IFR in VMC with new IMC

[imtaylor]

Recenty got my IMC and part of a PA28 group based in Newcastle. Planning to go down to Chester this week but just nervous now about flying IFR above the clouds. Have little experience of flying in cold conditions and after a mate of mine sent me a "You Tube" vid of the leading edges all whited out, I'm terrified of falling out of the sky or getting caught out by ice and plummeting to the earth!

So, questions are
1. I appreciate it depends on the adiabatic rate etc. but has anyone been "iced" before (and was it slow and steady or fast and terrifying) and presumably, you just declare a "pan" and get down sharpish?

2. Flying IFR this of year generally, do you just simply avoid the clouds as much as possible? If so, what do you do if you ask for vec ILS at your destination which then takes you through clouds?

3. Forecasting cloud tops - is it possible? Other than Synoptic forecast, do you just assume cloud tops are out of your reach - period?

ta v much.

[Fuji Abound]

1. Icing (or the rate of) is difficult to predict with certainty. I recall many years ago asking my mate about icing. He spotted a Cb and headed for it. Very shortly after we entered the screen went completely white and VF was impossible for a short while after we exited. Of course the very light icing melted really quickly but it was a useful demonstration I will always remember. If you have no way to deal with ice (which you dont in a PA28) expect this to happen if you enter icing conditions because while you are watching the wing edges the screen frosting over will come as more of a shock. Icing will of course almost always only occur in cloud so as long as you can get yourself out of cloud (above or below) the ice will usually stop accumulating and will more than likely dissipate (indeed quickly if the outside temperature is above freezing). Minor incurrsions with ice as long as you have an escape route are therefore no cause for a pan but for a quick exit and careful observation. Obvioulsy exposure to ice in cloud with a high mositure content for any length of time is a very dangerous game indeed and one you will rarely win. On a very few occasions conditions can catch you out. Flying last winter in good VFR we were very surprised to find we were accumulating ice quite quickly. Several others reported the same conditions and returned to base. On went the fluid and the "problem" was solved. However it demonstrates it is possible to accumulate ice on a cold airframe when the moisture content in the air is high even though the flight conditions are visual. Such circumstances are however rare.

2. IFR flying is about avoiding the clouds at any time of year :). They are wet and bumpy and only really good for giving the aircraft a clean. As I indicated earlier if the temperature is below freezing expect ice - make sure you have an escape route and if you dont, avoid the clouds at all cost. Punching through ice "laden" clouds to VMC on top takes experience which, with all respect, you probably dont yet have. People like IO540 can do this very safely when the conditions suite but with many more hours experience to their credit. On an IAP if you are vectored into cloud and the temperature is below freezing of course you can expect to build up ice. Unless the conditions are extreme it is highly unlikely clouds that close to the surface will be convective or laden with moisture so the rate of accumulation is likely to be very small given the time you will be in cloud. However note my earlier comment that the screen might well frost over. If you are in any doubt for the same reasons the clouds should be avoided. Personally I wouldnt fly if there was significant IMC on the approach with low cloud and freezing conditions to the ground unless the aircraft was de-iced.

3. There is plenty on that subject on here in very recent times - use the search function.

Now do me a favour and read the threads on FCL008 - because sadly you may not have your IMCr for very long so enjoy it while you can. :) You might even want to express your views on that thread.

[S-Works]

Now do me a favour and read the threads on FCL008 - because sadly you may not have your IMCr for very long so enjoy it while you can. You might even want to express your views on that thread.

Ah yes, because we can see how his extensive IMC training prepared him for the job at hand........ ;);)

[Radar]

Ah yes, because we can see how his extensive IMC training prepared him for the job at hand...

Ouch .... that's gotta hurt !!!

[ab33t]

Dont even think about it I fly a Malibu extensively throughout Europe and this piece of kit is FIKI certified , I avoid icing like the plaque if I can help it . Get someone with a bit of experience flying and dealing with these conditions . ppp -ppp

[tdbristol]

Some experience of icing and some suggestions:
(a) as others have said, avoid it (by of course avoiding cloud if the temp is below zero).
(b) by all means, ask ATC for a course change if you need it to avoid cloud when the temp is below zero
(c) when planning, ensure that each leg where you may have cloud you also have the ability to stay above MSA and be sure to stay a reasonable amount above zero, i.e. so you can descend from icing conditions into conditions where any ice will melt well
(d) my experience of encountering ice is the first effect is a rapid decrease in airspeed (~10kts), likely due prop icing rather than wing ice (which can be hard to differentiate from cloud moisture on the wing if the icing is light).
(e) the temp in cloud can surprise and drop by a few degrees in seconds, to go from 2C to below zero (even in benign stratus), so keep a good eye on the ASI and OAT gauge and be prepared to ask ATC for a 'descent due icing'. If you are collecting ice DON'T wait to see what happens; DON'T hesitate, get on to ATC straight away. My experience is that ATC react immediately and are entirely willing to accommodate and give you whatever lower level you need (even in busy airspace). You can't wait, but reacting quickly means that light icing doesn't need to be a 'pucker up' moment.

For cloud tops you could look at meteoblue dot com (look at 'Cross section' tab after logging in)

[Fuji Abound]

Ah yes, because we can see how his extensive IMC training prepared him for the job at hand........ http://images.ibsrv.net/ibsrv/res/src:www.pprune.org/get/images/smilies/wink2.gif


Perhaps you would care to enlighten us with your actual ice encounters during your IR training particularly if you undertook this during the summer months danw south. There again maybe your training was in somewhat wilder territory where it is a great deal colder in which case I suspect we will all have something to learn.

[IO540]

1. I appreciate it depends on the adiabatic rate etc. but has anyone been "iced" before (and was it slow and steady or fast and terrifying) and presumably, you just declare a "pan" and get down sharpish? Airframe icing (as distinct from carb icing which is a very different piece of physics) happens when you fly through supercooled water droplets (which basically requires flight in IMC). These droplets can exist between 0C and about -15C, possibly a bit lower in convective clouds.

I don't think the adiabatic rate is related to this.

The extent to which aircraft performance (wing lift, drag etc, and prop efficiency) is affected depends very much on the aircraft. Old designs tend to be less affected, whereas something like a Cirrus are reportedly strongly affected.

The existence of supercooled water is highly statistical. You could fly along for 10 mins and get not a drop. Next 10 mins, you pick up 5mm (which is usually enough to impact performance). In extremes, in convective cloud especially, you could pick up inches in minutes (freezing rain e.g.). Thin stratus cloud is normally OK for a bit...

Strategy depends on the aircraft deice equipment and varies between pilots, from "never touch IMC below 0C", through "OK to climb/descend through it, but never fly in IMC enroute (that's me; I will climb to FL200 if necessary to stay above rising tops), to pilots who always go (some of whom fly deiced planes) but only occassionally write about it...

2. Flying IFR this of year generally, do you just simply avoid the clouds as much as possible? If so, what do you do if you ask for vec ILS at your destination which then takes you through clouds? You are descending so should be out of it pretty quick.

But yes, the winter is a problem because on cold days your primary escape route (a descent below the 0C level but without hitting the ground etc) is closed off, and whatever ice you pick up you have to land with. That's the price you pay for not having a jet :)

3. Forecasting cloud tops - is it possible? Other than Synoptic forecast, do you just assume cloud tops are out of your reach - period?There are various methods but none are that great. The UK Met Office does not release its 3D model other than to commercial weather repackagers so one has to turn to the U.S. run GFS model e.g. here (http://www.arl.noaa.gov/ready/cmet.html). You have to use data like Soundings. But tops forecasts are rarely accurate; let's say the tops are forecast for 6000ft, you should assume they could be at 10000. I will scrap flights if the tops are forecast above 16000 because my economical ceiling is 18000 and max is 20000.

Occassionally, especially in a large high pressure area, the tops are accurately forecast, and the layer is very thin e.g. base at 1500ft and top at 2500ft. But usually in those cases you can see blue sky in holes, and then it's obvious.

Generally, in warm front conditions, you can forget it because the tops will be say 25000ft and the climb in icing conditions will be too long/risky unless you have the full deice kit. In those conditions you have a fairly uniform sky colour - indicative of a great thickness. But - frontal conditions aside - most clouds can be climbed through because the layer is so obviously thin.

In practice, in the UK, due to controlled airspace bases, cloud tops are normally too high for VMC on top flight to make sense unless one has an IR.

imtaylor - I will send you an email with more stuff.

[Pace]

Imtaylor

The whole point of icing whether the aircraft is ice capable or not is to get out.

If the aircraft is ice capable you can hang in there longer if its not you cannot.

You basically have two choices in an icing layer. You either climb up where it is too cold for ice to form or you descend to where its too warm for ice to remain as ice ie an altitude below the freezing level.

If you are in a small low powered single you are not going to make a good job of climbing especially if you are carrying ice so your only alternative is to descend into warmer air where ice will melt off.

So that is your guiding rule of thumb! Dont fly in cloud in a single low powered aircraft unless you know that you can descend and melt off the ice while still above terrain.

On your climb out note where the zero degree level is! does that give you a good margin above the highest terrrain. If you know that any ice you pick up will be carried to the ground dont go!

I can remember years ago flying IFR training for the IR. we were in a PA28 having struggled in cloud up to FL80. Both me and the instructor missed the ice build up until I had full power and could not maintain altitude with 70 kts IAS. We asked for a lower level and were cleared to FL60 with the instruction "not below". FL60 came and went as we sailed on down to FL40 powerless before the ice melted off and the aircraft behaved normally.

The hills came up to 2000 feet in that area so imagine had the air been colder and the ice had not melted off :\

Note the 0 degree level and if its not high enough dont go!

Pace

[IO540]

I normally find the 0C levels being forecast reasonably well - plus or minus 2000ft for sure.

Forecasting tops is much harder.

[Sir Niall Dementia]

I agree with IO540 that the forecast freezing levels are normally very accurate.

From the tone of your first post I gained the impression that you do not feel confident in what you are planning, if so take an instructor with you. If he says its a no-go then take heed and learn from his experience.

Consider the potential weight gain and changes to aerodynamic profile of ice. You may find that sudden, heavy Ice accretions can take you straight over MTOW, aerodynamic surface profiles will change and suddenly your'e a test pilot flying a new type in conditions which are already worrying you.

I can echo Pace's experience, except in my case it was in a Navajo. The met men got the freezing levels wrong as well as the rest of the forecast, I was going into Zurich and ended up putting out a mayday as the aircraft went below MSA with full power and the de-icing boots unable to cope. 500' later I was in the clear with the ice shedding and an awful lot of years added to my age.

Nowadays I fly things which cruise well above icing levels but still get it on climb and descent. the build up tends to be slow and insidious, or very fast and obvious. When flying in my own time if the forecast freezing level is less than 2000' above MSA, with IFR conditions the hangar doors stay shut and the garage doors get opened.

[Johnm]

Rules of thumb are that ice can form in cumulus anytime. In summer likely to be light in winter can be severe. In stratus it's normally much less of an issue. In some cases high humidity without visible moisture on a cold day can cause ice (as mentioned above) again that's not usually too much of an issue.

I've had ice in Cu in May in South West Scotland at 5000 ft, I had ice last week over Cranfield climbing through Cu to FL 070.

The biggest risk by far is below rain cloud with an aircraft below zero. Freezing rain will really spoil your day.

BTW I'm an IMCR holder and would have been asking the same questions soon after my test, experience comes with time:ok:

[IO540]

ice can form in cumulus anytime

You still need the OAT (= airframe temp) to be below 0C.

I tend to find that if cruising in sunshine and the OAT is say +1, immediately upon entering cloud it drops by about 3 degC i.e. to -2.

So on comes the prop TKS, before entering any such IMC (I have prop only, not the full kit).

The actual flying strategy depends somewhat on whether one is flying on an IR, or (below CAS / OCAS generally) on the IMCR. The IMCR strategy is simpler - is the 0C level below the MSA? The IR implies high altitude flight and the strategy is very different.

That is the cautious approach. There are individuals who "just go". This "usually" works because most of the time there is very little ice :) IMHO this is not the way to do it.

The impact of various levels of caution on the despatch rate is significant. I might do 75% (with pure legal VFR it might be 25%, on a long trip of say 700nm), and with a seriously deiced plane equipped with radar one might achieve 98% or more. Once I was at Biarritz and some jets departed for Spain, and came back half an hour later saying they could not penetrate the weather...

[imtaylor]

Thanks for the (mostly) helpful comments.

My views on the IMCr are irrelevant really but sufficed to say, I have my own opinions which some won't agree with. What will be, will be and I'll decide what to do if and when changes are made. There is little that I can do to change FCL008's views or opinions and they will make whatever decision they think appropriate, even if I disagree.

When I fly, i am extremely cautious and careful and I never take any chances. Contrary to (some) IR holder's opinions, I am not some half-wit, who ventures out into IMC at the drop of a hat, thinking that i am invincible - and I never intend to.

thanks.

[IO540]

FCL008 is just a committee.

EASA committees draw up proposals. Normally each member signs an NDA so nothing gets out. They don't make law. The proposal later goes for a comment period. Then somebody higher up in EASA looks at what (if anything) to do with it.

[Fuji Abound]

Based entirely on what I have seen so far something square, made out of metal, and usually kept in a corner comes to mind for some of it.

The only trouble is they would probably want to recyle it.

Who knows it might be more useful the second time around.

imtaylor

Dont take Bose too seriously he has some issues with this stuff. :)

However, your views really do matter. I know, I know no one turns out to vote any more because they think it is a waste of time - they are all the same, but it matters that we try and influence policy. After all it doesnt take long to punch out a letter. Its called democracy - and unfortunately it is the best we have. :)

[Pace]

Imtaylor

There is a lovely saying " If you dont push the limits you will never find what lies beyond ". Dont take that literally especially with flying but there are times when you need to be at the edge of your comfort zone to gain experience.

It is only by being in icing conditions inadvertantly or otherwise that you will get to appreciate and respect icing.

I flew with an old ferry pilot who could literally smell icing. He knew where it would be and knew where to go to get out of it.

I have had many encounters with ice and have to say that it scares me.

I have placed this in the forum before but it was the most bizarre and unusual icing situation that happened to me flying a Seneca Five twin to Inverness several years ago.

I was airways and knew there was a cold front with a wall of embedded CBs running west to east across the north of Scotland.

I knew to get any chance of finding a gap through I had to eyeball the wall.

I climbed to try and stay on top of the lower stuff. Fl100, Fl120, the screen was covered, I was working the boots and had the prop anti ice on.

FL130 I struggled on top. There was a shuuder through the airframe.
Three electric cables to the left angine prop deice had sheared meaning that side wasnt clearing.

The Seneca five has counter rotating props. Next second a huge chunk of ice flew from the left prop right across the nose and struck the right prop bending the tip.

In turn the right prop threw the ice block into the side of the nose punturing a hole. The block then came back into the screen smashing into a snow storm of a million fragments.

With the speed of the aircraft the left prop must have projected the ice at one heck of an angle forward for it to come back and hit the right prop.

I found a hole through the CB wall and landed at Inverness.
Unlikely but true. The one prop was replaced and the aircraft still bears the repair job to the nose.

That is icing for you! so beware. Step into the clouds bit by bit and learn :eek:

Pace

[Brooklands]

I normally find the 0C levels being forecast reasonably well - plus or minus 2000ft for sure.

IO, did you really mean two thousand feet? It doesn't seem that accurate to me.

Brooklands

[bookworm]

Rules of thumb are that ice can form in cumulus anytime. In summer likely to be light in winter can be severe.

Not sure where that comes from. My impression is that there's a lot more ice around in summer, it's just higher up. The higher absolute humidity and greater vertical extent of cu in summer tend to create more problems. May and June tend to be worst, with greatest instability.

In stratus it's normally much less of an issue.

That's certainly true, though stratiform cloud can still catch you out. Last January I descended from clear blue into a flat layer of SC between about 2500 and 4500 ft. At 5000 ft the temperatures were positive, so I blithely assumed the SC would be ice-free. ATC stopped my descent at 4000 ft, the temp fell to -2 degC and the ice went on faster than I can remember in stratiform cloud. No emergency, particularly with boots and prop-deice, but it certainly got the attention!

[IO540]

Pace - sounds like you have been involved in some serious "boundary pushing" operations ;)

I have come across commercial pilots; "commercial" in the sense that they got paid for flying, and would have been sacked if they refused due weather, and they had a real can-do attitude. But they also had planes with rubber boots which should cope with a reasonable amount of ice.

A lot of pilots are fools who take off without any plan, and some get themselves into real trouble. One even wrote about it on an open forum; the original posting (commented on here (http://forums.flyer.co.uk/viewtopic.php?t=19997&highlight=tb20) - not all the comments make sense but his original story is there) even includes a photo taken after he landed, showing what must have been several inches of ice on the leading edge. That was a TB20 - very similar to what I fly. I am suprised he didn't get busted by the FAA because his flight plan would have taken him above the mandatory oxygen level and he didn't have oxygen (another stupid aspect).

IMHO ice is not anything to be afraid of. One just needs a clear strategy, and an escape route e.g. if the terrain is 14k (mountains), the 0C level is forecast for 10k, then you don't go unless VMC is assured and you will have enough fuel at all times to turn back and reach an airport which can be descended to in warm air.

Brooklands - yes I reckon temps aloft are reasonably forecast - at least for the purpose of the strategy which I am suggesting. If however one accepts a flight whose long (say hours) enroute section is in IMC then one needs to be more careful, and IMHO have a de-iced plane.

Imagine yourself flying along, NON de-iced, at say FL150, terrain at FL100, 0C probably FL080, with an aircraft ceiling of say FL180 (a typical non turbocharged figure), and looming in front of you is a solid wall of IMC (a front, or clouds caused by an updraught up a mountain) rising to maybe FL250. Whether to proceed or turn back is what separates the brave from the smart, IMHO ;)

[Tmbstory]

Johnm:

In the past I did a lot of cloud seeding for rain making experiments, so had to deal with lots of icing problems.
Seeding strata form cloud at the minus 5 degree C level, icing was often a major concern. The key to success was the relationship of the temperature at the the lowest safe altitude to the freezing level. If they both coincided, you should not be there.

Regards and remember that we all had to learn, to become experienced.

Tmb

[Pace]

10540

I did not see anything in the article which states he didnt have an oxygen bottle on board.

Remeember the FAA say up to 12500 unlimited, to 14000 for 30 minutes above 14000 oxygen all the time and 15000 passengers on oxygen.

His biggest problem was using an aircraft which was not up to the job although compared to other non deiced /anti iced single pistons the Trinidad appears to carry ice well.

I never fly any trip without an "out" in the one above I knew if i dropped to 6000 feet the ice would come off but because of severe storms to the north and a dickie radar IMC below freezing wasnt a safe option to get to Inverness but a descent and alternative into Glasgow was and was always open to me.

The prop deice failure was a failure! the ice hitting the prop was a one in a million.

Some of us fly because we have to (within reason) others of us fly because we dont have to.

Pace

[IO540]

Pace

That 'confession' was originally posted on the Socata user group site; a few years ago. A long thread followed and he confirmed he had no o2. He then changed his story a little (when the 12.5k/14k/30mins rule was mentioned) and it was possible he was just within the 14k/30mins rule. But how daft to do an altitude flight like that, without o2.

I don't think he is stupid. The problem is that PPL training is still stuck in the Middle Ages, but aircraft capability has moved on in the past 50 years.

IMHO he was obviously hypoxic but he was adamant (in the later discussion) that he wasn't.

I think a non-deiced TB20 is up to any job within its operating ceiling, so long as prolonged icing conditions are avoided. I have been straight over the Alps at FL190 - in VMC.

The gotcha is when people see IMC ahead (one can hardly miss it), see that they won't be able to out-climb it, and just carry on into it, fingers crossed. It's OK for the odd bit but not when one could be in it for hours. I think that story is a good example of this, of an occassion where somebody very nearly didn't get away with it.

[Captain Stable]

IMHO he was obviously hypoxic but he was adamant (in the later discussion) that he wasn't.You might well be correct, IO540. In my experience people who have been hypoxic are rarely aware of it.

But on the subject of the thread, a golden rule I have obeyed for quite some time in aviation, and in all circumstances, is:-

NEVER allow your options available to reduce to a total of one.

If you find yourself in icing conditions, particularly in something like a PA28, you need to be able to get out of it. You need to be able to climb out of it, or descend out of it, or turn round back the way you came. If any of those options is your only one, you are in deep doodoo.

In illustration, I was once operating a police flight on surveillance at night. Our local base was open H24, and clear. Other regional airports closed at 22:00. After that time, I was listening to the Volmets. One major airport shut through fog, and another, nearer us, was heading the same way. As soon as that one was down to minima, I announced to the police crew that I was pulling off the job. They were outraged - we were on an important job, our home airport was still open, etc. etc. I ignored the protests and went straight home. We landed in good vis, but by the time we had parked up and were leaving the aircraft, we couldn't see the other side of the airfield.

To sum up, ALWAYS leave yourself a bolthole - ALWAYS have a Plan "B" - ALWAYS have a usable diversion airfield.

[IO540]

Yes, fair enough, though it depends on what exactly those "two" options are...

Having two airports always in reach is obviously a good idea. Doable, assuming a functioning plane.

But there are scenarios in SE flight when an engine failure is not going to leave you with two options.

[Captain Stable]

Agreed 100%.

So my answer to the OP would be never, NEVER fly into known or likely icing conditions in an aircraft such as a PA28. Don't EVER do it in something like a Seneca, either. In fact, don't EVER do it in anything unless it is specifically cleared for flight into known icing.

And if, inadvertantly, in icing conditions, get TF out - a.s.a.p. And descent is the best way. You should know where the 0 deg level is, and should know where the high ground is, and should know where the cloudbase is. What you almost certainly DON'T know is where the tops are and whether you can get out on top.

I've been in icing conditions in a totally unprotected TB9. One NAV/COM, one ADF, no pitot heat, no nothing else.

It wasn't fun. We lost all comms, lost all pitot/static info, managed to carry out a v. limited panel 180 and descent, fell out of the bottom of the cloud in a little ball of ice. :uhoh:

[IO540]

Here I must disagree with advice so categorical. Risk management in flying is not so black and white.

So my answer to the OP would be never, NEVER fly into known or likely icing conditions in an aircraft such as a PA28. How do you define "known icing"?

1) Any cloud below 0C?
2) Any prolonged IMC below 0C?
3) Hours of enroute IMC below 0C?
4) KNown IMC with forecast embedded CBs, below 0C?
5) A forecast of "icing conditions" (such as is permanently a - useless - feature of F215)?

This stuff has been done to death in FAA-land.

Anyway, the risk depends on escape routes. If terrain is 1000ft, 0C is at 5000ft, and you want to penetrate a visibly thin stratus layer (plenty of blue-sky holes so probably no thicker than 2000ft) whose base is 5000ft, why not? The worst that can happen is that when you see ice building up, you descend into warm air, continue the flight / go back home / etc.

Don't EVER do it in something like a Seneca, either. In fact, don't EVER do it in anything unless it is specifically cleared for flight into known icing.Senecas can be FIKI cert. Plenty of them have been used for quasi commercial work like mail delivery to remote areas, with inches of ice hanging off... Not my taste in planes but a Seneca is reasonably capable. A turbo Seneca with eletric props and boots is a lot more capable than my TB20.

And if, inadvertantly, in icing conditions, get TF out - a.s.a.p. And descent is the best way. You should know where the 0 deg level is, and should know where the high ground is, and should know where the cloudbase is. What you almost certainly DON'T know is where the tops are and whether you can get out on top.Unless you launched into a totally uniform-colour sky (e.g. warm front conditions) you will have a pretty good idea of the tops - a few thousand feet above. Not much use to a UK IMCR holder (due to typical Class A bases) but I am picking holes in the generality of the above statement.

I've been in icing conditions in a totally unprotected TB9. One NAV/COM, one ADF, no pitot heat, no nothing else.That was dumb. Why did you do it?

It wasn't fun. We lost all comms, lost all pitot/static info, managed to carry out a v. limited panel 180 and descent, fell out of the bottom of the cloud in a little ball of iceThe PIC on that flight was dumb.

A duff pitot heat is a no-go item at any time. Below about +5C one can get significant speedo errors, if unheated.

It gets better though. If the pitot heat doesn't work, why not? Is it because the cable is broken? It goes past the fuel tank. I would never fly with any electrical defect that involves wiring in the wings, no matter how irrelevant it might appear. I trained in PA38s with defects like that - operated by an AOC holder no less so obviously this was OK..... :yuk:

So that isn't a great example :)

My suggestion would be to understand the risks, understand escape route planning, and manage the flight so as to keep the exit routes open.

An IR helps a lot because it removes airspace class issues - climb is limited by a/c performance only. One picks a day on which the weather in the terminal areas is OK, and that leaves the enroute section to deal with, and since you are in VMC you can see 50-100nm ahead and you ain't going to accidentally fly into icing conditions or anything else.

Winter flight in the UK remains a problem, because if the 0C level is on the deck, one will have to land with any ice collected, which is a bad idea if not de-iced. Not being able to do a lot in bad winter weather is the price one pays for not having a jet and an IR :)

Finally, FIKI doesn't mean a lot. My TB20 can be FIKI on G-reg but not on N-reg. Is this because icing is different with "N" on the side? No; it is because the FAA wants two alternators and some other stuff (it's a TKS system). But the raw mission capability v. ice of the two examples is exactly the same.

[vanHorck]

Thx IO !

Yes, a turbo Seneca with her old fashioned hershy bar wings, good boots, electric props and window de-ice is most certainly FIKI and handles ice well.

Light icing is not an issue, moderate icing can be and indeed always a minimum of 2 options to stay alive!

[Captain Stable]

Sorry, IO - I didn't make it clear. There was no pitot heater on the aircraft. Not a case of an inop heater - it was never there in the first place.

I was a relatively new PPL/IMC/B. The other guy (when mentioning his name I always cross myself and hang out the garlic) was rather more experienced. I didn't know then quite how effing stupid he is. I am, at least, grateful that I learnt a few lessons from him - e.g. about not getting into a situation like that, but mostly about never trusting someone else with my money - the illegitimate son of a lady of the night.... :mad:

[robert mailer]

Hi imtaylor, just pass my imc, so i now how you feel,i am treating my imc, the same as my ppl, just pushing a bit more with every flight,my 1st flights have just been imc to get on top(realy good fun)and a bit of imc to get down, with experirnce will do more,but as i only fly for fun,have no plans to fly soild imc in 0 temps, got to go to work the next day, all the best,:) have fun, ps think the imc course great,made me a better pilot in every way,should be my standard for every ppl:ok:

[debiassi]

Seems to be a few conflicting opinions regarding icing. The one common thing is if it causes concern then thats good because icing is a killer. Ice will accrete on an airframe in the temperature range of +2 to -20c. Although icing can occur outside this temperature range, it is very unlikely. The only physical limiting factor is -40. The type of icing encountered will depend on the temperature and the amount of moisture present. The more hazardous formations will occur in warmer air close to the freezing point.If your a novice and wish to climb through cloud to get vmc on top, you need to plan very carefully. The main thing to check is the freezing level. If you are likely to encounter cloud above the freezing level then to attempt to fly through cloud in a non de iced aircraft could well be suicidal. There is a big difference in flying in vmc with foggles
compared to flying in real ifr. Its probably worth highlighting the intended use for the IMC rating. To allow pilots to take off in conditions below vfr minima to allow pilots to fly into improving weather. It certainly wasnt designed as a license to go cloud chasing. I would suggest exercising extreme caution because when you get an ice induced tail stall when approaching to land, theres absolutely no room for error. If your carrying any amount of ice, and the surface temperatures are close to freezing, then its unlikely the ice will sublimate, there will probably be handling anomolies and if you have visible icing on the leading edges of the wing, there will be proportionately more on the elevator/stabilator.

[IO540]

I am not sure that ice acceretion cares much whether one has an IMCR or an IR. The difference is that with an IMCR you generally cannot climb high enough (in the UK, usually Class A base being too low) whereas with an IR one has an enroute IFR clearance which totally ignores the airspace class and - subject to ATC climb restrictions - one can climb straight up to one's filed level, and to any level above that if necessary.

With an IR, the game becomes purely one of aircraft performance versus weather. It's a much safer way to fly, but one does have to understand both of these factors to a greater depth than if flying at low level.

That said, many flights can be done at low level, or even genuinely VFR, which would be unsafe at "IR" levels due to icing conditions or embedded nasties. In many cases a VFR flight is also much shorter (due to not flying SIDs/STARs).

The slightly perverse catch here is that in many places abroad one could be illegal if one flew at a low level because a Eurocontrol IFR flight plan cannot be filed at a low level, and a VFR flight transitioning into IMC will be illegal :) Your only way out is to ask for an IFR clearance and a climb - into the higher altitude conditions which you wanted to avoid in the first place...

[fholbert]

Recenty got my IMC and part of a PA28 group based in Newcastle. Planning to go down to Chester this week but just nervous now about flying IFR above the clouds.

If you're above the clouds and not in visible moisture you won't build ice. It's that simple. Always have an out.

If you do build ice keep flying the plane! I hear pilots panic because a little ice has found a home on the airframe. Faced with the following three of us starting building ice same route and altitude.

Level 11,000
Bases 9,000
Freezing level 8,000
MEA 4,000The two Cessna pilots behind me were in full panic mode. I'd been building ice very slowly for 50 miles and hadn't even asked for an altitude change. I was embarrassed for those guys.

[debiassi]

Maybe the pilots behind had a healthier respect of the potentially deadly effects of airframe icing. Even a little ice can severely disrupt the airflow on the lift generating surfaces and if you see ice accreting on the leading edge of a wing, it will most certainly be accreting proportionately more on the tail. A lot of pilots in the cruise phase may well be on autopilot so anomalies in handling may be masked until it is too late. Ice accretions as little as medium grade sandpaper can increase drag by 25% thus making a higher angle of attack and power setting necessary to maintain the same airspeed. This will also increase stall speed. In severe icing, an aircraft could lose its aerodynamic properties in minutes.The example you quote puts you fairly close to the freezing level and this is the temperature range where the most hazardous formations are likely to occur ie at the warmer temperatures closer to freezing. It is in this temperature range where you would be most likely to encounter severe icing in cloud. Some aircraft seem to handle icing better than others but no two icing encounters should be considered the same. Just because an aircraft flew ok with icing on one occasion doesnt mean it will always do so. Icing is complex and each encounter is different. A comprehensive understanding of the subject is a must for any pilot who will fly without maintaining a visual reference to the surface.

[Timothy]

Dave,

There is a significant difference between having a healthy respect for ice and allowing it to spook you.

I suggest that you are both right. Allowing ice to form on a non-deiced airframe is a bad idea. However, if it does happen, it is the time for careful, considered thought about what should be done next, not to start thrashing around wildly for a bolt-hole.

It is remarkable how much ice an aircraft will carry and still fly (though that does depend on the excess power available). But if you land carrying ice you may possibly risk a tailplane stall, and if that happens the recovery is counter-intuitive, so requires careful preparation.

Incidentally, although you learn a lot more about icing on an IR course than IMCR, there is no shortage of study material the IMCR pilot can read about icing.

[fholbert]

Maybe the pilots behind had a healthier respect of the potentially deadly effects of airframe icing.

No, it sounded like they knew book stuff about ice but had never seen it before. They knew all the buzz words but were so shook up by the experience they went into panic mode over trace to light ice. No matter what happens one needs to be calm and fly the airplane.

Respect ice, try to stay out of it. If it happens it's not the end of the world. Simply go to your plan B. You do have a plan B?

Should one confess to ATC?

[IO540]

No reason to be spooked because

Freezing level 8,000
MEA 4,000offers an obvious escape route - a descent.

Whether one would get IFR ATC service below 8000 is a European factor, but safety has to come first. However, is the MEA of 4k valid all the way to destination??? If not, a landing may have to be considered ASAP.

Who is "Dave"? I know some here know each other but many don't. I see that as one big plus of pprune - people are judged purely on the value (or otherwise) of what they contribute.

Should one confess to ATC?

In the USA, I can see one might not because of the whole fuzzy FIKI issue and possible FAA enforcement. In Europe there is no known enforcement and I would not hesitate to say to ATC something like "request immediate descent due to icing" even though the more normal form would be "due weather" which I would use in e.g. Spain or Italy because much of their ATC speak poor English and may not understand "icing". Followed by a Pan call 20 seconds later if they don't respond, and later a Mayday and a descent.

[debiassi]

Tim, I disagree, there are some exceptional and free courses available regarding this topic. Whilst I would never advocate a pilot to panic, I would definately subscribe to a pilot limiting his exposure to icing conditions. I am actually a commercial ferry pilot flying the North Atlantic routes so it was in my interest to learn all I could about icing and the exit strategies. Now its not always an option to be able to descend due to terrain etc but if in stratiform cloud and icing is encountered, a change of altitude of 3000ft will almost always take you out of icing, even if you remain in cloud.. Whilst this is good information to be aware of, you also need to know more as if the cloud was cumuliform, then the icing conditions could span many thousands of feet and climbing could be a bad option where as a change of lateral direction of around 5 miles would almost always take you out of icing conditions providing there wasnt a cluster. Again, a little bit of information can be a dangerous thing. If a pilot has all of the information, then he can make an educated decision. I am actually amazed how little is taught about icing even in the IR sylabbus as its one thing that when flying IFR you will definately at some point encounter. Without doubt, the best way to limit exposure to icing, is to plan thouroughly when on the ground. It may be possible to change your route slightly and dramatically reduce the risk. If there is a temperature inversion, the risk of running into supercooled liquid is significantly higher etc etc. If your route takes you along the windard side of a mountain range, then the air being lifted will be forced to cool quicker and represent a greater icing threat. Consider flying along the leeward side but of course account for mountain waves and turbulence on the leeward side. Let me add this you tube link of an instrument rated pilot flying a cessna caravan. This is what can happen when a pilot doesnt understand enough about icing. After the event, she even wanted to fly back into icing conditions, even after a near death experience. It really is an interesting bit of information.
YouTube - Aircraft Icing Near Disaster (http://www.youtube.com/watch?v=SDnZD1J62Fc)

[Timothy]

Who is "Dave"? I know some here know each other but many don't. I see that as one big plus of PPRuNe - people are judged purely on the value (or otherwise) of what they contribute.That is partly true, Peter, but an awful lot that is posted here is more understandable if you know about what the same people have written elsewhere and, when it comes to political debate (on FCL.008, for example) what political stance and organisations they represent.

I also think that it is easier to refrain from abuse if you can picture the real person you are addressing rather than a Secret Seven codename.

Dave,

As you know, I have also done my fair share of flying in icing conditions, and, as with all emergencies I still say that, unless the icing is severe, it is best to remain calm and consider the options carefully.

[debiassi]

Hey Tim, I just read your response again, I thought your previous comment ended intimating there was a shortage of study material, I read there is a shortage instead of there is no shortage so my apologies there. That was the only thing I was disagreeing about. See what I mean about a little bit of knowledge now eh? lol
Regards
Dave

[IO540]

That is partly true, Peter, but an awful lot that is posted here is more understandable if you know about what the same people have written elsewhere and, when it comes to political debate (on FCL.008, for example) what political stance and organisations they represent.Sure; though I don't myself know who "Dave" was. I probably have emails but would have to search them all for matches. Definitely never met him.

The alternative is to expose everybody's full names, but then almost nobody will write anything frank about anything.

I have met a lot of people here but I still call them by their nicknames :)

Anyway, Debiassi is right in that icing tends to be vertically limited, and anyway (in stratus cloud) it has to be constrained to a band about 8000ft thick (0 to -15C), but one needs to qualify that with aircraft performance. A turbocharged engine will deliver a much better climb rate at say FL140 (say +1000fpm for a typical turbocharged/turbonormalised 250HP tourer) whereas despite flying a "pretty quick" IFR tourer I would be getting only about +300fpm up there, and that translates to a lot more exposure to icing conditions. And even with de-ice equipment it won't take a lot of airframe ice accretion (that doesn't get shifted) to eliminate that +300fpm margin altogether. That's why my options are VMC on top for the whole enroute section, or a descent option.

But one should not be scared of icing, and that is not a helpful way to teach anything.

[derekf]

But one should not be scared of icing, and that is not a helpful way to teach anything.
Not sure what you mean about this.
I agree you should not be scared of icing, but you should understand the issues and respect them. You should be taught this so that you're not scared (as this can lead to panic/problems), but you should understand and respect the issues so as to not be blase about it.

[dont overfil]

This is a good thread learning from other peoples experiences. Awareness and options is what it's all about. I would like to share an experience which has not been mentioned yet.
I was flying a PA28 Archer at FL55 just above a thin stratus layer whose tops were forecast to be about +2. The actual temperature was nearer -2 and despite being vmc started to pick up just a hint of frost on the leading edge.and round the temp probe. As I started the descent to my destination there was a sudden vibration and a line of oil began running along the top of the cowling. Power and all indications were normal and after calling a mayday we were given vectors to an uneventful ILS at our destination.
The vibration was caused by prop ice and the leak caused by the breather icing over.
The lesson learned was a tiny bit of ice in one place can mean a big bit somewhere else and don't expect the forecast to be exactly correct.
DO.

[IO540]

That sounds either like a bodged breather pipe, or bad maintenance, DO. The crankcase breather pipe is behind the engine, in fact it should be between the bulkhead screwed to the back end of the engine, and the firewall.

The bit of the breather which sticks out into the airflow at the bottom of the plane could ice over, but the pipe itself is supposed to have a hole part-way up it (protected by the cowling) which will remain clear should the exit get blocked.

That hole also serves as a vent to prevent airflow past the exit end from creating a vacuum and sucking the oil out of the crankcase.

Sounds like that hole is missing, or was blocked up.

Prop icing is a funny one. I have a TKS prop and see no measurable speed loss with say 3-5mm of clear+rime ice on the leading edges. I therefore think that some of the stories of 10-20kt speed loss at the first hint of ice are actually caused by prop icing and resultant loss of power.

[hum]

Chap I knew landed having spent a worrying time in the soup in a 182 'just below' the freezing level...

Thought he had an engine problem & snagged the aircraft afterwards as he could not get more than 18" MP despite being at FL80....

My guess is that he had intake icing even though no airframe icing was apparent...

Know how the air gets to your engine and consider what would happen if you were flying in moist air close to freezing point ... I've had intake icing on more than 1 occasion caused, I suspect by local pressure (and therefore temperature) drop in the intake. Know if you have an alternate air system and keep it in mind if you get an unexpected MP drop close to icing conditions... Aircraft can do reasonably well with airframe icing present, but intake icing can be very bad news indeed...

Happy New Year :)

[debiassi]

A lot of newer aircraft do indeed have an elevated secondary breather escape as a lot of aircraft actually went down in cold weather operations due to that exact problem in earlier aircraft. I know a lot of ferry pilots who adapt the oil crankcase breather pipe as part of winterization techniques.

[dont overfil]

IO540As you say it was sloppy maintenence. No "whistle slot" in the breather pipe.On a separate note. In a C172 at FL85 in spring I kissed the top of a large cumulous for perhaps 15-20 seconds and emerged with the screen frosted over and icicles streaming back from the struts. (And probably elsewhere that I could not see.)DO.

[dont overfil]

What's happening here?