Airworthiness Directive · Amendment 39-18452 · Engine fuel system wiring
The Boeing Company Airplanes
This AD applies to The Boeing Company Model 757-200, -200PF, -200CB, and -300 series airplanes; certificated in any category; except airplanes equipped with a flammability reduction means (FRM) approved by the FAA as compliant with the Fuel Tank Flammability Reduction (FTFR) rule (73 FR 42444, July 21, 2008) requirements of 14 CFR 25.981(b) or 14 CFR 26.33(c)(1).
We are adopting a new airworthiness directive (AD) for certain The Boeing Company Model 757 airplanes. This AD was prompted by fuel system reviews conducted by the manufacturer. This AD requires modifying the fuel quantity indication system (FQIS) wiring to prevent development of an ignition source inside the center fuel tank. We are issuing this AD to prevent ignition sources inside the center fuel tank, which, in combination with flammable fuel vapors, could result in a fuel tank explosion and consequent loss of the airplane.
Within 72 months after the effective date of this AD, modify the fuel quantity indication system (FQIS) wiring to prevent development of an ignition source inside the center fuel tank, using a method approved in accordance with the procedures specified in paragraph (i) of this AD.
For airplanes used exclusively for cargo operations: As an alternative to the requirements of paragraph (g) of this AD, do the actions specified in paragraphs (h)(1) and (h)(2) of this AD, using methods approved in accordance with the procedures specified in paragraph (i) of this AD. To exercise this alternative, operators must perform the first inspection required under paragraph (h)(1) of this AD within 6 months after the effective date of this AD. To exercise this alternative for airplanes returned to service after conversion of the airplane from a passenger configuration to an all-cargo configuration more than 6 months after the effective date of this AD, operators must perform the first inspection required under paragraph (h)(1) of this AD prior to further flight after the conversion.
(1) Within 6 months after the effective date of this AD, record the existing fault codes stored in the FQIS processor and then do a BITE check (check of built-in test equipment) of the FQIS, in accordance with the Accomplishment Instructions of Boeing Service Bulletin 757-28-0136, dated June 5, 2014. If any nondispatchable fault code is recorded prior to the BITE check or as a result of the BITE check, before further flight, do all applicable repairs, and repeat the BITE check until a successful test is performed with no nondispatchable fault found, in accordance with the Accomplishment Instructions of Boeing Service Bulletin 757-28-0136, dated June 5, 2014. Repeat these actions thereafter at intervals not to exceed 750 flight hours.
(2) Within 72 months after the effective date of this AD, modify the airplane by separating FQIS wiring that runs between the FQIS processor and the center fuel tank wall penetrations, including any circuits that pass through a main fuel tank, from other airplane wiring that is not intrinsically safe.
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.
Aircraft
