Airworthiness Directive · Amendment 39-22841 · Equipment/furnishing
The Boeing Company Airplanes
This AD applies to Boeing Model 737-600, -700, -700C, -800, and -900 series airplanes, certificated in any category, as identified in Boeing Alert Service Bulletin 737-25A1544, Revision 4, dated February 15, 2022.
The FAA is superseding Airworthiness Directive (AD) 2009-01- 02, which applied to certain Boeing Model 737-600, -700, -700C, -800, and -900 series airplanes. AD 2009-01-02 required an 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, inspections for cracking of the frames around the attachment holes of the subject brackets, and repair if necessary. AD 2009-01-02 also requires installing new, improved fittings for all support brackets of the A/C outlet extrusions between BS 360 and BS 907. This AD was prompted by numerous reports of multiple cracks in the frame around the attachment holes of the support bracket of the A/C outlet extrusion, and the determination that certain repairs might develop fatigue cracks that could result in the inability of the frame to sustain limit load and therefore must be inspected. This AD would continue to require the actions specified in AD 2009-01-02 and would also require repetitive inspections for cracking of certain repairs, and repair if necessary. The FAA is issuing this AD to address the unsafe condition on these products.
This paragraph restates the requirements of paragraph (f) of AD 2009-01-02, with new material. Before the accumulation of 36,000 total flight cycles, or within 72 months after February 27, 2009 (the effective date of AD 2009-01-02), whichever occurs later, except as required by paragraph (i) 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, or Boeing Alert Service Bulletin 737-25A1544, Revision 4, dated February 15, 2022; except at the locations identified in the notes of Step 3.B.1 of Part 1 of the Accomplishment Instructions of Boeing Special Attention Service Bulletin 737-25-1544, Revision 1, dated January 16, 2008, or Boeing Alert Service Bulletin 737-25A1544, Revision 4, dated February 15, 2022. As of the effective date of this AD, only use Boeing Alert Service Bulletin 737-25A1544, Revision 4, dated February 15, 2022, for the actions required by paragraph (g) of this AD.
(1) For any support bracket attached with three or more rivets: No further action is required by paragraph (g) 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 February 27, 2009 (the effective date of AD 2009-01-02), whichever occurs later, except as required by paragraph (i) of this AD, do general visual, 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 Boeing Special Attention Service Bulletin 737-25-1544, Revision 1, dated January 16, 2008, or do general visual, low-, 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 Boeing Alert Service Bulletin 737-25A1544, Revision 4, dated February 15, 2022. If any cracking is discovered, before further flight, repair the cracking in accordance with Part 3 of the Accomplishment Instructions of Boeing Special Attention Service Bulletin 737-25-1544, Revision 1, dated January 16, 2008, or Boeing Alert Service Bulletin 737-25A1544, Revision 4, dated February 15, 2022, except as required by paragraph (k)(2) of this AD. As of the effective date of this AD, only use Boeing Alert Service Bulletin 737-25A1544, Revision 4, dated February 15, 2022, for the actions required by paragraph (g)(2) of this AD.
This paragraph restates the requirements of paragraph (g) of AD 2009-01-02, with new material. Except as required by paragraph (i) of this AD: Before the accumulation of 36,000 total flight cycles, or within 72 months after February 27, 2009 (the effective date of AD 2009-01-02), 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, or Boeing Alert Service Bulletin 737-25A1544, Revision 4, dated February 15, 2022. As of the effective date of this AD, only use Boeing Alert Service Bulletin 737-25A1544, Revision 4, dated February 15, 2022, for the actions required by paragraph (h) of this AD.
This paragraph restates the compliance time specified in paragraph (h) of AD 2009-01-02, with no changes. For airplanes on which Boeing Business Jet (BBJ) lower cabin altitude modification is incorporated in accordance with Supplemental Type Certificate (STC) ST01697SE (6,500 feet maximum cabin altitude in lieu of 8,000 feet): Before the accumulation of 18,000 total flight cycles, or within 72 months after February 27, 2009 (the effective date of AD 2009-01-02), whichever occurs later, do the actions specified in paragraphs (g) and (h) of this AD.
For Groups 1 through 4 and Group 6 as identified in Boeing Alert Service Bulletin 737-25A1544, Revision 4, dated February 15, 2022: Except as specified in paragraph (k) of this AD: At the applicable time specified in Table 2 of the “Compliance” paragraph of Boeing Alert Service Bulletin 737-25A1544, Revision 4, dated February 15, 2022, do a detailed inspection and a high-frequency eddy current inspection for cracking of the repaired area at frame BS 907, and do all applicable repairs before further flight, in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 737-25A1544, Revision 4, dated February 15, 2022. Repeat the inspections thereafter at the applicable time specified in Table 2 of the “Compliance” paragraph of Boeing Alert Service Bulletin 737-25A1544, Revision 4, dated February 15, 2022.
(1) Where the Compliance Time column of Table 2 in the “Compliance” paragraph of Boeing Alert Service Bulletin 737-25A1544, Revision 4, dated February 15, 2022, uses the phrase “the Revision 4 date of this Service Bulletin,” this AD requires using “the effective date of this AD.”
(2) Where Boeing Alert Service Bulletin 737-25A1544, Revision 4, dated February 15, 2022, specifies contacting Boeing, this AD requires repair before further flight using a method approved in accordance with the procedures specified in paragraph (m) of this AD.
(3) For airplanes on which BBJ Lower Cabin Altitude STC ST01697SE (drs.faa.gov/browse/excelExternalWindow/0812969A86AF879B8625766400600105.0001) has been incorporated, the flight-cycle related compliance times for the inspections required by paragraph (j) of this AD are different from those specified in Table 2 of the “Compliance” paragraph in Boeing Alert Service Bulletin 737-25A1544, Revision 4, dated February 15, 2022. All initial compliance times specified in total flight cycles or flight cycles must be reduced to half of those specified in Table 2 of the “Compliance” paragraph in Boeing Alert Service Bulletin 737-25A1544, Revision 4, dated February 15, 2022. All repetitive interval compliance times specified in flight cycles must be reduced to one-quarter of those specified in Table 2 of the “Compliance” paragraph in Boeing Alert Service Bulletin 737-25A1544, Revision 4, dated February 15, 2022.
The aircraft, engines and makers this AD names, by the model designations in its text. A model listed here may still be outside the AD's serial ranges.
Aircraft
