Originally Posted by
Mostly Harmless
At the peak gust, that's 19 kts of crosswind and 9 kts of tailwind, not 21 kts of tailwind.
For Runway 14, a wind of 260/16G21 (last one given by ATC) will give at peak gust 11kts tailwind and 18 kts xwind, but previous wind readings from TWR prove that is was changing constantly so touchdown wind only the FDR will tell us.
Max tailwind per B747 FCOM is 15kts.