Airworthiness Directives; Boeing Model 737-600, -700, and -800 Series Airplanes

This amendment adopts a new airworthiness directive (AD) that is applicable to certain Boeing Model 737-600, -700, and -800 series airplanes. This action requires a one-time inspection to detect cracking of the rear spar stiffeners in the wing center section; and modification of crack-free stiffeners, or repair of cracked stiffeners. This amendment is prompted by a report of severed rear spar stiffeners of the center wing, which resulted in cracking in the adjacent keel beam structure. The actions specified in this AD are intended to prevent failure of the keel beam structure.