Cat 2 in operation but Cat 3 actually flown
 

Well, the following situation happened today. Airport was reporting Cat2 operation in progress. On our charts the minimum for a Cat2 is 102`RA. My captain decided to use the Cat 3a minimum of 50`. I asked him, during the approach briefing if we are going to fly a missed approach if we having no contact at 102`RA. He denied, and said he would continue to the 50`RA minimum because the protection zones and separation would be the same.
Indeed the protection and separation is the same for a cat2 and 3 operation, but are we allowed to just ignore the cat2 "limit" and go straight to the cat3a minimum even though it is not officially in progress?

Thanks for any replies, I greatly appreciate it.

Check your co.ops manual, there should be a list of approved Cat2/3 airfields and runways, you should be able to answer the q from that.

But it's not just the weather which determines Cat II or Cat III. Maybe the ground equipment was not up to Cat III standard so it would surely be foolhardy to go down to Cat III limits??

If the Captain is visual at Cat2 limits then keeping the autopilot engaged is only limited by the minimum autopilot ht. This would apply in Cat1 or even a visual approach.

well the airfield is able to handle a cat3 operation. I later on called the tower and explained the situation. He said that the separation and protection zones are absolutly identical, the reason why he is not doing cat3 operation is because there might be airplanes which can just do a cat 2 landing. These airplanes could otherwise not fly the approach.( weather was below cat1 but not cat3)

nevertheless the question is, if you don`t see anything at your cat2 minima and you are equipped to fly cat 3 approaches, can you just go down these 50 more feet to the cat3 minima, even though the airport is officially not in cat 3 operation?

Absolutely a big fat NO GO.

The protection zones and ATC separation might well be, but there is absolutely no garantee that the LOC or GS deviation is within lCAO Annex 10 limits beyond the CAT II minimum point.

I know because it was my previous job to declare ILS CAT I, II or III a or b capable.

Most ATC controllers dont understand the matter...knob pushers too.

@ robinr200

thank you for your quick response. How does this work? Is there somewhere
a "switch" where you change the Loc and GS signal in a more precise signal? And if yes, do these signals somehow change when you have cat1, cat2 or cat3 in operation. If you could supply me with a little bit more information that would be great.

It's likely to be related to the accuracy/availability of the monitoring sensors. There are a number of reasons that a cat III installation may be 'downgraded' for a period.

We have procedures so that operations are safe - even if we don't know as much as Robin. If the ILS is declared as only able to support cat II approaches there is a good reason - and the aircraft crew should use the relevant procedures rather than second-guessing things about which they do not have all therelevant information. Same principle applies to controllers of course.

Why don't airports just say "Low Visibility Procedures in force" unless the ILS is downgraded, a la UK.

We recently had a diversion because the airport was giving cat III but the A/C was only cat II. The RVR's were above cat II minima but the Cap't did not think he was allowed to make a approach!:ugh:

<<Most ATC controllers dont understand the matter...knob pushers too.>>

I think that's a bit off-side, especially considering my response earlier!! Air Traffic Controllers DO understand and there's a lot more to the job than knob-pushing!!

cat2&3
 

hello,
in one of our airfield briefings we have, quote : "during LVP(Low Visibility Procedures), ATIS/TWR will report either cat2 or cat3 in operation according to limiting weather at the time, therefore a cat2 report does not necessarily mean a cat3 is unavailable but should be requested." end of quote.
B738NG operation.
bm.

ATC has absolutely no idea what capability your aircraft has in regards to CAT I, II, or III. Even the latest and greatest aircraft will have issues…..op specs, crew pairings, aircraft downgrade, etc. There (to my knowledge) is nothing on the “strip” to indicate aircraft capability for low vis operations.


Adding to the confusion…..recently approached an airport (US) advertising CAT I weather on the ATIS. We were in a Cat III aircraft going to a Cat III runway (no notams otherwise). It was going to be a tight Cat I approach, so we requested/advised we would like to do a Cat III. Controller said “you can do whatever you want to do”. I thought they had to enforce hold lines, check monitors, etc. for Cat III ops.

Any ATC out there who would like to address?

In the States, the ILS critical areas are protected to two levels. The first is in effect when the either the ceiling is below 800 feet OR the visibility is below 2 miles. In this case, ground vehicles are limited, CAT II/III hold lines are used, etc.

The second level is in effect when the ceiling is below 200 feet OR the visibility is below RVR 2000. In this case, the preceding aircraft must be clear of the ILS critical area before the following aircraft reaches the middle marker (or, in any event, where the middle marker used to be). This is specifically intended to prevent ILS signal interference from the preceding landing aircraft at a rather inopportune moment.

If the ILS approach that Shore Guy mentions was tight, it is likely that the ILS critical areas were fully protected. This is not quite the same as LVPs in Europe, but achieves the same goal with regard to ILS signal integrity. (Harmonization note: the ILS critical area in the US is parallel with the ILS sensitive area in the UK.) The controller's remark seems to me a rather rude but pointed reminder that he, the controller, doesn't tell you what is legal for your airplane and certificate and what is not.

Having said all that, I discovered a couple of years ago that the local government versus federal government battle in the United States extends right to our doorstep. At JFK, I am told that the Port Authority controls the ILS critical area protection, and they automatically initiate the procedures of removing ground vehicles and so forth when the weather crosses the appropriate threshold. The tower separates aircraft for the requisite spacing, but does not truly "control" the surface operations in this respect.

In terms of whether you can fly a CAT III approach when the tower says CAT II ops are in use...in theory, a ground equipment degradation should be either NOTAM'ed or included in the ATIS broadcast. For example, the ATIS at Stansted occasionally appends a comment at the end of the broadcast: ILS radiating Category I" which I suspect indicates the system is not fully monitored or some such deficiency. Absent any such advisory or NOTAM, and presuming that the runway is suitably certified and the aircraft and crew are also, there should be no reason not to execute a CAT III approach.

But as someone has said, the simpler solution is to simply ask whether the airport can currently accept a CAT III approach.

Yup...the Commander could have been absolutely correct.
Maybe.

It depends.
We are CATIIIA qualified, enroute to CATIIIB, in short order.
Type, L1011.
The gold standard (yes, even after all these years, the 'ole L1011 was CATIIIB certified, right out of the factory...:ok

Nothing finer.
Doubt?
Ask the folks who fly the aeroplane....:E

Why did I think we would hear from him?.......

Yes, the 1011 was ahead of its time, yadda, yadda....

But the controller does not know if you have a RA or ILS receiver out, or a high mins captain, no Ops Spec approval for Cat III, etc., etc.

That is my point.....a controller cannot look at the strip, see L-1011, and assume Cat III.

Well, because the Captain was wrong.

If a higher grade approach is available (e.g airport is CatIIIb capable) it should be available to operators capable of using it. It will safe-guard against sudden WX changes. But if the RVR is sufficient for the best approach YOU are capable of exisits (CatII in this cas) there is nothing stopping you commencing the approach to your minima.

As to the opening question, the opposite is also true. If only CatII is available, only to CatII do you go!

I think the airport was at fault in this case, if everything for CatIII was available, they should have said so.

Not only ahead, way ahead...and from about 1976 or so, with a Hamilton Sundstrand FMS that would knock your sox off.
RNP 01 if the software is updated.
First on a widebody jet transport.
Superb, even today.

But, to the original question.
No, the ATC folks do not know your particular status, this must be determined on the FD and actioned accordingly.

thanks for all your replies so far! Yes we should have better asked the controller about the cat3 status. Nevertheless we had already contact slightly below the cat1 minima.

CAT II/III minima are based on various requirements as well as ground equipment.

One being that Touch down zone lights are required for CAT III ops and not for CAT II.

Another is that center line lights are required every 15m for CAT III and every 30m for CAT II ops.

With that being said WK, the airport you landed at may have had the equipment that satisfy CAT II operations and not CAT III. Refer to the 10-1 or 10-9a pages of the Jeppys. Also, you Ops Specs may limit your operations to minima greater than CAT III regardless what is contained in the Jeppys. RA minima are set as appropriate.

Regardless of the technical requirements I'm absolutely certain you cannot fly to Cat lll minimums unless the airfield is declaring cat lll ops. There is nothing to stop you flying cat ll mins when cat lll ops are in place so the airfield controllers logic is backwards.