There’s normal, and then there’s normal. Which is to say that while much of aviation relies on routine procedures and aircraft configurations, among other things, there are exceptions to most norms. For example, the FAA long ago declared a “normal” landing to be one with an airplane’s wing flaps, if any, fully deployed. That’s not the same as saying we always must extend full flaps before landing, no matter what. Like in a stiff, gusty crosswind, for example, whose presence means the landing is not “normal.”
Instead, airplane design and the wind conditions themselves are factors that can strongly argue in favor of partial- or no-flap crosswind landings. The runway we’re trying to use is a big part of the decision also, since good technique for a gusty crosswind is to add half of the gust value to the final approach speed, often designated VREF. Greater speed on approach and landing means a lengthier runway requirement. Another consideration is whether going around is a likely outcome of the approach, since many airplanes don’t climb well with full or partial flaps deployed.
