Flying with skis

Have you ever wondered what it’s like to fly with skis?

Flying with skis presents its own set of challenges, according to Steve Williams, an Alaskan DPE, ATP, IA, and A&P whose company, Acme Cub Training, specializes in modifications for the Piper Super Cub PA-18 and other Cub models. He’s also a flight instructor who teaches flying on Bushwheels, floats, and skis.

Who better to ask about the safest way to fly with skis?

“Ski flying is some of the most forgiving flying if the snow is good and the light is right,” he said. “It is very difficult to ground loop an aircraft on skis. The plane just slides sideways.”

Alaska’s early aviation pioneers developed skis for aircraft in the 1920s and perfected them up into the 1940s. Many of those developments are still being used on general aviation aircraft today.

Many are Alaska legends — Carl Ben Eielson, Harold (Thrill-em, Spill-em, no Kill-em) Gillam, and Bob Reeve — who designed and built their own skis for a variety of aircraft, including Stearman, Fairchild, Hamilton, Stinson, Travelair, and the Ford Tri-motor. 

Reeve of Reeve Aleutian Airways is said to have made skis for his Fairchild 71 from a metal sign from a lodge in Northway Alaska after it burned down.

Today’s Alaska bush pilots, a new breed of bravado wintertime pilots and aircraft owners, have developed their own techniques and use a variety of skis and aircraft modifications during the snowy winter months.

Advice from a Pro

While out flying with Steve Williams one crisp winter day, he passed along some valuable tips about ski flying techniques and flight safety.

After all, landing and taking off on skis requires landings that sometimes turn into overnight camping trips in sub-zero weather. That requires a high degree of self-sufficiency, proficiency, and preparedness.

According to Williams, the most important thing about ski flying is the light. 

“You have to have good light, contrast and shadows,” he said. “When you get overcast skies, and you look at the snow, all shadows disappear. With snow you cannot see terrain or ditches. All those features go away in flat light.”

“To understand the conditions, you have to have the right light,” Williams emphasized.

Second most important thing? What’s under the snow?

“Snow conditions cover up what is below,” he said. “Sometimes, you get overflow under the snow. Making a touch-and-go pass to check the snow once is not enough.”

He suggests before landing on the snow to drag the skis over the snow several times.

“Then check to see if the snow goes black,” he said.

Those holes in the snow filling up with water is not good, he noted.

“If you land in it or stop, it will suck you in,” he warned.

Once your plane goes into overflow, the water freezes to the bottom of the skis, requiring a lot of work to get the ice off your skis and the plane flyable. 

According to Williams, swampy ground under tundra and muskeg is some of the worst for overflow because the water is always moving under the snow.

“You have to fly over and look at moose tracks, which are usually deeper, to see if they have filled with water,” he said. “I also drag a spot five or six times to see if there is overflow.”

“I landed on a river one time and saw lots of evidence of snow depth flying back and forth overhead,” he said. “I landed, throttled back, and ended up in some overflow under the snow that had frozen and gained 10 knots over my landing speed as I was gliding along the overflow under the snow.”

Another thing to watch for is the type of snow and snow depth.

“I have touched down before and had the snow so deep it was going over my windscreen,” said Williams. “I spent a day-and-a-half packing a runway on snowshoes before getting out. The only way to know the depth is to keep dragging the snow.”

Other dangers are landing on crusty snow that has sugary snow under the crust.

“Once you slow down, your tailwheel will fall through the snow crust and that will exposes your tailfeathers to snow and possibly damage your fabric,” he added.

Dragging back and forth is not just for landing, but also for takeoff, according to Williams. 

“My technique is to make the runway long by dragging back and forth, but to land short of that runway, then taxi to it so you can get on the dragged strip later for takeoff,” he shared.

Another aspect of ski flying is landing on lakes and areas of glare ice.

“This is very, very dangerous because you are basically out of control,” he said. “You have to use your ailerons in reverse to make a turn, but it’s best to find another landing place unless you want to spend the night — or a few days — having parts flown in for your busted-up airplane.”  

There are ski-drags — ice brakes — available, Williams related.

“Airframes Alaska has Bear Claw ski drags that work with your hydraulic brake system and Atlee Dodge has something coming out soon for its carbon fiber straight skis,” he reported.

For safety, Williams says he generally will fly with two other aircraft for a flight of three to help if one of the planes is stranded or in need of help.

Williams, who also flies a vintage Cessna 180, prefers straight skis to the wheel-skis for Cubs, but uses hydraulic wheel skis for off-airport landings in the Cessna.

“I have flown the 1,049 mile Iditarod Sled Dog Race from Anchorage to Nome in March with straight skis, penetration skis, and the hydraulic wheel skis that really help make this kind of trip a success being able to land on paved airport runways and on Village checkpoints on rivers,” said Williams.

According to Williams, the FAA will not allow getting a tailwheel endorsement with an aircraft on skis (unless it has hydraulic wheel skis in the wheel down position) but no endorsement is needed to fly any plane on skis.