Summary
We propose to adopt a new airworthiness directive (AD) for certain The Boeing Company Model 737-100, -200, -200C, -300, -400, and -500 series airplanes. This proposed AD was prompted by reports of cracks in fuselage frames, and a report of a missing strap that was not installed on a fuselage frame during production. This proposed AD would require an inspection to determine if the strap adjacent to a certain stringer is installed, and repair if missing; repetitive inspections of the frame for cracking or a severed frame web; and related investigative and corrective actions if necessary. This proposed AD also provides optional actions to terminate certain repetitive inspections. We are proposing this AD to detect and correct missing fuselage frame straps and frame cracking that can result in severed frames. Continued operation of the airplane with multiple adjacent severed frames, or the combination of a severed frame and fuselage skin chemical mill cracks, can result in uncontrolled decompression of the airplane.