IMC rating

[big.al]

Having only passed the skills test in May, I'm still trying to build hours (and keep current with the bl**dy British weather - last two weekends I have had to cancel)....:mad:

But thinking for the future, I'd like to know exactly what 'privileges' the IMC allows and whether it is worth the investment.

Please could someone clarify the differences in weather/visibility minima and airspace restrictions for someone having an IMC rating as opposed to little 'ol BIG.AL with just a shiny new SEP PPL(A).

Thanks folks!

[sunday driver]

IMC rating - good fun !! Better to get your hours into 3 figures first, probably.
Allows you to fly in the airspace already accessible with your PPL, with the additional benefit of not needing to look out of the windows.
Gives you the confidence to indulge in CFIT in foul weather as well as fine.
Needs regular practice to retain currency, but might give you the ability to dig yourself out of a hole you should never have got in in the first place. Or might not.

[rustle]

Hi big.al,

I'll dig out the definitive document references (CAA), but in the meantime think of it as an IR with restrictions. (The IR "rights" are easier to find on CAA website)

Restrictions compared to IR:

UK only, including IOM, Channel Isles
DH/MDH are higher (absolute minimums 500' precision/600' non-precision QFE)
No class A airspace (TMAs and ALL UK airways)

Benefits compared to vanilla:

IFR in upto class D (not A, B, C)
VFR above the cloud layer (brilliant - worth it for this alone)
SVFR minima lowered to 3km from 10km
Makes you more "aware"

CAA only require 10 hours post PPL for rating issue. (Plus course and exam passes :) )

HTH for starters --> read Thom book 5 that has a load of info.

[bookworm]

Rustle described an excellent way of thinking about the privileges.

However it's worth mentioning two things:

1) the higher DH/MDH are recommendations, not a legal requirement

2) there is a legal requirement that flight visibility below cloud is 1800 m or more for take-off and landing.

[rex]

I am studying IMC at the moment. Good fun and challenging, but bloody hard sometimes. When you flip the goggles and see the approach lights after an ILS it's worth it

REX

[Crowe]

bookworm

your post suggests that I, as an IMC holder, could fly an ILS down to 200' perfectly legally? (before I get jumped on, I'm not suggesting that this is a great idea, though it might be better than a diversion if clouds are say 400' agl and you're low on fuel).

Are you sure that's right? I was always told the DH of 500' was sacrosanct until you get the coveted IR.

[Fuji Abound]

Crowe - yep I agree with bookworn, the only reasonable interpretation of the legislation is that the DH/MDH are recommendations so you could operate down to the same legal minimium as an IR holder subject to 1800m rule.

Shame much of the CI is class A.

[bluskis]

Information reaches me that the IMC rating cannot be used in the Channel Islands.

[rustle]

bluskis:

Standards Document No 25 V 1 Part 1 General Information

1.1 The IMC Rating is a UK National rating and not a JAA rating. As such it is only valid for flight in UK territorial airspace, and in Channel Islands and Isle of Man airspace.

1.2 An IMC Rating (Aeroplanes) is valid in both single engine and multi-engine, single pilot aeroplanes. If the IMC Rating test is flown in a multi-engine aeroplane then some aspects of asymmetric flight will be tested.

1.3 An IMC Rating (Aeroplanes) is valid for 25 months. Any revalidation or renewal of the rating will be valid for 25 months from the date of the revalidation or renewal flight test.

:)

[Crowe]

Fuji & bookworm

thanks - I'll have a closer look at the law, and bear it in mind for future flights - while I wouldn't deliberately make a flight expecting 200' cloud base, it's worth bearing in mind for the more marginal cases of 300-500' (particularly relevant for EGNM, where the elevation is 662' and you can often get caught out).

After all, I think a current IMC holder in a slow light single is entirely capable of an ILS to 200-300'.

Cheers

[Keef]

The IMC rating is valid in the Channel Islands - except for flying in IMC in the Class A bits.

IMC holders do get enhanced SVFR minima in the Class A, which helps.

You certainly can fly an ILS down to "IR minima" with your IMC, but woe betide you for ignoring the CAA "recommendation" if it all goes wrong. Better be in full & current practice.

[rustle]

Keef,

"IMC holders do get enhanced SVFR minima..."

Probably one of the few situations where a reduction is an enhancement :D

[bookworm]

Crowe

Yes, indeed, you have to interpret my comments with a large dose of common sense.

I think instrument currency is probably more important than the level of initial training when deciding on minima (and I'm speaking as a not very current IR holder).

Nevertheless, I would caution anyone against trying to fly an ILS down to 200 ft without a lot of practice first: the last 30 seconds can be pretty tricky, and a pilot who makes heavy-handed corrections can get into trouble rapidly.

With non-precision approaches, just remember that you shed the extra 200 ft cushion at your own risk. With a little altimeter error and position error, the hard bits may well start about 150 ft below the nominal MDA/H, assuming that you're within the protected area laterally. Throw in a taste of turbulence and wind shear, and you get into Lamplugh's "terribly unforgiving" territory quite quickly.

[englishal]

I would caution anyone against trying to fly an ILS down to 200 ft
So long as you don't go full scale deflection, and so long as you don't bust your DH, you'll be fine :D

EA;)

[Crowe]

Cheers chaps

certainly something to think about. I'll try a few ILS with the foggles down to 200' with a guy I trust in the right seat and see how it goes.

I seem to remember doing an ILS down to 50' with an instructor on my IMC training, but it's a bit different on your own than with an ex-RAF nutter shouting at you if the needle goes off by more than a millimetre!

[excrab]

Flying an ILS down to 200 feet might not be a very good idea, as 200 feet is the system minima for a cat 1 ILS to which should be added a correction for altimeter error with the aircraft in landing configuration ( position error ).

Many light single engine aircraft and some twins don't quantify this error in the POH or AFM, and the recomendation is to add 50 feet to system minima for a precision approach.

Thus even for an IR holder in current practise DH in a light single should be 250 feet, not 200.

[bluskis]

So as I now understand it, an IMC rating allows only reduced viz for a SVFR within the Channel Is zone, and full priveleges once you enter one of the airport zones.

This is in line with the information published in the Guernsey Flying Club journal, but is slightly more restrictive than a quick read of the geographic extent of the IMC priveleges, mainly because the Channel Is zone is class A.

Apparently it also reverts to French control after certain hours, perhaps after the island airports are closed anyway?

[SKYYACHT]

At the risk of sounding a pedant, I though that one could not fly VFR on top. To be operating under Visual Flight Rules, you must be operating under VFR minima, which effectively means in sight of the ground, clear of cloud etc etc. As far as I am aware, if you use the IMC rating to climb through cloud, then once above the tops, you are then operating VMC on top, rather than VFR on top.

Anyone have any thoughts or opinions on that?

Blue skies

[bookworm]

SKYYACHT
At the risk of sounding a pedant, I though that one could not fly VFR on top. To be operating under Visual Flight Rules, you must be operating under VFR minima, which effectively means in sight of the ground, clear of cloud etc etc. As far as I am aware, if you use the IMC rating to climb through cloud, then once above the tops, you are then operating VMC on top, rather than VFR on top.

No, that's a contradiction. "VMC" are by definition meteorological conditions in which you could operate VFR. VFR does not require sight of the surface, though if you are not in sight of the surface the cloud clearance and vis minima can be greater.

PPLs without an IMC rating may not operate out of sight of the surface, even if the conditions are VMC.

englishal
[Flying an ILS to 200 ft] So long as you don't go full scale deflection, and so long as you don't bust your DH, you'll be fine

Well yes and no. The problem is that if you are heavy handed with corrections, you can find yourself in a very difficult position as you go full scale deflection. In particular, less experienced pilots have been known to see that the bar is drifting down in the latter stages of the approach, put in a fistful of nose down elevator, and end up going full scale below the glideslope with a startling rate of descent. If you add that to a little human nature in not wanting to throw away an approach that can be salvage, and I think that a little practice flying the needles to 200 ft is a good idea before trying it in IMC.

excrab
Yes, a good point. With a PEC of 50 ft, it may say 250 ft on the altimeter, but you're still flying the approach down to 200 ft height. You're just applying a calibration correction to the instrument you use to measure it.

[englishal]

BW ;)

Yep, I know what you're saying. In the 'ideal' world then there's no problem going to minimums, but as you say some people will try and salvage the approach by overcorrecting. The thing to remember is that when FSD is reached and / or minimums, a missed approach is called for...no question...As people have already suggested, its wise to apply your own personal minimums, to whatever you feel happy with.

SY, On the subject of 'VFR ontop', there is an exception in the ANO basically saying that if you hold an IMC rating then the 'in sight of surface' bit is no longer applicable [as BW already mentioned]:)

Cherio
EA