Airworthiness Directives; Lockheed Model L-1011-385 Series Airplanes

This amendment adopts a new airworthiness directive (AD), applicable to all Lockheed Model L-1011-385 series airplanes, that requires repetitive inspections to detect cracking of the fuselage skin in the areas of the left- and right-hand stringerless sidewall window belts, and repair, if necessary. This amendment is prompted by reports of fatigue cracks found in the fuselage skin where the skin thickness steps from 0.40 to 0.23 inch. The actions specified by this AD are intended to detect and correct cracking of the fuselage skin, which could result in reduced structural integrity of the airplane.