Airworthiness Directive · Amendment 39-14867 · Boeing Model 737-200, -300, -400, and -500 Series Airplanes
Boeing Model 737-200, -300, -400, and -500 Series Airplanes
This AD applies to Boeing Model 737-200, -300, -400, and -500 series airplanes; certificated in any category; as identified in Boeing Special Attention Service Bulletin 737-53-1216, Revision 1, dated June 8, 2006.
The FAA is adopting a new airworthiness directive (AD) for certain Boeing Model 737-200, -300, -400, and -500 series airplanes. This AD requires a one-time inspection of the frames between station 360 and station 907 to determine if a subject support bracket for the air conditioning outlet extrusion is installed, and related repetitive investigative actions and repair if necessary. This AD also provides an optional preventive modification that ends the repetitive investigative actions. This AD also requires a one-time post-modification/repair inspection for cracking of each repaired/modified frame. This AD results from numerous reports indicating that frame cracks have been found at the attachment holes for support brackets for the air conditioning outlet extrusion. We are issuing this AD to detect and correct such cracking, which, if the cracking were to continue to grow, could result in a severed frame. A severed frame, combined with existing multi-site damage at the stringer 10 lap splice, could result in rapid decompression of the airplane.
You are responsible for having the actions required by this AD performed within the compliance times specified, unless the actions have already been done.
Perform a one-time general visual inspection of the frames between station 360 and station 907 to identify the support brackets for the air conditioning outlet extrusion attached with a two-rivet configuration, in accordance with Part I of the Accomplishment Instructions of Boeing Special Attention Service Bulletin 737-53-1216, Revision 1, dated June 8, 2006. Do this inspection at the applicable time specified in paragraph 1.E., “Compliance,” of the service bulletin, except, where the service bulletin specifies a compliance time after the issuance of the service bulletin, this AD requires compliance within the specified compliance time after the effective date of this AD.
For each frame with a subject support bracket identified during the inspection in accordance with paragraph (f) of this AD: Perform a medium-frequency eddy current inspection for cracking of the frame around the attachment rivets of the support bracket, and a high-frequency eddy current inspection for cracking of the frame adjacent to the inboard fastener hole, by doing all the actions specified in and in accordance with Part I of the Accomplishment Instructions of Boeing Special Attention Service Bulletin 737-53-1216, Revision 1, dated June 8, 2006, except for paragraph 3.B.2. of Part I (which was already done in accordance with paragraph (f) of this AD). Do the initial inspections at the applicable time specified in paragraph 1.E., “Compliance,” of the service bulletin, except, where the service bulletin specifies a compliance time after the issuance of the service bulletin, this AD requires compliance within the specified compliance time after the effective date of this AD. If no cracking is found, repeat the inspections thereafter at intervals not to exceed the repeat interval specified in paragraph 1.E., “Compliance,” of the service bulletin, until paragraph (h) or (i) of this AD is done.
For any frame in which cracking is found during any inspection required by paragraph (g) of this AD: Before further flight, repair the cracking by doing all applicable actions in accordance with Part III of the Accomplishment Instructions of Boeing Special Attention Service Bulletin 737-53-1216, Revision 1, dated June 8, 2006. Then, do paragraph (k) of this AD, at the time specified in that paragraph. Doing this repair ends the repetitive inspections required by paragraph (g) of this AD for each modified frame.
(i) For any frame on which a support bracket for the air conditioning outlet extrusion attached with a two-rivet configuration is installed: Doing all actions associated with the preventive modification in accordance with Part II of the Accomplishment Instructions of Boeing Special Attention Service Bulletin 737-53-1216, Revision 1, dated June 8, 2006, ends the repetitive inspections required by paragraph (g) of this AD for each modified frame. Do the requirements of paragraph (k) of this AD on each modified frame at the time specified in that paragraph.
Actions accomplished before the effective date of this AD according to Boeing Communication M-7200-02-01292, dated August 20, 2002; are considered acceptable for compliance with the corresponding actions specified in paragraphs (f), (g), (h), and (i) of this AD, as applicable.
For each frame repaired or modified in accordance with paragraph (h), (i), or (j) of this AD, as applicable: Within 24,000 flight cycles after doing the modification/repair, but after a minimum of 18,000 flight cycles after doing the modification/repair, do one-time detailed inspections for cracking of the repaired/modified frame, air conditioning attach brackets, and stringer clips, by doing all actions in accordance with Part IV of the Accomplishment Instructions of Boeing Special Attention Service Bulletin 737-53-1216, Revision 1, dated June 8, 2006. If any cracking is found during the post-modification/repair inspections, before further flight, repair the cracking using a method approved in accordance with paragraph (m) of this AD.
Inspections/modifications/repairs done before the effective date of this AD in accordance with Boeing Special Attention Service Bulletin 737-53-1216, dated January 27, 2005, are acceptable for compliance with the corresponding actions required by this AD.
