Airworthiness Directives; Boeing Model 757 Airplanes and Model 767-200, 767-300, and 767-300F Series Airplanes

We are adopting a new airworthiness directive (AD) for all Boeing Model 757 airplanes and Model 767-200, 767-300, and 767-300F series airplanes. This AD requires revising the Limitations section of the airplane flight manual to advise the flight crew of procedures to follow to ensure that a fuel filter impending bypass condition due to gross fuel contamination is detected in a timely manner. This AD was prompted by an error in the operating program software (OPS) of the engine indication and crew alerting system (EICAS). The error prevents the display of an advisory message to the flight crew of a left engine fuel filter contamination and imminent bypass condition, which may indicate an imminent multiple engine thrust loss or engine malfunction event due to fuel contamination. We are issuing this AD to prevent malfunction and thrust loss on both engines, which could result in a forced off-airport landing.