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#11
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Glaze Ice
On Feb 2, 7:38*am, Tom De Moor
wrote: In article , says... METAR EBOS 021550Z 22009KT 8000 FEW020 SCT032 01/M01 Q1017 R08/290095 TEMPO 3000 -SHSNRA BKN012= OK sure - but one should surely reading something more into that temp and dew point. *Too close for me. *What do others think? SHSNRA Showers Snow Rain. In our club are now two camps: 1 person, convinced that dry snow will not cause freezing ice and all the rest who don't know the differance by sight between a cloud full of dry snow or freezing rain and who will chicken out by not flying through. I am with the rest ;-) Where is the summer staying? Tom De Moor With nearly a lifetime of flying real IFR in light aircraft, I've found almost all generalities about ice accumulating on aircraft to be wrong on occasion. Ultimately, you get what you get. If you have a well thought out escape route, you'll probably survive. If not..... Examples: Ice CAN accumulate in clear air. It's usually Graupel but can be just very light supercooled mist. Neither block visibility enough to be easily seen from a distance. The kind of freezing rain described by the first poster is rare but almost always fatal to an aircraft. As a result there are few 1st person stories of encounters with freezing rain. The only real ice removal strategy for aircraft is to find warm air - FAST. De-Ice equipment just buys a little time. Simply recording temperature layers while climbing has saved me several times. Usually, but not always, if the air temperature is -10C or lower, virtually all supercooled water droplets have already frozen out and the resulting snow will just bounce off the airplane. I've seen significant ice at -30C. Icing is always worse over mountains. It's amazing how much ice you can pick up flying through a cooling tower plume. |
#13
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Glaze Ice
Ice CAN accumulate in clear air. *It's usually Graupel but can be just very light supercooled mist. *Neither block visibility enough to be easily seen from a distance. The kind of freezing rain described by the first poster is rare but almost always fatal to an aircraft. *As a result there are few 1st person stories of encounters with freezing rain. Let me relate an iceing story that happened to me. I was on a cross country in my PA 140 across the cascades. The weather was clear, the winds calm. The temp was well below freezing. As I let down on the west side of the mountains I encountered scattered clouds with light showers. The temp. was well above freezing. After landing at Longview I pulled up to the fuel pump to top off the tanks for the return flight. To my surprise the fuel tanks were covered in ice. The fuel had retained the cold temps enough to freeze the light rain showers contacting the tank area. I felt no loss of lift as the rest of the wing was clear. I wondered what the outcome might have been with a large leading edge tank. Ed |
#14
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Glaze Ice
"brian whatcott" wrote in message ... I did an Oxford instrument ground school long ago. One of the weather topics was glaze ice. This was described as extremely dangerous, in that supercooled rain could impact and flow to a glassy ice layer over the wing in seconds, which tended to pull the aircraft down pronto. In the last three days, I actually witnessed an event. It was a ground forecast of "freezing rain". It was devastating. As you know, most of the US distributes power almost entirely on overhead lines. In the local (SW Oklahoma) counties, there are trees quite close to power lines. Tree branches sagged to the ground in minutes and the majority shed limbs into the road and onto power lines before your eyes. Many power poles could not hold up the half-inch coat of ice on the lines, in a moderate crosswind and splintered - often a half dozen in a row. One county (Harmon) estimated about 3 to 4 weeks to repair the 2000 or so power lines that were down on broken poles before electric power could be restored there. For people who are used to living in Tornado Alley and don't easily shock - this was a new one on them! There was a rush on motor generators. There was no gasoline to be had for a day or more after, til the generator sets were set up at strategic gas stations to serve huge lines of customers. Some small towns are reporting sewage farm pump failures, others say went drinking water pump stations out. The local AM radio station used for emergency reporting, went out after a while - its antenna was glazed, which mismatched the transmitter, which then fried. The city set up strategic industrial generator sets - of which the smartest siting after the water and sewage utilities, was at a 24 hour diner - where the utility crews could go to rest and eat. Moral: If you fly into glaze ice, fly down or fly up, but fly OUT quick as you can! Brian W I was attending a AOPA sponsored CFI renewal clinic in Albuquerque (1986) when an example was given of how fast clear ice could form on a supercooled airframe in a very short time. A DC-3/C-47 was landing in the Pacific Northwest. (Washington or Oregon) They were clear of ice until inside of the outer marker. The ice formed so fast that adding full power only slowed their sink rate. They crash landed short of the runway and the rescue crew had to use fire axes to get the flight crew out. The ice was over 1/4 inch thick over the entire airplane. Assuming a 120 mph approach speed and a distance between 3 to 4 miles from the outer marker to the runway threshold the entire event took less than two minutes. I have been searching for information but have not found anything so far. Since this was part of the course I wonder if anyone else might recall the story? -- A man is known by the company he keeps- Unknown Anyolmouse |
#15
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Rogallo
Like me, You may have missed Rogallo's obit late last year.
He died near the first flight site in North Carolina. How appropriate! He gave his Rogallo patents to the Country at the time of Sputnik. His design gave birth to hang-gliding, ultra lights, powered parachutes, Light Sport Aircraft and a new birth of enthusiasm for flying (just) in reach of the average person. Francis Rogallo - 2009 Brian W |
#16
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Rogallo
"brian whatcott" wrote in message ... Like me, You may have missed Rogallo's obit late last year. He died near the first flight site in North Carolina. How appropriate! He gave his Rogallo patents to the Country at the time of Sputnik. His design gave birth to hang-gliding, ultra lights, powered parachutes, Light Sport Aircraft and a new birth of enthusiasm for flying (just) in reach of the average person. Francis Rogallo - 2009 Brian W Thank you for this posting, it motivated a search http://www.nytimes.com/2009/09/05/us/05rogallo.html more at http://www.google.ca/#hl=en&source=h...64381002806979 Happy landings, |
#17
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Glaze Ice
In article ,
says... In article , says... METAR EBOS 021550Z 22009KT 8000 FEW020 SCT032 01/M01 Q1017 R08/290095 TEMPO 3000 -SHSNRA BKN012= OK sure - but one should surely reading something more into that temp and dew point. Too close for me. What do others think? SHSNRA Showers Snow Rain. Yeah, but it's broken at 1200'. So I wouldn't be flying in it (who would?). I'm far more concerned about the possibility of fog and carb icing due the dew-point and temp. If the WX deteriorated to IMC I'd be on the ground already. If the plane and pilots are IMC/IFR (and it was me), I wouldn't fly in that - not in a 172 with no de-icing. In our club are now two camps: 1 person, convinced that dry snow will not cause freezing ice and all the rest who don't know the differance by sight between a cloud full of dry snow or freezing rain and who will chicken out by not flying through. I am with the rest ;-) I on your side on that. Where is the summer staying? Pretty nice in NZ at the mo, 20C here at present. -- Duncan. |
#18
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Glaze Ice
On Mon, 01 Feb 2010 20:12:36 +0100, Mxsmanic wrote:
Mark writes: Wrong. Buy a plane that has a de-icer. They are only $500,000 or so. Deicing equipment protects you while you find your way out of icing conditions. It does not allow you to fly through icing conditions indefinitely with impunity. Shutup, I'm a pilot, you're not. They even allowed me to skip the 40hrs minimum rule. -- Mark inventor/artist/pilot/guitarist/scientist/philosopher/ scratch golfer/cat wrangler and observer of the mundane. And much much more including wealthy beyond anything you can imagine. My website http://www.hosanna1.com/ www.myspace.com/gayincarolina |
#19
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Glaze Ice
There are many stories like this, and they are to be heeded...
I listened to a pilot tell his story about landing with 1/4 inch of ice on his Archer... 10 Years later, telling his story, his hands were shaking... He oviously did everything right, and was very lucky he was within the range of a long runway, as he was decending 300 fpm at full power! Burned it on at 90 knots, no flaps. I had no idea a Cherokee could fly at all with that much ice... The speed with which it can accumulate is legendary. Cheers! Dave On Tue, 2 Feb 2010 15:17:55 -0600, "Anyolmouse" wrote: "brian whatcott" wrote in message m... I did an Oxford instrument ground school long ago. One of the weather topics was glaze ice. This was described as extremely dangerous, in that supercooled rain could impact and flow to a glassy ice layer over the wing in seconds, which tended to pull the aircraft down pronto. In the last three days, I actually witnessed an event. It was a ground forecast of "freezing rain". It was devastating. As you know, most of the US distributes power almost entirely on overhead lines. In the local (SW Oklahoma) counties, there are trees quite close to power lines. Tree branches sagged to the ground in minutes and the majority shed limbs into the road and onto power lines before your eyes. Many power poles could not hold up the half-inch coat of ice on the lines, in a moderate crosswind and splintered - often a half dozen in a row. One county (Harmon) estimated about 3 to 4 weeks to repair the 2000 or so power lines that were down on broken poles before electric power could be restored there. For people who are used to living in Tornado Alley and don't easily shock - this was a new one on them! There was a rush on motor generators. There was no gasoline to be had for a day or more after, til the generator sets were set up at strategic gas stations to serve huge lines of customers. Some small towns are reporting sewage farm pump failures, others say went drinking water pump stations out. The local AM radio station used for emergency reporting, went out after a while - its antenna was glazed, which mismatched the transmitter, which then fried. The city set up strategic industrial generator sets - of which the smartest siting after the water and sewage utilities, was at a 24 hour diner - where the utility crews could go to rest and eat. Moral: If you fly into glaze ice, fly down or fly up, but fly OUT quick as you can! Brian W I was attending a AOPA sponsored CFI renewal clinic in Albuquerque (1986) when an example was given of how fast clear ice could form on a supercooled airframe in a very short time. A DC-3/C-47 was landing in the Pacific Northwest. (Washington or Oregon) They were clear of ice until inside of the outer marker. The ice formed so fast that adding full power only slowed their sink rate. They crash landed short of the runway and the rescue crew had to use fire axes to get the flight crew out. The ice was over 1/4 inch thick over the entire airplane. Assuming a 120 mph approach speed and a distance between 3 to 4 miles from the outer marker to the runway threshold the entire event took less than two minutes. I have been searching for information but have not found anything so far. Since this was part of the course I wonder if anyone else might recall the story? |
#20
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Glaze Ice
Dave wrote:
OK... So you are a pilot, and Mx is not? Just FYI, you are responding to a troll that hangs out in rec.aviation.piloting and many other groups. The perp can be IDed by viewing all headers of a post and looking for an "X-Authenticated-User" header, and if it has one, has the following value: X-Authenticated-User: $$gwx18quhxz9-wu_g$qv3bkmank |
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