Glacier Flying Tips from Merrill Wien
Actually, glacier flying usually means mountain flying, too. It's very important to be aware of the wind direction and velocity and have an understanding what affect that wind will have where you will be flying. Flying on the lee side of a mountain ridge usually means downdrafts and the windward side usually means updrafts, and depending on your direction it could also mean downdrafts in the whole area of intended landing. This happened to me once on the McCall Glacier in the Brooks Range. As I descended into the gorge, I became aware of strong downdrafts and I could not hold altitude even with full power. Fortunately, I had made many landings there and knew where I wanted to land, so it was like a forced landing with power.
Keep track of where the real horizon is, because there IS no horizon -- only mountain ridges, so fly up the glacier and find a place to turn around. You might think you are flying level before turning around since there is a tendency to relate your level flight with the slope of the glacier. As you start to turn, you notice that your airspeed has fallen off and even with full throttle, you might not be unable to maintain enough altitude above the glacier to complete the turn. In order to fully evaluate the landing altitude and surface conditions, it is important to be able to take a close look at the landing area, especially if you have not landed there before.
About 8000MSL at the Brooks Range, 1957
Look for crevasses, the condition of the surface, and if there is any side slope. Until you get a good look at the surface from a shallow angle, side slope is hard to detect. Although making the turn around up the glacier for a downhill pass can be hazardous, it is better than flying up the glacier because it is usually impossible to out-climb the glacier. My first landing at the head of the McCall Glacier was a hairy landing. I thought that I had picked a good spot and approach direction. Just before touchdown, I realized that the landing area sloped down to the right. I added full power and turned into the slope, landing somewhat sideways. Another lesson learned -- check the side slope on the down-glacier run.
Once you have determined the touchdown altitude, it is a good idea to start your final approach at two or three hundred feet higher. You will think that you are going to overshoot but don't be fooled. When you put full flaps down, the airspeed will fall off rapidly. Since you are generally landing on a steep slope you'll stop quickly, but you do not want to stop before you do a 180 to point downhill for your takeoff. The trick is to go to full power and start your turn at just the right speed so that the centrifugal force of the airplane will keep it level in the snow without sliding sideways and getting stuck. If you stop rolling it's very hard to get moving again to make the turn. If you make it about half way around and stop, the airplane very likely will slide sideways causing the skis to knife edge into the snow and then it is stuck but good, and in a Cessna 180 or 185, all the gas drains out of the high wing tank through the vent.
Don't put the flaps down on take off in a crosswind. I was on a skiing trip to Aspen in 1958 and on the way there I read an article about a fellow that was landing on mountain tops in the area. A picture of his airplane was on the cover along with the well-known skiers he was dropping off for virgin skiing. I decided to look him up when I got there. He was very nice, we had dinner together and he invited me to go with him the next day for some landings on the mountains. I accepted and I would soon regret that decision. When were taking off at Aspen, he slammed the throttle in and put both hands on the wheel. I thought this might not be a good idea. When we landed at 12,000 ft., he didn't make it around for the 180 turn downhill and the ship became buried in the snow. We shoveled for two hours with our skis and finally got it pointing downhill on top of four feet of new snow. The plan then was that he would takeoff alone while I took movies and come back and pick me up. As he was getting ready to takeoff, he put his flaps down too soon, which reduces the air over the rudder until some airspeed is achieved. He could not keep it straight and buried it again. We lost most of the gas out the vent the first time and this time we lost the rest of the fuel out the other vent. Even if we could get it unstuck we did not have enough fuel to get back. He was lacking in mountain experience but he was an excellent deep snow skier and I was not. After six hours of skiing to a road I was completely exhausted and my muscles were sore for weeks.
A Commando sits on three feet of ice at Lake Chandalar
Caution: Slippery When Wet!
Another very important rule would be to try to have direct sunlight for landing so you are not landing in a white-out, especially in an area where you have not landed before. If you are familiar with the landing area you can get by with it if you have previously put some dark objects along the landing area -- sorta like throwing a rock out in a seaplane over glassy water so you have some depth perception -- but they say that if the engine quits in a Seabee, the airplane will beat the rock to the water. The best skis to use would be straight skis but the problem is you are generally departing from an airport with no snow. Therefore, wheel skis are the next best thing. The best and most expensive skis would be hydraulic wheel skis that lift the wheel completely out of the snow. The fiberglass skis that have the wheel fixed in a big hole in the ski work well if there's enough slope to allow acceleration on takeoff. These skis are very popular because they are lighter and will handle most requirements -- and they're also less expensive -- but there's more drag on these skis from the main wheel and the little wheel on the end of the ski to keep the ski from scraping on the dry runway.