Summary
We propose to supersede Airworthiness Directive (AD) 2011-23- 05, which applies to certain The Boeing Company Model 737-300, -400, and -500 series airplanes. AD 2011-23-05 currently requires repetitive inspections for cracking of the 1.04-inch nominal diameter wire penetration hole, and applicable related investigative and corrective actions. Since we issued AD 2011-23-05, an evaluation by the design approval holder (DAH) indicates that the fuselage frames and frame reinforcements are subject to widespread fatigue damage (WFD). This proposed AD would add new inspection areas, a modification that terminates certain inspections, post-modification inspections, and repair if necessary. We are proposing this AD to detect and correct fatigue cracking of the fuselage frames and frame reinforcements, which could result in reduced structural integrity of the airplane.