Summary
We propose to adopt a new airworthiness directive (AD) for certain Boeing Model 757 airplanes, Model 767 airplanes, and Model 777- 200 and -300 series airplanes. This proposed AD would require repetitive inspections for damage of the electrical terminal at the left and right flightdeck window 1, and corrective actions if necessary. This proposed AD would also allow for replacing the flightdeck window 1 with a new improved flightdeck window equipped with electrical connections, which would end the need for the repetitive inspections for that flightdeck window 1. This proposed AD results from several reports of electrical arcs at the terminal blocks of the electrically heated flightdeck window 1. In more than one of the incidents, the arcs resulted in open flames. We are proposing this AD to prevent smoke and fire in the cockpit, which could lead to loss of visibility, and injuries to or incapacitation of the flightcrew.