Summary
We propose to adopt a new airworthiness directive (AD) for certain The Boeing Company Model 747-400, and -400F series airplanes. This proposed AD was prompted by multiple reports of integrated display unit (IDU) malfunctions and mode control panel (MCP) malfunctions. This proposed AD would require installing new software, replacing the duct assembly with a new duct assembly, making wiring changes, and routing certain wire bundles. We are proposing this AD to prevent IDU malfunctions, which could affect the ability of the flight crew to read primary displays for airplane attitude, altitude, or airspeed, and consequently reduce the ability of the flight crew to maintain control of the airplane.