Autoland question

[skelsey 765]

 

 

Now if I find weather to be below the cat I mins, do I need a special clearance to fly a cat II or III approach with ILS set on both receivers or do I need to advise the controller for the second approach?

 

I'd be interested to hear from those with better legal grounding than I on this topic, but this is what I would do.

 

Essentially, the question moves from being a technical issue to a legal and operational issue.

 

If you have briefed a CATI approach with a DH of xxx, then if you get to DH and can't see anything you must go around.

 

What you do next then becomes a question of what your airline requires for a CATII or CATIII approach.

 

Most that I am aware of would require the airfield to be in LVPs before conducting an actual CATII or CATIII approach. Certainly, the ILS must be safeguarded and the appropriate power switching done on the ground (backup generators fired up etc). So it would be sensible to advise the controller that your at CATII/III capable -- however, you will need to wait until the airfield has implemented all the appropriate safeguarding procedures before you can actually perform the approach.

 

Likewise on the T7 -- if the airfield is not in LVPs, there is no guarantee that the ILS backup generators are running, the ILS critical areas are protected etc etc, so you should only bug the CATI DH.

 

Once you have the appropriate safeguarding in place you can then perform a CATII or CATIII approach -- as far as I know most airfields once in LVPs will safeguard to CATIII standards (if available) so assuming you and the aircraft are qualified you would probably set up for a full CATIII rather than faff around with a CATII DH, possibly not get in and have to come back for a CATIII.

[kevinh 409]

 

 

This isn't true, unless it's specified in the OpSpec. You would want to be careful of autolanding in visual conditions as the controllers are not protecting the ILS critical areas, which means signal interference could be an issue. That close to the ground, you wouldn't want that.

It may not be required but surely you ought to declare you intend to make a practice autoland so that ATC can ensure the CAT II/III holding points are used.

[Budbud 227]

Most that I am aware of would require the airfield to be in LVPs before conducting an actual CATII or CATIII approach

 

So listening to ATIS "LVP in progress" would be the trigger to select a DH and setup for ILS cat II or cat III.

If not then remain with MDA and setup for ILS cat I?

 

I guess that the airport would then switch to LVP as soon as below cat I minimum?

[PHXMD-11 86]

 

 

From the passengers' perspective, every landing is an autoland.

 

Never a truer word spoken.

[downscc 1,327]

 

 

The CATs simply denote signal strength, clarity and reliability, to a particular certification standard

 

This caught my eye. I agree that reliability and performance are key factors in the category certification but was not aware that signal strength or clarity (which is a function of signal/noise ratio and hence signal strength) was a factor. I am familiar with flight checks from my career in the AF in ground communications-electronics (all the ground electronics at the airfield), but do not recall different flight checks for different categories. That is probably just my lack of direct knowledge, since I was ususally more concerned about gophers eating the coax from the PAR to the RAPCON LOL.

[Daniel choen 23]

[mgh 89]

At Heathrow the airport rules are:

Cat II and Cat III can be used subject serviceability of the required facilities by operators whose minima are accepted by the CAA and by serviceability of the required facilities.

Special ATC Low Visibility Procedure will be applied to Cat II and Cat III operations  Pilots will be infoemed when these are in operation by Arrival and Departure ATS or by RTF.
 

Also, at Heathrow training flights are not permitted. At other airports it will will subject to prior permission. ATC will not disrupt operations to ensure the CAT II/III holding points are used.

[scandinavian13 5,192]

 

 

On the NG, to set up for a cat I, afaik, you may set the ILS frequency on only one nav and course only on the corresponding side of the MCP.
Now if I find weather to be below the cat I mins, do I need a special clearance to fly a cat II or III approach with ILS set on both receivers or do I need to advise the controller for the second approach?

 

This one is best discussed by mentioning the concept of restriction. In aviation, the general rule of thumb is:

• If you are given less restriction, you can operate at your discretion at a higher level of restriction; but
• If you are given more restriction, you cannot operate at a lower level of restriction.

In other words, the weather permits visual operations, you can dial in and use the ILS signal as a guide, and many operators suggest or require this of their crews. You cannot, on the other hand, get cleared on a CAT III approach, and fly it using with only visual references.

 

More specific to your question, ATC will assign and clear people onto the appropriate ILS approach for the weather. Which CAT you can fly is related to your capability (as a crew, and as an airframe), and you would have to advise ATC if you were incapable if they told you to expect an approach that you couldn't fly. ATC doesn't have a master list of who can fly what (though they do have a general idea from working experience - plus, different aircraft in the fleet may not be capable), so they say "expect [X] approach," and it's up to you to advise if unable. The note of LVP in the ATIS (as Simon mentioned), notes that CAT II and III approaches are in use, and would be a good time to consider your options and prompt ATC if you were incapable.

 

 

 

For the T7, the setup is the same whatever the cat is except for the mins. But when picking up a mins MDA or DH should I automatically set the lower mins available or cat I and go-around if below mins?

 

Mins only matter if you can't see the ground. As soon as you see the runway environment, the concept of mins is moot. Regardless, set the mins for the approach that you've been told to expect and are cleared on. If it's a non-LVP day, then just set the standard ILS mins. If it's visual, then you don't need to set anything, even if you're using the ILS signals as a guide.

 

 

So listening to ATIS "LVP in progress" would be the trigger to select a DH and setup for ILS cat II or cat III.

If not then remain with MDA and setup for ILS cat I?

 

I guess that the airport would then switch to LVP as soon as below cat I minimum?

 

LVO is a little more specific than the mins alone. LVO/SMGCS plans are set up per airport, and each one has its own weather trigger. Just listen to the ATIS to determine if it's in those ops or not. Either way, you use the mins for the approach you've been told to expect (and modify it to the one you're cleared on, if necessary - rare, but can happen) once you check in with the approach controller.

 

 

 

Again, I must stress that weather days like this, in most of the world, are extremely rare. An ILS is going to be a standard (CAT I) ILS the majority of the time. It's the exceptional days where you fly CAT II and CAT III, and in those cases, flights usually end up getting delayed/cancelled until the weather moves on. The CAT II/III approach is used more as a "we're already in the air, the weather came in earlier than we'd planned, and we'd prefer to not divert somewhere else" kind of thing in most places. Additionally, approval for these types of operations doesn't come cheap (remember, SWA, and other operators use the HGS in an effort to sidestep the autoland requirement of CAT III, and the HGS is not cheap), so coming across the operation is even rarer, as there are fewer operators who are approved for it.

[Budbud 227]

Hi,

 

Thanks for the great explanations. I think my "problem" comes from the fact that I'm only faced to that kind of situation in a sim environment (IVAO) where most of the time you are provided with partial information (no ATIS when no ATC and sometimes fancy ATIS with human ATC...).

 

It happened to me several times to be well below cat I minimum and not to see any reference to LVP because the controller didn't specify it in the ATIS. In this case, I always wonder whether I should notify the ATC that I'm gonna fly ILS cat II or cat III.

Of course it doesn't really matter as the ILS signal is always perfect in fsx and never subject to interferences (which could be a great improvement in a future sim by the way).

But it is just in an attempt to get the most realistic immersion.

Sometimes I set up initially for a cat I and change to cat II or III while descending on the glide to avoid a go-around if I'm tight on the schedule. Sometimes I just go around and set up for a new approach...

 

I guess the change in configuration should not be done so late in the approach.

 

But most of all, I must be overthinking all this a bit because it's nothing more than a flight sim.

 

Flying VFR only in real life keeps me well away from these considerations!

What? My DR-400 is not certified cat III??? how possible is that!!! Ok, it is not even IFR certified... 

[gmoneyprs 2]

 

 

Never a truer word spoken.

 

Maybe not for long; I can only imagine some new a la carte options from Spirit, Frontier or Ryanair.

[Dave_YVR 968]

It may not be required but surely you ought to declare you intend to make a practice autoland so that ATC can ensure the CAT II/III holding points are used.

As a general rule ATC will not protect the critical area's for a/c conducting a practice autoland or coupled approach. Different separation standards exist as well when operating Cat II or III with respect to both arrivals and departures.

[downscc 1,327]

 

 

I guess the change in configuration should not be done so late in the approach.

 

Right, once established on an approach you are married to it until it fails then you go around. Don't marry more than one approach at a time.

[scandinavian13 5,192]

Kyle, thanks for answering. I couldn't agree more, we always have something to learn, I accept your comment. Definitely learned something new today. Also simmers are very upset when they discover their knowledge is limited. Thanks again for taking your time to answer, much appreciated!!

 

Glad to help. For what it's worth, I hold the same view of guys with other certs/ratings, too. I've just seen a few private pilots get cut out of the social circle for trying a little too hard to fit in, if you get what I mean, so I wanted to head that off just in case.

 

Each cert/rating group has its own type of behavior and related pitfalls. I don't need to know that you have one - just let the knowledge speak for itself (and asking questions may give away what cert/rating you have, but there's value in that humility, ya know?). We had one guy walk up at an airshow and show us his ATP for some reason. After he'd talked to us for a bit and left, we all kinda just sat there and tried to figure it out. Best we could figure out is that he wanted us to trust him and talk shop with him or something... *shrugs*

[Budbud 227]

 

 

Right, once established on an approach you are married to it until it fails then you go around. Don't marry more than one approach at a time.

 

Thanks for the precision. One bad habbit to give up. It won't be so hard as I don't switch from catI to catII/III everyday anyway!  :smile:

[skelsey 765]

 

 

An ILS is going to be a standard (CAT I) ILS the majority of the time. It's the exceptional days where you fly CAT II and CAT III, and in those cases, flights usually end up getting delayed/cancelled until the weather moves on.

 

Just for clarity -- it's worth mentioning that the reason flights end up getting delayed or cancelled in bad weather is rarely to do with the weather itself (i.e. pilots/airlines saying "we're not flying in that!"), and more to do with the impact LVPs have on airport flow rates. If you have an airport operating at capacity and all of a sudden you have to extend the final approach spacing for each aircraft by a mile or two as part of the ILS safeguarding, departing aircraft have to use different holding points and taxi routes and so on, you can very quickly rack up a heck of a lot of delay -- which inevitably results in some flights dropping off the schedule altogether.

 

As an example, at Heathrow the landing rate is ~45 aircraft an hour: if you put even one extra mile between those aircraft, you're looking at about 25 seconds extra per aircraft -- do that for an hour or two (and bear in mind the minimum separation will likely be much greater than just one more mile than usual) and you'll have hours worth of arrival delays. Ultimately this eventually leads to diversions (when aircraft in the air don't have enough fuel left to keep holding) and aircraft being out of position, which subsequently results in delays and cancellations all over the place (and in some cases literally all over the world as the tightly-packed schedules for aircraft and crews begins to topple, domino-like).