Airworthiness Directive · Amendment 39-21586 · Fuel
The Boeing Company Airplanes
This AD applies to The Boeing Company Model 737-600, -700, -700C, -800, -900, and -900ER series airplanes, certificated in any category, Line Numbers (L/Ns) 1 through 7596 inclusive, except L/Ns 7352, 7362, 7377, 7417, 7457, 7522, 7587, and 7592.
The FAA is adopting a new airworthiness directive (AD) for certain The Boeing Company Model 737-600, -700, -700C, -800, -900, and -900ER series airplanes. This AD was prompted by significant changes made to the airworthiness limitations (AWLs) related to fuel tank ignition prevention and the nitrogen generation system (NGS). This AD requires revising the existing maintenance or inspection program, as applicable, to incorporate the April 2019 or November 2020 revision of the airworthiness limitations document. The FAA is issuing this AD to address the unsafe condition on these products.
Within 60 days after the effective date of this AD, revise the existing maintenance or inspection program, as applicable, to incorporate the applicable information specified in Section A, including Subsections A.1., A.2., and A.3, of Boeing 737-600/700/700C/800/900/900ER Special Compliance Items/Airworthiness Limitations, D626A001-9-04, dated April 2019; or November 2020; except as provided by paragraph (h) of this AD. The initial compliance times for the airworthiness limitation instruction (ALI) tasks are within the applicable compliance times specified in in paragraphs (g)(1) through (14) of this AD.
(1) For AWL No. 28-AWL-01, “External Wires Over Center Fuel Tank”: Within 120 months after the date of issuance of the original airworthiness certificate or the original export certificate of airworthiness, or within 120 months after the most recent inspection was performed as specified in AWL No. 28-AWL-01, whichever is later.
(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 date of issuance of the original airworthiness certificate or the original export certificate of airworthiness, or within 120 months after the most recent inspection was performed as specified in AWL No. 28-AWL-03, whichever is later.
(3) For AWL No. 28-AWL-19, “Center Tank Fuel Boost Pump Automatic Shutoff System”: Within 12 months after the date of issuance of the original airworthiness certificate or the original export certificate of airworthiness, within 12 months after accomplishment of the actions specified in Boeing Service Bulletin 737-28A1206, or within 12 months after the most recent inspection was performed as specified in AWL No. 28-AWL-19, whichever is latest. This AWL does not apply to airplanes that have complied with paragraph (s) of AD 2011-18-03.
(4) For AWL No. 28-AWL-20, “Over-Current and Arcing Protection Electrical Design Features Operation—Boost Pump Ground Fault Interrupter (GFI)”: Within 12 months after the date of issuance of the original airworthiness certificate or the original export certificate of airworthiness, within 12 months after accomplishment of the actions specified in Boeing Service Bulletin 737-28A1201, or within 12 months after the most recent inspection was performed as specified in AWL No. 28-AWL-20, whichever is latest.
(5) For AWL No. 28-AWL-23, “Center Tank Fuel Boost Pump Power Failed On Protection System”: Within 12 months after the date of issuance of the original airworthiness certificate or the original export certificate of airworthiness, within 12 months after accomplishment of the actions specified in Boeing Service Bulletin 737-28A1248, or within 12 months after the most recent inspection was performed as specified in AWL No. 28-AWL-23, whichever is latest. This AWL does not apply to airplanes that have complied with paragraph (s) of AD 2011-18-03.
(6) For AWL No. 28-AWL-24, “Spar Valve 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 737-28A1207, or within 72 months after the most recent inspection was performed as specified in AWL No. 28-AWL-24, whichever is later.
(7) For AWL No. 28-AWL-29, “Full Cushion Clamps and Teflon Sleeving (If Installed) Installed on Out-of-Tank Wire Bundles Installed on Brackets that are Mounted Directly on the Fuel Tanks”: For airplanes having line numbers (L/N) 1 through 1754 inclusive, within 120 months after accomplishment of the actions specified in Boeing Service Bulletin 737-57A1279. For airplanes having L/N 1755 and subsequent, within 120 months after the date of issuance of the original airworthiness certificate or the original export certificate of airworthiness, or within 48 months after the effective date of this AD, whichever is later.
(8) For AWL No. 28-AWL-35, “Fuel Quantity Indicating System (FQIS)—Center Fuel Tank In-Tank Component and Wire Harness Protection Features-Separation from Center Tank Internal Structure”: For airplanes that have incorporated Boeing Service Bulletin 737-28-1356, within 120 months after accomplishment of the actions specified in Boeing Service Bulletin 737-28-1356, or within 120 months after the most recent inspection was performed as specified in AWL No. 28-AWL-35, whichever is later.
(9) For AWL No. 28-AWL-37, “Fuel Quantity Indicating System (FQIS)—Built in Test Equipment (BITE) Test”: For airplane L/Ns 6987 and 7000 and subsequent, within 750 flight hours since the date the most recent BITE test was accomplished as specified in AWL No. 28-AWL-37, or within 750 flight hours after the effective date of this AD, whichever is later.
(10) For AWL No. 47-AWL-04, “Nitrogen Generation System—Thermal Switch”: Within 22,500 flight hours after the date of issuance of the original airworthiness certificate or the original export certificate of airworthiness, within 22,500 flight hours after accomplishment of the actions specified in Boeing Service Bulletin 737-47-1003, or within 22,500 flight hours after the most recent inspection was performed as specified in AWL No. 47-AWL-04, whichever is latest.
(11) For AWL No. 47-AWL-06, “Nitrogen Generation System (NGS)—Cross Vent Check Valve”: Within 13,000 flight hours after the date of issuance of the original airworthiness certificate or the original export certificate of airworthiness, within 13,000 flight hours after accomplishment of the actions specified in Boeing Service Bulletin 737-47-1003, or within 13,000 flight hours after the most recent inspection was performed as specified in AWL No. 47-AWL-06, whichever is latest.
(12) For AWL No. 47-AWL-07, “Nitrogen Generation System (NGS)—Nitrogen Enriched Air (NEA) Distribution Ducting Integrity”: Within 6,500 flight hours after the date of issuance of the original airworthiness certificate or the original export certificate of airworthiness, within 6,500 flight hours after accomplishment of the actions specified in Boeing Service Bulletin 737-47-1003, or within 6,500 flight hours after the most recent inspection was performed as specified in AWL No. 47-AWL-07, whichever is latest.
(13) For AWL No. 47-AWL-09, “Nitrogen Generation System—Oxygen Sensor”: Within 18,000 flight hours after the date of issuance of the original airworthiness certificate or the original export certificate of airworthiness, or within 18,000 flight hours after the most recent replacement was performed as specified in AWL No. 47-AWL-09, or within 36 months after the effective date of this AD, whichever is latest.
(14) For AWL No. 28-AWL-101, “Engine Fuel Suction Feed Operational Test”: Within 7,500 flight hours or 36 months, whichever occurs first, after the date of issuance of the original airworthiness certificate or the original export certificate of airworthiness; or within 7,500 flight hours or 36 months, whichever occurs first, after the most recent inspection was performed as specified in AWL No. 28-AWL-101; whichever is later.
As an option, when accomplishing the actions required by paragraph (g) of this AD, the changes specified in paragraphs (h)(1) through (3) of this AD are acceptable.
(1) Where AWL No. 28-AWL-05 identifies wire types BMS 13-48, BMS 13-58, and BMS 13-60, the following wire types are acceptable: MIL-W-22759/16, SAE AS22759/16 (M22759/16), MIL-W-22759/32, SAE AS22759/32 (M22759/32), MIL-W-22759/34, SAE AS22759/34 (M22759/34), MIL-W-22759/41, SAE AS22759/41 (M22759/41), MIL-W-22759/86, SAE AS22759/86 (M22759/86), MIL-W-22759/87, SAE AS22759/87 (M22759/87), MIL-W-22759/92, and SAE AS22759/92 (M22759/92); and MIL-C-27500 and NEMA WC 27500 cables constructed from these military or SAE specification wire types, as applicable.
(2) Where AWL No. 28-AWL-05 identifies TFE-2X Standard wall for wire sleeving, the following sleeving materials are acceptable: Roundit 2000NX and Varglas Type HO, HP, or HM.
(3) Where AWL No. 28-AWL-20 specifies the operational test for left center tank fuel boost pump relay R54 and right center tank fuel boost pump relay R55, for airplanes that have complied with paragraph (g)(2)(ii) of AD 2011-20-07, Amendment 39-16818 (76 FR 60710, September 30, 2011), or that have installed Supplemental Type Certificate (STC) ST02076LA, that action does not apply.
Except as provided in paragraph (h) of this AD, after the existing maintenance or inspection program has been revised as required by paragraph (g) of this AD, no alternative actions (e.g., inspections), intervals, or CDCCLs may be used unless the actions, intervals, and CDCCLs are approved as an alternative method of compliance (AMOC) in accordance with the procedures specified in paragraph (k) of this AD.
Accomplishment of the revision required by paragraph (g) of this AD terminates the requirements specified in paragraphs (j)(1) through (7) of this AD for that airplane.
(1) The revision required by the introductory text to paragraph (h) and paragraph (h)(1) of AD 2008-06-03.
(2) All requirements of AD 2008-10-10 R1.
(3) The revision required by paragraph (g) of AD 2008-17-15.
(4) The revision required by paragraph (k) of AD 2011-18-03.
(5) All requirements of AD 2013-15-17.
(6) The revisions required by paragraphs (i)(1)(i) through (iii) of AD 2018-20-13.
(7) All requirements of AD 2018-20-24.
