If you really want to know you will have to burrow down in the certification documentation. It has everything there. I would be surprised if the spec is near a grade 5 though. just due to the required infinite fatigue life. Engine structural fasteners can evolve to be quite unique depending on failure history. Particularly, main, head, connecting rod etc.
__________________
Bill
RV-7
Lord Kelvin:
“I often say that when you can measure what you are speaking about,
and express it in numbers, you know something about it; but when you
cannot measure it, when you cannot express it in numbers, your knowledge
is of a meager and unsatisfactory kind.”
|