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To avoid hijacking the other thread about brackets I’d like some input on the practice of substituting bolts for rivets. I’m well aware the view here is that rivets are preferred. Doing some research on the matter I found the following in the Cessna 100 Series Manual:
19-52A. REPLACEMENT OF HI-SHEAR RIVETS with close-tolerance bolts or other commercial fasteners of equivalent strength properties is permissible. Holes should not be elongated and the Hi-shear substitute should be a smooth push fit. Forging may be spot-faced the least amount necessary for proper seating of the fasteners.
Without getting into the weeds of rivets vs. bolts (covered well in the other thread), does this paragraph constitute manufacturer’s guidance authorizing the substitution?
This is more an academic question than anything. I’m wondering if all those aircraft flying with bolts are legally airworthy.
19-52A. REPLACEMENT OF HI-SHEAR RIVETS with close-tolerance bolts or other commercial fasteners of equivalent strength properties is permissible. Holes should not be elongated and the Hi-shear substitute should be a smooth push fit. Forging may be spot-faced the least amount necessary for proper seating of the fasteners.
does this paragraph constitute manufacturer’s guidance authorizing the substitution?
Good question. I'm going to say it provides guidance, but not authorization. First off, to the best of my knowledge, the 100 series maintenance manual is not FAA approved, so, at best, it is acceptable data, not approved data, so you'd still need a field approval. Secondly, the paragraph above is quite specific in that it calls for close tolerance bolts or equivalent, and "push fit", (a light interference fit) which means you have to ream the holes to size. By the time you get done doing that you could have riveted it on a half a dozen times... I also suspect the cost of that many close tolerance bolts would make your head spin.
Steve, I think I may have confused you. If you're paying your A&P to rivet it on, he can do it in 1/6the the time it would take to ream all those holes (to match) so he can install those clo$e tolerance bolt$.
John, I was just giving you AP guys a little razzing! A few rivets and a 1/2 hour's worth of riveting time will be WAY cheaper (and easier) than all the work required for and the expense of close tolerance bolts.
If it weren't for AP/IAs, us owners would be in a world of trouble!
