No way in hayell they are going to ground the MD-11 - it would put FedEx completely out of business - they have something like 130 M10s and M11s up and even a few D10s - it represents the bulk part of their long distance fleet. The airplane has known quirks - I was just reading about how a few seemingly trivial pilot inputs at FL350 put an M11 into a very unstable regime and nearly tore up the partially composite stabilizer. This is a matter of training and luck - these poor guys were probably just in the wrong place when the wrong gust caught them. Perhaps we will see new directives but they will NOT ground the MD-11 - nor should they.
-drl