I don’t think we’ve actually gotten confirmation on what caused the failure yet. While loose bolts were found during a fleet wide inspection of that area of the aircraft, the tightness of the bolts that keep the door plug in place is irrelevant to the failure, as the locking pins in the end is what actually keeps the nuts from falling off, and thusly allowing the bolts to slide out of the holes where the keep the door from being able to move on its track.

To my knowledge we also haven’t gotten confirmation as to whether the mis-assembly happened at Spirit, where the door was first installed, during the subcontractor’s installation of the satellite data antenna, where the door plug may be removed for acess, or during finally integration by Boeing itself.

To be fair it doesn’t actually matter, as Boeing is responsible for inspecting the things they build at the end of the day and they’ve been having a lot of trouble since getting bought out by McDonall Douglas with cost cutting and penalizing their QA inspctors when they find something that needs to be redone, but it is likely more complicated than just a failure to tightnen bolts to spec.