UK (civil) ATC absolute minima procedure

[ATCOJ30]

Has anyone reading this post been made aware of the UK CAA ATC Absolute Minima procedure on the RTF or heard of it elsewhere? It's been enshrined in MATS Part 1 (the UK CAA ATC manual for all civil ATCOs) for a couple of years now but very few commercial pilots that I've spoken to know anything about it.

The procedure is intended as a safety-net to stop pilots making approaches in very poor weather. It does not apply to approaches to runways that are equippped with a Cat 2/3 ILS. It does not give ATC the right to impose an approach-ban either, since the final responsibility rests firmly with the pilot.

Basically, regardless of what your Ops Manual says, if you commence an approach (definition: when you first accept radar vectors or leave the holding facility) and the RVR is below the published absolute minima for that approach aid, ATC have to warn you that you may be contravening UK legislation by continuing the approach and they will file an MOR if you then descend below 1000ft aal, when the RVR is still below that absolute minima figure.

It makes no allowance for what I believe to be an entirely legal procedure, whereby, irrespective of the RVR, you may continue the approach to the outer marker or 1000' or final approach fix (as appropriate) and THEN re-assess the RVR as you approach that point/level, if that is what is stated in your Ops Manual.

Comments invited please.

[keithl]

Yes, speaking for my own organization, we are aware of the procedure. In sim scenarios, I have always assumed that crews will proceed as far as 1000ft/OM or equivalent and re-check RVR, as you describe. Our Ops Manual only repeats the standard Approach Ban wording.
I must say, I have often wondered how ATC know when to start the spiel if they don't know (e.g. non-radar) how close you are getting to 1000ft. Or do you say "cleared for the ILS, not below 1000ft", or something?

[ATCOJ30]

Keithl: thanks for that. ATC are required to pass the initial RTF message, stating that the RVR is below the absolute minima for that particular approach and requesting your intentions when you declare an intention to commence the approach (defined as first accepting vectors for an instrument approach or leaving the initial approach/holding fix) and the RVR is below the absloute minima.

So, as an example, if the absolute minima for the Cat 1 ILS is, say, 700m RVR and you declare an intention to commence the approach with 600m RVR at that time, you should receive the spiel. If you then confirm that it is your intention to continue with the approach, you get the second RTF message, re. possible contravening UK legislation etc.

[411A]

Typical UK nonsense...tail wagging the dog, with regard to minimums, and aircraft landing.
In the US, it's...cleared to land if you have landing minima.
The pilot determinds same.
Not the turkey in the tower.

[Bright-Ling]

411A - as always a well informed post from you, you numpty.

Tail wagging dog???

Or tail protecting idiots making approaches........

Before this legislation came in I watched a 'N' registered aircraft approach in 100M RVR on a CAT 1 Loc/DME only to a runway with no centreline markings.

Unfortunately the lights he saw were the edge lights on the grass which he straddled perfectly until he stopped. (Thank heavens he was in a British http://www.stopstart.fsnet.co.uk/flags/uk.gif built biz jet so he didn't lose his undercarriage whilst transversing 5 taxiways at 90 degrees!)

Spot the turkey.

(These are published absolute minimas now defined by the aerodrome authority as part of its operating licence - not actually defined or determined by the controller)

ATCOJ30:

Yes - I appreciate what you are saying as regarding the confusion. I told a (foreign) pilot just yesterday it was below the absolute minima after electing to make an approach. He simply accepted it and diverted. I know not of any pilot who insisted they should make an approach below minimas. Having said all that, it is annoying that we have to make the legal transmission if needed.

B-L

[360BakTrak]

'Turkey in the tower'??? I think the term 'numpty' was a bit too polite Bright-Ling! I can think of a few better words!:)

[keithl]

Just to add (before this thread descends into namecalling like so many others) that pilots of course don't routinely read MATS, but the procedure was described in an AIC (49/2002) and that's how they should know about it. UK pilots anyway.

[411A]

Not only turkeys in the tower, there seem to be a few in big airways...recall the low pass over the Heathrow Penta hotel by a BA747 trying to land on 28R.

Approach 'bans' are certainly nothing new in the UK...and just as useless.
You would think that a country that pioneered CATIII would have more sense.All part of the nanny state (CAA) saying....we know better than you (the Commander).
'Tis called, backward thinking.
Nothing new in the UK.

[keithl]

Pleee-eze don't respond, 360 and B-L. We can all draw our own conclusions about 411A, from his words. I hate the way sensible discussions get hijacked by this sort of thing on PPRuNe.

[spekesoftly]

For the sake of clarity, I will reply to 411A's last post. If he would take the trouble to re-read the second paragraph of the first post, he should understand that 'Absolute Minima' do not apply to CATII/III approaches, nor does the procedure impose an approach ban, or remove the pilot's final decision.

[Bright-Ling]

Well said.

Actually it was 27R (I think that the pilot may have committed suicide a few years back) why do we let people like 411A join in with grown up conversation?

B-L

[604guy]

Just for interest, in Canada we have an approach ban. While not providing the exact quote the gyst of the regulation is: refering to CAT 1 approaches only, an aircraft may not proceed beyond the FAF with an RVR of less than 1200 (ft) unless it is a training flight and there is no intention to land. There is no spiel given to the crew, they are just advised of the current RVR with the expectation that the crew should be aware of what is stated in the CARs. If the RVR should go below 1200 after the a/c has gone by the FAF it is up to the crew to determine the course of action.

[Red Four]

Another aspect of Absolut Minima procedure that seems less than sensible to me, is that the AM for a Visual Approach is set at 800metres (Countrywide?), which is often less than the AM for the various VOR/DME, ILS, NDB, SRA approaches at the same airfields.

In times of low vis, surely we should be encouraging aircraft to make a 'proper' instrument approach, rather than encouraging a dirty dive for the runway to be made at the first call of 'visual'? However with the 'proper' IAP absolute minima often above that of a visual approach, the reverse often seems to happen.:(

[411A]

Ah yes, the 'visual approach' in the UK.
Another bit of complete nonsense, as Red Four has indicated.
More backward thinking.

The UK CAA has had a few good ideas...just not very many, or often.

[ATCOJ30]

I'm beginning to wish I hadn't started this thread! Thanks to all (well, nearly all..) for the comments. Interesting one about the visual approach AM too vs. instrument AM.

I think "duty-of-care" comes into this whole issue and I know that is highly contentious with ATCOs and pilots alike. In this particular, matter, just how far should ATCOs go in offering info/advice to pilots to stop someone making a smoking crater in the ground (or worse?). Personnally, I don't have a problem with the principle behind the AM procedure or even in the imposition of a weather-related approach ban, but it's the wording of the MATS 1 SI, the assumptions made therein, the anomaly with the JAR approach procedure for pilots, the required timing of the RTF messages and the contradictory nature RTF messages that irks me. Still, there you go....

[Daysleeper]

An interesting thread, pity its been a bit hijacked.

It brings up 2 points. The first is that when it comes to prosecution, it is much easier to play an atc tape to a jury which clearly shows (sounds) the pilot being told what he is about to do is illegal, than it is to try and explain the intracies of an approach ban.

The second being that , having just come across the worlds first CAT3 turboprop in France recently, it is not such a bad idea and I think I can see what the feds are getting at.

ATCO330, the decision to continue or not has to be made by 1000' or final fix as appropriate , ie you cannot go below that point, unlike decision height where you make the decision at DH but the aircraft can descend below during the go around.

So for those who don't value their lives enough, try to value your licences, simple really.

[Miserlou]

I thought that one had to have the required RVR (or converted metviz in it's absence) before leaving the the IAF and that one may continue only to FAF or 1000' if the RVR falls below this after starting the approach.

Regardless, does anyone have a link to the document in question?

My advice is to ignore 411a. I've never known him to have anything worth saying.

[Daysleeper]

Miserlou

you can start an approach in any conditions but can only proceed beyond the final fix or equivalent position unless you have the required RVR. Once beyond Final Fix you can continue to DA regardless of changes to RVR, though obviously it may be better not to if the vis is dropping rapidly

[411A]

Likewise for the USA, Daysleeper, except that the private operator has no such restriction.
This does not mean however, that the private operator, having passed the FAF, and received an RVR that is below landing minima (for the particular class of aircraft) won't get a letter from the FAA, asking for an explanation.
If the explanation is...I had landing minima at DA, then all is well, provided metal isn't bent....or one wandered off into the weeds.

The FAA relies on the competience of the pilot to properly execute an instrument approach, and go-around if the runway (or runway environment, approach lights etc) are not in sight at the appropriate time.

It may well be that the UK CAA has no such confidence, (and who could blame them, from some of the misguided comments here?), from those that may simply lack the skill and ability to properly fly an instrument approach to minima, and thereafter land or go-around as required.

[Bellerophon]

411A

...the competience of the pilot...

People might just pay slightly more attention to your comments about "competence" if you could at least manage to spell the word correctly. ;)

Regards

Bellerophon

[bookworm]

The FAA relies on the competience of the pilot to properly execute an instrument approach, and go-around if the runway (or runway environment, approach lights etc) are not in sight at the appropriate time.

It may well be that the UK CAA has no such confidence from those that may simply lack the skill and ability to properly fly an instrument approach to minima

Rather, I think, that the CAA lacks confidence in the superhuman powers of pilots who are wilfully unable to distinguish between the phrases "in sight" and "probably there somewhere". :)

A ban on descent below minima is extremely difficult to police. The absolute minima procedure is at least enforceable. I make no judgement on whether it's a good thing or a bad thing overall.

[411A]

Well Bellerophon, if the best you can do is point out small spelling errors, perhaps the logical place for you is in the 'misguided' camp...:yuk:

[eyeinthesky]

An interesting point arose somewhere in the mudslinging started by our contributor from across the Pond.

The approach ban in the UK applies equally to landing traffic as it does to training. This seems a bit daft, as if you are practising instrument approaches and intend to go around at DA then why do you need to worry about the RVR for landing, provided you can fly back to an airfield where you can land?

With regard to:
'The FAA relies on the competience of the pilot to properly execute an instrument approach, and go-around if the runway (or runway environment, approach lights etc) are not in sight at the appropriate time.'
That'll be why there are several fatal accidents every year in the USA where these 'competient' (sic) pilots failed to fly the approach properly or failed to go around when they should and ended up in a smoking hole. How many of them would have continued or would still be alive if they had been warned of an FAA investigation if they commenced the approach?

I'm not in favour of over-regulation, but must agree that if the rules are restated and clear-cut, then you've only got yourself to blame if you break them and have to face the music (or your Maker) as a result.

[Tinstaafl]

The risk factor throughout an approach varies depending what part of the approach the aircraft is in. The overall safety is dependent on the combination of all the parts and is predicated on a successful conclusion to the approach ie a landing.

A missed approach is a different matter. Increased risk. Just look at the minimum terrain separation that is provided: only 100'.

I think the reasoning behind approach bans is based on the statistical safety for approaches ie preventing a high likelyhood of a missed approach.

[411A]

Tinstaafl,
Ah...how can a missed approach (ie: overshoot) be considered any more dangerous than the instrument approach that it follows?
Seems to me both are normally approved maneuvers, for which no 'emergency' is declared.
Both are trained for in the sim, both are accepted in normal line operations, even with one engine inoperative...(talking transport aircraft here).

Yes, suspect we have noticed both rather poorly done (sim and line) yet they require no special qualifications, beyond the stipulated license of course.

[Tinstaafl]

I saw a publication (from Oz CASA? An AIC perhaps? Can't remember) outlining the design of instrument approach procedures & giving the risk factors for each segment of an approach. The missed approach had the highest factor. I'm pretty sure the publication stated that the overall risk for xyz approach was predicated on concluding with a landing at the end of it.

It was years ago when i saw it & I don't have it any more so I can't refer.

The man to ask would be OzExpat. He designs approaches for a living.