The crab method is executed by establishing a heading (crab) toward the wind with the wings level so that the airplane's ground track remains aligned with the centerline of the runway. This crab angle is maintained until just prior to touchdown, when the longitudinal axis of the airplane must be quickly aligned with the runway to avoid sideward contact of the wheels with the runway. If a long final approach is being flown, the pilot may use the crab method until just before the roundout is started and then smoothly changing to the wing low method for the remainder of the landing.
The wing low method will compensate for a crosswind from any angle, but more important, it enables the pilot to simultaneously keep the airplane's ground track and the longitudinal axis aligned with the runway centerline throughout the final approach, roundout, touchdown, and after landing roll. This prevents the airplane from touching down in a sideward motion and imposing damaging side loads on the landing gear.
To use the wing low method, the pilot aligns the airplane's heading with the centerline of the runway, notes the rate and direction of drift, then promptly applies drift correction by lowering the upwind wing (Fig. 9-11). The amount the wing must be lowered depends on the rate of drift. When the wing is lowered, the airplane will tend to turn in that direction. It is necessary, then, to simultaneously apply sufficient opposite rudder pressure to prevent the turn and keep the airplane's longitudinal axis aligned with the runway. In other words, the drift is controlled with aileron, and the heading with rudder. The airplane will now be side slipping into the wind just enough that both the resultant flightpath and the ground track are aligned with the runway. If the crosswind diminishes, this crosswind correction must be reduced accordingly or the airplane will begin slipping away from the desired path.
To correct for very strong crosswind, the slip into the wind must be increased by lowering the upwind wing a considerable amount. As a consequence, this would result in a greater tendency of the airplane to turn. Since turning is not desired, considerable opposite rudder must be applied to keep the airplane's longitudinal axis aligned with the runway. In some airplanes, there may not be sufficient rudder travel available to compensate for the strong turning tendency caused by the steep bank. If the required bank is so steep that full opposite rudder will not prevent a turn, the wind is too strong to safely land the airplane on that particular runway with those wind conditions. Since the airplane's capability would be exceeded, it is imperative that the landing be made on a more favorable runway either at that airport or at an alternate airport.
Flaps can and should be used during most approaches since they tend to have a stabilizing effect on the airplane. However, the degree to which flaps should be extended will vary with the airplane's handling characteristics, as well as the wind velocity. Full flaps may be used so long as the crosswind component is not in excess of the airplane's capability or unless the manufacturer recommends otherwise.