Airworthiness Directive · Amendment 39-22959 · Powerplant
The Boeing Company Airplanes
This AD applies to all The Boeing Company Model 737-600, -700, -700C, -800, -900, and -900ER series airplanes, certificated in any category.
The FAA is adopting a new airworthiness directive (AD) for all The Boeing Company Model 737-600, -700, -700C, -800, -900, and -900ER series airplanes. This AD was prompted by two engine fan blade-out (FBO) events that resulted in the separation of engine inlet cowl and fan cowl parts from the airplane. In one event, fan cowl parts damaged the fuselage, which caused loss of pressurization and subsequent emergency descent. This AD requires replacing specified inlet cowl aft bulkhead fasteners for certain airplanes; for certain other airplanes, inspecting the inlet cowl aft bulkhead fastener and replacing the fasteners if rivets are found, and, for all airplanes, replacement of the crushable spacers used in the attachment of the inlet cowl to the engine fan case; or as an option, installing a serviceable inlet cowl. This AD also requires revising the existing maintenance or inspection program, as applicable, to incorporate new airworthiness limitations (AWLs). The FAA is issuing this AD to address the unsafe condition on these products.
Except as specified by paragraph (h) of this AD: At the applicable times specified in the “Compliance” paragraph of Boeing Special Attention Requirements Bulletin 737-71-1938 RB, Revision 1, dated June 27, 2024, do all applicable actions identified in, and in accordance with, the Accomplishment Instructions of Boeing Special Attention Requirements Bulletin 737-71-1938 RB, Revision 1, dated June 27, 2024.
Note 1 to paragraph (g): Guidance for accomplishing the actions required by this AD can be found in Boeing Special Attention Service Bulletin 737-71-1938, Revision 1, dated June 27, 2024, which is referred to in Boeing Special Attention Requirements Bulletin 737-71-1938 RB, Revision 1, dated June 27, 2024.
(1) Where the Compliance Time columns of the tables in the “Compliance” paragraph of Boeing Special Attention Requirements Bulletin 737-71-1938 RB, Revision 1, dated June 27, 2024, refer to the original issue date of Requirements Bulletin 737-71-1938 RB, this AD requires using the effective date of this AD.
(2) Where System Airworthiness Limitation No. 4, as identified in Boeing Special Attention Requirements Bulletin 737-71-1938 RB, Revision 1, dated June 27, 2024, requires incorporation of solutions to address potential engine nacelle maintenance errors, solutions consist of a re-designed fan cowl latch and keeper and application of high visibility paint on the interior of the integrated drive generator (IDG) door.
(3) Where Collins Aerospace Service Bulletin 737NG-71-007 referenced in Boeing Special Attention Requirements Bulletin 737-71-1938 RB, Revision 1, dated June 27, 2024, specifies use of Bonderite M-CR 1200S Aero, 10P4-2NF primer, EC-117S converter, TR19 thinner, or T20 thinner, this AD also allows for equivalent material substitutes as specified in paragraph 2.C., “Material Necessary for Each Inlet Assembly,” of Collins Aerospace Service Bulletin 737NG-71-007 referenced in Boeing Special Attention Requirements Bulletin 737-71-1938 RB, Revision 1, dated June 27, 2024.
After the existing maintenance or inspection program has been revised as required by paragraph (g) of this AD, no alternative actions may be used unless the actions are approved as an alternative method of compliance (AMOC) in accordance with the procedures specified in paragraph (k) of this AD.
