Summary
We propose to adopt a new airworthiness directive (AD) for certain The Boeing Company Model 737-100, -200, and -200C series airplanes. This proposed AD was prompted by a report of a severed upper butt strap, and cracks in the forward skin and bonded doubler, on one airplane. This proposed AD would require repetitive inspections for cracks and a chemical spot test in the area of station (STA) 908, and related investigative and corrective actions, if necessary. For certain airplanes, this proposed AD would require an inspection and modification. We are proposing this AD to prevent cracks at the adjacent mating skins (forward and aft), which could initiate just above stringers S-4R and S-4L; and could grow and result in a decompression event.