Hate to tell you, but the commercial 609 is still quite alive, and Bell
claims an order backlog. Bell market studies a couple of years back
projected 45% of the small tilt rotor market would be US and foreign
governments.

Whatever the origins of the Apache composite blade, going back to the
AH-64B, MSIP, etc. the technology to make the things got a chance in a
commercial development - 530F. That's how these things sometimes work,
and denying yourself a commercial avenue denies you development
opportunities that pay off later. Would Boeing Mesa have been better
just learning how to make the Apache blade from scratch today?

Flaw tolerance does indeed equate to ruggedness - the margins to
tolerate flaws caused by damage and keep flying. That is a good thing
for any helicopter - military or civil.

HW