What planes can and can't do - Wind

One important thing when talking about aerodynamics is that the speed which is relevant in lift generation is the relative speed between air and wing. Speed relatively to ground has no influence, except for take-off and landing.

If wind is blowing, planes will take-off and land in opposite direction, so for the same air speed (needed to generate lift) the ground speed will be less, so the ground roll will be shorter, and more controllable.

The problem with wind start when they are fluctuating. If there is a sudden change in wind speed during an approach (what is called a "windshear"), the relative airspeed could be significantly changed, leading to potentailly strong changes in lift, then in vertical speed.

By chance, modern airliners have computers that know the airspeed from airspeed sensors, and groundspeed from GPS, so they can detect any windshear and notify them to pilots. The only "cure" is just to apply full power, and go arround for a second approach.

The other major issue with wind is when it is not blowing parallel to the runway. As the plane is moving relatively to air, the only way to maintain a straight ground track (needed for landing, isn'it ?) is to fly with the nose in the wind direction, flying in a "crabby" fashion.

This is perfectly ok to maintain a trajectory relatively to ground, but raises an issue, as the landing gear are not orientable, so immediately before (in some case after...) landing, the plane must be put in line with the runway.

Some examples of this technique are shows in the following video. Please understand that clearly, what you will see is indeed very good pilot skills, not bloody pilots missing their landings.



The next video is from a simulator (no airline will ever allow its pilots to even try such an approach), but it is very good for demonstration, as it shows the same approach from outsite and inside the planes, with angles that would be impossible to shoot from in reality.



The next time you will have a firm landing in crosswind conditions, or a go arround, please remind that this is how to do. And a go arround is never a bad option.