Airworthiness Directives; The Boeing Company Airplanes

We are adopting a new airworthiness directive (AD) for all The Boeing Company Model 707 airplanes, and Model 720 and 720B series airplanes. This AD was prompted by reports of scribe-line-related fatigue cracks on Model 727 airplanes, which are similar in design to Model 707 airplanes, and Model 720 and 720B series airplanes. This AD requires inspections for scribe lines in the skin lap joints, external approved repairs, external features, skin butt joints, and decals; and related investigative and corrective actions if necessary. This AD also requires surface finish restoration. We are issuing this AD to detect and correct scribe lines, which can develop into fatigue cracks in the skin and cause rapid decompression of the airplane.