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Gear leg bracket bolts

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Hi Murray,

Unfortunately, no one on this forum is privy to the stress analysis relating to the selection of fasteners that hold this bracket in place. However, If the design calls for four fasteners (it does) you can safely assume it needs to have all four fasteners, that they need to be the specified fasteners (by part number or size and grade), that they need to be accompanied by the specified hardware (nuts & washers), that the need to be properly assembled, and that they need to be tightened to the specified torque (or a standard torque for that size and grade of fastener if no other torque is specified). The maintenance manual provides this information.

From the photos you sent it appears that the outboard fastener is not the correct part (C9996060 I think), does not have the specified washer (C9996565), and has not been properly torqued (80 in-lb). This should set off a bunch of alarm bells. I would go back through the maintenance logbook and figure out who did this work. I would then very carefully examine every other job he did, or might have done, on this aircraft. And yes, I'm afraid this may be an enormous job.


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One thing I have noticed and not specific to gear bolts is that the soft washers will dish out for high torque applications. It's an obvious issue on engine mount bolt washers on the inside of the cabin where the carbon fiber will conically crush. I now use a hardened washer over the original washers which solves the problem for high torque applications. 

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