Airworthiness Directive · Amendment 39-18511 · Fuselage
The Boeing Company Airplanes
(1) This AD applies to The Boeing Company Model 737-300, -400, and -500 series airplanes, certificated in any category, as identified in Boeing Alert Service Bulletin 737-53A1339, dated August 12, 2014.
(2) Installation of Supplemental Type Certificate (STC) ST01219SE (http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgstc.nsf/0/ebd1cec7b301293e86257cb30045557a/$FILE/ST01219SE.pdf) 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.
We are adopting a new airworthiness directive (AD) for certain The Boeing Company Model 737-300, -400, and -500 series airplanes. This AD was prompted by reports of fatigue cracking found at the left-side and right-side upper frames, at a certain area. This AD requires repetitive medium frequency eddy current (MFEC) inspections for cracking of the left-side and right-side upper frames, and repair (including open hole high frequency eddy current (HFEC) inspections for cracking of fastener holes) if necessary. This AD also provides an optional preventive modification, which terminates the repetitive inspections at the modified location. We are issuing this AD to detect and correct fatigue cracking of the upper frame, which can grow in size and result in a severed frame, leading to rapid decompression and consequent reduced structural integrity of the airplane.
Except as required by paragraphs (i)(2) and (i)(3) of this AD: At the applicable times specified in table 1 of paragraph 1.E., “Compliance,” of Boeing Alert Service Bulletin 737-53A1339, dated August 12, 2014, do a medium frequency eddy current (MFEC) inspection for cracking on the left-side and right-side of the upper frame at station 360 between stringer 13 and stringer 14, in accordance with Part 2 of the Accomplishment Instructions of Boeing Alert Service Bulletin 737-53A1339, dated August 12, 2014. If no cracking is found, repeat the inspections at the applicable times specified in table 1 of paragraph 1.E., “Compliance,” of Boeing Alert Service Bulletin 737-53A1339, dated August 12, 2014. Accomplishment of the actions specified in paragraph (j) of this AD terminates the repetitive inspections required by this paragraph at the modified area only. The initial and repetitive inspections required by this paragraph may be terminated in the area under repairs installed prior to the effective date of this AD, provided they meet the requirements of paragraph (g)(1) or (g)(2) of this AD.
(1) Repairs were installed to eliminate previously found cracking and were approved by the Boeing Organization Designation Authorization (ODA) with an FAA Form 8100-9.
(2) Repairs were installed for damage other than cracking that have been re-evaluated and approved by the Boeing ODA with an FAA Form 8100-9 that includes an alternative method of compliance (AMOC) statement to paragraph (h) of this AD.
If any cracking is found during any inspection required by paragraph (g) of this AD: Before further flight, repair the cracking including doing an open hole high frequency eddy current (HFEC) inspection for cracking of the holes, in accordance with Part 3 of the Accomplishment Instructions of Boeing Alert Service Bulletin 737-53A1339, dated August 12, 2014, except as required by paragraph (i)(1) of this AD. Repair of any crack terminates the initial and repetitive inspection requirements of paragraph (g) of this AD for the repaired area only. If any cracking is found during any inspection required by this paragraph, before further flight, repair using a method approved in accordance with the procedures specified in paragraph (l) of this AD.
(1) Where Part 3 and Part 4 of the Accomplishment Instructions of Boeing Alert Service Bulletin 737-53A1339, dated August 12, 2014, specifies contacting Boeing for repair instructions: Before further flight, repair using a method approved in accordance with the procedures specified in paragraph (l) of this AD.
(2) Where Boeing Alert Service Bulletin 737-53A1339, dated August 12, 2014, specifies a compliance time “after the original issue date of this service bulletin,” this AD requires compliance within the specified time after the effective date of this AD.
(3) Where the Condition column of table 1 of paragraph 1.E., “Compliance,” of Boeing Alert Service Bulletin 737-53A1339, dated August 12, 2014, specifies a reference point “on the original issue date of this service bulletin,” for this AD the corresponding reference point is on the effective date of this AD.
Modification of an inspection area specified in paragraph (g) of this AD, including open hole and surface HFEC inspections for cracking of the area to be modified, in accordance with Part 4 of the Accomplishment Instructions of Boeing Alert Service Bulletin 737-53A1339, dated August 12, 2014, except as required by paragraph (i)(1) of this AD, terminates the repetitive inspections required by paragraph (g) of this AD at the modified location only.
Tables 4 and 5 of paragraph 1.E., “Compliance,” of Boeing Alert Service Bulletin 737-53A1339, dated August 12, 2014, specify post-modification airworthiness limitation inspections in compliance to 14 CFR 25.571(a)(3) at the modified locations, which support compliance with 14 CFR 121.1109(c)(2) or 129.109(b)(2). As airworthiness limitations, these inspections are required by maintenance and operational rules. It is therefore unnecessary to mandate them in this AD. Deviations from these inspections require FAA approval, but do not require an alternative method of compliance.
