Thanks InitRef. The NTSB recommendation (A-94-38) concerning inspection of composite structures seems very limited in extent:
"Require inspection using nondestructive ultrasound "A" scan inspection techniques of composite elevators on MD-11 airplanes that are known to have been operated outside the design buffet boundary."
I presume that the NTSB regards their other recommendations as sufficient to prevent the *first* operation of the a/c outside the design buffet boundary.
The NTSB report of this 1992 incident describes a very similar one (pitch and roll oscillations with elevator skin loss following turbulence) that happened to an Alitalia MD-11 on 26 Aug 93.