Comment by adolph
11 hours ago
An interesting substory that is simultaneously reminiscent of the Fogbank story and how Hayek's "curious task" is much more broadly applicable:
There is a good cautionary tale here from the Space Shuttle era. That vehicle
had heat resistant tiles that had to be attached to the aluminum belly of the
orbiter. A special cloth had been certified for wiping the aluminum clean
before applying the primer that securely bonded the tiles to the metal. After
years of uneventful use, tile engineers discovered that new replacement tiles
were no longer curing properly.
A careful investigation revealed that the supplier of that special cloth had
changed the lubricant used in the machine that sews its hem. Minute amounts
of the lubricant were being deposited on the stitching, and enough of that
residue was getting on the aluminum skin to prevent the tile adhesive from
curing properly.
In medical device manufacturing you have systems in place that your vendors have to disclose changes to their manufacturing process that hopefully can catch stuff like this before people die. I can see how minute stuff gets easily passed off as not an important change.
Especially if the real change is a couple levels separated from the problem. For instance, I can imagine a situation where the manufacturer of that "special cloth" didn't even change anything themselves, but their lubricant supplier silently changed the formula of their sewing machine oil. (Or maybe even that one of the suppliers to the lubricant company changed something - it's turtles all the way down.)
Yes, you would also audit the quality system for your suppliers to confirm they are sufficiently controlling for upstream changes. In theory you can have all your ducks in a row.
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