How do aircraft tyres straighten themselves when landing in a crosswind?
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For crosswind generally an aircraft can perform the approach (potentially all the way to landing) in two basic ways:
* Using a sideslip. The aircraft “dips” one wing towards the wind to offset the crosswind. Using this technique the aircraft wheels remain aligned with the runway and there are minimal side forces.
* Using a crab angle. The aircraft is turned sideways into the wind. If maintained until touch down, there will be some side forces on the landing gears. However, on large aircraft, the landing gears are engineered to withstand the side forces during crosswind landings.
Often pilots will land with a combination of sideslip and crab angle. E.g., use a crab angle during an approach but partially or completely de-crab (potentially with some sideslip) during flare and subsequent touchdown.
If fully landing on a crab, airplane will naturally straighten itself due to momentum and forces on the landing gear the. The pilot also provides control inputs (rudder & aileron) to control the direction of travel.
Note: sideslip is limited during landing due to wing clearance from the ground. Crab angle is usually limited by the amount of crosswind and the condition of the runway.
For small, high-wing planes like Cessnas, sideslip is probably the preferred method. The high-wing gives plenty of sideslip angle to work with and the landing gears on small planes don’t take well to a lot of side forces.
On the opposite spectrum, some very large aircraft have [main gears that can be steered / swiveled](https://www.youtube.com/watch?v=nhVD3E0-0Wc)so they can land crabbed even in very high crosswind conditions.
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