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tomboo
2nd Dec 2011, 19:59
This will be my first winter as a PPL. Any thoughts or advice? Particularly carb ice and cold related issues !

A and C
2nd Dec 2011, 20:08
Don't fly an aircraft with ANY ice on the airframe !!

IO540
2nd Dec 2011, 20:10
Carb ice is nothing to do with the winter!

You should go to your flying school and ask for a refund (not kidding).

BackPacker
2nd Dec 2011, 20:27
Like IO540 said. Or hit the books and look what they say about carb ice. I also think there's an AIC or something about it.

Winter offers fantastic flying opportunities, but you've got to keep track of the weather and seize the moment. You can't expect bookings three or more weeks in advance to work.

Best flying is just after a cold front has passed through. Unlimited visibility, crystal clear air, excellent aircraft performance, virtually no turbulence. And if the cold front dumped a lot of snow, you get an amazing scenery too.

Technically speaking, like A&C said, don't fly with ice on the airframe. Be careful with all kinds of scrapers as windshields are easily damaged: Ask the owner/operator how they want you to de-ice the plane. Revise your starting technique as winter is really hard on the batteries. Ideally you will want to start the engine immediately but this only works with proper priming and the right throttle/mixture setting. Be gentle on the engine too: warm it up properly, don't make rapid power changes if you can avoid it, shut it down properly. Know how the heater and defrost work - it's not always obvious, and sometimes quite different from what you find in your car.

On larger airports you may find that not all intersections and taxiways get equal priority in getting cleared. Even at your home airport, you might get different taxi routes than normal. If you go to minor airports, particularly grass strips, you might find the snow not cleared at all. Remove wheel spats in advance as they easily clog up, and keep a very careful eye on the brakes during the preflight.

RTN11
2nd Dec 2011, 20:33
Get to the airfield an hour earlier than normal to make sure you have time to de-ice the plane properly. Don't do a rush job with a credit card, make sure you get all the ice off, and don't neglect the elevator.

Don't fly through a snow shower, it's really not very fun.

The only big issue of carb ice in winter is a taxi over wet grass when the temp is in the right range. Talk to an instructor and look at the carb ice table, found in many locations such as LASORS. In flight it's more common in summer temps, but continue regular checks as usual.

Scottishflyer182
2nd Dec 2011, 21:11
Hi Tomboo,

I used to post here regularly and ask for help and advice but stopped, as you see from the second reply, some of these guys are so up their own arse’s you don't really get any useful help. It really pisses me off...........

As a new Pilot you do have a lot to learn now that you've got your licence, Well done BTW.... I know before I even type this I'll be corrected or told that its poor advice but WGAF. Some of the best flying days are clear blue skies in the winter, no thermals its as smooth as silk and really good fun. What you need to watch for is any visible moisture (rain or clouds) if its very cold, So don't fly on cold days when its raining or be tempted to fly through some fine clouds.

Flying is a continual learning process, enjoy it.

SF

RTN11
2nd Dec 2011, 21:20
speak for yourself, I was trying to give some constructive advice.

One more thing is make sure you take plenty of warm clothes when you fly. You never know when your heater will pack up, or worst case your engine fails and you end up somewhere cold waiting for help. Maybe even pack some sort of emergency supplies like they advise you do in your car, blanket, torch etc.

Also the low sun is very annoying. Think ahead if you're going to end up making an approach close to sunset with the sun right in your eyes. It may not seem normal to bring sunglasses in December, but I use them more than I did in June.

IO540
2nd Dec 2011, 21:24
I used to post here regularly and ask for help and advice but stopped, as you see from the first reply, some of these guys are so up their own arse’s you don't really get any useful help. It really pisses me off...........You may have inadvertently hit the nail which applies to so many questions on pilot forums.

Too many people post one-liners, which can be answered only with an essay. Obviously I have no idea whether the original poster wanted an essay but you don't need a PhD, or indeed much if any knowledge of aviation, to know that a one-liner such as

This will be my first winter as a PPL. Any thoughts or advice? Particularly carb ice and cold related issues ! is hugely unlikely to elicit a useful one-line reply.

Some one-liners can be answered in a flash; e.g. if you ask what is the minimum # of hours for a JAA PPL, the answer is a simple 45.

But not this one.

There is actually a lot of experience on this forum but most of the writers have written a lot of stuff, over years, helping people out. Most are not going to bother when the original writer has just thrown in a one-liner question. Whether you like it or not, that's human nature.

If somebody wants a half decent reply on a somewhat wide topic, they need to make a bit of an effort, and show that they have given the questions some careful consideration. Probably easier said than done if posting off an iphone but there lies another common problem..... :ugh:

ZeeDoktor
2nd Dec 2011, 21:24
You didn't say where you fly? Give the briefings more time, choose an alternate as if it were your destination, because very likely it will be, and like the others say, never fly with any ice at all. If you do encounter icing conditions, remember that your safe escape could be to climb, not descend.

Take this as an incentive to start on that instrument rating also!

Doc

Scottishflyer182
2nd Dec 2011, 21:25
Hi RTN11,

I was not talking about you as yours was not the second reply,

Your advice was constructive and I think helpful to Tomboo.

SF

IO540
2nd Dec 2011, 21:30
I would not say "zero ice" is a must.

What is important is to not have it on the flying surfaces (wings, elevator).

Having some on the hull is OK, within reason, in general. It does increase friction but it won't increase the stall speed (of either the wing or the elevator) which is what normally gets people who have not de-iced their plane properly.

Scottishflyer182
2nd Dec 2011, 21:32
That's much better IO540........... some useful advice....

SF

IO540
2nd Dec 2011, 21:54
Which bit... the one about people writing one-line questions can't be expecting useful answers, or the one about ice?

Scottishflyer182
2nd Dec 2011, 21:56
:) who knows

RTN11
2nd Dec 2011, 22:03
Ice is obviously the hot topic.

The fact is it's a complete unknown. On a PA28, you could probably get away with 1mm, maybe 2mm or even more but where is the point where it is too much and you will notice the affect, possibly leading to a spin and fatal accident.

That's why it's better in this case to be over cautious and make sure there is absolutely no ice anywhere on the airframe.

Pilot DAR
2nd Dec 2011, 22:11
When flying in below freezing temps, consider carefully the need to follow the flight manual recommendations for possibly adding alcohol to deice the fuel. Avgas with ice crystals has put me on the ground twice (the second time, alcohol had been prohibited, I had that reversed!).

Winter is a magnificent time to fly, as cold as -15C just gets better. -40C is getting too cold...

bad bear
2nd Dec 2011, 22:17
no carb icing here!

Mad Dogs and Glider Pilots - YouTube (http://www.youtube.com/watch?gl=US&feature=share&v=x46ffIbdRA0)

A and C
2nd Dec 2011, 22:49
I read all sorts of rubbish on these forums about Nif-Naf & trivia invalidating the C of A because of some sort of leagal rubbish.

Ice invalidates the flight manual because of the laws of physics.

Only one of the rule infractions carrys the death penalty.

Pilot DAR
2nd Dec 2011, 23:25
The fact is it's a complete unknown. On a PA28, you could probably get away...with none.

It's quite well known.

Airframe ice and winter flying are only somewhat related. My worst experience with ice had us falling 6000 feet, in control, at maximum power, and below best rate climb speed. It was August, over the south of France. We fell to warmer air, and continued on, much the wiser.

If you are flying VFR, and encounter ice, and turn around to exit at the first sign, you will be safe. Other than that, this is a whole different discussion, and not really centered on winter flying.

Anyone who intentionally continues flight in icing conditions in a non equipped aircraft is a fool.

RTN11
2nd Dec 2011, 23:41
That was my point.

I've seen guys go flying without clearing the hoar frost and get away with it.

The chances are, you could possibly get away with a small amount of ice on an aircraft not cleared for it.

However, you are entering completely unknown terriotory by doing so, and so the safest bet by far is to make sure you clear all the ice from the whole airframe before you fly, and do not enter icing conditions while enroute unless you have the kit to deal with it.

Plus, you're adding to the chance that something will go wrong, and if it does you're in serious trouble. Even if the accident is not fatal, how is the aircraft owner/insurance company going to view you knowingly going flying with hoar frost still on the wings. It simply isn't worth the risk.

IO540
3rd Dec 2011, 07:19
In these debates, everybody who wants to look good will always take the position of an absolutely clean airframe.

It is a bit like arguing against CRB checks for PE teachers ;)

But, as I said, there is a world of difference between muck on the wings etc, and muck on the hull. The latter is just a bit of friction. People fly with planes covered in dead flies... The former is what is going to get you because it messes up the lift.

And different planes have different tolerances.

I don't fly a PA28 (nowadays) but a few mm as absolute maximum sounds reasonable.

This is structural ice. Carb ice is a completely different issue.

A and C
3rd Dec 2011, 08:06
It is not a case of looking good, it is a case of flying an aircraft with unknown propertys due to the changed wing shape.

I would agree that a small amount of hore frost on the fuselarge is not likely to result in any aerodynamic problems with the flying of the aircraft however will it result in problems with the static ports and give errors in the ASI readings ?

Older low tech wings are likely to be less effected by ice however the newer composite aircraft are using wing sections that are far more advanced and the shape is far more critical so much so that gliders are fitted with devies that clean flys from the leading edges in flight to maintain performance.

The whole ice subject is so fraught with unknowns that the only policy in my view is no ice unless the flight manual offers some advice on the subject.

Jim59
3rd Dec 2011, 11:03
I've been flying a lot recently and always do through the winter. Some of my tips would be:

Fill up the tank after flying. Full tanks get less condensation in them.
Clean the windscreen well before every sortie. Flying into a low sun with a dirty windscreen is very difficult - especially if there is poor visibility anyway.
If you will be landing into sun late in the day you might want to have second thoughts about departing!
Enough has been said about ice / frost on the airframe.
If on grass it will be wet - allow for the longer landing distance.
If muddy at the end of the day, and frost is expected, do you really want to give it a good wash and fill all the hinges and other orifices with water?

Pull what
3rd Dec 2011, 12:00
On a PA28, you could probably get away with 1mm, maybe 2mm or even moreCan you explain how you have come to this conclusion? I assume you have test flown a PA28 with more than 2mm of ice adhering to the airframe.

It does increase friction but it won't increase the stall speedWrong - ice always increases the stall speed by reducing Cl and increasing weight.
Friction? Ice increases friction- so your car stops more quickly on ice does it?


Many years ago the CFI of the Edinburgh flying school was seen to be religiously sweeping all the snow from the wings of a C152. Minutes later he spun in on take off.

FirstOfficer
3rd Dec 2011, 13:23
Greetings,

please check:

List of Safety Sense Leaflets | Publications | CAA (http://www.caa.co.uk/application.aspx?catid=33&pagetype=65&appid=11&mode=list&type=sercat&id=21)

Safety sense leaflet 03 - Winter Flying

:ok:

IO540
3rd Dec 2011, 13:26
ice always increases the stall speed by reducing Cl

On the wing/elevator, yes.

tomboo
3rd Dec 2011, 13:33
Thanks for all the helpful advice, see, a one liner can inspire some useful responses and also start an argument! Amazing. Further more, when I read a post I don't like I don't respond!

As for the direct criticism of my own flight training, I'm afraid you misunderstood my question, rtn11 got it. I simply wanted to know if there were any issues that the PPL syllabus doesn't cover.

I would hope that we are all calm, friendly and reasonable in the air! It seems to me a lot of the threads degenerate into a willie waving competition, with some really useful stuff thrown in!!!!

Happy days

Pull what
3rd Dec 2011, 13:40
please check:

List of Safety Sense Leaflets | Publications | CAA (http://www.caa.co.uk/application.aspx?catid=33&pagetype=65&appid=11&mode=list&type=sercat&id=21)

Plus
Safety Sense Leaflet 14: Piston Engine Icing

Pull what
3rd Dec 2011, 13:47
As for the direct criticism of my own flight training,

Dont worry about that incorrect remark, carb icing has plenty to do with winter-autumn spring and summer too-its not seasonal, it is temperature and humidty related. As we all should know in this country you can get any of the so called seasons anytime. Ive got summer flowers in flower in my garden and its December!

RTN11
3rd Dec 2011, 17:53
Can you explain how you have come to this conclusion? I assume you have test flown a PA28 with more than 2mm of ice adhering to the airframe.

I've certainly flown with at least 1mm of rime ice on the leading edge. Didn't fall out of the sky, and as soon as we descended it melted right away.

The whole point is that it is a complete unknown, noone knows how much you can get away with until it's too much and there's a serious problem.

Obviously, if it had been much more than 2mm, and we had intentionally stalled, things could of been more lively, but this was a simple IMC lesson, and picked up a small bit of ice shortly before commencing the approach, so I saw no big issue in continuing as normal knowing warmer air was only a few hunderd feet below.

IO540
3rd Dec 2011, 19:16
I agree with that, but let me inject a little bit of reality.

How long has the PA28 been out? A few decades. Countless tens of thousands are (or have been) flying.

I simply do not buy that 2mm is going to bring one down. I am not a 20,000hr pilot (and anyway most of those do it in a big jet) but I have seen enough IFR, and since nearly all formal IFR I do is high altitude (Eurocontrol flights) I have seen plenty of icing. Summer or winter, some icing on almost every flight, FL140+.

Most of it is just light, but 1-2mm is really easy to pick up. You can get it in seconds. I wouldn't bat an eyelid at 2mm; it is barely visible as a bit of frost in between the rivets on the leading edge, and it doesn't show up on the speedo at all. And the shape of my wings is not much different from a PA28.

If you fly a plane which will plummet at 2mm (and I am sure there are some laminar designs that will do that) you better forget all flying in IMC below 0C unless you have full TKS (£30k or so - more than most PA28s are worth) and you use it - ~ £200 per hour is what it costs. Or rubber boots, and they better be working (many aren't) but few modern and potentially ice-sensitive designs use boots.

My guess is that 2mm of rime is going to increase PA28 Vs by a few kt. So you won't be doing a max performance landing into Deanland :)

I am also pretty sure there is plenty of urban knowledge on this, but they are not going to be posting it here because most are renters and are going to get a bad name :)

What you can't do is just sit there and let it build up and up and up, with no way out (which usually means a descent into warmer air). If in IMC below 0C you have to watch it like a hawk and be considering your options. But that applies to any non-deiced plane. One cannot embark on a flight in potentially freezing IMC, for 1-2hrs, with no way out.

If you have an IR, then you would file for FL100+ and climb up through the thin layer discussed and sit there in sunshine. With the IMCR you are basically a "VFR" flight as far as ATC are concerned (declaring yourself "IFR" does not get you anything) and you get pushed down below CAS, and that is the one area where an IR is useful in the UK over an IMCR. With the IMCR, winter flying is mostly going to be below cloud unless one can be sure one can climb above it without going into CAS.

500 above
3rd Dec 2011, 20:32
http://http://www.aopa.org/asf/publications/sa11.pdf

http://http://aircrafticing.grc.nasa.gov/courses.html

1 of 3, Aircraft icing loss of control - YouTube

http://http://video.google.com/videoplay?docid=3493859021331008391

All the best.

The500man
4th Dec 2011, 08:58
This might also be of interest: Aircraft Icing Training - Courses (http://aircrafticing.grc.nasa.gov/courses.html)

goldeneaglepilot
4th Dec 2011, 09:31
Simple advice - if you are a newish ppl holder, dont fly the aeroplane with ice on it. Some aircraft are more tolerant than others, but why take the risk? I disagree with IO540, trying to put a figure on what is an acceptable amount of ice on a PA28 can lead to deaths, thats why its not in the POH - how do you measure the ice? where do you measure it? Those are all valid questions. Why not just follow the POH? CLEAR the ice / frost off before flight. If you are in flight and you get some ice that was not predicted, do something to change whats happening before your trying to fly a giant ice cube, climb, descend or turn back, dont blindly push on in an aircraft not equipped for ice thinking it will get better. Its too big a gamble.

If you want extreme for airflow disruption due to objects on a wing, try the Rutan Longeze, the SLIGHTEST precipitation in the air reduces cruise by 10kts, and you often feel the aircraft trying to pitch nose down with a reduction in airspeed BEFORE you even see the visible precipitation.

To say that the TB20 has a similar wing to the PA28 is even more ludicrous of IO540. Even small changes in planfom, aspect ratio, chord thicknes or most important of all airfoil section can have dramatic effect on an aircraft performance and tolerance to different things.

IO540
4th Dec 2011, 10:49
We are talking cross-purposes (as usual).

I didn't write that one should takeoff with any ice on the wings or the elevator.

I was referring to the hull (the cockpit exterior, etc).

My other comments on how much ice a PA28 could perhaps carry refer to in-flight icing, and decisions based on that.

I will leave this discussion now, because like I said it is like arguing against CRB checks on PE teachers.

dont overfil
4th Dec 2011, 11:04
I have experienced prop ice on a PA28 when there was no more than a hint of frosting on the leading edge of the wing. Not pleasant!
I have also had the engine breather ice up. The result was oil being pumped out of the front crankshaft oil seal over the cowling and windscreen.
Ultimately if you don't takeoff with ice on the flying surfaces and don't fly in rain or cloud when it's below zero you should be OK.
Ice often forms first around the OAT probe above the screen on PA28s.It is a good early warning.
If you do fly in cloud in winter, always have an escape plan.
D.O.
ps Not flying today. Runway covered in ice and snow.

Jumbo Driver
4th Dec 2011, 11:06
IMHO this thread is beginning to degenerate from what is safe or not safe towards a potentially dangerous set of "what-you-can-get-away-with" opinions.

The Summary on the final page of the Safety Sense Leaflet 3 - Winter Flying (http://www.caa.co.uk/docs/33/20110217SSL03.pdf) says it all.

Please read it. Do not fly with ice or frost or snow on the aircraft and do not fly in icing conditions. It is really quite simple.


JD
:)

Pilot DAR
4th Dec 2011, 11:48
"what-you-can-get-away-with" opinions.

Yes. This to me is one of the few, but major problems with PPRuNe. The "P" does stand for professional, does it not? There are many things I have done, and survived, but that does not mean that I'm going to describe them here, or suggest that they are safely possible. I'm not going to mention them at all, or simply state that based upon my experience, they should not be attempted. It's the only moral and and "professional" thing to do.

I have first hand knowledge of the skill and experience of about ten PPRuNers, the rest of you are a guess to me. I will not be the one who describes something I know may be possible, albeit with lots of skill, many variables, and a big risk, to an audience of people whose skill and experience is unknown to me. It is the safe, conservative, and professional thing to do, to first say, follow the Flight Manual, and there after, generally "if you have to ask - no".

Similar to fooling around in icing, we recently had a thread inviting comments about aerobatics in non aerobatic aircraft. We do not need to "ramp up" the excitement on PPRuNe, by increasing the threshold of risk the participants should accept as normal. If anything, based upon increasing tribal knowledge, the threshold should be reducing, unless new technology is mitigating it. We have deiced aircraft, use them for icing conditions, we have aerobatic aircraft, use them for aerobatics, we have floatplanes, use them for water landings.

Some silly pilot sees or reads about water skiing wheel planes (Ok, I'm assuming), and then an a plane is up side down in the Derwent river. Apparently that pilot tried something else that did not work either. He did not know that the technique is not possible in tricycle aircraft! I sure hope the advice to attempt that was not presented on PPRuNe.

My entire job is to test and evaluate modified aircraft to assure that they do what they are supposed to, don't do what they should not, and have a margin of safety to allow for variance in pilot skill. I sure am not gong to participate here in enticing pilots of completely unknown (to me) skill and judgement, into those risky corners I spend my working day trying to keep them out of!

Contributors here would, in my opinion, do best to offer advice, which conforms as closely as possible to the approved and accepted practices usually presented in the Flight Manual, or national regulations.

goldeneaglepilot
4th Dec 2011, 11:55
From the CAA safety booklet:

e) Ensure that the entire aircraft is properly de-iced and check visually that all snow, ice and even frost, which can produce a severe loss of lift, is cleared. This includes difficult-to-see ‘T’ tails. If water has collected in a spinner or control surface and then frozen, this produces serious out-of-balance forces. There is no such thing as a little ice.

RTN11
4th Dec 2011, 15:22
I had to stop a private hirer today. He was happily sat in the aircraft, having deiced the wings, about to start up. He had completely negelected to deice the elevator, which in many ways is more serious than wing ice.

Thorough de-icing of the whole aircraft should simply be standard, even the fuselage (although good covers prevent most of this).

Johnm
4th Dec 2011, 19:26
The start point is zero ice on the flying surfaces and windows before you taxi. Use a proper de-icer and don't attempt to scrape it off with credit card or similar as it won't work and will do damage. Don't simply rely on fuel drain tests to ensure no water in the fuel, 'cos the water may well be lumps of ice! Make sure that you are reasonably confident that there was no ingress into the tanks while the aircraft was standing.

While taxiing (ESPECIALLY on grass) make sure that you use carb heat extensively, but don't leave it on for take off.

As a new PPL you won't be flying through clouds but you might have to fly through visible precipitation and you may pick up a bit of ice. If you do, don't panic but be sure to add a few knots to approach speed until over the threshold if it's still there at low altitude.

Those really cold gin clear days when the air is smooth and you can see for miles and aircraft performance is at its best are a delight for pilots, enjoy!

mm_flynn
5th Dec 2011, 06:09
I know many readers already know this, but for the benefit of the OP...

It is important to understand there are two totally separate icing issues under discussion and they effect performance very differently

1 - Airframe icing collected inflight

Usually involves only the leading edge of the airfoil and windshields
Increases stall speed due to extra weight
Increases/changes stall characteristics due to changing airfoil shape
May result in an airfoil that is 'unflyable' if you make a configuration change (like extending flaps)


2 - Frost collected when parked.

Usually involves the whole upper surface of the airfoils
Acts by increasing friction (which contrary to an earlier post is actually true). A small degree of roughness on the wing surface can substantially slow the circulation of air above the wing.
Has negligable effect on weight
Can have a dramatic effect on lift due to the reduced circulation discussed above (which is the fundamental physical aspect of lift)


1 - Can be addressed with deicing/anti-icing kit, descent into warmer air.

2 - Can only be addressed with preflight clearing of ice.

The way 2 seems to kill people is, you rotate slightly above normal, climb in ground effect, stop climbing due to reduced circulation, pull pack to increase climb rate, Stall/Spin into the ground.

This does seem to be more common on modern airfoils and even two turbines pushing you sometimes results in the above.

goldeneaglepilot
5th Dec 2011, 08:36
Totally agree with the above post, a sad lesson can be learnt from reading the AAIB report for the crash of N90AG at Birmingham in 2002. Part of the report says:

During the morning, other witnesses stated that they had seen frost or ice on the wing surfaces of N90AG prior to departure.
Other aircraft, which had been parked overnight, were de-iced during the morning, with associated reports of moderate to severe ice or frost accumulations. Neither crew member requested de-icing, so N90AG was not de-iced prior to departure.

Sadly 5 people died due to the surfaces not being cleared.

Rod1
5th Dec 2011, 08:40
tomboo

There are a lot of people who will try to help you but more info would be useful! You have been given post after post on deicing but for all we know you fly an aircraft kept in a hanger. What sort of thing do you fly and from what sort of airfield?

If you want to keep the exact location secret fine, but give us a clue…

Rod1

Francis Frogbound
6th Dec 2011, 08:45
Rod1 and PilotDAR; very very good points.

I love winter flying, but it needs to be treated with great respect, after the Birmingham crash our simulator instructors came up with a demo on what it would be like on the jets we fly and it was not fun.

On my own aircraft (PA32) I use a soft brush on all surfaces and fluid on anything that won't clear by brush. A phenomenon I have seen is light ice left around the cowling/cabin area which melted in the heat from the engine/cabin and then ran back as water to the tail to create clear ice.

I have seen the anti-balance tab on a PA34 ice up and cause a nose up pitch moment. Finally I once flew a PA28 into unforecast ice in a hold (during ATPL training) the aircraft took up the charactersitics of a shot duck and came down no matter what either me, or the instructor did.

Watch how a large commercial aircraft is de-iced sometime, the flying surfaces are cleared with hot fluid and as far as possible the whole fuselage is cleared as well. Ice weighs a lot and taking off at MTOW with a couple of mil on the fuselage would put you over weight, outside of flight envelope limits with all the possible ramifications.Ice changes the shape and weight of an aircraft and means that you are flying an unknown quantity, that is the field of test pilots and best left to the likes of PilotDAR.

FF

robin
6th Dec 2011, 09:13
My aircraft is hangared so ice is not usually the worst problem. That is trying to get it started in very cold conditions like we had over the past 2 winters.

The danger is in over-priming when starting and I've seen a number of engine fires resulting from when pilots crank and pump the throttle vigorously.

Francis Frogbound
6th Dec 2011, 09:26
Robin;

When I bought my aircraft the previous owner threw in a PowerVamp external power unit. It is an absolute life saver in winter, charge it at home, keep it warm and take it to the airfield with you.

FF

peterh337
6th Dec 2011, 10:06
Finally I once flew a PA28 into unforecast ice in a hold

How do you forecast ice?

proudprivate
6th Dec 2011, 10:14
How do you forecast ice?


When there is (visible) moisture in below freezing temperatures.

Unforecast ice is when you are flying in the clouds (e.g. during a hold) and the temperature is lower than forecast; or when you fly high up in known sub-zero temperatures and you encounter an unforecasted cloud layer.

You are not allowed to fly into "forecast ice", i.e. into conditions you know will create icing, in an aircraft not equipped to deal with it as per POH.

Fuji Abound
6th Dec 2011, 10:54
Yes. This to me is one of the few, but major problems with PPRuNe. The "P" does stand for professional, does it not?


It does, but few on this forum are "professionals" in the sense they make a living from flying, and few are "professionals" in the sense that they have enough experience to stand apart from the majority who are relatively low hours PPLs. Please, that is not meant in a condescending way, it is a statement of fact.

There is not a professional who does not change his attitude to his profession with experience. That rubs both ways - some start off cavalier, get away with it, and become more restrained, others "go by the book" when they start out, but with time take a few "risks".

Ah, I hear some say, a professional should never take risks. If you are in the first group I hear your voice louder than most, beause that is what the non risk takers would say.

However, lets for one moment be realistic. There is risk taking and there is using your best judgement.

I recall the first time I "saw" ice. My mate was a BA training captain , ex RAF fast jet instructor - enough pedigree for me. I said I had never experienced ice and wondered what it was all about. A smile hovered on the edges of his lips as he said "I have control". We headed for a small (and I mean small) CB, and literally as we entered the cloud the windscreen frozen over completely. We reamined in the cloud for a short while but long enough to accumulate a reasonable amount of rim on the wings. Out we came into bright sunshine and within a very short time the windscreen cleared and the ice vanished. It was a very good lesson for a yound and very inexperienced pilot.

So whats my point.

Ice is dangerous - very dangerous, and best avoided at all cost. However, if you fly often and if you fly in more challenging IMC conditions you will encounter ice - not you might, you will. You might even encoutner ice in VMC. I recall a flight last year at night in very good VMC. It was below freezing down to the gorund and the air had been very humid during the day. As we departed en route there were half a dozen aircraft in the area - they all reported icing and not being deiced returned. I was fly a deiced twin and we also started to accumulate a surprising amount of ice.

So coming back to the "P" and the opening post - its your first winter season. Treat winter flying with the up most caution - make sure you depart with a clean airframe and dont fly IMC (I am guessing you dont have an IMCr or IR anyway). The usual rule of avoiding IMC conditions at all costs remains as sound as ever. Leaving aside the exceptional conditions I recounted earlier you will not accumulate ice in good VMC. As to the "P" when you have your IMCr or IR you will need a good understanding of icing and you will encounter icing at some time however careful you are unless you dont use your rating in earnest. You will learn what to do, when to do it and how far you can "push" the limits - or you will kill yourself. Simple really. Best you learn slowly by experience with others who have been there and done it than by yourself. Being a professional means above all else knowing how to deal with the unexpected and knowing when the right thing to do is get the hell out and when the safe thing to do is something else.

So it is easy to say never fly a non deiced aircraft in icing conditions but if you have an instrument rating and fly IFR you will unexpectedly encounter ice and you will have to deal with it.

Fuji Abound
6th Dec 2011, 13:10
Proudpilot - I think you will find IO540s question was a little tongue in cheek - if you will reflect we know that if there is visible moisture in below freezing conditions then that COULD cause icing - however that is not a forecast it is a statement of the actual conditions. In reality most area forecasts in the UK and Europe "warn" of the possibility of icing when often there is none. Forecasting icing conditions is still a very inexact science; it is true that if you never fly in conditions where the outside air temperature is below freezing and substantially true that if it is below freezing but there is no visible moisture you will not encounter icing but it is equally true that conditions below freezing and with visible moisture will not result in icing.

peterh337
6th Dec 2011, 13:26
I have never seen a forecast system for in-flight structural icing conditions, which tells you anything that is not obvious from one look at the MSLP chart.

Icing is a highly localised phenomenon, in both space and time. For 5 minutes, no ice. Next 5 mins, you get 1mm. Next 5 mins, you get 5mm. I don't see any weather model ever being any good for this.

If somebody finds a good website for this, I'd like to know.

RTN11
6th Dec 2011, 16:45
have never seen a forecast system for in-flight structural icing conditions, which tells you anything that is not obvious from one look at the MSLP chart.

Icing is a highly localised phenomenon, in both space and time. For 5 minutes, no ice. Next 5 mins, you get 1mm. Next 5 mins, you get 5mm. I don't see any weather model ever being any good for this.

If somebody finds a good website for this, I'd like to know.

F215 from metoffice.gov.uk offers a low level forcast (below 10,000') for the UK and F415 for Europe.

The symbol for moderate ice is a semi-circle (like a smile) with two vertical lines in the centre. Severe is three vertical lines.

See the key at the bottom of the page.

Pilot.Lyons
6th Dec 2011, 18:10
I know someone that asked their instructor how much frost can we go up with (the wings etc were apparently whiteover) and the cfi said that will be ok just get in and go!

And that didnt end in disaster but certainly didnt fill them with knowledge

Jumbo Driver
6th Dec 2011, 19:59
There are old pilots ... and there are bold pilots ...

JD
:)

RTN11
6th Dec 2011, 20:00
Certainly at some schools, pressure is put on Flight Instructors to get in the air early. This can sometimes mean going up in weather that isn't 100% suitable for the lesson, or pushing the boundries a bit more by flying with ice on the wings.

Deicing fluid is expensive, and is often overused (quite rightly) by people being over cautious, rather than used sparingly. From the point of view of the CFI/school owner, this is wated money, and even more wasted by the aircraft being on the ground being deiced.

Jumbo Driver
6th Dec 2011, 20:05
... and there are also cowboys ...

JD
:hmm:

Sir Niall Dementia
6th Dec 2011, 20:11
PeterH337/IO540,

There isn't one, and I doubt there ever will be one, the technology doesn't yet exist so we get hit with the blanket "NOT APPROVED FOR FLIGHT INTO KNOWN ICING" for almost all GA aircraft which basically leaves the pilot to decide if there is a risk of icing or not.

I spent a couple of hours in the simulator with Francis Frogbound while Verticalhold of these pages put us through a variety of icing scenarios which had been created by the training torturers. The worst case was in the middle altitudes where you would cruise a TB20, taken from FAA and CAA reports on rapid ice accretion it went from happy campers to "where the f++*! did that lot come from?" in a very short time and serious problems due to the rapid weight increase.

The day job aeroplane can even warn me of windshear, I really wish the bugger could warn of ice ahead rather than just telling me its' happening,
my playtime aeroplane only comes out when the sun is shining at this time of year and so I've never seen ice on her, but I don't think she'd do to well with it.

Pilot DAR
6th Dec 2011, 20:24
The following is one of the many very relevant passages from an accident report:

Frost contamination of the wing upper surface would cause the loss of approximately 19% of maximum lift coefficient, which would result in the stall speed in the turn being approximately 67 KIAS rather than 60 KIAS. Increased drag caused by frost contamination would result in a reduced rate of climb, explaining why the aircraft reached 200 to 300 feet when calculations show the aircraft should have reached 400 to 500 feet agl. The aircraft's stall warning system, with an audio and visual warning, should have activated 5-10 knots above the normal stall speed. As the pilots apparently did not react to recover from a stall warning and impending stall, it could be surmised that the stall warning did not activate before the aircraft stalled, indicating that the aircraft stalled before its speed reduced to 65-70 KIAS. Frost on the wings would result in a higher than normal stall speed and also inhibit normal impending stall indications such as buffet. When the aircraft stalled, it entered a spin, uncharacteristic of this airplane. Frost on the wings would explain the loss of control and abnormal after-stall characteristics of the aircraft. There had been frost during the previous night, and although no one apparently saw frost on the aircraft lifting surfaces before or after the accident, there is no plausible condition other than frost contamination that would explain this accident. It is therefore concluded that there was frost on the aircraft's lifting surfaces when the aircraft took off.

The whole report is here: (It's a very good read!)

Transportation Safety Board of Canada - AVIATION Reports - 2003 - A03O0088 (http://www.tsb.gc.ca/eng/rapports-reports/aviation/2003/a03o0088/a03o0088.asp)

If that does not give you the frost willies, I don't know what would.

I flew this aircraft just before the other pilots crashed it. I can assure readers, that it has a "high lift" wing, in the sense that pilots like the ubiquitous PA-28 wing, and lots of power to maybe help yourself out of a tight spot. The crash pilot was said to be very experienced on this aircraft type, and with winter flying.

http://i381.photobucket.com/albums/oo252/PilotDAR/Jims%20DAR%20Testing/FoundTUP.jpg

http://i381.photobucket.com/albums/oo252/PilotDAR/Jims%20DAR%20Testing/TUPwreckage.jpg

(sorry about the photo file size, Photobucket said it shrank them to 400 x 400, but I have my doubts)

Do you still want to fly with frost?

Sir Niall Dementia
6th Dec 2011, 20:41
Here's another one from Swindon of all places:

http://www.aaib.gov.uk/cms_resources.cfm?file=/Gippsland%20GA8%20Airvan,%20G-CDYA%2006-11.pdf

peterh337
6th Dec 2011, 20:42
It's curious how the FAA changed its advice over the years. They used to say polished frost (which is smooth) is OK to depart with, but now they want it all removed.

I can see why they used to allow a departure with frost if polished to a smooth surface - the average spamcan aerofoil is not going to be that critical if the layer is reasonably even. But personally I would remove it all. A bit of TKS fluid does it OK. I bet polishing the stuff takes just as much elbow grease.

Sir Niall Dementia
6th Dec 2011, 20:59
Peterh337;

Now you are entering into an area of serious arse covering. With the ambulance chasing lawyers there are in the US the FAA had to come up with clear instructions rather than grey areas, and rightly or wrongly they went for the most restrictive they could so that if a pilot went flying with a bit of ice it was his fault and the FAA could say "told you so" in court, EASA is going exactly the same way and I can see things getting a lot worse.

TKS is a good fluid for de-icing, Ive just never found a really good TKS system on and aircraft. Hot intakes and leading edges for me every time!

bartonflyer
6th Dec 2011, 21:03
A bit off topic for the initial question, but I certainly remember this - quite some years ago now, I trained to do a PPL/IR at Humberside on a Grumman Cougar, equipped with a TKS anti-ice and de-ice system. Lots of training, take off, ask "any ice" every 500' up in the climb and every time the answer was "no-ice"
Then came the day of the IR test, with CAA examiner on board , taxied out, took off, shutters closed and climbing away on instruments - "any ice" I said - back came the answer - "affirm - ice building" - "bl**dy h*ll" - I looked out of the side widow and sure enough there was a lovely layer of ice all along the leading edge - switch on the TKS to de-ice and the next thing was ice coming off the props hitting the fuselage - I certainly learned from that just how quickly ice can build up and I'd never want to fly in any aircraft that wasn't equipped to deal with it.....

But to the OP - fly in winter, it's great, but look for those cold clear days

btw - I passed the IR test!!

Maoraigh1
6th Dec 2011, 21:26
Just watch the weather. 25 years winter VFR flying from Inverness, and I've never encountered airframe icing. One risk not mentioned so far is 8/8 overcast, with a high cloudbase, and snow starting to fall from it. I've taken action to avoid this a few times. I have never flown into a snowshower. Visibility will be too poor. I would not attempt to take off with visible ice.
P.S. Is carb icing more likely on Konsin treated runways, and at temperatures which would seem too low? I'd have thought the runway mixture vapour pressure would not do this, but the O200 seems to react otherwise.

peterh337
6th Dec 2011, 21:28
Ive just never found a really good TKS system on and aircraft. Hot intakes and leading edges for me every time!

I have prop-only TKS, which works magnificently. Never had any ice on the prop (as far as one could tell) or the windscreen. And it costs little - 2 litres of the stuff lasts 1-2hrs on max flow (I don't use the low flow setting) and costs about £20. I get through ~2 litres a year, running it always in IMC below 0C.

The full TKS system, now costing ~£30k, is reported as similarly effective, and effective way beyond any certification limits, but maybe it is airframe dependent. It also avoids bridging, runback ice freezing, and punctured boots :) It also costs a packet, getting through some £200 in an hour, potentially. It's not an enroute solution, for that reason.

bartonflyer - didn't the examiner warn you well in advance of entering IMC conditions, so you had time to turn on the TKS? One "cannot" just turn it on when there is already a buildup, supposedly (though I gather that usually does work). I have my JAA IR test sometime soon and will need to sort this out, otherwise I will have to fly the entire test with the prop TKS running on full bore.

bartonflyer
6th Dec 2011, 21:33
Peter337 - no, it was unexpected - cloudbase around 450' as I recall, not particularly cold - we went up, straight into cloud and very shortly afterwards there was the ice!! Had the temperature on the ground been lower I would have set it to "anti-ice".

Mind you, this was some years ago now - memory may be playing tricks :\

RTN11
7th Dec 2011, 12:04
The most dangerous part of flying is still going to be driving to the airport, particularly with ice and snow on uncleared roads. Plan extra time to complete this journey, and don't get caught out. Particularly since a lot of GA airfields are in the middle of nowhere and quite difficult to get to by road. I've lost count of the number of times I've gone skidding past the entry gate, no matter how slowly I'm going.

pudoc
7th Dec 2011, 14:59
Taxi slow especially on grass. I have seem some magnificent looking holes in the ground where pilots taxi fast in winter and have to brake for a corner and they simply can't slow down, especially down hill.

I'd strongly suggest investing in some carbon monoxide detectors if you plan to use the cabin heat. Might just save your life.

I also find priming before the walk around to be helpful on the old 152s.

goldeneaglepilot
7th Dec 2011, 15:47
Peterh337

Why the apparent change of user name? you post earlier under IO540, with advice about safety and flying with ice/frost on the plane.

The posts under this user name seem same style of information

If you had lost the password I'm sure they would have given you another one!!

mrmum
7th Dec 2011, 18:11
GEP,
I've been thinking that myself, maybe 14018 is a significant number?