Airworthiness Directives; The Boeing Company Airplanes

We propose to adopt a new airworthiness directive (AD) for all The Boeing Company Model 737-100, -200, -200C, -300, -400, and -500 series airplanes. This proposed AD was prompted by a report of a crack of the forward leg of the left front spar lower chord and cracks on the lower wing skin at three fastener holes common to the nacelle outboard side load fitting. This proposed AD would require repetitive inspections for cracks on the front spar lower chord, inspar skin, and wing skin, and corrective action if necessary. We are proposing this AD to detect and correct fatigue cracking of the forward leg of the front spar lower chord, inspar skin, and wing skin common to the nacelle outboard side load fitting, which could adversely affect the structural integrity of the wing.