Ann: Structural Monitoring Systems Investor Webinar, page-80

I actually have what I think they call a test coupon ie it is two pieces of metal sheet joined together with a pair if rivets. (It is about 250mm long and 30mm wide.) I presume in a test one end is fixed firmly and the other end vibrated. The CVM device encircles one of the rivets. It was given to me by Ross Love at the AGM.

In terms of how big might a crack be before it is detected the first capillary which encircles the rivet - and I guess is the vacuum capillary - is just 3mm away from the edge of the rivet.

I suggest a 3mm crack is not going to cause a catastrophic event and anything larger than that is going to cause the vacuum to be lost. I don't know how fast cracks grow but given the current service schedule is about 9 months for APB testing by eddy current there is fair chance if a crack commences then over 9 months it could be well past 3mm.

This Boeing certification engineer doesn't seem to understand the real life situation. A theorist with no practical background.

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