Originally Posted by
midnight cruiser
Thank you; that's certainly my interpretation, and though it could be interpreted either way, logically a perpendicular gust or ground effect variation in windspeed is not going to affect the IAS, so there shouldn't be an addition. (In practice, of course a couple of knots for mum, or more empirically, a knot or three for the sin of the crab angle, same thing. but ref+ 15, fluctuating+20 and you're in trouble on a short wet runway with no head component..
Boeing give the same advice as we used to give as an aircraft manufacturer. You can have zero headwind component but a gust factor addition. They even have a table that I was going to post but I am unable to until I reach 8 forum posts. It gives an example of runway 36 and a wind of 090 15 gusting 25 and shows an approach speed of VREF+10. Hope this helps.