Originally Posted by
dera
The big question is: Why do you have to know that when you're on final? Does it make any difference? No it doesn't. You fly the approach, and if you can keep it stable, you continue. If the crosswind exceeds your or planes capability, you go around. Simples.
Well it does in some places. For example, our ops manual gives the max demonstrated in the POH as a max crosswind (and please don't start a discussion about max demonstrated v crosswind limit as I'm sure we are all clear). If the crosswind is outside the POH figure, then our procedure is to divert to somewhere where there is a more into wind runway. So it really is necessary to be able to calculate the crosswind both when joining and when on final.
As for continue until the crosswind exceeds your or your aircraft's capabilities, that's a recipe for disaster. It's a bit late to discover your assessment of either's abilities was a bit optimistic as the undercarriage collapses due to a sideways load.