SE IFR Personal Minima

[justanotherflyer]

What are yours?

[S-Works]

MSA enroute, 500ft on approach, but then I am the same in a twin!

[IO540]

Published minima on approach.

MSA en-route.

[Fuji Abound]

"Published minima on approach.

MSA en-route."

So when do you make the transition from en-route to approach?

[tmmorris]

Were you thinking of more like '1000ft forecast cloudbase and 3000 viz takeoff/landing' (which are mine, as I don't fly IFR that often)?

I do that to allow for the cloud/viz to be a bit worse than forecast, and a bit for 'the wife & kids' (I'm really fine to IMCR minima, in practice).

Tim

[IO540]

Fuji Abound

I think that happens when flying the IAP. They start at or above the MSA.

Obviously there is a separate issue when going to an airfield without an IAP. I've done one or two things I wouldn't do again :O But generally I wouldn't descend in IMC below 1000ft AGL.

[Chuck Ellsworth]

My minimums for single engine IFR in IMC are zero / zero...as in I never fly IFR single engine...:ok:

Chuck E.

[Aussie Andy]

Just passed my IMC flight test today (woo-hoo!) so I am listening eagerly to what people do in practice - especially keen on tips for suitable personal minima to be starting with. MY general sense of it is I basically don't want to set out on purpose on a "hard IMC" day. Does 1000' base, clear layer above, / 3k vis sounds like an OK starting point?

Andy

[NorthSouth]

I've had an IMC Rating for about five years but rarely use it so I still count myself very much a novice. I'd say if you're starting out, you don't really want to give yourself a double burden (cloudbase AND visibility) straight away. IMC Rating's great for times when there's a layer of cloud to get through but you're pretty confident that, once through that layer, the visibility will allow you to see the runway straight away. If the vis is only 3km you could be coming out of cloud a long way before you get visual with the runway, which means carrying on following your instruments for a long way down the approach. Also, if vis is only 3km and you're operating to the IMC Rating absolute minimum MDH of 600ft for a non-precision approach, you'll need to work fast to get to the runway from 600ft at 3km - that's only 1.6nm.

NS

[S-Works]

Being pedantic IMC only has a forward viz minima not a decision height minima. It has a RECCOMENDATION of 600ft but there is no reason for a current and experianced pilot to go to published minima.

If you can fly the approach then you should be able to fly it all the way in. If you cant then I would suggest that you should not be flying on the instruments in the first place.

[UL730]

Landing – Published approach. JAR – OPS 1 (Aerad) CAT 1 minimums plus 50’ position error, temp corrections plus single crew RVR minimums - 800m >

Circling - JAR-OPS 1 - MDA

Take off – JAR-OPS 1 LVTO – depending on R/W edge & centre line lighting and published flight path performance. Single engine operation div considerations < 30 minutes to alternate.

En route - MSA

Divs – CAT 1 alternative – assume non precision RVR > minima and Circling MDA. 1 hr plus or minus ETA > forecast weather minima.

Icing – light icing only.

Weather - reject flight in heavily embedded TS, rotors and some MTW. (Tornadoes and NS above freezing level – stay in bed)

Personal - Fit to fly IFR criteria – duty hours and health. In current practise and within licenses..

Autopilot - Features big on MEL. Must be operational for flight > 1 hour or complex high workload short trip.

ETOPS - PNR’s, Crit Points and divs.

National differences where appropriate.



NO SCREAMING KIDS IN THE BACK SEATS. :uhoh:

[bookworm]

All good contributions so far. No one has really mentioned enroute cloud ceiling and vis, which is presumably where SE minima are likely to differ a bit from ME minima.

Do you fly over a solid layer of OVC005, even if you have an ILS at each end of the trip?

[Fuji Abound]

"Do you fly over a solid layer of OVC005, even if you have an ILS at each end of the trip?"

In my opinion exactly right and the point I was inferring earlier.

Of course it boils down to the level of personal risk you are prepared to take and the confidence you have in your engine. If you are assured your engine will never fail then:

"Published minima on approach.

MSA en-route."

would work fine (also assuming you are current and really up too speed).

However if the engine fails approaching the airport which is at its published minima and you break cloud at 1,000 feet or even less short of the airport how successful is the forced landing likely to be?

The other "interesting" combination is those days with clear VMC for miles above about 500 feet but with the ground completely obscured by fog.

It is questionable whether routes such as the Lee Valley enable you to comply with the land clear rule. I wonder whether in fact you might be equally open to criticism for flying with an undercast down to 500 feet?

[IO540]

Do you fly over a solid layer of OVC005, even if you have an ILS at each end of the trip?

I would if it was open countryside, or water. Not above mountains though.

What does one do about forests? I think that's the hardest one. There aren't many in the UK but there are plenty in Europe. Most mountaneous terrain I've flown over had lots of valleys in between.

also assuming you are current and really up too speed

That's a bit of a catch-22 isn't it? :O

[tmmorris]

Good point NorthSouth. You've almost persuaded me to up my personal minima to 4000 viz so that when I reach MDH on a non-precision approach I can see the runway! (600ft should come at 2nm for a 3deg approach path; 2nm = about 3700m according to my wristwatch...)

But then I could go around for a low-level circuit to land - and 3000m viz is plenty for that, unless you fly enormous circuits.

Tim

[FlyingForFun]

I notice quite a few people have said "MSA" as an en-route minimum.

Now, here's a question for you, from someone who admits to being an IMC novice (that's me): MSA is the highest known obstacle within 5nm of your track, plus 1000'. So if there's a 1000' mast 4.9nm off track, your MSA is 2000' above ground. And you won't fly with a cloud-base of 1999' feet above ground.

Which sounds very good, until you compare it with flying single-engine at night - where you will be well below 1999' (in fact, maybe a couple of hundred feet at the very best) before you can identify a suitable landing site.

The only slight advantage of night-flying, with regards to engine failures, as compared to flying with a low cloud-base is that at night you can see built-up areas and lit obstructions in order to land clear of them. So is it not possible to plan an IFR route which keeps you clear of built up areas and towers, fly that route with a cloud base of just a couple of hundred feet above ground, and be at least as safe as you would be flying cross-country at night? (Granted, of course, that there are people out there who don't fly cross-country at night for this reason, but there are also plenty of people who do.....)

I don't know the answer, by the way - I've never flown in that kind of conditions. (The cloud base at the airfield would most likely be below my personal minima if the en-route cloud base was that low for most routes anyway.)

FFF
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[englishal]

MSA or MEA, and published IAP minima. Just make sure you have enough fuel to reach an alternative where chances are the situation is better (the average light aircraft could reach half the airfields in the UK so you have a few to choose from).

I try not to think about what would happen if the engine quit, at night, IFR over mountains;) Fate is always hunting, and if its not your day, its just not......

[IO540]

I would much rather have 500ft of daytime vertical space in which to look for a field, than any amount at night.

Statistically, night forced landings come out better than the 100% death that one might expect, but that might be because the sample is skewed: those that have "night" hours in their logbook tend to choose the early part of an "official night" when there is still plenty of light. That's what I do but I still have very few night hours (under 20).

At night one might see a town but perhaps not a village. But even a single tree, say 8" thick (that's enough to stop a 1000kg car dead from 70mph, killing everyone inside) is enough to kill you and statistically, over open countryside, one is far more likely to get one of those than one is likely to get a house.

Also, any time when flying, one should use a GPS ;) and that will enable one to route away from built up areas. It is even possible to have an en-route display of the 1:25k O/S maps.

[cblinton@blueyonder.]

Agree fully with IO540

I often fly over long water crossings (with boat and jackets) and am told how dodgy it is by SEP night flyers. I would far rather an engine failiure over water with time to prepare, and make the relevant calls than to get one at night with all kinds of obstacles in your way that you wont see.

[DFC]

Some very intersting comments here that show a wide variation in understanding of the Single Engine IMC IFR world. Some worthy of note are;

"Only light icing" - Are any single engine aircraft certified for flight in icing conditions?

"1000ft above all obstacles 5nm either side of track" - The law requires the aircraft to be at all times 1000ft above all obstacles within 5nm of the aircraft. Following that system and being just 0.001nm off track is thus illegal! - Better to check 10nm or more either side of track and keep the aircraft within 5nm of track! I am shocked at how many IMC pilots use this dangerous figure!

Using a MDH of 600ft means that an adequate reference is required before descending further (defined in the AIP). Thus if one wants to keep to a 3deg glideslope then one must leave 600ft at about 2nm and that requires 3700m visibility. However, if the circling height is 600ft or less then one can use a lower visibility (1800m perhaps but sublect to procedure minima) and stay at 600ft until the MAP followed by a steep straight in if possible or a circle round to the same runway if it is needed to get the height off! Yes one can circle to the same runway!!!!- an important option for IMC holders!!!

I won't bother to comment of what the CAA has said already about IMC minima.

What risks pilots take themselves is up to them. However, the insurnace company and the legal representatives of injured parties could use the CAA's safety recomendations as an indication of what the average pilot should follow as a minimum.

Personally- Using an IR in a SE aircraft -

Take-off - Visibility depends on aircraft performance - 1500m minimum but more if something like an Arrow and the forced landing area in the first few miles is marginal. Ceiling 1000ft AGL

Enroute - As for Take-off

Landing - As for Take-off

Critical for single engine IFR flight is to get as high as possible as soon as possible. That gives the longest glide posibility or the longest time in the air after an engine failure. Flying at or just above MSA is a fools game unless there is absolutely no other option.

Most importantly of all is that absolutely no IMC flying is carried out unless the flight or atleast that portion of it has been planned IFR.

regards,

DFC