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 repetitive inspections for corrosion or cracking of the keel beam splices, and corrective action, if necessary. This action also provides an optional terminating action for the repetitive inspections. This action is necessary to find and fix corrosion or cracking of the keel beam splices, which could result in failure of the keel beam and consequent failure of the forward fuselage of the airplane. This action is intended to address the identified unsafe condition.