Smith: “Are you implying that the aerospace fastener manufacturers cut corners in order to win contracts?”

GH: No, it’s a matter of manufacturing goals and simple economics. The aerospace market is price dominated. In order to get the contract, the fastener manufacturer’s goal is to meet the specification at the least cost, not to produce the best possible part.

This means that they are going to use the least expensive steel and manufacturing processes that will meet the specification. There is nothing wrong with this approach.

It certainly does not mean that certified aerospace fasteners are unsafe in any aspect. They will do the job for which they were designed.

There is another factor. Airframe and aircraft engine manufacturers design their components to a very high margin of safety. Further, aerospace structures are designed to be “fail safe.” There is a back up or second line of defense for virtually every structural component so that an isolated failure will not lead to disaster. They are also subjected to frequent and rigorous inspections.