Summary
We propose to adopt a new airworthiness directive (AD) for certain Boeing Model 737-600, -700, -700C, -800, and -900 series airplanes. This proposed AD would require inspections for scribe lines in the fuselage skin at lap joints, the splice strap at certain butt joints, the skin or doubler at certain approved repair doublers, and the skin at decal locations; and related investigative and corrective actions if necessary. This proposed AD results from reports of scribe line damage found adjacent to the skin lap joints, decals, and wing-to- body fairings. We are proposing this AD to detect and correct scribe lines, which can develop into fatigue cracks in the skin. Undetected fatigue cracks can grow and cause sudden decompression of the airplane.