AD 2021-26-28 Airworthiness Directives; The Boeing Company Airplanes

Models named: 757-200, -200PF, -200CB, -300 series. Read the applicability below — it usually turns on serial or part numbers too.

This AD applies to all The Boeing Company Model 757-200, -200PF, -200CB, and -300 series airplanes, certificated in any category.

Comply with this AD within the compliance times specified, unless already done.

Except as provided by paragraphs (h) and (i) of this AD, within 60 days after the effective date of this AD, revise the existing maintenance or inspection program, as applicable, to incorporate the information specified in Section E., “Airworthiness Limitations—Systems,” of the Boeing 757 Maintenance Planning Data (MPD) Document, Section 9, Airworthiness Limitations (AWLs) and Certification Maintenance Requirements (CMRs), D622N001-9, dated September 2020; except this AD does not require incorporation of the information specified in Subsections E.2 and E.4. The initial compliance time for doing the airworthiness limitation instruction (ALI) tasks is at the times specified in paragraphs (g)(1) through (12) of this AD. (1) For AWL No. 28-AWL-01, “External Wires Over Center Fuel Tank”: Within 120 months after the most recent inspection was performed as specified in AWL No. 28-AWL-01. (2) For AWL No. 28-AWL-03, “Fuel Quantity Indicating System (FQIS)—Out Tank Wiring Lightning Shield to Ground Termination”: Within 120 months after the most recent inspection was performed as specified in AWL No. 28-AWL-03. (3) For AWL No. 28-AWL-14, “Main and Center Wing Tank Fueling Shutoff Valve Body and Actuator—Fault Current Bond”: Within 120 months after the most recent inspection was performed as specified in AWL No. 28-AWL-14. (4) For AWL No. 28-AWL-20, “Center Tank Fuel Override Boost Pump Automatic Shutoff System”: Within 12 months after accomplishment of the actions specified in Boeing Service Bulletin 757-28A0081 or Boeing Service Bulletin 757-28A0082, as applicable; or within 12 months after the most recent inspection was performed as specified in AWL No. 28-AWL-20; whichever occurs later. (5) For AWL No. 28-AWL-21, “Over-Current and Arcing Protection Electrical Design Features Operation—Boost Pump Ground Fault Interrupter (GFI)”: Within 12 months after accomplishment of the actions specified in Boeing Service Bulletin 757-28A0078 or Boeing Service Bulletin 757-28A0079, as applicable; or within 12 months after the most recent inspection was performed as specified in AWL No. 28-AWL-21; whichever occurs later. (6) For AWL No. 28-AWL-25, “Motor Operated Valve (MOV) Actuator—Lightning and Fault Current Protection Electrical Bond”: Within 72 months after accomplishment of the actions specified in Boeing Service Bulletin 757-28A0088, or within 72 months after the most recent inspection was performed as specified in AWL No. 28-AWL-25, whichever occurs later. (7) For AWL No. 28-AWL-26, “Center Tank Fuel Boost Pump Power Failed On Protection System”: Within 12 months after accomplishment of the actions specified in Boeing Service Bulletin 757-28A0105, or within 12 months after the most recent inspection was performed as specified in AWL No. 28-AWL-26, whichever occurs later. (8) For AWL No. 28-AWL-30, “AC Fuel Pump Fault Current Bonding Jumper Installation, Main and Center Tank”: Within 24 months after the effective date of this AD, or within 72 months after the most recent inspection was performed as specified in AWL No. 28-AWL-30, whichever occurs later. (9) For AWL No. 28-AWL-33, “Full Cushion Clamps and Teflon Sleeving Installed on Out-of-Tank Wire Bundles Installed on Brackets that are Mounted Directly on the Fuel Tanks”: Within 24 months after the effective date of this AD; or within 144 months after accomplishment of the actions specified in Boeing Service Bulletin 757-57A0064 (Part 2 through Part 10 of the Work Instructions); or within 144 months since the most recent inspection was performed as specified in AWL No. 28-AWL-33; whichever occurs later. (10) For AWL No. 47-AWL-04, “NGS—NEA Distribution Ducting”: Within 17,300 flight hours after accomplishment of the actions specified in Boeing Service Bulletin 757-47-0001 or Boeing Service Bulletin 757-47-0005, as applicable; or within 17,300 flight hours after the most recent inspection was performed as specified in AWL No. 47-AWL-04; whichever occurs later. (11) For AWL No. 47-AWL-05, “NGS—Cross Vent Check Valve”: Within 17,300 flight hours after accomplishment of the actions specified in Boeing Service Bulletin 757-47-0001 or Boeing Service Bulletin 757-47-0005, as applicable; or within 17,300 flight hours after the most recent inspection was performed as specified in AWL No. 47-AWL-05; whichever occurs later. (12) For AWL No. 47-AWL-07, “NGS—Thermal Switch”: Within 48,000 flight hours after accomplishment of the actions specified in Boeing Service Bulletin 757-47-0001 or Boeing Service Bulletin 757-47-0005, as applicable; or within 48,000 flight hours after the most recent inspection was performed as specified in AWL No. 47-AWL-07; whichever occurs later.

This AD was prompted by significant changes, including new or more restrictive requirements, made to the airworthiness limitations (AWLs) related to fuel tank ignition prevention and the nitrogen generation system. The FAA is issuing this AD to address ignition sources inside the fuel tanks and the increased flammability exposure of the center fuel tank caused by latent failures, alterations, repairs, or maintenance actions, which could result in a fuel tank explosion and consequent loss of an airplane.

This AD affects the ADs specified in paragraphs (b)(1) and (2) of this AD. (1) AD 2012-12-15, Amendment 39-17095 (77 FR 42964, July 23, 2012) (AD 2012-12-15). (2) AD 2018-20-13, Amendment 39-19447 (83 FR 52305, October 17, 2018) (AD 2018-20-13).