Airworthiness Directives; Lockheed Martin Corporation/Lockheed Martin Aeronautics Company Airplanes

We are superseding Airworthiness Directive (AD) 95-26-11 for all Lockheed Martin Corporation/Lockheed Martin Aeronautics Company Model L-1011 series airplanes. AD 95-26-11 required repetitive inspections to detect cracking of the fittings that attach the aft pressure bulkhead to the fuselage stringers, repetitive inspections to detect cracking of the fittings and of the splice tab of the aft pressure bulkhead, and corrective actions if necessary. This new AD requires repetitive inspections to detect cracking of the fittings that attach the aft pressure bulkhead to the fuselage stringers, repetitive inspections to detect cracking of the fittings and of the splice tab of the aft pressure bulkhead, repetitive inspections for cracking of certain aft fuselage skin panels, a structural modification, a post- modification inspection program, and corrective actions if necessary. This AD was prompted by a determination that the fittings at stringer attachments to the upper region of the aft pressure bulkhead are subject to widespread fatigue damage (WFD). We are issuing this AD to prevent simultaneous failure of multiple stringer end fittings through fatigue cracking at the aft pressure bulkhead, which could lead to rapid decompression of the airplane.