Action
Notice of proposed rulemaking (NPRM).
Summary
We propose to adopt a new airworthiness directive (AD) for certain The Boeing Company Model 737-300, -400, and -500 series airplanes. This proposed AD was prompted by reports of cracking at certain fastener locations in the window corners of the window belt area. This proposed AD would require repetitive high frequency eddy current (HFEC) inspections for fatigue cracking in certain fastener locations in the window corners of the window belt area, and related investigative and corrective actions if necessary. This proposed AD would also provide an optional preventive modification that would terminate the repetitive inspections at the modified location. We are proposing this AD to detect and correct fatigue cracking around fastener locations that could cause multiple window corner skin cracks, which could result in rapid decompression and loss of structural integrity of the airplane.