Originally Posted by
Plumb Bob
Note the bolt hole in the roller guide
.
Final checks for the emergency door equipped MAX9 would not include making sure the lock bolt holes in fact have bolts installed.
Final checks for the plug equipped MAX9 would have a check/sign off for lock bolts installed.
Assembly crews (such as the folks putting in the interior panels) would be used to seeing those bolt holes in your picture empty on the emergency exit door equipped models. I wonder if this particular airframe was the first after a run of a few airframes equipped with emergency exit doors. Perhaps complacency or rushing though the task of checking all the doors/plugs: then signing off a whole page of sign offs could be a factor.