Summary
This document proposes the adoption of a new airworthiness directive (AD) that is applicable to Boeing Model 747-400, 757, and 767 series airplanes. This proposal would require a revision to the Airplane Flight Manual that would advise flight crews to monitor the engine indication and crew alerting system (EICAS) for ``status'' level messages pertaining to impending engine fuel filter bypass. This proposal also would require the installation of upgraded EICAS computers that provide ``advisory'' level messages to indicate such bypass conditions. This proposal is prompted by a finding that EICAS computers currently installed on these airplanes do not provide an appropriate indication to the flight crew of an impending engine fuel filter bypass condition. The actions specified by the proposed AD are intended to ensure that the flight crew is appropriately aware of conditions involving a severely contaminated airplane fuel system and the associated increased potential for engine power loss.