What was found
A CRACK HAD DEVELOPED IN THE LOWER CABIN DOOR FRAME ASSY AT THE AFT HINGE ATTACH AREA. THE CRACK WAS 2.75 INCHES LONG, RUNNING FORE AND AFT IN THE LOWER RADIUS WHERE THE SKIN AND STRUCTURE ARE RIVETED TOGETHER. THE FRAME ASSY WAS REMOVED AND REPLACED WITH A NEW PART. THE DOOR DOES HAVE THE EXTENDER KIT INSTALLED, BUT THE CRACK DOES NOT APPEAR TO HAVE BEEN CAUSED BY THIS. POSSIBLY A FAILED DOOR CABLE AT A PREVIOUS TIME APPLIED ADDITIONAL STRESS TO THIS AREA.