AD FAA-2017-0807

We are adopting a new airworthiness directive (AD) for all The Boeing Company Model 737-100, -200, -200C, -300, -400, and -500 series airplanes. This AD was prompted by reports of cracking in the webs of the stub beams at certain fuselage stations. These cracks are the result of fatigue caused by cyclical loading from pressurization, wing loads, and landing loads. This AD requires repetitive inspections for cracking of the webs of the stub beams at certain fuselage stations, and applicable on-condition actions. We are issuing this AD to address the unsafe condition on these products.