I riveted the access cover reinforcement ring and nutplates on tonight.  As you can see, the sealant gets everywhere.  I didn’t take any pictures of it, but MEK cleans all of this up nicely.  I used NAS1473-A08 instead of the K1000-08 nutplates called out in the plans.  These nutplates are enclosed and have an o-ring seal that prevents fuel from seeping out around the threads as can happen with a regular nutplate.

Here is the outside of the rib.  Flush rivets are used here because a rubberized cork gasket is used between the rib and the access plate.