whenrealityhurts re “…you can be assured of maintaining control…”
There is no such assurance in a max demonstrated crosswind; you have no idea how much margin there is from a limit condition – primarily because the manufacturer has not been there.
In addition the test only assumes an ‘average’ pilot, a task which does not require undue skill or strength – experience and ability are not defined. How do pilots judge themselves before a max crosswind landing, how many times have they done it before, and what is their currency? Not known, and often misjudged.
Furthermore, the manufacturer does not have to consider runway conditions, but most do now publish guidance for wet conditions. The manufacturers’ tests may not record the type of runway surface – lateral friction characteristics; this might affect the ability to stay on the runway; as might tyre conditons.
Also, the manufacturer may measure the wind speed with a more sensitive system than used by ATC, thus the ‘tower’ wind might be differ, and in operations the accuracy of wind reporting can be ‘significantly’ different.
Then there are gusts … !
See #10 to #13.