Not sure what the heck happened but I could use a little "Global Warming" right about now.




http://www.backcountrypilot.org/gallery/thumbnails.php?album=155

We had a C-340 that was setting down like that this winter. It looks like it could do some damage.

Desert Rat wrote:We had a C-340 that was setting down like that this winter. It looks like it could do some damage.

Maybe...maybe not. Maybe the snow load is applied so slowly and evenly that the tail sits down a little bit at a time, so by the time it touches...no slammy. There's probably a tail skid on there anyway. Is that the kinda of damage you were talking about?

Mark- This snow might suck for flying, but the mountain was great today!

If there is enough weight in the snow (and this was pretty wet) it could do some structural damage, if there was enough accumulation. I think there was approx one foot at the most and I don't believe that would be enough. It was pretty amazing to see 50 or so planes with all their tails stuck to the ground. It's been more than thirty years since I have seen snow like this. It'll be weeks before our beloved grass strip will be back in business.

Mark

The winter of 92 in Fairbanks we had a lot of snow. At least two or three airplanes were not cared for properly, and the wings collapsed, due to snow load.

The wings weren't designed to take much stress in that direction, remember. Most light aircraft are stressed for 3.8 g's right side up, but only 1.8 upside down. This snow load has the same net effect as a negative G load. The way they test wings for loads is to load them with sandbags. Sorta the same approach.

MTV

mtv,

Your correct. It actually would be fairly easy to do the math for a particular plane. The only real variable would be water content of the snow which would affect the weight per cubic foot. The rest is a fairly simple equation. Might be a good thing to know if O22 Columbia has suddenly become part of the Snow Belt...

BTW, I sold a 1969 M model 182 to somebody (I think his first name was Manny) in Fairbanks years ago. N91510.

I see the registration now shows:
Registration Type: Co-Owned
Address: 914 Nordale Road
North Pole, AK 99705
United States
Region: Alaskan

Mark

A few years ago we were up a lake torture in quebec looking at a 185 for sale .This was an old military strip .The canadian outfitters use this for a winter tie down area for the arctic circle lodges. Lines of beavers,cubs,cessna 180 and 185's and 206's covered with ice and snow.I mean 3 to 4 inches of clear ice on the wings and tail surfaces.Some snow on top of that.I just could'nt beleive it.90% of them on floats jst wintered there.I asked the old frenchman showing us the 185 about it and he said wont hurt em.I have been to lots of places in the winter,but never seen nothing like that.No tracks out to the inner rows of planes.Had to wallow thru 3 feet of snow to look at the 185.Looked like no one had even walked to the inner rows of planes all winter,and this was march.Need less to say the 185 was a big bummer,but did'nt look like the snow and ice had hurt it.My father still comments on it once and awhile.I dont think a one time storm will hurt em much,but who knows?

H2O content is key. "California concrete" is some of the heaviest snow around, whereas Fairbanks snow is more like fine dry dust, and apt to be blown off by the next breeze.
But, my squaretail spent the last 16 years in Fairbanks, and the plastic part on the bottom of the tail was broken from the snowloads pushing the tail to the ground there.
At least this cold winter air's nice & thick!

"California concrete" is some of the heaviest snow around

Although these last couple storms in the Sierras have been uncharacteristically cold, dry, and light. Really, really nice skiing snow...almost Utah-like. Though I can't speak for the lower elevations on the other side, Mark.

That is one reason having hangar is so nice though, until your poorly designed hangar roof collapses from the snowload and ends up crushing your baby anyway.

We had a heavy snow ice event here just after I bought my plane and before there was a hangar available. I went out every few hours and swept off the accumulation of snow and finally banged ice off with a rubber hose. Most planes tied out had damage to tails and antenna's, others needed fabric repair and at least one, had wing failure. Water weights 62.4 pounds per cubic foot. If say you had a modest 4 inches of saturated snow and/or ice, most Cessna's have about 175 sq feet of wing... doing the simple multiplication... that is about 3500 pounds on the wings alone, add the 1500 pounds on top of the fuselage and tail... plane now at a gross weigh of 7000 pounds... that'a asking a lot and I would think, well past design limits. I shudder to think about the damage that a foot of wet snow would cause.

Zane, probably no tail skid on the tri-gear plane, only a tie down ring.

Bob's calculations would greatly exceed the -g loads for this aircraft new. Having substantial time on the aircraft, would only make it worse. I'd be concerned about damage to the bulkheads in the tailsection as well as the wings.

Brings new meaning to "always hangared" in the ads you see.

BobWhite wrote:... plane now at a gross weigh of 7000 pounds... that'a asking a lot and I would think, well past design limits. I shudder to think about the damage that a foot of wet snow would cause.

Yeah, that would be roughly equivalent to one of my landings, so I guess the gear should be OK.

Fortunately, snow is mostly air. When I lived in Canada, they said 1" of rain was equivalent to 10 or 12 " of snow. And even ice weighs less than water or else it wouldn't float. Even packed wet snow has to weigh less than water or it would be the leading cause of heart attacks north of the Ohio river. I would think a single storm might not be too terrible, but if you allow it to accumulate over a winter, melting, freezing and being packed by the next storm, it could be serious. The worst would probablly be an ice storm followed by wet snow and high winds. I can remember an incident at Lake Hood not too long ago where many aircraft had wing strut failures from the intense wind. They were mostly (or all?) taildraggers whose wing struts had buckled from the tailwind pushing down on the wings.

Supercubber wrote:Zane, probably no tail skid on the tri-gear plane, only a tie down ring.

Yeah, mostly. The 152 I learned in though had a tie down eyelet with an additional piece of steel wrapped around it in skid fashion. Maybe it was a custom thing.

Water weights 62.4 pounds per cubic foot. If say you had a modest 4 inches of saturated snow and/or ice, most Cessna's have about 175 sq feet of wing... doing the simple multiplication... that is about 3500 pounds on the wings alone, add the 1500 pounds on top of the fuselage and tail... plane now at a gross weigh of 7000 pounds... that'a asking a lot and I would think, well past design limits. I shudder to think about the damage that a foot of wet snow would cause.

Except that snow usually falls aroun 15:1 air/water mix, at least what we've been getting here in Reno lately. It could be much more dense in the PNW.

4" = .3 ft
.3 ft x 175 sq ft = 52.5 cu ft snow
52.5 cu ft snow x 62.4 lbs per cu ft = 3276 lbs
3276 lbs / 15 = 218 lbs on wings.

Not as bad as preiously reported, and the load is fairly uniform, but enough of it between ribs could prob deform the skin.

Yellowbelly is quite right! Ice is about 8% less dense than water, hence water expands when frozen. Thus four inches of ice on a Cessna would weigh closer to 4500 than 5000 pounds. Snow varies... very dry power might have 3% water content... very wet snow approachs 25% water content. Thus a foot of very wet snow would again be something on the order of 5000 pounds on a Cessna. Durning the ice storm I mentioned earlier, some planes had accumulations of ice that were certainly well over four inches. Several Cessna's had landing gears so spread that the belly was resting on the ice under the plane. Once melted... is there damage, or maybe I should say visible damage, beside broken antenna's? Really makes you think when you are selecting a plane to buy.

As the mathemeticians are figuring out, it takes a good bit of snow to ruin an airplane, but Bob White has it right: It may be in some ways better off if the wings did collapse, than some unsuspecting person buy a "new" airplane, and proudly fly away, not having any clue what stresses that machine has endured.

There is no doubt that snow can ruin perfectly good airplanes. I've seen one Maule, one Taylorcraft and one Cessna 172 essentially destroyed by accumulations of snow. It's a pity in some of these cases, that the owners of the neighboring airplanes didn't sweep a bit of snow off from time to time while clearing their airplane.

Nice thing about FAI is that others will keep an eye on your plane for you. Another reason to not be a stranger, I guess.

Too bad in any case when a servicable machine is destroyed for no reason at all.

MTV

I have two horror stories about ice covered airplanes. The first happened about 35 years ago. We had a "Silver Thaw" here in Portland and the local Beechcraft dealer had a brand new 58TC Baron covered with ice, sitting outside on it's butt like the cessna pictured above. A lineboy decided to clear off the ice with a BALLPEEN HAMMER! The ice transferred each blow into the skin below, He destroyed the airplane.
Second one was one of Horizon's Metroliners on RON in Montana received a layer of ice overnight. This time the weapon of choice was a broom handle with the same results and a $100K repair bill to reskin the wings.
Y'all be carefull out there.

A lineboy decided to clear off the ice with a BALLPEEN HAMMER!

I've heard pneumatic sheet metal shears work good for that too. Whoops!