credibiltiy

It seems that if there are two possible causes for a helicopter accident,
the preferred one for the manufacturer is the one for which they have no
fault. That certainly is the best for them. However, lets say that a low
hour helicopter suffers a failure directly attibutable to fatigue. Further
lets assume that the helicopter had had a prior series of hard landings or
other beyond normal stress loadings. Now lets further assume that the
fatigue failure occurred at a point in the helicopter drive system where a
diameter change was machined into the shaft without any radius or attempt at
a proper fillet which yielded a strong stress riser.
Lets say that the kit manufacturer is very aware that a number of kits have
been sold with the same machining flaw.
Should the kit manufacturer issue a service advisory statement advising all
owners of those ships of a potential safety issue caused by those parts?
What should their action be? Recall and supply exchange parts for no
charge? Recall and supply exchange parts for their cost? Change the
machining process and ignore the other parts out there?
How about sell the business to someone else and just duck and hope that
nothing bad ever comes from the above?