Airworthiness Directive · Amendment 39-15488 · Boeing Model 757 Airplanes and Model 767-200, 767-300, and 767-300F Series Airplanes
Boeing Model 757 Airplanes and Model 767-200, 767-300, and 767-300F Series Airplanes
Superseded. A later AD replaced this one: AD 2011-25-11. Comply with the one in force.
This AD applies to all Boeing Model 757-200, -200PF, -200CB, and -300 series airplanes, and Model 767-200, 767-300, and 767-300F series airplanes, certificated in any category.
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.
Comply with this AD within the compliance times specified, unless already done.
Within 30 days after the effective date of this AD, revise the Limitations section of the applicable AFM to include the following. This may be done by inserting a copy of this AD into the AFM.
“If the STATUS cue shows while on the ground after engine start or during flight, select the status page on the secondary EICAS display, and verify the “L ENG FUEL FILT” message is not shown. If the “L ENG FUEL FILT” message is not shown on the status page, the secondary engine parameters may be reselected on the secondary EICAS display, or the display may be blanked. If the “L ENG FUEL FILT” message is shown on the status display, accomplish the ENGINE FUEL FILTER non-normal checklist as published in the Boeing Quick Reference Handbook. If on the ground, check the Dispatch Deviations Guide (DDG), or operator equivalent.
In the event that the status level “L ENG FUEL FILT” and advisory level “R ENG FUEL FILT” messages are simultaneously shown, an impending fuel filter bypass condition exists on both engines. With both messages shown, airplane fuel system contamination may be present and may result in erratic engine operation or flameout.
Further flight crew action in response to either or both the “L ENG FUEL FILT” status-level message and the “R ENG FUEL FILT” advisory level messages being shown are not established by Boeing or the FAA. Any further flight crew action should be determined by individual operator policy.
Boeing policy on flight crew use of status-level messages has not changed. After engine start, any condition having an adverse effect on safe continuation of the flight appears as an EICAS alert message (Warning, Caution, or Advisory). If other status-level messages are shown as a consequence of complying with these temporary operating instructions, the flight crew should respond in accordance with the appropriate operator policy.
Dispatch of the airplane with an inoperative EICAS display unit is prohibited.
(g) If all affected airplanes in an operator's fleet have been verified by the operator to have EICAS computer part number S242N701-1001 and only EICAS OPS versions other than Version 6 software that are FAA approved for that airplane, then accomplishment of the actions specified in paragraph (f) of this AD is not required.
The aircraft, engines and makers this AD names, by the model designations in its text. A model listed here may still be outside the AD's serial ranges.
