<_< ------I believe there are only two, or three, out there to date! There are two lines producing 767 winglets. One at MCI, and the other at TUL. The first was the proto type, and took MCI about eighty days to produce. The last one MCI produced was turned out in forty five days. The first for TUL is taking about eighty days. I hear there are issues about getting parts, and how those parts are fitting. But once those issues are resolved, and those working it get a little more experience at whats going on, those times should come down considerably! Although I hear TUL has been utilizing quit a few more workers on their project than MCI! ------ As far as cracks, haven't heard either! Although, if you think about it, they are beefing up that wing considerably, limiting it's flexibility somewhat.