Summary
This document proposes the adoption of a new airworthiness directive (AD) that is applicable to certain MD-11 series airplanes. This proposal would require a one-time visual inspection to detect discrepancies of the seat tracks and adjacent structure underneath lavatories, and repair, if necessary. This proposal also would require installation of a non-metallic barrier on the bottom of each lavatory foot fitting, and replacement of existing seat track fittings with new seat track fittings. This proposal is prompted by reports of galvanic corrosion found on the seat tracks at attachment points under certain lavatories. The actions specified by the proposed AD are intended to prevent corrosion of seat tracks and adjacent structure. Corrosion of the seat tracks and adjacent structure could result in shifting of lavatories, which could lead to injury of passengers and crew, as well as damage to aircraft structure and systems.