I was torquing the -4 hardware for the corner brackets on the main gear box (IV-P) and noticed they kept relaxing. I would tighten to 70 inch-pounds (the max listed in AC 43.13) then come back later and find they had loosened so that it might require a quarter turn or more to regain the value. This happened several times and I started to wonder if the carbon might be getting crushed. Today I found that the bolts had stayed at 70 but now I'm wondering about the added stress that pressurization might put on the material under the heads.

As the range for the fastener is 50-70 inch pounds would it be a good idea to use a lower value? What have others done? Thanks-  Bill Wade