Originally Posted by
midnight cruiser
Oh dear!
Crosswind, not headwind! If there's no head component, (90° across), then i you should NOT be adding an approach speed wind additive, and if you do, you are operating completely outside your performance calculation and risk an overrun (you can manually increase from the +5kt on the Boeing opt vref entry if you insist on adding speed anyway, but even that, I think it's supposed to be washed off prior to touchdown, from memory).
Incorrect. FCTM clearly states add all gust factor up to 15 knots for a gusty cross wind. Maintained until touchdown.