Airworthiness Directives; McDonnell Douglas Model MD-11 Series Airplanes

This amendment supersedes an existing airworthiness directive (AD), applicable to certain McDonnell Douglas Model MD-11 series airplanes, that currently requires a revision of the Airplane Flight Manual (AFM) to alert the flightcrew that both flight management computers (FMC's) must be installed and operational. That AD also requires an inspection to determine the serial number of the FMC's; and follow-on corrective actions, if necessary, which terminate the AFM revision. That amendment was prompted by a report indicating that, due to incorrect multiplexers that were installed in the FMC's during production, certain data busses failed simultaneously during a ground test. This amendment removes the terminating action from the existing AD. The actions specified in this AD are intended to prevent loss of airspeed and altitude indications on both primary flight displays in the cockpit, and/or loss or degradation of the autopilot functionality due to installation of incorrect multiplexers, and consequent failure of the data busses.