Summary
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 cracks in the body station (STA) 303.9 frame web and doubler at fastener holes common to the stop fitting at stringer 16 left (S-16L). This proposed AD would require repetitive surface high frequency eddy current (HFEC) inspections for cracking of the STA 303.9 frame web and doubler at the stop fitting at S-16L, and applicable on-condition actions. We are proposing this AD to address the unsafe condition on these products.