If vectors to a runway 90 degrees off the prevailing wind make your palms sweat, if you sometimes pick airports based more on avoiding crosswind landings than their proximity to your destination, youre not alone.
Crosswind landings have been causing anxiety attacks in pilots for a long time now – along with crunched wingtips and bent landing gear – and will apparently continue to do so for the foreseeable future.
Although all student pilots learn crosswind techniques, once on their own they tend to avoid crosswind landings whenever possible. The biannual tune-up often doesnt help much, as many instructors are just as willing to seek out runways where the wind will be more inconvenience than nuisance. If the accident record is any indication, landing in stiff crosswinds is something many pilots havent thought about in a while.
Heres a typical case: The pilot of a Cessna 182 is headed for an airport that has only one narrow, paved east/west runway. The Unicom operator and the windsock agree that the crosswind is directly across the runway. The pilot decides to land to the east. He runs into a little turbulence on the approach and elects to increase his final approach speed to 80-85 knots, with 20 degrees of flaps.
He keeps a good crab angle into the crosswind from the left all the way down final. At about 50 feet up, the pilot kicks out the crab angle with the rudder and lines up with the runway centerline. But – not for long. Drift to the right starts immediately. The pilot makes a couple of frantic little turns into the crosswind and then flares for landing.
After a wobbly flare (left wing down, wings level, left wing slightly down), the Cessna 182 floats 1,000 feet down the runway before settling down hard on the main gear. Still rolling too fast, the 182 skips and porpoises three or four times.
Because the pilot didnt maintain the wind correction during the bounces, touchdown is at an angle to the left and off the runway centerline. At touchdown, the nosewheel whips around and the airplane heads for the left edge of the runway.
The pilot makes several efforts to regain control with the rudder and brakes, but what little luck he had has run out. Listen to the runway edge lights ripping into the tires and rims, then the heavy crump of hitting a mudhole. Once the nose wheel has sheared off, there is the slow rise of the airplane to almost vertical. The final clang of prop strikes – with sudden engine stoppage, the bent engine mounts and firewall – all go along with the scenario. Visions of astronomical repair bills flash by, as well.
Now theres not much left to do but cut the master switch and get out. Next is the struggle to get out of the belt and harness, crawling across control yokes and instrument panel, to face the head-shaking rescuers below.
Tune-up Time
For most pilots, crosswind skills need constant review – a thinking review. The chances of making a poor or misjudged landing are greatly increased in crosswind conditions. It may start with a poorly flown traffic pattern, where an error in correcting for drift in the pattern or on final approach complicates the end result.
You certainly need to keep control authority in any landing, but its particularly important to remember in a crosswind landing. In order to maintain sufficient control authority you may need to use a bit higher speed on approach, which means you are going to use up more runway than usual. Make sure you have enough runway to safely land.
Taildraggers can get very squirrelly in a 3-point landing attitude during a crosswind. Use the wheel (or two-point) landing, but be ready for the higher approach and landing speed. Many pilots flying tricycle gear airplanes use partial flaps to ensure better control authority in the landing phase. Again, the stall speed will be higher.
Compensating for a crosswind drift on final approach is basic but, for those who sleep through landings, here are the basics:
First, of course, is to reduce power to idle or whatever power setting your airplane normally requires on any final approach. Most pilots then use the wing down procedure, which is actually a slip.
The most important part of the wing-down method is to keep the fuselage (and therefore the wheels) aligned with the runway centerline. This is to keep the side loads on the landing gear to a minimum. To prevent side loads – which the landing gear is not strengthened for – merely stop the side drift so the airplane will not be moving sideways when it touches down.
When you first turn from base to final, line the airplane up with the runway, as if there were no crosswind. Dont laugh. Runway alignment is a problem, even for some high time pilots.
The curved windshields that are installed in most light airplanes create optical illusions that can lead to confusion as to what is exactly straight ahead. Most pilots tend to look out of the center of the windshield, but – because they are sitting on the left side – they need to look out slightly to the right of center.
These pilots usually find that they almost always land on the left side of the runway. They generally need to make last minute adjustments to the approach path, just before the flare, which is not the time to be making the landing more complicated. Because they need to maneuver the airplane on final to get the runway to appear in what they see as the center of the windscreen, they end up with an oscillating approach.
Most flight instructors have seen this in student pilots and tried to correct it, but its not easy. Sometimes it just cant be done. Even instructors have problems learning to find the true runway centerline when they first begin sitting on the right side of the cockpit.
Off on the Right Foot
Alignment with the runway centerline is very important as you turn from base to final with a crosswind. Line up the airplane with the center of the runway as if there were no crosswind and, with the crosswind from the left, watch the airplane begin to drift to the right side of the runway. Once you see the drift is to the right, put in enough crab to the left to stop the drift. Its surprising how many students, higher certificate applicants and professional pilots have forgotten this one.
About 100 yards from the end of the runway put the left wing down – into the left crosswind – but keep the nose and landing gear wheels aligned with the centerline of the runway. To do this, of course, will take opposite rudder. Left wing down, correcting for drift, means right rudder to stop the turn.
There is another little quirk to be ready for. When you put in the right rudder correction, with the left wing down, the wings will tend to roll level. Youll need to put in more left aileron to keep this wing leveling reaction from happening. By and large, the failure to correct for the opposite rudders wing-leveling effect is what you see when you watch someone doing a less than satisfactory crosswind landing. Its usually wing down, wing up, wing down, wing up all the way in.
This rolling from one side to the other is certain to produce undesirable results at touchdown. When the airplane is level, the crosswind takes over and the landing is made while drifting. Not enough rudder and the airplane may touch down turning into the wind slightly. Either way, its hard on the tires and landing gear.
As you slip toward the runway, its important to remember that the rate of descent will be greater than in a normal glide. Precisely how much greater depends on how much wind there is. Youll likely need power to slow the sink rate.
Crossed Up
Some pilots like to set up a slip almost as soon as they turn final rather than crabbing into the wind. They reason that they wont have the sudden change from the crab angle to the slip in the last seconds, just before touchdown. They usually set in a small amount of power to slow the sink rate, then proceed right to the touchdown on one wheel. They like the idea that the crosswind correction is already in as they touch down.
A real danger haunts this kind of approach. With crossed controls, they are setting themselves up for a stall or potential spin at an altitude too low to make a recovery. Sometimes, especially when approaching a short runway, the pilot might try slowing down. Crossed controls, low airspeed, short final – all the wrong inputs.
Crossed controls are to blame for many of the accidents that happen when pilots are turning base to final, but trouble can also crop up during a final approach slip. During a true wing-down slip straight ahead, stalling is difficult. But it can happen if a flat slip develops.
Imagine that the pilot lets the normal wing-down attitude move to a position of almost wings level, with the nose still yawed away from the flight path, then continues to hold enough aileron to balance the bank created by the opposite rudder deflection. If the angle of attack gets too high, the airspeed decreases and the airplanes longitudinal direction moves back toward the pre-slip heading.
If strong rudder action is taken to return to the original slip direction, a dangerous condition has developed – the airspeed is low and the controls are crossed. Expect the airplane to stall and roll in the direction of the rudder being held, or toward the low wing.
Recover by releasing the slip control pressures, regaining straight and level by coordinated control use, and increasing power, as necessary.
Passengers are seldom able to get used to the slip technique, especially if the slip is put in early on a long final. It can lead to some hysterical outbursts from first time passengers, which can be distracting.
Speed Control
Controlling airspeed is important while doing a slip, but the airspeed indicator could indicate excessively low or high values. This depends on the location of the aircrafts static source and the direction of the slip.
An airplane with a single static port on the left side of the fuselage will have an airspeed indicator that reads low in a left slip and high in a right slip.
Other airplanes have a Y-type system, which has static points on both sides of the fuselage. It has smaller indicated airspeed errors, and theyre equal in a slip to the right or left. As a general rule, believe what the pitch attitude shows you rather than the numbers on the airspeed indicator. If you have ever had a plugged pitot tube and then landed without too much trouble, you understand this point well.
Due to the slight loss in the vertical lift component produced by the wing when the airplane is in a slipping descent, increase the approach speed slightly. When slipping, add 5 percent to the 1.5 Vso airspeed on final. Lets say that 1.5 Vso for your airplane is 55 knots, so youd add roughly 3 knots – not a large increase. If the wind is reported gusting from 10 to 20 knots, that is a 10-knot difference. Cut that in half, or 5 knots. Add that to the 58-knot speed for slipping and youd want to fly 63 knots on final, which should set you up for a minimum landing roll. In the case of a single static point, you probably wont have an accurate reading. Unless you know the airplane well, rely more on the normal final approach pitch attitude of the airplane.
The use of flaps on crosswind landings has been a matter of hangar debate for decades. To a certain extent the answer depends on the aircraft and the pilots technique.
The Pilots Operating Handbook is the ruling authority regarding any limitations of the aircraft. Most, however, are mum on the issue or say only Flaps – As Required. However some POHs prohibit slips at a full flap setting, because of blanking out of control surfaces. Others warn that a slip will uncover fuel-outlet ports in a low tank, causing fuel starvation. Know the book on this one.
Without guidance from the POH, use half flaps or takeoff flaps minimize the problems with gusts.
Once youve settled on an approach speed, stick with it. Stretching the glide isnt a good idea in a slipping configuration any more than it is in a normal approach. If it looks as though you are going to barely clear obstacles on final or land short, apply the power and hold the normal approach attitude – keep the nose down.
There will be a tendency for the nose to rise as you apply the crosswind correction. Dont let the angle of attack get too high or you enter cross-control stall country.
Flare for the Dramatic
As the speed decreases in the landing flare, its going to be necessary to apply more control deflection, since the effectiveness of the controls declines with the speed. But touchdown should be made with the wing down.
This is where things usually come apart, since the many psychological impacts of the primary instructor have left their dents in our conscious acts. We know the wings have to be level to get both main wheels on the ground at the same time. Regardless of your gut feeling, however, the crosswind effect remains unchanged. The touchdown should be made with the wing down, landing on the windward side wheel. With one wing lowered into the wind and opposite rudder in, there is also some good protection from the usual side gusts at touchdown.
On the rollout, the crosswind is still there. Youll need to hold enough aileron into the wind to prevent the windward wing from coming up as the airplane rolls down the runway.
Where many pilots come to grief on crosswind landings is timing the flare and waiting for the airplane to land. Because of the extra speed, the airplane may float a bit farther down the runway. Impatient pilots are sometimes too abrupt with the controls during the flare. Ballooning is mainly the result of a rapid pitch change, which causes an unwanted altitude gain and leaves the wings close to a stall.
If power is added properly as the aircraft settles, the touchdown may be cushioned. The increase in power can prevent the airspeed from decreasing too rapidly and the wings from losing lift, although it does come at the cost of using more runway.
Landing on Porpoise
Dont just push forward on the yoke in an attempt to get the nose back down. The low airspeed, if coupled with a low angle of attack, can result in a high sink rate and the wrong attitude for contacting the ground. Striking nosewheel first is usually followed by a porpoise – bouncing from the main gear to the nosewheel – and then the damage starts. After a couple of hard smashes on the nosewheel, it will collapse. Later you may discover a bent firewall, damaged engine mounts, a dinged propeller and big repair bills on the horizon. Going around is better.
A better procedure is to release some of the backpressure on the yoke, and be prepared to take faster elevator action in the last part of the landing. In the final portion, power may needed to cushion the touchdown.
A key point is that the increase in power also means an increase in torque. That means adjusting the rudder deflection to keep the airplane straight as it squeaks onto the runway. Having been in the right seat for hundreds of ballooned landings, Ive noticed that the crosswind correction is almost always released by the pilot, or is just not enough. Another thought to keep in mind is that there is an immediate increase in the effect of a crosswind as the airspeed decreases.
Even if you have the balloon under control, the higher than normal sink rate can lead to a bounce. The best and safest procedure for a severe bounce is to execute an immediate go-around. An attempt to salvage a landing from a hard bounce, with airspeed bleeding off and with a nose-high attitude, would be extremely hazardous. A minor bounce can be corrected with a shot of power, but remember to keep crosswind controls in. A bounce that occurs in a crosswind landing is going to call for some of the best skills a pilot may have.
After the upwind main wheel strikes the runway, the other wheel will touch down immediately following, followed by the bounce. The wings will be level and the airplane will drift rapidly. If the airplane touches down again while the airplane is drifting sideways, you can count on trouble.
This kind of landing will put very extreme side loads on the landing gear, which can result in damage. This strong sideways inertial force will create a moment around the main wheel, once it makes ground contact, tending to swing around, or tip the airplane. Once the windward wingtip is lifted by this moment, one main wheel will then carry all the weight and shock. Damage is highly probable. The crosswind will also act on the fuselage surface – in back of the main wheels. This will also turn the airplane into the wind.
Limits to Your Authority
There is a final warning to using the wing down crosswind landing method. At some point, you can run out of the control that you need to carry you through to the landing. When you sideslip into a very strong crosswind, youll need a large, lowered upwind wing correction. It will take a large amount of opposite rudder, maybe all that you have available, to keep the nose aligned with the runway. You may run out of rudder control.
Well, choose another runway, or even a taxiway if fuel is a problem. Or you can reach into your bag of pilot skills and bring out the crab method.
Its really the only way for low wing aircraft in a strong crosswind. And the pilots of larger and heavier low and mid-wing birds almost always use the crab method. Its simple enough.
Make a crosswind approach using the crab method on final approach, keeping the wings level. Regardless of the crab angle it takes to do it, keep the ground track of the airplane lined up with the runway centerline. Hold the crab angle until the last part of the flare (it takes discipline), just before the stall. Then kick out the crab angle with rudder, keeping the main wheels lined up with the runway centerline.
It takes practice to get it right. You dont want to touch down with the crab correction in, due to the excessive side load pressures on the tires and the landing gear. Its close to all of the phases of a normal approach, except for the final re-alignment with the runway centerline, just before the stall. This method does take a high degree of timing and judgment – and practice.
Which one is best? Most pilots would probably agree that the wing-down slip technique consistently gives the most satisfactory results.
The most experienced pilots tend to use a combination of both methods. Drift is corrected on final approach by using the crab angle into the crosswind. On flare the aircraft is yawed around with rudder to line up with the runway centerline, the upwind wing is smoothly lowered and the rudder pressure adjusted to stop any turn. The touchdown is made in the same way as the wing down method – on the upwind main wheel.
Of course the important thing is that you must keep your attention focused totally during crosswind takeoffs and landings. You can never relax until the engine is shut down and the aircraft is parked.
The people who do the best with challenging crosswind landings are the people who practice them whenever there is an opportunity. They usually start with the light variety, but rapidly progress to making even strong ones look easy and smooth.
Also With This Article
Click here to view “Maximum Crosswind Velocity Can be Exceeded – Sometimes, by Some Pilots.”
-by Raymond Leis
Raymond Leis is a CFII and ATP with more than 23,000 hours.
