Airworthiness Directives; Boeing Model 747 Series Airplanes

This amendment adopts a new airworthiness directive (AD), applicable to certain Boeing Model 747 series airplanes. This AD requires repetitive inspections to detect cracks and corrosion around the lower bearing of the actuator attach fittings of the inboard and outboard flaps. This AD also requires repetitive overhauls for certain actuator attach fittings or repetitive replacement of the fittings with new fittings, as applicable, which terminates the repetitive inspections. This AD also provides for replacement of actuator attach fittings with improved fittings, which terminates all requirements of this AD. This amendment is prompted by reports of cracks on the lower bearing journal of the inboard actuator attach fittings of the outboard trailing edge flaps due to stress corrosion. The actions specified by this AD are intended to detect and correct cracking on the actuator attach fittings of the trailing edge flaps, which could result in abnormal operation or retraction of a trailing edge flap, and consequent reduced controllability of the airplane.