Battson wrote:

UtahMaule wrote:Does that look deep?????

Judging by the tail fin, it looks about 6" or so

That is more than I would ever plan on messing with. Seems like if you can't see ground through it, it's always too deep to risk it.

And, that's the point. But, in unknown LZ, how do you know how big those rocks are that stick through the snow? Are they two inches or ten? Can be pretty hard to tell, not to mention all the other "gotchas" that snow can cover up.

And, I've landed on big tires in over a foot of snow.....the kind of fluffy stuff you get in interior AK sometimes, and this was the first snow of the season, and I was landing on a frozen lake, and I'd been working in that area every day since before the snow fell, and....

MTV

mtv wrote:Battson,

Sorry if I came across as short. I for one have screwed the pooch on a snow landing, because in the conditions ambient it simply wasn't possible to evaluate the situation and the surface, AND I wasn't bright/informed enough to realize that.

I've landed on wheels in snow, and on snow a good bit on skis. I tell folks that ski flying is the most fun you can have in an airplane.....but, if you play in the snow enough, you're going to break something.

I was lucky and just broke an axle, but I've also slept out a couple other times I'd really rather not have because I misjudged snow conditions. I can build a one person shelter in record time now, so I'll probably never get stuck again.....yeah, right!

MTV

Sorry if I took that wrong. it can be hard to understand the tone just reading the text (sometimes in a hurry).
I appreciate where you are coming from. Nothing speaks like experience, "been there, done that".

After all - that is why I ask you guys first.

My advise is worth nothing. And safest bet is don't land in snow. But if you do, be a student of the snow. Pay attention to what type of snow fell and what it's been exposed to since it hit the ground. If we have really cold weather and it's a dry snow and it stays REALLY cold. It doesn't matter how deep it is. You can't hardly tell your even in it. But it's all about the condition of the snow and it can change in matter of minutes. And it can be in layers of differing condition. There are at least two zillion variables for you to consider.

More worthless advise...... I'm a dragger. Some times a lot. Just a touch, look, repeat. Over and over. That works well on any unknown surface including snow. But perfect the art of dragging on sand, dirt, mud, rocks.

And in snow I'd get the biggest tires you can and lots of horse power. You'll need em.

Getting a pair of hydraulic wheel skis may be an option for you too Mr. Battson. These run 8.5.6.6 tires... Your friends will love them.

I've landed on snow-covered paved runways several times over the years, stock Cessna-size tires, and only once did I not ask someone on the ground to first measure the snow. On that occasion, my very first, I landed the TR182 some 35 years ago at Greybull, WY, the new snow turned out to be just about 2" deep on the level, and the airplane touched down very softly and then slowed very, very rapidly without braking. I concluded that in the future, I'd limit my snow landings to less than 2", and so I have.

The last time I did that, just about 3 years ago, I landed my P172D at Kelly Airpark between Denver and Colorado Springs. The landing was easy, and at about 1 1/2" of snow with me being the first one to land that day, it was similar to the Greybull landing--soft landing with a very rapid slowing, without braking. Taking off was actually more difficult, as some of the snow had melted and some of it was pretty slushy, so that it tended to grab the gear unequally. I used a standard soft field take off, the airplane was pretty light (just me with 3/4 tanks), but the take off roll was longer than I expected, and I was glad when it broke free, as the back and forth grabbing of the mains was unpleasant.

From seeing pix of the aftermath of misjudging snow depth and the ability of even tundra tires to handle it, I think even if I had fat tires on my airplane, I'd still limit myself to 2", measured.

Cary

A few year back... As the story goes. Tok junction...fresh snow. Two aircraft coming in one going out. Incoming asked for a condition report. All he got was...I just left Tok. The first aircraft lands and promptly stops upside down. The student pilot who departed Tok didn't report he departed Tok Junction from the highway.

Last fall decided to check out Skwentna. Called for a runway condition report. Was told, "I heard an airplane earlier". Circled over the strip. 2 Cessna 207's on the apron. Three tracks on the runway.. I land....800 X 6's.....with 60 pounds of gravel against the rear bulkhead. I stopped in less than 50'..... Those were not tracks made by an airplane...
Mark M.

I find that if I can see the color of the ice through the snow then I can operate fine. Otherwise I go somewhere else.

Utah is right, you have to be a diligent student of snow and there are a zillion variables to it. And as Zane points out, giving advice on a public forum is fraught with issues. Hey, so and so said this would work...yah right...so why is the airplane upside down? so don't do it like Gump says - argh...

Here's some things I've run into with tires and snow.

I could hardly tell I was in some of this. (powdery and cold, no thaw/freeze cycle had hit it yet, nor was it crusty underneath - straight to lake)










But this... nearly put me on my back... hard to tell the difference right? (lesson learned)

I once landed on Lake Hattie west of Laramie in about 6" of snow, knew the depth was same as in town, no problem With stock 106hp PA-12. Getting off after fishing was different, had to back taxi in my tracks until I could get one wheel up, then could get TO speed.

Forgot to mention, sitting at Lake Hood Seaplane Base watching the action, nice way to spend a vacation. Turbine Otter just landed, lots of Beavers here too.

Rule of thumb:

Off Airport Snow + Wheels - Skis = Wreck



This is a rule of thumb. Meaning, given enough chances it WILL happen. It doesn't matter how big your compensation-tires are.

I haven't seen this mentioned yet so will add two cents.

Went out with a friend to check on his cabin on a snow covered frozen lake in Southcentral AK. Two questions come to mind; how deep is the snow and is the ice capable of supporting the airplane which was on wheels. We knew there was decent ice in Anchorage and had good reason to believe the lake would be OK but one needs to approach these things cautiously. We took along a couple big chunks of firewood (cheap and expendable) and dropped them from several hundred feet and watched them bounce several times and then slide along the ice. This told us the snow was thin and light (no crust) and that the ice was reasonably competent. With that we elected to drag the wheels and then land on another pass. Worked out that time. Drop what you have and you might learn something useful. But remember you are a test pilot.

Second thought is that IF you use your brakes when taxiing in snow you shouldn't be too surprised if one wheel or both is frozen on your next landing. Warm brake rotor plus snow makes water, which turns to ice in flight. You don't want the next landing to be a geaser, instead you might think about thumping the wheels firmly to break the ice bond if any.

Dropping rocks (or wood) will tell you if the ice is hard. One time I dropped a couple and came back to look. They were plainly visible obviously having bounced. Came back to drag the lake and it felt like the snow was grabbing at the tires with claws...powered up and out of there. Had not noticed that the rocks were sitting on top of a snow crust. Figured out pretty quick that what I wanted was as close to bare ice as I could find...

I've landed on lake ice but not snow. But then the only reason I was willing to land was because it was fresh and cold and I first walked out on the lake and chopped a hole to see how thick. I lived on lakefront for a long time and skiing on the lake taught me just how variable it is. On top of the snow variability itself, you can have water overflow on top of the ice, invisible under the snow. My skis would become blocks of slush, I'd hate to experience that in an airplane.

8GCBC wrote:Getting a pair of hydraulic wheel skis may be an option for you too Mr. Battson. These run 8.5.6.6 tires... Your friends will love them.

Skis would definitely be fun, same we only see a little snow to sea-level most years.

We ended up going for a look in spite of the possibility of snow, with a back-up plan in case the snow was too prolific. It turned out the snow was fine for landing, about 4" in depth. We went at midday, so we knew it would be soft and melting given ambient conditions. I was able to spot a 12" drift which had collected in some brush at the south end of the airstrip, so landed past the brush in 4" of snow. No problems, it just behaved like a wet-surface landing (zero brakes...). I was able to taxi through the 12" drift with no problem, it just compressed under the tires.

By the time we took off (2 days later) the snow had melted back, about one inch remaining, but we had a serious crosswind. Slewed the plane the whole way down the airstrip during the take-off roll - at about 15 degrees to the direction of travel. Big smooth tires are not ideal for gaining traction on slippery surfaces. With the passengers, all our gear, and our load of skins / heads we needed a comparatively long round roll, steering was a lot of work!

Wet, melting snow, footprint in the wheel track to give an idea of scale, taxiing in deeper stuff was fine:

Good work! Your situational awareness was obviously heightened. Breaking down the variables both positive and negative regarding the type of snow (you deal with) was a good plan.

Thank you for the thread. Great information.

Thanks to all for the information - I am definitely glad to be much more aware of the risks. It kept me safer on the day. However little I know today - I knew much less beforehand.

Yet another factor to consider: I found out the hard way that drifts can be really hard to see due to flat light conditions. I was on the skis but the principle applies to wheel snow landings, maybe even more so. NOW I always consider the prevailing wind in the area, and closely inspect the lee side of any obstructions (old buildings in my case) for drifts, especially when landing the lee side. Just another part of the potential complexity of snow landings, this effect will vary tremendously depending on how big the drift causing obstruction is, how long it's been since it last snowed, what kind of snow it is, what the wind has been since, the temps. I never think as hard then when setting up an off airport ski landing, there is so much "going on", it's all hard to see, and to top it off you have no brakes! I can't wait.....

First off, fun in the snow is a conflict in terms.

Tim

qmdv wrote:First off, fun in the snow is a conflict in terms.

Tim

You wouldn't make a good Canadian Tim. We love snow!

Here is a good example of how not to snow landing the wheels. I was in a few days earlier and the snow was super solid and perfect.



Assume nothing about the condition of the surface from the air.