Airworthiness Directives; Boeing Model 747, 757, 767 and 777 Series Airplanes

The FAA is superseding an existing airworthiness directive (AD), which applies to certain Boeing Model 747, 757, 767, and 777 series airplanes. That AD currently requires modifying certain drip shields located on the flight deck, and follow-on actions. This new AD removes certain airplanes that are included in the applicability statement of the existing AD, and requires modifying additional drip shields on the flight deck of certain other airplanes. This AD is prompted by a determination that certain airplanes have drip shields that are not adequately resistant to fire. We are issuing this AD to prevent potential ignition of the moisture barrier cover of the drip shield, which could propagate a small fire that results from an electrical arc, leading to a larger fire.