Control The Crosswind!

Ignoring the two really big crosswind controversies---do you crab all the way down final and kick it out at the last moment or carry a wing-down, sideslipping configuration to the runway?---there are tons of other factors that affect both schools, but still have a bit of debate attached. Is it advisable to use flaps or not? Do you always carry more speed over the threshold in a crosswind? How do you accommodate gusts? The list may not be endless, but it's certainly a long one.

Hands down, the most important factor in trying to analyze what kind of situation you're getting yourself into on final is the age-old question "How much wind are we talking about here?" But when we ask that question, we're doing so within the mental framework represented by, first, the airplane's capabilities, and then your own as they relate to that airplane. An old hand in a Bonanza, for instance, is going to see a 15-knot wind much differently than does a C-152 student. So, within reason, you can't just talk wind speed. You have to talk about it within the limits of your own experience and proficiency as well as what you're flying.

Of course, all of the foregoing considerably changes as the wind moves off the nose and becomes The Dreaded Crosswind(!). Even a crosswind is good, however, because except for a 90-degree barn-burner, part of every crosswind is down the nose and slows down the airplane. Part of every crosswind is exactly 90 degrees to the airplane, though, and it's that component that keeps us worried.

One of the few POHs with a wind chart in it showed that this particular airplane's limit with the wind 20 degrees off the nose was 60 mph! When it was 40 degrees, the wind limit was 30 mph, and when it was 90 degrees to the runway, the airplane was rated at 20 mph demonstrated crosswind. If those numbers seem high, think of it this way: They've proven this airplane will handle 20 mph right across the runway. So, when it's at 20 degrees, it takes 60 mph to generate a side component of 20 mph.

When the wind is coming at us from an angle, the airplane and the pilot combination become even more critical because every airplane has the aforementioned limit. At some point, even at full aileron and full rudder, it can't maintain a straight line. It should be noted, though, that the crosswind limitation of most airplanes is much higher than the crosswind limitation of most pilots.

We've said that the amount of wind and its direction is paramount to deciding whether or not we're actually going flying. Then we have to toss in gusts, which easily can have more effect than everything discussed to this point. It's the gusts that make any wind difficult. Even a really high crosswind is no sweat if it's steady, while a much smaller wind with hard gusts can be a bear. Suffice it to say that as the gust spread starts to become a sizable proportion of an airplane's stalling speed, it's time to sit up and take notice.

The reason we don't all destroy airplanes in every gusty crosswind landing is because the strength of the wind goes down as you get closer to the runway. In theory, the wind is zero right on the surface (in the boundary layer), then builds up to the level reported at about 15 feet off the ground. In nearly all winds, the most critical time is as you're working your way down into ground effect because, once in ground effect and closing on the runway, the wind gradient attenuates and life gets a little less hectic. There are exceptions to that rule, however. Again, see the sidebar for these exceptions.

Gusts also are the determining factor as to the speed and flap issue. As for the flaps, some POHs will tell you what to do in a given situation. A lot of old heads, however, say the higher the gust spread, the less flaps should be used. In a steady wind, the flaps just act like flaps, although as the wind gets really crossed, excess flaps often begin to act as additional side area, so more rudder is required to keep it straight. Flaps, however, accentuate the effects of gusts, making balloons higher and the attendant speed bleed off at the top of a balloon more severe.

So, do you use flaps in a normal crosswind? Yes. Do you use lots of flaps? It all depends on the wind and the airplane.

Is it advisable to add speed in the approach for a crosswind? Generally speaking, no. But what about gusts? An old rule of thumb says that you increase the approach speed by half of the gust factor. The reasoning is that if a gust died, you still would have enough speed in the bank that you could control it more effectively. Some folks have interpreted that to mean faster is better in a crosswind, and that's just not the case. Increased speed means increased float, and you'll be floating along right in that band where the wind is the strongest, and too much speed will expose you to its effects longer. So protect yourself against the gusts, but don't think whistling across the threshold at warp speed is the way to handle every wind.

Now let's talk all about the big controversy---the "how do we fly the final approach" argument. We'll let each school of thought speak for themselves.

Reading The Wind
One fact of life is that you'll never see the exact same wind twice. For that reason, it's important you take a little time before either taking off or landing to try to read the wind so you have some idea of what you're getting into.

If the wind appears to be anything even remotely out of the ordinary, sit there and study the sock. Don't just glance at its direction and stiffness and let it go at that. During the second or two you're looking at it, the wind sock could be lying to you in a big way because you're catching it in transition from one place to another. Keep your eyes on it long enough to see how stiff the sock becomes and how soft it gets, as that's your gust spread. Then notice how it changes direction. Are the direction changes caused by the gusts or are they independent of the gusts? This is important stuff to know.

A gust spread in which the gusts always come from a different direction than the main wind means you're in for a rougher-than-normal ride. You'll be set up to handle the main body of the wind, but when a gust comes, it not only tries to affect your lift, but for a split second or two, greatly changes the amount of crosswind correction you're going to need. For instance, if the high side of the gust always switches the wind from 30 degrees off your nose to 60 degrees, it's really going to be testing your ability to read how much the airplane is drifting and change the bank angle accordingly.

You also want to compare the gust spread to your stall speed. As the gusts approach 20% to 25% of your stall speed, you have to be aware that they're going to want to pick you up or slam you down during the flare, so be prepared to behave accordingly.

On downwind, look for telltale signs about the surface winds. Flags are good, as is smoke. Sometimes, you'll see dirt flowing or trees bent over partway down the runway. Water gives a good graphic view of what's happening right on the surface.

Nevertheless, you have to deal with whatever you find. A runway can cross through all sorts of micro-climates, and just because you've decided it's a such and such kind of wind, don't commit yourself to flying it that way. Always use your analysis of the wind as a guide, but make up your mind to deal with the wind on a second-to-second basis, constantly reevaluating your analysis of it and altering the way you handle it. Just because you ask the tower for the wind and they say it's 120 at 10, never forget that they aren't measuring the wind where you'll be landing and that they're never right.

The "Crab Down Final And Kick It Out At The End" Approach
The goal here is to minimize the amount of time you're busting your butt, trying to fly a straight line with a wing down. We keep the nose into the wind and simply fly final the same way we fly downwind, when there's a wind trying to push us, with the nose crabbed into the wind.

The beauty of this kind of approach is that you aren't constantly adjusting your bank angle and rudder to keep it lined up; the airplane pretty much does it automatically. You cross the threshold with the nose into the wind and then start worrying about getting it straightened out before hitting the runway.

Some people say you can fly it right into the flare that way and kick it straight just before touching down. The downside here is that as soon as you start to take the crab out, the airplane will start drifting, so you have to do it at the last second, and even then, you'll have a little drift when you touch down. You also stand a chance of having an inopportune gust die and plant you on really crooked. But what the heck? That's what the tricycle gear is good at, straightening itself out, right? Wrong!

The other school of thought features those pilots who fly the crabbed approach. They don't want the airplane to touch down in a drift. As they start bringing the nose up to the flare, they gently slide into a sideslip, putting the wing down into the wind and pulling the nose straight with the rudder.

If there's a downside to this kind of approach or landing, it's that there isn't much time when you pull the nose of the aircraft around and put the wing down to judge the effect of the wind. A lot of the top dogs do it this way, and their experience lets them see the wind as it starts to move them and their airplanes, and they simply cancel it out at the last moment.

The "Slip Down Final And Keep It Lined Up All The Way" Approach
Rather than take a chance with the last-minute drama of the crabbed method of handling a crosswind, some pilots opt for setting up the airplane in a sideslip well before they reach the runway. The theory behind the wing-down-on-final way of thinking is that nothing is being left to chance or last-minute reactions. Proponents of this school of thought also feel they're in better shape to handle gusts because they're already set up in a stable position, albeit with a wing down.

An advantage to the wing-down approach is that mentally you're already reading the changing crosswind and changing the bank angle and rudder accordingly. If it's a steady wind, you're just sitting there, crossed up and watching it happen. But if it's gusty, you're earning your pay, as you're constantly changing the rudder and aileron combination to cancel out the side component so you're always pointed right down the centerline.

There is some disagreement as to how far out on final you should slide into the slip. Some pilots fly the entire final that way. Others crab until within something like 1,000 feet of the threshold and then slide into the wing-down position. Either way, pilots from both schools of thought fly the last portion of final in the same way.

Regardless of which approach is used, crabbing or sideslipping, it's easy to see that too many pilots think too hard about the crosswind. They try to intellectualize it, and you can almost hear them thinking, Okay, the wind is from the right, so I put the right wing down and use left rudder!or is it the other way around? Don't think about it. Just use whatever rudder is needed to keep the nose right in front of you and keep a wing down to kill the drift, as simple as that.

The bottom line is that there is only one acceptable goal---touching down with the nose on the centerline with no sideways movement whatsoever. Granted, you can paste on a tri-geared airplane almost any way you want, with the nose to the side and drifting, and it will still almost always straighten itself out with a minimum of fuss. But the operative phrase there is "almost always." There will be situations in which the airplane won't be able to cope with the terrible situation that the pilot has left for it to sort out without bending something. Besides, even if it's a minor misalignment or drift, it's not the right way to do it. If you disagree with this advice, however, remind me to never loan you my airplane.

Truly Dangerous Winds
Once in a while, you'll find a wind that has some sort of characteristic that makes it truly dangerous. You don't find them often, but when you do, it might not be a bad idea to find another airport on which to land.

Hard-Edged, Direction-Changing Gusts
Sometimes you'll watch the sock and see it blowing one direction in a mild manner, then it will violently snap one direction or the other, stand out straight for a couple of seconds, then drop back into the original mild mode. These winds become especially dangerous when they're snapping from in front of the wingtip to behind the wingtip.

If, when you're low and getting ready to flare, the wind snaps hard from in front of the tip to behind it, what you're experiencing is a form of shear. Instantly your airspeed falls, taking the airplane with it. It doesn't have to be a big wind to have this effect; as little as 10 knots will do it. In some aircraft and some conditions, it's as if you've chopped off the wings. The only cure is instantaneous full power while, at the same time, fighting the urge to pull. The power will pitch the nose up anyway because of landing trim, so your job is to hold a stable, slightly nose-up attitude and hope the airplane powers out of the sink before you kiss off the runway too hard.

"Right Down To The Deck" Winds
As we've mentioned, most winds gradually die off as you get close to the ground, but once in a while, you'll see one that maintains its velocity down to a foot or less off the runway. Sometimes these winds won't even be rough or gusty, so you don't know anything is wrong until you're ready to touch down and find that as your speed goes away and your aerodynamic control becomes weak, you can't keep the airplane from drifting. It's as if you're caught in white-water rapids that are trying to pull your feet out from under you.

Although it depends on the airplane and the situation, most of the time, hard application of upwind aileron and downwind rudder will sort things out, but not always. The safe money drops the hammer and goes around and, once clear of the runway, swings the nose into the wind to maintain the centerline.