@what next: excellent report, thank you. Other than choosing a better airplane, what do you think you should have done better? Stop the descent and climb back up when you realized that you were picking up ice? I presume you knew the cloud base and roughly also the temperature profile so you could expect continued icing. Have you thought about a rapid descent (> 2000fpm)?
"There is some amazing research going on into surface finishes which prevent ice sticking"
Yes - this is presumably it?
http://www.avweb.com/avwebflash/news/NewTechnologyForIceRepellentWings_206841-1.html
In a deiced aircraft the best way to handle ice is to avoid it. In a non deiced aircraft, and that means any aircraft not certified for flight in known icing conditions the ONLY way to handle icing is to avoid it. That means the OAT is above freezing when you are in cloud or if it is freezing you are not in cruising in cloud. Climbing or descending can be done safety but only with a guaranteed out. That means for a descent there is above freezing temps above the MEA or you wil be below the cloud. Climbs are more problematical as the worst icing is often just before you break out on top. So if you are going to climb through you must have a recent PIREP of the tops and ideally have only a few thousand feet to climb. Before climbing go to full power, not climb power and accelerate to max speed before starting the climb.
In any case, even if you are in a deiced airplane as soon as you start getting ice you should do something. Climb of descend as appropriate immediately don't just stay there chugging along in cruise watching the ice accumulate.
The only time I didn't follow that advice I paid the price. I was in a deiced Navajo flying over the mountains to Vancouver. I was 7 miles from the fix that would let me descend to an altitude below the freezing level when we started picking up ice. By the time I made it to the fix I was at full power, best rate of climb airspeed and starting to loose altitude. If I had 3 or 4 miles further to go I would have descended into terrain......
I agree with Big Pistons, avoid the ice. The type I most prefer to encounter ice in is the Piper Aztec. It will carry some ice. A C172/182 will carry ice, I have seen it, but it is not worth the risk. Anyone who tells you it's okay to do in a non icing certified aircraft is very foolish.
Three times in my flying career, I have been flying an aircraft which was descending or not in control due to icing. You would think that once would have been enough, but the second was a Twin Otter over the south of France in August - who'd suspect ice?
The third time was the most scary, it happened while ferrying a very new Cessna 303 with my friend Bill....
Bill and I were ferrying a Cessna 303 from Canada to England, for delivery to it’s new owner. With lots of Cessna 310 and 340 experience, I felt extremely comfortable flying the 303, and off we went. This particular aircraft was very well equipped, with full IFR equipment as one would expect, and full known icing equipment. So there we were, flying in IMC, though often with a view of the ground, but picking up ice. No problem, I just selected on all of the deicing equipment, and had a look around the aircraft to assure that is was functioning. The boots on the wings, and just the very tips of the horizontal stabilizer could be seen, and I was able to confirm that they were operating as expected. Obviously, the boot on the vertical fin could not bee seen, and this was an act of faith.
After a while, and while obviously picking up some ice, a slight twitch in the yaw axis developed. It was about what you’d feel if you were alternatively pushing the pedals a little. I looked over at Bill’s knees, and asked, “Are you playing on the pedals down there?” But as I asked, I observed that his knees were still, so this was not his doing. Next I scanned the engine instruments – they indicated that the engines were both purring. The twitching in yaw got a little worse, and was now noticeable in pitch as well. Whatever it was that causing the twitching was making be nervous. When I’m nervous, I like to be closer to maneuvering speed (Va), in case something unexpected happens. So, I pulled the power back, and began to slow down…
As the plane slowed, we were suddenly rodeo riders, the plane was yawing and pitching violently, though roll control was prefect the whole time. Yaw was ten degrees either side uncontrollably, and pitch, though harder to estimate, was enough to give us quite a variation in “G”. Whatever the problem, slowing down made it a lot worse, so I sped up, and it settled down. The only thing it could be was airframe ice, nothing else would seem to have changed since we took off. But this was a known icing certified aircraft! So I flew as fast as I could, knowing that whatever it was, was getting worse, and we were still in the ice. At the higher speed, anything bad which happened, would happen worse, and faster! I had to get out of the ice.
We were able to descend, flying up the valleys in the mountains, not far from Wabush, Labrador. We were lucky enough to find warmer air, and the ice slowly shed on it’s own. An hour or so later, I landed in Shefferville, Quebec for fuel. Of course, slowing down, was an exercise in extreme caution. But the plane handled perfectly. The after landing visual inspection revealed no ice, or other defects at all. Mystery… Our trip continued….
Bill was flying the leg from Iceland to Scotland. I was bored. Searching for some new stimulus, I found the previously unread flight manual for the aircraft, and browsed. Among the commonly found white pages, was an uncommon fluorescent red one. To it’s corner, stapled a tiny zip lock bag, which contained a placard. My interest was peaked now (better late than never). The information on the page instructed that flight into known icing conditions was prohibited, and at the first encounter, an immediate 180 degree turn was to be executed. The placard in the zip bag simply said “Flight in icing conditions prohibited”. Well that was clear! But, with the placard in the bag, and the bag in the book, and the book in the glovebox, the pilot (who had not bothered to read the book prior to flying) had no way of knowing! To read on, it turns out that because the Cessna 303 has a “crucifix” tail, meaning the horizontal stabilizer is mid way up the vertical stabilizer, their respective leading edges form a cross. The middle of this cross was not deiced, and thus a block of ice would form there, and disrupt the smooth airflow over the tail. The result was (in several cases) fatal inflight breakup of the aircraft, due to loss of pitch and yaw control. This, I could imagine! This flight manual page, and placard were required by airworthiness directive 86-01-01.
The final instruction on the page was to install the placard. I did.
I understand that soon an electric pad was developed for installation on the offending leading edges, to correct this design deficiency.
I learned from that to read the flight manual before flying. I don’t know how close we came to breaking that plane up in flight, but it was a lot closer than we should have come!
In years later, my friend Bill was solo ferrying a PA28-235, and encountered unforecast ice. He told me after the accident that with full power applied, he was descending (at night) at 2000RPM, 70 KIAS, and 2000 FPM, and hit the ground that way. I went to meet him in the hospital the next morning. He was months in the hospital after that.
Ice terrifies me.....
Achimha,
Congratulations on getting your IR. The responses to your question are unlikely to have lessened your fear of flying in icing conditions. Icing can be very serious as the posts confirm. But in my view if you want to use your IR you are need to become familiar with flying in potential icing conditions. Otherwise you will never use your rating as a means of private air transport in the UK, To climb on top and descend back down often means picking up a bit of ice, but it is no big deal if you have a clear plan of how to deal with it. The plan is get out of it by climbing further or descend, having thought about the terrain ground temperature issue before hand. Sometimes you will be in controlled airspace and find that you are in cloud and starting to pick up ice. An immediate call to the controller requesting a change to x level due icing will lead to swift and helpful response. I will fly in clouds at minus degrees but never if the surface temperature is below 5 deg.
I quite agree... ice is not to be feared, but one needs to use the weather data cleverly (the traditional aviation weather forecasts like SigWx are IMHO not very useful for non-deiced planes) and one needs a clear Plan B.
What I am not happy about is when some pilots (nobody here, yet) write, without considerably qualifying it with their aircraft type, deice equipment list, etc, that icing is rare and flying through e.g. frontal weather in icing conditions is fine. It will be fine - until it gets you.
I have picked up some ice about 90% of the time in IMC between 0C and say -10C. 1-3mm builds up just about every time and is completely routine. Apart from the one "controlled experiment" I described, it was never an issue because the flight was planned and done so that not enough time was spent in the stuff.
I have to say that this is why my squawk list in the US on the new plane included replacing the heated windshield at a nosebleed price - it worked but not properly (thin wires, large thermal gradient and pressurisation cause problems with it in the Pa-46). The deicing equipment is not something to cut corners on.
Good morning!
@what next: excellent report, thank you. Other than choosing a better airplane..
... Every airplane, even the better ones, has a limited tolerance regarding icing. There are quite a few airliner accidents (even fairly recent ones like Colgan Air 3407 into Buffalo in 2009) that were caused by icing.
what do you think you should have done better? Stop the descent and climb back up when you realized that you were picking up ice? I presume you knew the cloud base and roughly also the temperature profile so you could expect continued icing.
With hindsight, two options come to mind: 1. Before we started picking up ice, we had come from clear air that was all over southern Sweden. So after a few minutes of getting more and more ice, and with a destination ATIS that reported snow showers and freezing temperatures on the ground, the best course of action would have been to turn back. As simple as that! That's what I brief my students now: If we pick up unpredicted or onforeseen ice in conditions where melting the ice during descent is not likely, we turn back. Without delay, without further discussion. 2. When it was clear that we would get into severe handling and performance difficulties with this airplane, we should have diverted to Stockholm Arlanda instead of continuing to Bromma. Bromma is in the middle of town and a failed go-around would almost certainly have resulted in crashing into houses, whereas Arlanda is outside town with enough clear space for a forced landing.
Have you thought about a rapid descent (> 2000fpm)?
I have done that on other occasions. But it really only helps when you are between layers or outside icing conditions in order to keep the exposure to ice to a minimum. In our case, the whole volume of air produced icing, so it wouldn't have made much difference.
Re: Jason's point. There's another reason to ensure that the windscreen heater is serviceable in a pressurised aeroplane. The windscreen strength drops right down if it's not in the right temperature range.
My personal most "not in the textbooks" - inadvertently flying into falling snow that wasn't visible outside of it in a flexwing microlight. Discovered eventually that I couldn't see forwards, but could see sideways - as soon as I turned my head the snow blew off my visor (and when I looked sideways I also eventually noticed that my arms had turned white). Very alarming as you can't see the wing leading edge in that position, and had visions of all sorts of nasty shapes building up. So I flew using minimal control inputs, watching for any change in handling or performance, got out of the conditions ASAP, and landed. On inspection, not a solitary flake of snow left on the aeroplane after landing.
My personal most disconcerting. "Just" cutting through a 500ft layer of cloud whilst climbing from 7000 to 9000ft in an AA5. Came out on top with the entire canopy iced up. Fortunately it melted off well before my destination - but a reason to have an IMC/IR that hadn't occurred to be before. If I had that "just" 500ft of cloud again in front of me in potential freezing conditions, I'd turn and climb before it.
G
I posted this on another thread this evening, just interested in folks' view on this - an electrical de-ice system which the manufacturers claim eliminates run-back. Surprised it is not more widely utilised to be honest..
