Airworthiness Directives; Boeing Model 737-200C Series Airplanes

This amendment supersedes an existing airworthiness directive (AD), applicable to all Boeing Model 737-200C series airplanes, that currently requires a one-time external detailed visual inspection to detect cracks of the fuselage skin in the lower lobe cargo compartment; repetitive internal detailed visual inspections to detect cracks of the frames in the lower lobe cargo compartment; and repair of cracked parts. That AD also provides for an optional preventative modification that constitutes terminating action for the repetitive inspections. This amendment requires accomplishment of the previously optional terminating modification. This amendment is prompted by reports of cracking in the body frames between stringers 19 left and 25 left and at body stations 360 to 500B. The actions specified by this AD are intended to prevent opening or loss of the cargo door during flight, and consequent rapid decompression of the airplane.