Summary
We propose to adopt a new airworthiness directive (AD) for certain The Boeing Company Model 737-700 and -700C series airplanes. This proposed AD was prompted by reports of early fatigue cracks at chem-mill areas on the crown skin panels. This proposed AD would require repetitive inspections for cracking of the fuselage skin at certain locations at chem-mill areas, and repair if necessary. We are proposing this AD to detect and correct fatigue cracking of the skin panel at the specified chem-mill step locations, which could result in rapid decompression of the airplane.