Airworthiness Directive · Amendment 39-19715 · Wings
The Boeing Company Airplanes
(1) This AD applies to all The Boeing Company Model 737-100, -200, -200C, -300, -400, and -500 series airplanes, certificated in any category.
(2) Installation of Supplemental Type Certificate (STC) ST01219SE does not affect the ability to accomplish the actions required by this AD. Therefore, for airplanes on which STC ST01219SE is installed, a “change in product” alternative method of compliance (AMOC) approval request is not necessary to comply with the requirements of 14 CFR 39.17.
The FAA is superseding Airworthiness Directive (AD) 2005-20- 01, which applied to all The Boeing Company Model 737-100, -200, -200C, -300, -400, and -500 series airplanes. AD 2005-20-01 required repetitive inspections of the vertical stiffeners at left buttock line (LBL) and right buttock line (RBL) 6.15 for cracks; and replacement of both stiffeners with new, improved stiffeners if any stiffener is found cracked. This new AD requires, depending on airplane configuration, replacing the vertical stiffeners at LBL and RBL 6.15 on the rear spar of the wing center section, installing angle and bonding jumpers, installing brackets, applying sealant, and applying paint. This AD was prompted by reports of cracks found in the left and right side keel beam upper chords when replacing vertical stiffeners. This AD was also prompted by possible degradation of the fault current bonding path that could introduce an ignition source in the fuel tank in the event of a fault current being imparted onto the fuel tank structure. The FAA is issuing this AD to address the unsafe condition on these products.
For airplanes identified as Groups 1 and 3 through 8 in Boeing Alert Service Bulletin 737-57A1269, Revision 2, dated October 11, 2018: Except as specified by paragraph (j) of this AD, at the applicable times specified in paragraph 1.E., “Compliance,” of Boeing Alert Service Bulletin 737-57A1269, Revision 2, dated October 11, 2018, do all applicable actions, identified in, and in accordance with, the Accomplishment Instructions of Boeing Alert Service Bulletin 737-57A1269, Revision 2, dated October 11, 2018. Depending on the airplane configuration, applicable actions include replacing the vertical stiffeners at LBL and RBL 6.15 on the rear spar of the wing center section, installing angle and bonding jumpers, installing brackets, applying sealant, and applying paint.
For airplanes identified as Group 2 in Boeing Alert Service Bulletin 737-57A1269, Revision 2, dated October 11, 2018: Within 120 days after the effective date of this AD, do actions to correct the unsafe condition, using a method approved in accordance with the procedures specified in paragraph (k) of this AD.
Accomplishment of the stiffener replacement required by paragraph (g) of this AD terminates only the repetitive inspections of the aft vertical stiffeners required by paragraph (h) of AD 2018-10-12 for that airplane only. All other requirements of paragraph (h) of AD 2018-10-12 remain in effect.
(1) For purposes of determining compliance with the requirements of this AD: Where Boeing Alert Service Bulletin 737-57A1269, Revision 2, dated October 11, 2018, uses the phrase “the Revision 2 date of this service bulletin,” this AD requires using “the effective date of this AD.”
(2) Where Boeing Alert Service Bulletin 737-57A1269, Revision 2, dated October 11, 2018, specifies contacting Boeing for repair instructions: This AD requires doing the repair before further flight using a method approved in accordance with the procedures specified in paragraph (k) of this AD.
