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

This document publishes in the Federal Register an amendment adopting Airworthiness Directive (AD) T99-13-51 that was sent previously to all known U.S. owners and operators of certain Boeing Model 737-700 and -800 series airplanes by individual telegrams. This AD requires revising the Airplane Flight Manual (AFM) to prohibit operation of the airplane under certain conditions; repetitive inspections of the tab mast fitting of the elevator tab assemblies to detect cracking; an elevator tab freeplay check; and corrective actions, if necessary. This AD also provides for optional terminating action for certain repetitive inspections. This AD requires installing an additional fastener on the tab mast fitting, which terminates the AFM revision and extends certain repetitive inspections. This action is prompted by a report of a severe vibration incident on a Boeing Model 737-800 series airplane; inspection revealed fracturing of the elevator tab mast fitting and excessive freeplay in the elevator tab. The actions specified by this AD are intended to prevent reduced controllability of the airplane due to excessive freeplay in the elevator tab or a free tab.