Well said, John.
I'll leave the first subject area to others, and make a simple observation regarding the second. The USMC discovered a serious problem in the Marana incident. The Bell/Boeing/USMC test team did what appears to be an extensive and technically rigorous flight test to establish the boundaries of the problem and establish corrective action procedures. They did that and the USMC and USAF aviators are now happy with what they fly.
There will inevitably be some comment that Marana represented a failure of that same test team to discover that particular problem. In response, my experience is that prior to flight test beginning on any new model, the entire test planning sequence is reviewed at many levels for rigor, completeness and of course adherence to contractual/specification requirements. What I am suggesting is that none of the experts involved saw this one coming, and along those lines, it is not the first time it has occurred within the industry.
Repeated for emphasis, and truth, with the doubled comment that this was a new technology being undertaken.
You won't predict it all. R & D means R & D, and part of the "D" ends up being "discovery."
For a case in point, consider how long it took to get the T-45, a fairly simple aircraft in comparison, untracked for the USN jet training missions and roles, adapted from a simple light attack aircraft. Even with a well known design, things come up that need fixing. Ten years into its service, there were still issues with nose wheel steering and ground handling that were being addressed in ECP's by NAVIAR and the manufacturer.
For a case nearer and dearer to my rotary flying days, there was the matter of how to die in an S-70 / Blackhawk when the Horizontal Stab runs itself full down, uncommanded.
That too got fixed after the team looked into a rigorous root cause anaysis and effective engineering solution. But as with many technologies (the moving horizontal stab was relatively new feature, and its FBW control, when Blackhawk entered the field) what we enjoy today was earned in blood.
As to Kadon bearings,
