Airworthiness Directives; The Boeing Company Airplanes

We propose to adopt a new airworthiness directive (AD) for certain The Boeing Company Model 737-400 series airplanes. This proposed AD was prompted by reports of cracking in the splice plate on the lower sill of the overwing emergency exit doors. This proposed AD would require repetitive inspections for such cracking and applicable on-condition actions. We are proposing this AD to address the unsafe condition on these products.