Airworthiness Directive · Amendment 39-15780 · Boeing Model 737-600, -700, -700C, -800 and -900 Series Airplanes
Boeing Model 737-600, -700, -700C, -800 and -900 Series Airplanes
Superseded. A later AD replaced this one: AD 2024-18-07. Comply with the one in force.
This AD applies to Boeing Model 737-600, -700, -700C, -800 and -900 series airplanes; certificated in any category; as identified in Boeing Special Attention Service Bulletin 737-25-1544, Revision 1, dated January 16, 2008.
The FAA is adopting a new airworthiness directive (AD) for certain Boeing Model 737-600, -700, -700C, -800 and -900 series airplanes. This AD requires a one-time general visual inspection of frames between body station (BS) 360 and BS 907 to determine if certain support brackets of the air conditioning (A/C) outlet extrusions are installed; medium- and high-frequency eddy current inspections for cracking of the frames around the attachment holes of the subject brackets; and repair if necessary. This AD also requires installing new, improved fittings for all support brackets of the A/C outlet extrusions between BS 360 and BS 907. This AD results from numerous reports of multiple cracks in the frames around the attachment holes of certain support brackets of the A/C outlet extrusions. We are issuing this AD to prevent frame cracking, which, if not corrected, could lead to a severed frame that, combined with cracking of the skin lap splice above stringer 10, 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.
Before the accumulation of 36,000 total flight cycles, or within 72 months after the effective date of this AD, whichever occurs later, except as required by paragraph (h) of this AD: Do a general visual inspection to determine if the support brackets of the A/C outlet extrusions between body station (BS) 360 and BS 907 have two-rivet attachment fittings in accordance with Part 2 of the Accomplishment Instructions of Boeing Special Attention Service Bulletin 737-25-1544, Revision 1, dated January 16, 2008 (“the service bulletin”), except at the locations identified in the notes of Step 3.B.1 of Part 1 of the Accomplishment Instructions of the service bulletin.
(1) For any support bracket attached with three or more rivets: No further action is required by paragraph (f) of this AD.
(2) For any subject support bracket having a two-rivet attachment fitting: Before the accumulation of 36,000 total flight cycles, or within 72 months after the effective date of this AD, whichever occurs later, except as required by paragraph (h) of this AD, do medium- and high-frequency eddy current inspections for cracking of the frame around the attachment holes of the support bracket, in accordance with Part 2 of the Accomplishment Instructions of the service bulletin. If any cracking is discovered, before further flight, repair the cracking in accordance with Part 3 of the Accomplishment Instructions of the service bulletin.
Except as required by paragraph (h) of this AD: Before the accumulation of 36,000 total flight cycles, or within 72 months after the effective date of this AD, whichever occurs later, replace the support fittings of all A/C outlet extrusions between BS 360 and BS 907 with new, improved support fittings, in accordance with Part 4 of the Accomplishment Instructions of Boeing Special Attention Service Bulletin 737-25-1544, Revision 1, dated January 16, 2008.
For airplanes on which Boeing Business Jet (BBJ) lower cabin altitude modification is incorporated in accordance with Supplemental Type Certificate ST01697SE: Before the accumulation of 18,000 total flight cycles, or within 72 months after the effective date of this AD, whichever occurs later, do the actions specified in paragraphs (f) and (g) of this AD.
(i) Actions accomplished before the effective date of this AD according to Boeing Special Attention Service Bulletin 737-25-1544, dated October 4, 2006, are considered acceptable for compliance with the corresponding actions specified in this AD.
