Vref+5 instead of Vref at threshold is 95m extra landing distance in my qrh so i guess vref+10 would be cumulative 190m.
Extra speed means extra chance to float hence even extra distance,i think 80m/sec.
So if a 10 kts gust correction is flown until landing and the negative gust never appears then landing distance +190m.
If the neg gust happens just as one touches down,vref is the speed hence no extra distance.
Simply a trade of possible extra landing distance against a possible underspeed at touchdown and all problems related to it.
Last edited by de facto; 22nd May 2012 at 02:05.