IMC minimium

[Fuji Abound]

"The limits for an aproach for an IMC holder are what ever it states on the approach plate +px error corection (if any)."

I noticed this comment in a previous post. The minimium for IMC holders use to be more cautious than for IR holders. What has changed and is it a good thing.

[Send Clowns]

The way I was told during my CPL (allows privileges of an IMC - I never had a UK PPL let alone IMC) the legal minima were the same as for an IRed pilot - i.e. what you quote. The recommended minima were somewhat higher, and it might be considered foolish to ignore CAA SRG recommendations.

However, I have been corrected here on this before, so would like a definitive answer with reference if anyone has it. I have given up trying to find information in CAA online documentation. This will allow me to speak with authority if asked once I am a flying instructor.

[SimJock]

In the IMC confuser and what I plan to use in the forthcoming exam are:

Precision Approach - Plate MDH + 200 + 50 PEC or 500ft aal whichever is greater

Non Precision - Plate MDH + 200 or 600ft aal whichever is greater

Have these changed then ?

[Keef]

SimJock

Those are the same numbers I learned for my IMC, long ago.

BUT ... the "recent" wisdom is that they are only "recommended" increases to the minima on the plates. The inference is that you can, in theory, legally continue down to the IR minima.

I suspect that may "technically" be right, but I'm not sure I'd advise it. You need to be very current to handle an approach to IR minima in real IMC.

Having done some ILS and NDB approaches today (under the hood) to keep my FAA IR current, I can tell you it ain't easy even if you are pretty current.

[distaff_beancounter]

I understood that it is the minima, for an IR rated pilot PLUS 200ft, with an absolute minimum of 500ft for a precison approach & 600ft for a non-precision approach. This is for an IMC rated pilot in current practice, which is defined as having done an instrument approach in the last 28 days.

As a semi-competant IMC rated pilot, (who does take regular practice of IF with an instructor, when rusty), I would not go below the above limits on my own.

BUT, as Send Clowns, asks, if this just the recommended limits or the LEGAL limits for IMC rated pilots? In all the CAA paperwork that I have seen, it is not really clear. :confused:

PS. Just had a look in LASORS 2002, but that just seems to say that for an IMC test or revalidation, the candidate must make a let down & approach to "Decision Height", but does not define DH, so do we assume that the IMC test is down to the SAME minima as the IR test? Now I really am confused
:rolleyes:

Mind you, the examiner who did my last IMC revalidation (in a twin) made me do a procedure ILS, assymetric & down to IR minima, but I assumed that is just 'cos he is sadist, who likes making me work hard :D

[SimJock]

AIP Aerodromes Section 1.1.2 Aerdrome Operating Minima Item 3.3.3 contains the relevant text.

http://www.ais.org.uk/uk_aip/pdf/ad/30101.pdf

although it 'recomends' adding 200ft to the IR DH the absolute minima is still 500/600ft. Earlier on in the document, calculated minima are said to be mandatory.

[GoneWest]

Had a "one to one" discussion on this very thing with an inspector from the CAA a couple of months ago.

A local ATC were getting p****d off by IMC students suddenly doing the go araound at almost two miles out - screwed up their plans for the aircraft behind.....and the guy ahead in the training system who is usually turning back to have another go.

CAA man said, quite categorically, that the 500/600 is RECOMMENDED not mandatory - and continued approach to plate minima is perfectly acceptable.

Personally, I disagree - and always went with the 500/600 idea.

BTW - Simjock....when you do your forthcoming exam, try not to use the phrase

Precision Approach - Plate MDH + 200 + 50 PEC or 500ft aal whichever is greater

A precision approach does not have an MDH.

[distaff_beancounter]

GoneWest Your post has just raised another question in my mind. :)

The initial IMC training that I did, plus refresher training since, for instrument approaches, has all been down to IR minima.

I assumed that this was for 2 reasons.

Firstly, it avoids annoying the ATC, as you mentioned, by go-arounds from 2 miles out.

Secondly, it makes the training far more useful, from my point of view. If I can fly an ILS down to 250ft fairly competantly, with an instructor, then I feel reasonably confident to do it down to 500ft on my own.

SO, what minima, do most IMC instructors teach to? :confused:

[englishal]

I'd take it down to minimums myself, especially if I wanted to get on the ground to go to the pub...:)

EA

[Romeo Romeo]

It looks like the document has been moved. I found it at http://www.ais.org.uk/uk_aip/aip/pdf/ad/30101.pdf section 3.3.2

It states:-

Pilots with a valid IMC/Instrument Weather Rating are recommended to add 200 ft to the Instrument Rated pilots' DH/MDH, but with absolute minima of 500 ft for a precision approach and 600 ft for a non-precision approach.

Now, the question is, what is recommended? I think it can be argued that everything after the 'recommended' is just that - i.e., it is only recommended that the absolute minima is 500/600 ft. If it is mandatory, then why wasn't it written:-

Pilots with a valid IMC/Instrument Weather Rating have an absolute minima of 500 ft for a precision approach and 600 ft for a non-precision approach and are recommended to add 200 ft to the Instrument Rated pilots' DH/MDH?

However, perhaps the point is that to get this low you must be current at getting this low. Certainly when I did my IMC and subsequent renewals, my decision height was based on this recommendation.

[distaff_beancounter]

Romeo Romeo Thanks for finding the very wording that was the subject of much dispute, at our local flying school, between, instructors, PPLs & students, on a Saturday morning, when it was TOO foggy even for IMC practice :)

The dispute being:-

Does the "recommended" ONLY relate to the first sub-clause "to add 200ft....." ?

Or does the "recommended" ALSO relate to the second sub-clause "but with an absolute minima of 500ft......" ?

Or, does the second sub-clause stand on its merits, & therefore the "absolute minima of 500ft......" means just that, so it is the LEGAL minima for IMC rated pilots ?

Now what we really need is a nit-picking pedantic flying lawyer, or just clarification from the CAA-SRG would do, please :confused:

[FormationFlyer]

Hi folks,

Well as an IR holder (and previous IMC holder) as well as an instructor i think the privilages & minima are quite clear.

You must remember that obstacles on the approach and in the surrounding area may case the plate minima + 200' to be HIGHER than your 500/600' minima...therefore it would be prudent (and hence recommended - not the wording) to ensure that you are above the IR minima.

The minima is...

The highest of:

1. 500' precision, 600' non-precision
or
2. OCH + PEC (precision) or OCH (non-precision)
or
3. circling minima if the intended approach will not land on the instrument approach's runway.

It is recommended that you add 200' to no.2 due to the nature of the difference between IMC & IR training. The reason the wording is the way it is, is that take RAF Brize Norton, precision approach gives something like 280' dh from the plate + pec. +200 to this - still means you only get 480' - therefore you can only fly to 500'.

The only time with an IMC rating you could legally fly to approach plate minima (+PEC) is when no2 above comes out at 500' or above on a precision app, and 600' or above on a non-precision.

In all cases extreme cold temp error corrections should be applied to the result.

I hope this clears it up.

FF

[FormationFlyer]

Oh yes - forgot to mention - with an IMC rating your are also limited to an RVR of 1800m minimum - or the approach plate minima if higher.

Even an IR rated pilot on an SPA must use 800m or the approach plate - whichever is the higher.

And also its illegal to descend below 1000' aal if your minima is not met/exceeded according to ATC/ATIS information.

Hope this helps,
FF

[Romeo Romeo]

The more I look at it, the more I think that the whole sentence is a recommendation. They could have made it clearer by reiterating the 'recommended' word in the second part of the sentence, but probably thought it was overkill. Certainly, if the 500/600ft rule were mandatory, then it could have been written to indicate this as demonstrated in my previous post.

I think the 1800m RVR is definitely mandatory although I can't find the reference to it in the AIP.

[StrateandLevel]

The legal minima is the System Minima. For practical purposes in light aircraft even IR rated pilots do not use this because their altimeters are uncalibrated, they add PEC.

The AIP advises IMC rated pilots to add the prescribed heights to give the minima you are all quoting. The Law however does not prescribe these additions, so unless you come below the system minima you are not illegal. To find out what is legal just read the ANO.

Common sense dictates that pilots scale their minima to match their experience. Hopefully we don't need laws to enforce common sense.

[Romeo Romeo]

Thanks for that S&L. From what I remember, the only document concerning flying which is enshrined in our laws is the Air Navigation Order. However as you also state Common sense dictates that pilots scale their minima to match their experience. Hopefully we don't need laws to enforce common senseand if you get it wrong, it carries an immediate death penalty!

[englishal]

"And also its illegal to descend below 1000' aal if your minima is not met/exceeded according to ATC/ATIS information"

Is this right? If so its a JAR thing. The pilot could still commence the approach, down to minimums, but once minimums are met then miss approach had to be performed....at least this is what the FAA state...

Cheers
EA:)

[QNH 1013]

FF, Just a small point but the "approach ban" preventing you from descending below 1000' aal only applies to the RVR and not to the cloudbase. It is still legal to make an approach if the reported cloudbase is below the DA or MDA (actually DH or MDH) but not if the RVR is below the required figure for the particular approach.
My reading of the 800 RVR limit for single-pilot operations is that it only applies to public transport flights. However, the CAA have said in the past couple of years that it applies to all flights. How this can change without a change to the ANO is beyond me. It is also odd in that most single-pilot approaches are made in cat A aircraft with a much lower threshold speed than most public transport approaches.

RR, I have a feeling that the 1800m RVR is a licence restriction for IMC holders rather than anything else. My ANO says that a PPL without any ratings must have a min visibility of 3km (outside controlled airspace).

[StrateandLevel]

Whilst a particular action may not be illegal, don't forget Articles 63 and 64. Endangering the safety of an aircraft and of any person or property.

Your actions must bear a test of reasonableness under the prevailing circumstances.

[distaff_beancounter]

FormationFlyer & Strateandlevel Sorry fellas, but I am now even more confused :confused:

I agree totally with FF's posting, & I do not fly below the limits that he set out, 'cos I know the my capabilities & I have a strong sense of self preservation :D

So, for example for an ILS, where OCH + pec = 250ft,

then my recommended minimum is the HIGHER of 450ft or 500ft, = 500ft

But is my LEGAL minimum .... 250ft or 450ft or 500ft?

Also for FF - as you are an instructor, could you confirm whether the CAA requires you to test IMC candidates down to the legal minima for IR holders, or the recommended (or legal?) minima for IMC holders?

Thanks for your help guys :)

[andrewc]

In the IMC test, the minima flown to are to 500' precision,
600' non-precision - assuming lower airfield minima.

While training my instructors would take me to 250' on
ILS approaches, where it gets significantly harder as the
beam width shrinks.

-- Andrew

[StrateandLevel]

db

Your minima is 500 feet as this is the recommended procedure for IMC rating holders unless you are not current (28 days) when you add another 100 ft!

Don't confuse Standard Operating Procedures with the Law.


Andrew is quite right.

[Keef]

Lots of good argument, but doesn't anyone know that "minima" is the plural of "minimum"?

Keef - in pedantic mood.

[Send Clowns]

Englishal

It is correct - you may not descend below 1000' on your approach until the RVR or visibility is above your minimum. That is ICAO law, as taught in the ATPL syllabus, and I believe incorporated into JARs.

My understanding is that the assumptions here that the extended RVR minimum for IMC-rated pilots is a mandatory limit is correct - this one is not a recommendation, but a requirement.

[Fuji Abound]

:) Having posted the question, and now read the ANO, it seems to me the most likely interpretation is that BOTH the recommended height addition to the minimum for IMC rated pilots AND the absolute minimum for IMC rated pilots are recommendations, but it would be legal for an IMC rated pilot to operate to the same minimum as an IR holder. In addition it would seem IMC rated pilots need to be aware of an RVR minimum of 1800m, somewhat higher than that for an IR holder.

Commonsense may well dictate otherwise, but my impression is that very many IMC holders believe their legal privileges are different from IR holders.

[slim_slag]

send clowns

you may not descend below 1000' on your approach until the RVR or visibility is above your minimum. That is ICAO law, as taught in the ATPL syllabus, and I believe incorporated into JARs.

In which case the FAA is in breach of ICAO laws.

FAR 91.175(d)Landing. No pilot operating an aircraft, except a military aircraft of the United States, may land that aircraft when the flight visibility is less than the visibility prescribed in the standard instrument approach procedure being used. It doesn't matter what RVR is reported (if it is reported at all), you can descend to 200 ft on the ILS to have a look-see for yourself what flight visibility is. How can you find out what flight visibility is if you cannot go below 1000ft to look? ATC definitely don't know what it is, they might not even be able to see if it's cloudy outside.


There are several minima relevant for an approach. If you bust one you might just die, bust another you might just lose your licence. I think this thread is trying to identify the latter, but I'll be damned if I have read an authoritative answer :)

Why are people so worried about upsetting ATC by flying the missed at "two miles out"? It's a valid flight profile, ATC should be prepared for it at any stage, and should separate traffic accordingly. Do you pay for a practice approach in the UK? If so, ATC should be nice to you, the paying customer. If they don't want you to fly the published missed procedure, what is wrong with them just saying "fly runway heading", politely of course?

[Chilli Monster]

Why are people so worried about upsetting ATC by flying the missed at "two miles out"? It's a valid flight profile, ATC should be prepared for it at any stage, and should separate traffic accordingly. Do you pay for a practice approach in the UK? If so, ATC should be nice to you, the paying customer. If they don't want you to fly the published missed procedure, what is wrong with them just saying "fly runway heading", politely of course? I quite agree. It might be worth pointing out here that the ATC getting annoyed comment was made by someone in Florida though ;). Yes, you do pay for practice approaches in the UK. UK controllers will, on the whole, give you your missed approach instructions in good time and will issue those based on procedural (9 times out of 10 vertical) separation. An early missed approach shouldn't therefore pose any problems.

CM

[sharpshot]

I can understand the need to be sure of your minima before you go for your IMC renewal and of course to have a darned good idea when doing your pre-flight planning.

But it sounds like a lot of you actually want to go off on days when conditions are going to get marginal and may actually be below your minima when you are making your initial approach.

Perhaps those that suffer from "Get home itis" whatever the cost should not get airborne if they cannot be sure of getting back to terra firma within limits. There's always another day when the sun might shine.

By the way, ATIS information usually gives met visibility, not IRVR's. IRVR's may fluctuate, with values being above your minima as you commence an approach which could easily dip below as you get closer.:eek:

Question: Nobody has mentioned continuing their approach at MDH for a short duration just in case a gap appears??

[bookworm]

I agree with Fuji Abound and RR's interpretation of the AIP. The word absolute is an antonym of relative or incremental, not recommended. I can't find any other sensible use of the word in which it means mandatory.

Note of course that the 1800 m flight vis for take-off and landing is mandatory. See ANO Schedule 8 B.

[eyeinthesky]

Sharpshot: You can ask for RVR values at any time, but ATC might not actually be recording them (if there is no IRVR equipment they need to send a bloke out to a designated spot by the runway to count runway lights..) above certain met visibility. If the reported visibility or RVR/IRVR values meet your minima then you can legally descend below 1000ft QFE and follow the approach to DA/DH/MDA/MDH as appropriate. If you get down there an can't see anything, then you have to execute the missed approach. Beware of being caught in the trap of being able to see the lights and land and then finding the official RVR is below the airport minima. Then you'll be in trouble!!

Your question about going to MDH/MDA and flying level is quite OK, provided you start the Missed Aproach no later than the Missed Approach Point (shown on the approach plate). Indeed, some people advocate descending to MDA/MDH fairly quickly after passing the FAF and flying level until you either see the lights or whatever or until you reach MAP, whichever comes first.

Remember, however, that if you are on a precision approach, you must commmence a Missed Approach IMMEDIATELY if you reach DA/DH and do not have the required visual reference to land.

[sharpshot]

Eye in the sky:

Thanks, I like where you are coming from!

I just happen to work & fly at well equipped airfield....have never actually had to go and count the lights at 60m spacing...yet!

On the occasions we have lost the transmissometers, and it's always in the middle of winter, we have to have good vis for hours to re-calibrate. Remember we lost a flight on Christmas day once because we could not give a midpoint value!!

Point taken about going round from the MAPT. And no, if on an ILS, I think friends in the tower would be apoplectic if they noted me at 600' at 4 DME:D :D

[FWA NATCA]

I work at a radar facility that works a lot of aircraft from C152's, corporate aircraft, to airliners that do pratice approaches on a regular basis (ILS's, VOR's, NDB's, GPS, and Back Courses, and the always enjoyable ASR)

Running a sequence with multiple acft some doing the instrument approach and some on a visual approach and with varying types of aircraft and speeds and to crossing runways, does tend to get challengeing.

AT FWA we let the tower issue alternate MA instructions because we don't want the pilot doing the published missed and tangling with another acft.

Mike