David, I agree with Beth. It took a lot of attention to detail to find the change you mentioned. It is interesting to note that the environment was such that even a "small" material change could cause a failure. Good work!
A great example of sticking to the problem and following the trail until total problem resolution is achieved. All I can say is I wish more engineers and companies practiced this kind of dogged determination to get to the truth. Kudos to you and your design team.
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