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 a one-time inspection to detect cracking of the bulkhead at fuselage station (FS) 1363 at butt line 42.5, and repair or additional inspections, if necessary. This action would add repetitive inspections to detect cracking of the bulkhead web and bulkhead cap (frame cap) at FS 1363, and repair, if necessary. This proposal is prompted by reports that additional, more extensive, fatigue cracking was found in the bulkhead web and cap. The actions specified by the proposed AD are intended to detect and correct cracking of the bulkhead web and cap, which could result in reduced structural integrity of the fuselage.