AD FAA-2015-2464

We are superseding Airworthiness Directive (AD) 2013-22-11 for certain The Boeing Company Model 747-400 and -400D series airplanes. AD 2013-22-11 required repetitive inspections to detect cracks in the floor panel attachment fastener holes of certain upper deck floor beam upper chords, repetitive inspections, corrective actions if necessary, and replacement of the upper deck floor beam upper chords. Since we issued AD 2013-22-11, we received a report that certain fastener holes in the upper deck floor beam upper chords may not have been inspected in accordance with AD 2013-22-11. This AD adds additional repetitive inspections for cracks for certain airplanes, and corrective actions if necessary. We are issuing this AD to detect and correct fatigue cracking in certain upper chords of the upper deck floor beam. Such cracks could become large and cause the floor beams to become severed and result in rapid decompression or reduced controllability of the airplane.