In Section 29 and I was looking at the SL-00033 just to familiarize myself with that area. On the main landing gear mounts, I noticed that on the forward support which attaches to fwd floor skin/floor rib, the aft bolt on both left and right sides hadn't been tightened. Looking it up in the plans I could see it was backed by a nutplate so very simple to tighten and properly torque. I told a friend who took delivery of his QB fuse just a few months before me and he noticed the same loose bolts. I'm not sure if it has anything to do with the cracking issue, but I sent an email to Van's to give them a head's up.