FAA on Friday issued an Airworthiness Directive (AD) requiring operators of Boeing 757, 767 and 777s to inspect or replace certain flight deck windows. The AD is aimed at preventing smoke, fire or cracking of the inner layer of the forward viewing window caused by loose electrical connections that are used to heat the window to prevent ice.
According to FAA, operators have two options: begin inspections within 500 flight hours and then continue at intervals that are specific for each of two window designs or install a new, redesigned window. The inspection takes about an hour.
Over the past two decades, there have been 11 reports of fire or flames on 757s (five events), 767s (three events), and 777s (three events). Improper installation resulted in loose, improperly torqued or cross threaded screws that can contribute to overheating and arcing. The most recent incident was a May 16, 2010 emergency landing by a United 757 at Dulles International Airport.
FAA said this AD affects 1,212 U.S. airplanes out of 2,619 worldwide. The estimated cost for the inspections is $103,020 total for U.S. operators. The window replacement is optional and would be an additional cost.