Airworthiness Directives; The Boeing Company Airplanes

We are superseding an existing airworthiness directive (AD) for all 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. That AD currently requires an inspection of the No. 2 and No. 3 windows on the left and right sides of the airplane to determine their part numbers, related investigative and corrective actions if necessary, and repetitive inspections of single pane windows. This new AD requires installing dual pane No. 2 and No. 3 windows. This new AD also removes certain airplanes from the applicability. This AD was prompted by loss of a No. 3 window in flight, which could result in consequent rapid loss of cabin pressure. Loss of the window could also result in crew communication difficulties or incapacitation of the crew. We are issuing this AD to correct the unsafe condition on these products.