The 10 kt limit is a performance limit, I think, because the data only goes up to 10kt tail. If you want data for 15 kt tail then I believe you'd have to ask Boeing and there would be an extra charge, I guess.
Historically I think it was Britannia Airways who were the first to put the B737-200 on the UK register in the 1960s. They asked Boeing to provide data for 15 kts tailwind - a wise move since in those days not many airports had ILS on both ends and also the policy was better to take off with a tailwind in a direction that avoided an emergency turn in the event of engine failure.
As has been said before whether you want to autoland with 15 kts tail is another matter. Also airports sometimes apply restrictions. If you look at the Notams for Nantes (LFRS) there is a note about autoland with "rear wind" - sounds a bit painful to me......
Last edited by fireflybob; 1st September 2010 at 13:20.