Summary
We propose to adopt a new airworthiness directive (AD) for all The Boeing Company Model 737-600, -700, -700C, -800, -900, and -900ER series airplanes. This proposed AD was prompted by reports of loose, worn, or missing attachment bolts for the main landing gear (MLG) center door assemblies. This proposed AD would require repetitive detailed inspections of the forward and aft MLG center door assembly attachments for loose, missing, damaged, or bottomed out attachment bolts; any wear to the retention clip assemblies as applicable; and applicable on-condition actions. This proposed AD would also provide an optional terminating action for the repetitive inspections. Since this is a rotable parts issue, the applicability of this AD has been expanded beyond the airplanes listed in the related service bulletin to include all airplanes on which the MLG center door assemblies may be installed. We are proposing this AD to address the unsafe condition on these products.