April 2006Features

Crosswind tutorial

Crab it or slip it, but don't avoid it! Four steps to better crosswind landings

"I don't want to fly with that guy anymore. He almost ran me off the runway," confided my good friend Dennis, a highly experienced business-jet pilot. "Did he land long? I asked, knowing full well that the Challenger can float halfway down the runway if you carry too much speed on final.

"No, no, no," he said, "he almost ran me off the side of the runway on account of the crosswind!"

Holy smokes! I thought. Here's a situation where a highly trained, very experienced jet pilot couldn't muster the basic stick-and-rudder skills to keep his jet from drifting perilously close the edge of the runway. That's bad. In fact, that's really bad. If the wheel of a 32,000-pound jet goes off into the mud at 120 knots, that's a roller coaster ride you may not walk away from.

The truth is, it really doesn't matter what size airplane you're flying, crosswind technique is crosswind technique. Pilots who don't learn how to cope with crosswinds early on never seem to learn to cope with them--that's why it's so important to learn now. So, with the sincere hope that you never go off into the mud, here are four steps to help make your crosswind landings easier and safer.

1. Get lined up early

You may have heard the old aviation adage "A great landing starts 10 miles out." What that really means is that a great landing usually follows a great approach. While a Chuck Yeager might produce a great landing from an unstable, rickety approach, the rest of us use the stabilized approach concept to give us a fighting chance.

A stabilized approach is nothing new; airline and business aviation pilots have been using it for years. It's so important they've incorporated it into their training programs and standard operating procedures. Basically, a stabilized approach is an approach where the airplane is lined up for the runway, on target airspeed, on glide path (electronic or visual), and fully configured for landing (flaps and gear down, propeller at high rpm). The airplane should be stabilized at an altitude no less than 500 feet above airport elevation.

It's best to line up early on the extended runway centerline. Here, the difference between heading and track becomes crucial. Heading, of course, it the actual heading of the airplane, or simply where the nose is pointed. Track, on the other hand, is the course it follows over the ground--the actual flight path referenced to the surface. In a no-wind condition, heading and track are the same. But throw a little crosswind into the mix, and you can see that the airplane will drift downwind as it flies.

To compensate for this drift, you're going to have to point the nose of the airplane into the wind slightly to set up a crab angle or wind correction angle to maintain a straight track. The amount of crab angle depends on the strength of the wind. And don't make the rookie mistake of trying to line up by putting the runway directly out in front of the windshield. If there's a good crosswind, and you're holding a crab, the runway may not be in front at all; it could easily be at your 11 or 1 o'clock position. The nice thing about flying with a wings-level crab angle (as opposed to a side slip with opposite rudder) is that it's much more comfortable for your passengers.

How do you know if you're on the extended runway centerline? That's another troublesome issue for students. One easy way to tell is to compare the far end of the runway to the near end. If the ends are positioned vertically, with the far end centered above the near end, then the airplane is on the extended centerline. However, if the far end is to the right of the near end, the airplane's to the right of the centerline. Conversely, if the far end is to the left, the airplane's to the left.

Another thing to keep in mind is that usually, you'll need less crab as you descend toward the runway, because the wind speed is being reduced by surface friction. However, if you're flying over a flat surface, like desert or water, the wind speed may not decrease as you descend. In that case, you may have to land with the full force of the crosswind at the surface. Moreover, surface inversions can cause a noticeable change in wind speed and direction during approach.

2. Use partial flaps

This is one of the best-kept secrets of crosswind landings, and surprisingly, many pilots don't even consider it! Since most general aviation airplanes have landing distances of fewer than 2,000 feet, runway length is rarely a factor even with partial-flap landings. For example, the pilot's operating handbook (POH) for the Cessna 172P states that for a flaps up landing you should allow for a 35-percent increase in landing distance. That's insignificant if you're landing on a 5,000-foot-long runway.

In a crosswind or gusty situation, however, full-flap landings can be more trouble than they're worth. This is because fully extended flaps present a larger surface area for that crosswind to affect, blowing you around. Flaps catch the wind just like a kite. Now while it's true that flaps lower your stall speed, allowing for a slower approach speed, you may not necessarily want that. Besides, that benefit usually comes at some intermediate flap setting before full extension; any further flap extension generally just adds drag. But don't just take my word for it, read what the manufacturer has to say in the POH. Here's an excerpt from the Normal Procedures section of a popular four-seat general aviation airplane: "Normal landing approaches can be made with power-on or power-off with any flap setting desired. Surface winds and air turbulence are usually the primary factors in determining the most comfortable approach speeds." (Italics added)

Plus, with partial flaps, your approach speed will have to be little faster. In the example above, along with the 35-percent increase in landing distance, the POH also recommends adding 7 knots to the approach speed for a no-flaps landing. In fact, assuming runway length is not a factor, adding extra airspeed is not a bad idea for any landing with crosswinds or gusts--with or without flaps. That's because a faster approach speed means better airplane control, especially lateral (or roll) control. In other words, with more airspeed, your ailerons will be more responsive--exactly what you want if gusty crosswinds are blowing you around. Just don't get carried away; coming in 15 or 20 knots faster than the recommended approach speed can cause problems. You will eat up more runway during the landing flare, and are subjected to crosswind effects for a longer period of time as you float--and float--down the runway.

3. Touch down on one wheel only

This seems like a no-brainer, but surprisingly many pilots just can't drive themselves to do it. Landing on both main wheels is fine when the wind's straight down the runway, but it's not desirable or safe when there's a crosswind. That's because you'll be touching down while the airplane's moving sideways or drifting downwind. Touching down while in a drift can cause damaging side loads on the tires, wheels, and landing gear--not to mention you and the airplane, if it results in a loss of control.

The only way to touch down without sideward drift is to land on the upwind wheel. The slight bank generates a slight horizontal component of lift, which cancels the crosswind component. Of course, the airplane seeks to turn when you bank it, so you'll have to hold some opposite rudder to keep the fuselage lined up with the runway. In other words, control drift with ailerons, control heading with rudder.

Thus, one of the marks of a great crosswind landing is a touchdown with little or no sideward drift. You're trying to touch down in a wing-low sideslip, on the upwind wheel, with zero drift, and with the longitudinal axis of the airplane (from the tip of the spinner to the tail) parallel to the runway. Accordingly, this crosswind landing technique is called the sideslip or wing-low method.

Therefore, at some point before touchdown, you'll have to transition the airplane from a crab to a wing-low sideslip. Depending on conditions, you could choose to do this at about 500 feet above the runway, or you could delay the transition until the airplane is closer to ground. It's all a judgment call that depends on the conditions at hand, your skills, and your comfort level.

When you do decide to transition, you'll do so by lowering the upwind wing slightly, while simultaneously adding opposite rudder pressure to keep the airplane's nose from turning. The resulting bank should be adjusted to keep the airplane from drifting, and the rudder pressure adjusted to keep the fuselage aligned with the runway. If the crosswind component lessens because of surface friction as you descend on your approach, you'll have to reduce the amount of bank and rudder pressure as required; flare and touchdown should be made while holding these corrections. Because the upwind wing is banked slightly, touchdown should occur on the upwind main first, followed by the downwind main, and finally the nosewheel.

4. Keep flying until you're stopped

Vigilance is the key here. A large number of pilots quit flying the airplane once it touches down. But this is precisely when you should be on the alert! Pilots let down their guard, become distracted, and end up losing control of the airplane to a wind gust. Never stop flying the airplane until it is shut down and chocked.

Consequently, you should hold those aileron and rudder crosswind corrections until the airplane has slowed to taxi speed. As the airplane slows down, the ailerons and rudder become less effective, so you'll have to add more control deflection. Finally, whenever crosswinds are involved, there are two figures in the POH you should be familiar with. The first one is the wind component chart. Given the wind speed and the angle between the wind direction and the runway, this chart shows you the headwind (or tailwind) and crosswind components. The use of this chart or its equivalent is a must whenever there's any doubt about how much crosswind exists for a particular approach and landing. Sadly, there have been more than a few high-profile airline and corporate jet accidents caused by a crew's miscalculations of tailwind or crosswind components where the use of this simple chart could have saved the day.

The other chart you should be familiar with is the taxiing diagram. This diagram shows the proper control positions to hold to maintain directional control and balance while taxiing in strong winds. This procedure should be memorized.

This is probably the most important tip of all: Learn to tackle crosswinds early in your flight training. Sure, crosswinds present some unique challenges, but they also allow you to savor the satisfaction of a properly executed "one wheel" crosswind landing. So, the next time the winds are blowing across the runway at your local airport, grab your instructor and under his or her tutelage go out and practice your crosswind landings until you've got them nailed. Whether you're an aspiring professional pilot or a recreational flier, you'll be making crosswind landings for the rest of your aviation career.

Christopher L. Parker is a CFI and an aviation author, speaker, and FAA remedial training specialist. He flies internationally as a contract captain on a Bombardier Challenger business jet and lives in Los Angeles.

Want to know more?
Links to additional resources about the topics discussed in this article are available at AOPA Flight Training Online.

Photography by Tyson Rininger