CAT 2 Approach

[diana62s]

Hello I have a question.

Condition: You fly a bizz jet (I don't fly one, hypothetical). Cat 1 approved. CAT2 is in use according to ATC. (LVPs). You are not CAT 2 approved but you are LVP approved, for low vis take off. Weather is Ceiling 100ft, vis 2000m, vv50m.

Question: Can you attempt an approach?

I was thinking, normally for an ILS you only need the visibility (or RVR) wich in this case is is greater than required for CAT 1. But since LVPs are in force and according to ATC the CAT2 is use. Can you attempt the approach with your cat1 minima? Or only when you are cat2 approved?

Thank you.

[galaxy flyer]

FAA World, you can always take a look (FAR 91 operation), but most international rules have some approach ban rule requiring the CAT I visibility. In your case, with 2000m, why is ATC requiring CAT II, it's CAT I weather?

GF

[chevvron]

Horizontal and vertical vis don't matter, if they have Cat 2 LVPs they must be able to transmit RVR readings. In any case many suitably equipped bizjets are approved by their individual aviation authorities to operate to lower than Cat 1 minima ie 300m RVR instead of 550m RVR.
Depending on aircraft Category, takeoff RVR might be as low as 250m

[Denti]

If the airport has LVP in force it offers that service, but it doesn't require you to use it. If you are only CAT I approved and the RVRs are at or better than CAT I you can of course try an approach. Most airports switch to LVPs well before the CAT I minimum is reached. If LVP operation would forbid you from using CAT I minima, what would be the point if you can never reach it?

[diana62s]

Thank you for your reply.

@galaxy_flyer: I don't know why ATC decided to use LVPs, but sometimes if LVPs were in force and the weather improves they keep the LVPs for a little while.
@chevvron: In this case the jet was not approved for LTS (Lower than standard).
@denti: So if you are only CAT1, but ATC uses LVPs (and a CAT2). But your vis/RVR is fine for the CAT1 you are allowed to use the CAT1 approach?

I understand that if the vis/rvr is good enough you can fly / attempt an ILS approach. But in this case the questions is if ATC uses CAT2 and you have CAT1 if you can attempt one.

PS I fly under EASA regulations, should be more or less the same as FAA

[Denti]

Yes, LVP in force just means that the ground segment is now switched into CAT II/III mode, which means that protected areas are kept clear, the standby power generator is running and they can switch within the prescribed time to the standby transmitter and whatever other preparations they have to make.

It is not a requirement to use CAT II minima, but you can do so if you want to. Whereas if LVP weren't in use you couldn't use them really, as you cannot be sure that everything is up to CAT II standards on the ground.

You can of course hop over to the ATC Forum and ask them about it, but guess it won't differ much.

[diana62s]

@Denti

Thanks for your answer! Very clear. I thought the same, but wasn't sure.

[Denti]

Generally you are correct of course. However there are some airports that do declare something like "LVP CAT II in operation" on their ATIS. Or CAT III if the weather is even worse. I have seen that at pretty much every german airport. When asked, the ATCOs told me that there is no real difference between CAT II and III, but that they do not want someone to divert because he thinks he is required to use CAT III operation when he is only CAT II approved.

Which, of course, is funny, in light of this discussion...

[dbee]

apart from the minimum RVR being lower, the real differences with cat 3a are a minimum of 3 autopilots and roll-out guidance; Cat 3c has no minimum RVR

[Denti]

Different topic, we were talking about the airport side and legal/operational consequences of the airport announcing LVP CAT II ops in progress.

Besides, three autopilots are not a requirement for CAT IIIa, nor IIIb for that matter.

[diana62s]

@dbee: That is not really the topic here...

@LookingForAJob: Thanks! That clears things up.

@Denti: Funny you mention it. Because I opened this thread because a friend of mine had to Go Around because there were confused if there were alowed to do the approach. This resulted in a divertion. ATC told them the CAT2 was in use. So after this little discussion it is now clear they were allowed to attempt the ILS (and with the 2000m VIS probably able to land).

Thanks all!

[eckhard]

The only place I came across it specifically reported Cat II only available - as I recall it was because the terrain profile just before the threshold played havoc with the radalt.

Interestingly, Manchester 05L only allows Cat 1 and Cat3. Cat 2 is not allowed because the valley of the River Bolin is below the point where the rad alt would normally read 100ft and the rapid fluctuations of the terrain profile make an accurate assessment of radio height impossible.

By the time you were approaching typical Cat 3 DHs of 50ft, you were over the threshold and therefore the terrain (runway) was nice and flat again.

[Chesty Morgan]

apart from the minimum RVR being lower, the real differences with cat 3a are a minimum of 3 autopilots and roll-out guidance; Cat 3c has no minimum RVR

Sorry to perpetuate thread drift but that is wrong.

Embraer 195 are CAT3a capable but have one autopilot, some have HUGS and the approach is flown with no autopilot.

737 with two autopilots are CAT3.

There are likely many more examples.

[Meikleour]

eckhard: Asturias in northern spain used to have a similar restriction due to RADALT terrain profile on 24.

[parabellum]

Condition: You fly a bizz jet (I don't fly one, hypothetical). Cat 1 approved. CAT2 is in use according to ATC. (LVPs). You are not CAT 2 approved but you are LVP approved, for low vis take off. Weather is Ceiling 100ft, vis 2000m, vv50m.
Just wondering what your Cat One DH is? (You can still attempt an approach with the wx you quote as the RVR is well above Cat One and hope to get lucky! ;))

[Piltdown Man]

When performing a CAT I ILS, the airport's LVP and ILS category status is irrelevant. What counts is that the ILS is on and the reported RVRs (not cloudbase) are at or above your minima. Only when operating to less than CAT I minima are these things important. Then, assuming you have had the appriopriate training and the aircraft you are flying is appropriately equipped and certified to operate less than CAT I do these things matter. Even then, expect huge variations amongst various operators.

PM

[Denti]

And then there is that in-between thing of "lower than standard CAT I" ;)