pdw wrote:That's the right line of questioning. I was checking WX data after-the-fact and noticed -11C at the surface at lift-off, which has to be at minimum 5 degrees colder up at the 5-8000 altitude ... and is forced down 20 minutes later, what gives ? How's that possible ?
I have not looked at the weather for the day so I'm just writing in generalities not specifics of the day in question. The temperature does not have to be cooler at 5000-8000ft altitude there could have been a temperature inversion.
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railroad wrote:I like your thoughts regarding the outcome Trey. This flight should not be described as a success.
However, I believe the pilot did an outstanding job of staying calm and professional. I think there is little to debate about his handling of the situation. There is much to debate regarding the events leading up to the incident. But as we debate this, it would help to stick to facts.
"Other companies and pilots were sitting on the ground that morning" ?? Please elaborate. If other companies or pilots had information regarding the icing that morning, that was so conclusive to park airplanes, it would be nice to share their sources. (I am not asking about the GFA or experience based knowledge, I am inquiring about the actual source of the information that was conclusive enough to have companies parking airplanes.)
That's like shooting your foot off, but doing an outstanding job of not bleeding to death. Should have left the gun unloaded in the first place?
Now, I've got a good chunk of flight time. I've flown Caravans on and off for the past 19 years. I'm actually current in the Van as we speak. I would not have launched with the WX information posted.
Illya
Generally if there is freezing rain then the temperature at altitude will be higher than at the ground. Google 'warm nose'. If that wasn't the case then you probably couldn't have freezing rain (it would be just normal rain).
This accident discussion is an excellent lesson in why pilots should be very, very careful when checking the weather.....eventually you will not be able to sleep before you can draw the present system in your mind.
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The hardest thing about flying is knowing when to say no
After over a half a century of flying no one ever died because of my decision not to fly.
railroad wrote:I like your thoughts regarding the outcome Trey. This flight should not be described as a success.
However, I believe the pilot did an outstanding job of staying calm and professional. I think there is little to debate about his handling of the situation. There is much to debate regarding the events leading up to the incident. But as we debate this, it would help to stick to facts.
"Other companies and pilots were sitting on the ground that morning" ?? Please elaborate. If other companies or pilots had information regarding the icing that morning, that was so conclusive to park airplanes, it would be nice to share their sources. (I am not asking about the GFA or experience based knowledge, I am inquiring about the actual source of the information that was conclusive enough to have companies parking airplanes.)
From the very first CBC article on the subject, from the third post in this discussion: "Buffalo Airways says it's holding some flights because of bad weather conditions."
If you're going to dismiss the GFA as not being reliable information, what more could be provided? Do you want samples taken by an aircraft specifically designed to measure icing catch rates? The GFA is a forecast created by trained meteorologists, and you can't just ignore it because you don't like what it says. Would you use an airport as an alternate when it doesn't meet the criteria because the TAF is just a forecast and can't be trusted? Would you ignore PIREPs that state that there's moderate icing because it's a different type of aircraft from the one you fly and therefore doesn't pertain to you? You don't get to pick and choose what weather info you use for flight planning.
I use the GFA everyday. I feel it gives me the best overall picture of what I may expect weather wise, as well, it later helps me understand what I encounter during flight. Had I been at work that morning, the GFA (clouds and weather) would have been my main source for weather information. I don't think the information in the GFA would have stopped me from flying that morning, but of course, I don't fly a caravan. If I was flying a Caravan, the trowel (occluded front) would have concerned me greatly, likely enough to keep me on the ground. Of course I am writing all this with the benefit of being a Monday-morning-quarterback with three cups of coffee and two hours of Sportscenter under my belt.
I would certainly not ignore a forecast prepared by the professionals; however, I admit I get frustrated with the guys who throw in the "possible icing" into almost every forecast from October until April. I believe it is there for someone's ass coverage, but it makes for an inferior product and reduces some of the credibility of the Forecaster. Unfortunately it appears to cause some pilots to even ignore it sometimes.
Anyway, the only reason I joined this thread at all was because I felt a poster stated some inaccurate information regarding other companies canceling flights that morning. It actually was accurate information. Yes, some companies and pilots did cancel and delay flights that morning, but to my knowledge, nobody stopped until after a pirep (from a company flying), and a Caravan hitting the ice.
Why was there no Icing mentioned in the TAF? People seem to be very quick to ignore this because icing was in the GFA, but that still does not excuse the fact it should have been in the TAF. Just looking at that GFA, it seems like textbook material. Anybody writing the TAF that morning would be forecasting based on that system on the GFA. It is elementary to expect ice with that system, as many have pointed out. The pilot missed it and so did the forecaster. Or did the pilot discredit it because of the forecaster?
To be the devil's advocate here, maybe the fact that pilots see icing in the GFA all the time, they look for another source to back it up. The TAF didn't back it up. The briefing from FSS for pireps, airmets and sigmets didn't back it up. The fact the forecast poor weather the evening before in Fort Simpson (which the company cancelled a flight for) did not materialize, all add up to give reason for giving less concern to the icing.
How would you have the icing put in the TAF if it occurred in cloud? Unless there was a ground-based layer forecast, which there wasn't, or freezing precipitation, which there wasn't, I don't see what would have been included in a forecast for the airport. It doesn't matter if there's icing in the clouds above the airport; if there isn't any on the ground, it won't be in the forecast.
railroad wrote:Oh, I also wanted to talk about that TAF.
Why was there no Icing mentioned in the TAF? People seem to be very quick to ignore this because icing was in the GFA, but that still does not excuse the fact it should have been in the TAF. Just looking at that GFA, it seems like textbook material. Anybody writing the TAF that morning would be forecasting based on that system on the GFA. It is elementary to expect ice with that system, as many have pointed out. The pilot missed it and so did the forecaster. Or did the pilot discredit it because of the forecaster?
To be the devil's advocate here, maybe the fact that pilots see icing in the GFA all the time, they look for another source to back it up. The TAF didn't back it up. The briefing from FSS for pireps, airmets and sigmets didn't back it up. The fact the forecast poor weather the evening before in Fort Simpson (which the company cancelled a flight for) did not materialize, all add up to give reason for giving less concern to the icing.
That icing should have been in the TAF.
Taf's do no forecast icing conditions. Even if the TAF says freezing rain, it does not forecast icing conditions such as rime, clear, light, moderate, etc.
This accident discussion is an excellent lesson in why pilots should be very, very careful when checking the weather..
Strangely enough the worst weather I have encountered over the years is a total surprise -- never mentioned anywhere - and all you can think is "where the fuk did that come from" -- computers are filling in the gaps -- Canada is a very large country with relatively few wx reporting stations -- I could never figure out how GFA's as presented by NAV Canada end and begin at provincial borders -- it's a piss pour format - why can't they make one complete map -- better still make it North America --
You wrote some very good points railroad, but I'm cutting to the important part. The part that the high-time, senior, soapbox preaching posters seem to be glossing over as they condemn this pilot from Tindi.
railroad wrote:I don't think the information in the GFA would have stopped me from flying that morning, but of course, I don't fly a caravan. If I was flying a Caravan, the trowel (occluded front) would have concerned me greatly, likely enough to keep me on the ground.
Tell the boss you are cancelling every winter flight in the Caravan due to forecast ice, that rarely appears as predicted, and then see how long you stay employed. Meanwhile, one accident does not constitute a crisis.
Donald wrote:
Tell the boss you are cancelling every winter flight in the Caravan due to forecast ice, that rarely appears as predicted, and then see how long you stay employed. Meanwhile, one accident does not constitute a crisis.
If there is moderate icing regularly in the forecast, shouldn't you just get a plane that can actually fly in moderate icing?
Liquid Charlie wrote:-- Canada is a very large country with relatively few wx reporting stations -- I could never figure out how GFA's as presented by NAV Canada end and begin at provincial borders --
I've heard it's cutting off like that at our international border so there isn't conflict with accountablilty for the other side, which might similarly be how the live weatherperson is not to influence pilot WX decision-making except to present the available information as accurately as possible. Best example of that kind of border-proximity issue is Pelee Island Airport (a Van accident there 10 years ago). U.S.A. in all directions: 50 miles north / 10 miles west is Michigan; 10 miles South and 10 miles East is Ohio. Certain systems can be somewhat more difficult to assess for that reason, and maybe not as straightforward to analyze speed-of-advance and strength of a pattern that's ushering in.
Donald, I certainly did not intend to condemn this pilot. I was clear in pointing out that I had the benefit of hindsight when saying I would likely stay on the ground if I was flying a caravan. I guess without that, I may very well have gone. Hard to say.
I stand corrected a little on the Icing in the TAF. You guys are correct in pointing out it will not forecast icing aloft. However, that system is the same one that went through Simpson the evening before, and the Simpson TAF included FZDR. So later, that system hits Yellowknife, and the TAF there does not mention anything about freezing precipitation? Was this just missed or was it omitted for an educated reason by the Forecaster? Either way, it was wrong. That was some of the worst FZDR I have seen in Yellowknife in a number of years.
As far as the need to fly in forecast icing, I am under the impression the Caravan Pilots at Air Tindis are not pushed to go. I have seen Twin Otters on the scheduled Caravan routes often during the shoulder season when icing is present. Maybe the Pilots put pressure on themselves, I don't know them all personally. I thought they are on a pay system that pays them whether they fly or cancel. The Otters are not that busy this time of year, which is rather convenient, so they are available to cover the flights.
Again, I am not standing on any soapbox here. I admit, that after much thought, I am still not certain what my decision would have been that morning. I would have been influenced by the omission of freezing precipitation in the TAF, and had a false sense of security because of it. I also would have been confident in delaying until daylight or passing it off to another company aircraft after seeing that GFA. But then again I like to fly, and I am one of those guys that likes to get things done, many of you guys criticize that "get er done attitude" but that's the way I am and I deal with it everyday as part of my decision making. It is a dangerous attitude, but I find it helps to admit it, and be honest with myself.
railroad wrote:I would certainly not ignore a forecast prepared by the professionals; however, I admit I get frustrated with the guys who throw in the "possible icing" into almost every forecast from October until April. I believe it is there for someone's ass coverage, but it makes for an inferior product and reduces some of the credibility of the Forecaster. Unfortunately it appears to cause some pilots to even ignore it sometimes.
I suppose if there is any cloud and it is below freezing, there can be ice potential so they just always mention it. Which means that it can get ignored by some. But as a pilot making a decision involving icing, if you see a front or trowel associated with the cloud, I would suggest leaning on the side of believing the forecaster. Near mountains (including smaller stuff like Appalachians) with its uplift and lake effect with its high moisture are other areas to watch out for.
There is often an area a couple of hundred feet below stratiform clouds where there is some freezing precip even though there is none reaching the surface. I would imagine it becomes a real big problem when the space between the clouds and the ground gets pretty small. Difficult to forecast but I try to mention it in low stratus conditions and air temps -5 to -15. I strongly suspect that is what caught Nancy in Winnipeg.
To provide some info for those that get caught in serious icing in freezing rain conditions....I know a test pilot who did inflight testing on the effects of severe icing on aircraft. They would fly a Twin Otter when there was freezing rain conditions. He told me that the vertical level of the severe icing was usually quite narrow and could usually be escaped by changing altitudes by an amount that was less than he expected. A few thousand feet or less.
From a vertical point of view for escaping these conditions, I would suggest going up first as you can always go back down.
pelmet wrote:
From a vertical point of view for escaping these conditions, I would suggest going up first as you can always go back down.
This advice (should be) is so obvious, that it tends to be overlooked. The caveat here, is don't take too long to make this decision. The one eighty should already have been performed, and the need for an immediate climb becomes apparent after the turn. Once ice has become a "problem" you may not be able to exercise the climb option.
Illya
Just a couple of quick thought about ice. If it's "got you" and you're running out of altitude, airspeed and ideas all at the same time:
Do NOT let that airspeed bleed off too much. Pick a speed, and try not to go below it. Yes, nose down.
Stay in corrodinated flight. Keep the ball centred. You stand a MUCH better chance pulling off a survivable outcome with wings level when you break out, than inverted.
Your power red lines have become decorations. There are no engine limits at this time.
Vary your RPM. Props shed ice better when not at a constant RPM. A clean prop can pull a dirty wing. A dirty prop? Not so much.
Stay in control of your aircraft. You may be going down, but keep flying the puppy.
Hopefully you'll never be in this situation.
Just another couple of thoughts.
I don't usually use my boots until I see a very slight reduction in either attitude or airspeed. My thoughts here are not to create "dirty" areas on the wing if the boots don't do a uniform job on the whole wing. They rarely do.
Crack the flaps if you're finding the aircraft maintaining a slight nose up attitude. This can allow ice to build under the wing. I'm told this is a bad thing.
StratusSmoke wrote:There is often an area a couple of hundred feet below stratiform clouds where there is some freezing precip even though there is none reaching the surface. I would imagine it becomes a real big problem when the space between the clouds and the ground gets pretty small. Difficult to forecast but I try to mention it in low stratus conditions and air temps -5 to -15. I strongly suspect that is what caught Nancy in Winnipeg.
Up til departure the YWG metar had 0C (5am), ... a north takeoff into 15-20kt blustery / light-snow ... turnout SE .. not very high and went down in 4 minutes. A W&B issue included (report / Oct 6 05 5:37). Meterological info in the report has 2C per 1000' ....
YZF/NWT here is -10C to -11C, but what's it at 3-4000' a few minutes later ? Less ?
StratusSmoke wrote:There is often an area a couple of hundred feet below stratiform clouds where there is some freezing precip even though there is none reaching the surface. I would imagine it becomes a real big problem when the space between the clouds and the ground gets pretty small. Difficult to forecast but I try to mention it in low stratus conditions and air temps -5 to -15. I strongly suspect that is what caught Nancy in Winnipeg.
Up til departure the YWG metar had 0C (5am), ... a north takeoff into 15-20kt blustery / light-snow ... turnout SE .. not very high and went down in 4 minutes. A W&B issue included (report / Oct 6 05 5:37). Meterological info in the report has 2C per 1000' ....
YZF/NWT here is -10C to -11C, but what's it at 3-4000' a few minutes later ? Less ?
What "caught" Nancy in YWG, was a warm airplane brought out into precip. Also know as a cantaminated wing on departure, plus the failure to maintain corrodinated flight (evidenced at the point of impact, loss of control while in flight) an attempt to maintain altitude, while the only defence at that point would be dashboard power and a controlled descent. That would have given her some say in where she ended up. Perhaps not graceful, but not a lawn dart. Hurt your feelings? Too bad, learn from it.
Illya
pdw wrote:
What "caught" Nancy in YWG, was a warm airplane brought out into precip. Also know as a cantaminated wing on departure, plus the failure to maintain corrodinated flight (evidenced at the point of impact, loss of control while in flight) an attempt to maintain altitude, while the only defence at that point would be dashboard power and a controlled descent.
Ok....I remember that accident a few years ago and read the report as well. I always wondered how it could have happened so quickly. The report details are vague now but I don't remember them mentioning that the aircraft was contaminated prior to departure. That would explain a lot.
The best thing to do(if realistically possible) if bringing a plane out from a heated into dry snow is to open the doors, wait a while for the temperature to decrease and then after the aircraft surfaces are cold, pull it out. Mind you in a place like YWG, de-icing should be fairly easy.
If (Nancy) had encountered inflight ice nasty enough to bring down her airplane four minutes into flight, she would have done an immediate one eighty! I suspect her problems were not apparent until she retracted flap. As the flaps went up, her lift went down. Struggling to maintain altitude would have led to rapidly diminishing airspeed, loss of control and the accident.
If you change configuration, and your handling goes downhill, undo whatever you did, right NOW!
I don't know the experience level of either of these pilots, but Caravans tend to be flown by pilots with limited experience to draw on. When the shit hits the fan, it can happen pretty quickly. Reactions can be critical, and thinking takes time.
Illya
