An additional quote from the "letter never sent" (except to the OIG):
So they do just a visual inspection of the head of the cotter pin to judge this critical inspection requirement with? What if the "end side" of the cotter pin under the sealant is gapped? They could never visually tell with sealant applied. I believe strongly that the inspectors on the 747/767 EBU line that were there when the sealant was applied before the cotter pins were put up for inspection actually never attempted to inspect those cotter pins at all. Why would they?—they couldn’t do it if they wanted to. If they did anything, they just looked to see if a cotter pin of any sort seemed to be present under the sealant at the end of the bolt —nothing more. Indeed, one of the inspectors who spent a lot of time on the 747/767 EBU line eschewed a mirror and flashlight in favor of a coffee cup to "inspect with"—and there was no way you could inspect what little remained uncovered by sealant of these cotter pins without a flashlight and mirror.
The Last Inspector