Airworthiness Directives; The Boeing Company Airplanes

We are adopting a new airworthiness directive (AD) for certain The Boeing Company Model 747-100, 747-100B, 747-100B SUD, 747-200B, 747-200C, 747-200F, 747-300, 747-400, 747-400D, 747-400F, 747SR, and 747SP series airplanes. This AD was prompted by several reports of electrical arcs at terminal "A" of the electrically heated flight deck window 1. This AD requires repetitive inspections for damage of the electrical connections at terminal "A" of the left and right flight deck window 1, and corrective actions if necessary. This AD also allows for replacing a flight deck window 1 with a new improved flight deck window 1 equipped with different electrical connections, which would terminate the repetitive inspections for that window. We are issuing this AD to prevent smoke and fire in the cockpit, which could lead to loss of visibility, and injuries to or incapacitation of the flight crew.