LANDING IN WINDY CONDITIONS
The weather may have changed significantly while you were up and away. If a summer shower has blown through, the prevailing wind direction could be very different than it was at launch. Or it may be completely reversed – daily – by passage of a shearline or sea breeze front! THINK, look around, ask questions – of yourself and anyone else available. If If you’re unsure, begin by assuming the worst. When altitude and time allow, fly around the field above pattern height to observe any activity – human or otherwise. Maybe operations were shut down for safety reasons hours before and no one is there to help secure your craft, in which case you should plan ahead exactly where you need to stop.
Sailplanes are generally safer than their powered counterparts, but one area where this is not necessarily true is final approach into a strong headwind. The problem is wind gradient, which every aviator should understand – but too few do. As you descend from stronger wind aloft on final approach, your airspeed will decrease. That means less aerodynamic lift and an increase in sink rate. (Control effectiveness also suffers!) The severity of wind gradient and the height at which it occurs cannot be precisely anticipated, and may change from one moment to the next. It might also lie at more than one level – and that aspect, too, can change quickly and often.
The defense against this degraded performance is more speed, or more height to trade for speed. A compromise, using a little extra speed and a little extra altitude, will keep whole process closer to normal and limit the disadvantages of each.
When strong wind is blowing straight across a runway, the problem of wind gradient will be greatest on base leg, regardless of which direction that crosswind is coming from. A wide pattern flown with the base leg into this crosswind might consume too much altitude too soon, leaving less than enough for final approach. For this reason, you should move your base leg (and perhaps also your downwind leg) closer to the threshold. Then, if it still looks questionable, angle the base leg in further, changing the aim point to a spot you know you can reach in normal landing configuration. As you roll out of this turn to final, the greater wind under your upper (windward) wing can make lowering that wing and lining up with the runway difficult and time-consuming. In this situation, many pilots instinctively fly a curved base-to-final leg, but that only delays leveling and lining up until the last, lowest moment – or prevents it completely. Instead, retain enough altitude to stay with the base leg until you can make a square final turn at comfortable height, allowing ample time to line up a straight final approach.
If the crosswind is from behind on base leg, that leg itself will take only a fraction of the normal time to complete, and an unwary pilot could turn final too late and too high. That would mean having to face the wind (and the gradient) on a long, curved, final approach, with that troublesome turn away from the wind, coming just before touchdown.
If you have the option of landing from left or right (especially in an off-field situation), choose a base leg into the wind for greater accuracy in the approach and touchdown. Either way, any wind gradient near the ground will mean less crosswind on late final, possibly making things easier at touchdown.
If you get too low on final, close your spoilers, smoothly lower your angle of attack (nose down), and use ground effect. Hold one hand STEADY on the stick and the other ready to reopen spoilers at the moment of touchdown. Steadiness is extremely important here, in every respect. The more you move either hand, the more difficult it will be to make a good landing.
When low short of their aim point, many pilots intentionally float up the runway at very low altitude to reach some pre-chosen, arbitrary touchdown point. Even in ordinary conditions, this is an unnecessary complication, and high wind conditions make it dangerous. To float parallel with the ground, you must be in a relatively high angle of attack with little or no airbrake. In that configuration, a sudden gust can throw you up ten or twenty feet, and a sudden lull in the wind can slam you down hard. The strongest winds demand that you just get the ship down simply as possible and work at keeping it there!
Then, as airspeed decreases after a crosswind landing, the tendency to weathervane will erode your directional control and pull you into the wind. Try to arrange for extra room on the ground upwind of where you intend to stop.
