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that wind, so that bank is keeping the airplane from drifting. So, a one-wheel landing on the up-wind tire is mandatory if the landing is to be done correctly.
What keeps the airplane from drifting downwind after the downwind tire (the second tire) touches down? The answer is NOT the ailerons, for the wings are now level and the horizontal component of lift is non-existent. The correct an- swer is rubber contact with the surface. That’s right, the friction of the tires to
moderate coefficient of friction, you’ll have some control, but there is no way to know for sure.
How much coefficient of friction do you have exactly? A pilot can get a clue at some of the big airports from braking-action reports, which give us an idea of what we’re going to experience. There’s also reports from other pilots who used the runway shortly before you which is super valuable information. But, wind and ice can create very dynamic
In the PA46 world, we usually lose two airframes (or more) each year to landing on contaminated runways with crosswinds. I suspect other airframes have commensurate losses. All of these accidents are avoidable. Simply put, if there’s a contaminated runway and a crosswind, do not land there. Find a run- way aligned with the wind.
An off-runway event almost always results in a prop-strike, a wing ding or a nose gear collapse. Rarely does anyone get seriously injured, but the insurance claims are always high. It’ll cost you downtime, hull-value loss and better- ment (a nasty little word in the insurance world that most owners are not prepared for in an insurance claim).
Of course, on an icy runway, there’s also the threat of a FOD event, mini- mized braking effect and reduced visual cues. And all of those can cause seri- ous problems that lead to an accident. But, the problem I see more often than not in the twin and turbine world is the attempted landing on a contaminated crosswind runway.
All of the above applies to a takeoff as well. If you understand the ground dynamics and aerodynamics of an ap- proach and landing, you can apply that understanding to a takeoff and arrive at the same conclusion. That conclusion is that rubber-to-ground friction is also required for a safe takeoff. If ice is pres- ent and a crosswind exists, find another runway or put the airplane back in the hangar. It’s better to be conservative and fly another day than to attempt a cross- wind takeoff on ice and end up in the ditch. I promise you’ll make headlines with your accident, and not the headlines you were hoping to make.
the ground is the only thing keeping the airplane on the centerline, and the rudder now has the job of controlling the direction of the airplane. Once the nosewheel touches down, there’s even more rubber helping to keep the airplane going straight. The nose wheel becomes more and more important for directional control as the rudder becomes less effec- tive with decreasing speed.
Having said all this, here is my pri- mary point with this article: If ice exists on the runway and a crosswind landing is attempted that has a side-force that exceeds the coefficient of friction of the tire to the surface, the airplane will drift with the force of the wind. Remember, the only thing keeping the airplane di- rectionally stable once the aerodynamics stop is the friction of the rubber on the ground. If a layer of ice exists, all bets are off. You might stay on the runway, and you might not.
If the ice between your rubber and the ground is “black ice” (which has virtually no coefficient of friction), you are just a passenger, and I hope you are a fortunate passenger riding in an airplane that stays on the runway. If it’s slushy ice with a
situations, and there are no assurances that the conditions have not changed. At smaller airports, it’s most often a guess- ing game. Don’t guess wrong.
I remember once landing a Saab 340 at the super long, super wide Runway 33L at KSPS (Sheppard AFB/Wichita Falls, TX). We had a full load of passengers and winter had arrived with much fan- fare: ice, snow and plenty of wind. The nighttime touchdown was uneventful, but then came the rollout. As the Saab slowed on the rollout (certainly under 40 knots), the airplane started to slide. If you never been in a sliding airplane, it is one of the strangest and most disconcerting feelings ever. It’s a helpless feeling, where time slows to a turtle’s pace and gives you pause to think to yourself, “Why did I try this landing?! Please don’t go in the ditch!” The enormous width of that particular runway saved my bacon for the airplane did not leave the runway, but when it finally stopped, the Saab was pointing into the wind, off centerline and two wide-eyed pilots were staring at each other in disbelief. I proceeded to crawl the airplane to the terminal for fear that I’d lose control again.
Joe Casey is an FAA-DPE and an ATP, CFI, CFII (A/H), MEI, CFIG, CFIH, as well as a U.S. Army UH-60 standardization instructor/exam- iner. An MMOPA Board member, he has been a PA46 instructor for 16-plus years and has accumulat- ed 12,000-plus hours of flight time, 5,500 of which has been in the PA46. Contact Joe at: www.flycasey.com, by email at joe@flycasey.com, or by phone at 903.721.9549.
8 • TWIN & TURBINE
February 2019