Airworthiness Directives; Boeing Model 747 Airplanes

The FAA is adopting a new airworthiness directive (AD) for all Boeing Model 747 airplanes. This AD 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, and related investigative and corrective actions if necessary. This AD results from loss of a No. 3 window in- flight. We are issuing this AD to detect and correct cracking in the fail-safe interlayer of certain No. 2 and No. 3 glass windows, which could result in loss of the window and consequent rapid loss of cabin pressure. Loss of the window could also result in crew communication difficulties or incapacitation of the crew.