 minimas unless ATC advise "LVP IN FORCE"

However:-

1/ Some ATC may be a bit slow implementing LVP and you may need to give them a nudge.

2/ In weather above LVP you may within your companies allowable proceedures carry out an Autoland for the intension of practicing LVO procedures ( or not, you may just want to complete an autoland for any other reason )with the caveat that you must be careful as the protected areas are not protected.


Clear

It always makes me chukle when some Pilot asks ATC for clearance to do a "practice autoland"! What's a practice autoland? Is that where you manually land it but pretend the AP did it :E

Be careful if/when you come to Japan, Nitpicker. There is no clue that LVPs are in force (SSPs, as they call them) and certainly no announcement on ATIS, as would be sensible and in common with most of the rest of civilised world. They initiate LVPs when the weather falls below certain criteria, which one is supposed to know. It doesn't help that the criteria differ for different airports:rolleyes:

Fair enough, ill keep that in mind but I've Operated into Japan for the last 20 years and still do, I'll be right thanks!! :ok: ( so far so good !! )

Actually YMML RWY 16 is another one where ATC don't follow their own published rules. They advise LVP in force way above their LVP trigger points!!

Arrived a month ago with 400' ceiling and 2000m Vis to "LVP in force" on the ATIS..........:bored: Where as their own books say "when RVR deteriorates below 550m and/or cloud base below 200' RVR LVP in force will be declared"

They apparently will soon do it the proper way.....:cool:

Maybe I should ask the question differently. The weather is 200 overcast. CAT 1 approaches are still being used. Perhaps we are tight on fuel and won't have enough fuel for a second approach. We want to make sure we get in.

Is it likely that ATC will oblidge if we ask for low visibility procedures to be implemented for our particular landing if we want to make sure to get in. Maybe it depends on traffic and runway layouts, etc. Maybe it disallows other aircraft or slows down arrival numbers per hour. Has anyone requested this when the weather is at or near CAT 1 minima?

LVPs based on visability, not ceiling. It would be a hard stretch to have ATC establish LVPS to accommodate one arrival with adequate visability, especially at the busier aerodromes.

The practice auto lands are done at airports that are LVP approved.
In my previous outfit,coming september,before the fog season starts,crew were told to perform practice auto lands and record the result(touchdown point,any deviations..) so when the time arrived in real LVP the aircraft was legal and crew refreshed their procedures as well;-)

You can always try to ask a practice auto land:E

Don't know in Japan or in any country where there might be different set of rules, but according to ICAO, the atc is required to implement low vis operation for take-off, not for the approach, even if the majority of airlines, if not all, require them for approach either.

Jammedstab,

Lets try and clear some of this up.

Firstly ATC units trigger LVP's depending on Vis and Cloud base to better assure both take off and approaches. The trigger depends on differing National criteria but is typically less than 200ft cloud base or 600m for Europe. A low vis takeoff is less than 400m by definition. ATC are reluctant to give LVP if above these trigger values for one reason.....the effect on flow rate. (Money !)

I have on several occasions asked for LVP with cloud just above or on 200ft base with the answer being sorry no. It is totally unacceptable to shoot a practice Autoland to get under the 200ft if no LVP. There is a reason you have a published DA !
Ironically practice Autolands should only be carried out on a good clear day. A practice autoland with no LVP is an experiment every time. What is regularly overlooked by crews is the need to only practice autolands on cat2/3 approved ILS's. A Cat1 ILS is only calibrated to 200ft. Anything lower and an autoland approach is a leap into the unknown

In you're question, if you have a low fuel situation then you can declare a Mayday and im confident ATC would then give you the LVP assurance