Summary
This document proposes the supersedure of an existing airworthiness directive (AD), applicable to all Lockheed Model L-1011- 385 series airplanes, that currently requires various types of inspections to detect fatigue cracking of certain areas of the rear spar caps, web, skin, and certain fastener holes; and repair or modification, if necessary. This action would reduce the repetitive inspection interval for all of the currently required inspections, except for the x-ray inspections. It also would revise the terminating modification provision for some airplanes. This proposal is prompted by reports of cracks found during the currently-required inspections, which had progressed to lengths greater than predicted. The actions specified by the proposed AD are intended to ensure that fatigue cracking is detected and corrected in a timely manner before it can lead to rupture of the rear spar, extensive damage to the wing, and spillage of fuel.