Airworthiness Directive · Amendment 39-18324 · Fuselage
The Boeing Company Airplanes
(1) This AD applies to The Boeing Company Model 737-100, -200, -200C, -300, -400, and -500 series airplanes, certificated in any category, as identified in Boeing Alert Service Bulletin 737-53A1323, dated December 6, 2013.
(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 ST01920SE 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 737-100,-200,-200C,-300,-400, and -500 series airplanes. This AD was prompted by reports of cracks in fuselage frames, and a report of a missing strap that was not installed on a fuselage frame during production. This AD requires an inspection to determine if the strap adjacent to a certain stringer is installed, and repair if it is missing; repetitive inspections of the frame for cracking or a severed frame web; and related investigative and corrective actions if necessary. This AD also provides optional actions to terminate certain repetitive inspections. We are issuing this AD to detect and correct missing fuselage frame straps and frame cracking that can result in severed frames which, with multiple adjacent severed frames, or the combination of a severed frame and fuselage skin chemical mill cracks, can result in uncontrolled decompression of the airplane.
For airplanes identified as Group 1 in Boeing Alert Service Bulletin 737-53A1323, dated December 6, 2013: At the applicable time specified in table 1 of paragraph 1.E., “Compliance,” of Boeing Alert Service Bulletin 737-53A1323, dated December 6, 2013, except as provided by paragraph (n)(1) of this AD, do the inspection for cracking of the frames and applicable repairs using a method approved in accordance with the procedures specified in paragraph (q) of this AD.
For airplanes identified as Groups 2 through 7 in Boeing Alert Service Bulletin 737-53A1323, dated December 6, 2013: At the applicable time specified in tables 2 and 3 of paragraph 1.E., “Compliance,” of Boeing Alert Service Bulletin 737-53A1323, dated December 6, 2013, except as provided by paragraph (n)(1) of this AD, do a general visual inspection of the frame at station 312 to determine if the strap adjacent to stringer S-22 right is installed, in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 737-53A1323, dated December 6, 2013. If the strap is not installed, before further flight, repair using a method approved in accordance with the procedures specified in paragraph (q) of this AD.
For airplanes identified as Groups 2 through 6 in Boeing Alert Service Bulletin 737-53A1323, dated December 6, 2013, that have accumulated less than 28,300 total flight cycles as of the effective date of this AD: Do the actions required by paragraphs (i)(1) and (i)(2) of this AD. Operators may do the repair of the frame at station 328 as specified in paragraph (m) of this AD as an optional preventive modification for that frame.
(1) At the applicable times specified in tables 4, 5, 7, and 8 of paragraph 1.E., “Compliance,” of Boeing Alert Service Bulletin 737-53A1323, dated December 6, 2013, except as provided by paragraphs (n)(1) and (n)(3) of this AD: Do detailed and eddy current inspections of the frame at stations 328, 344, and 360, as applicable, for cracking or a severed frame web; and do all applicable related investigative and corrective actions; in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 737-53A1323, dated December 6, 2013, except as specified in paragraph (n)(2) of this AD. Do all applicable related investigative and corrective actions before further flight. Repeat the applicable inspections thereafter at the applicable time and intervals specified in paragraph 1.E., “Compliance,” of Boeing Alert Service Bulletin 737-53A1323, dated December 6, 2013, until the inspection required by paragraph (i)(2) of this AD is done.
(2) At the applicable time specified in tables 4, 5, 7, and 8 of paragraph 1.E., “Compliance,” of Boeing Alert Service Bulletin 737-53A1323, dated December 6, 2013, do the actions specified in paragraph (i)(2)(i) or (i)(2)(ii) of this AD. Accomplishing the initial inspections required by paragraph (i)(2) of this AD terminates the inspections required by paragraph (i)(1) of this AD.
(i) Do detailed and eddy current inspections of the frame at stations 328, 344, and 360, as applicable, for cracking or a severed frame web; and do all applicable related investigative and corrective actions; in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 737-53A1323, dated December 6, 2013, except as specified in paragraph (n)(2) of this AD. Do all applicable related investigative and corrective actions before further flight. Repeat the inspections specified in this paragraph thereafter at the applicable time and intervals specified in paragraph 1.E., “Compliance,” of Boeing Alert Service Bulletin 737-53A1323, dated December 6, 2013.
(ii) Do detailed and eddy current inspections of the frame at stations 328, 344, and 360, as applicable, for cracking or a severed frame web; and external detailed and eddy current inspections of the fuselage skin for cracking; and do all applicable related investigative and corrective actions; in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 737-53A1323, dated December 6, 2013, except as specified in paragraph (n)(2) of this AD. Do all applicable related investigative and corrective actions before further flight. Repeat the inspections specified in this paragraph thereafter at the applicable time and intervals specified in paragraph 1.E., “Compliance,” of Boeing Alert Service Bulletin 737-53A1323, dated December 6, 2013.
For airplanes identified as Groups 2 through 6 in Boeing Alert Service Bulletin 737-53A1323, dated December 6, 2013, that have accumulated 28,300 total flight cycles or more as of the effective date of this AD: At the applicable times specified in tables 4, 5, 7, and 8 of paragraph 1.E., “Compliance,” of Boeing Alert Service Bulletin 737-53A1323, dated December 6, 2013, except as provided by paragraphs (n)(1) and (n)(3) of this AD, do the inspections specified in paragraph (j)(1) or (j)(2) of this AD; and do all applicable related investigative and corrective actions; in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 737-53A1323, dated December 6, 2013, except as specified in paragraph (n)(2) of this AD. Do all applicable related investigative and corrective actions before further flight. Repeat the applicable inspections specified in paragraph (j)(1) or (j)(2) of this AD thereafter at the applicable time and intervals specified in paragraph 1.E., “Compliance,” of Boeing Alert Service Bulletin 737-53A1323, dated December 6, 2013. Operators may do the repair of the frame at station 328, as specified in paragraph (m) of this AD, as an optional preventive modification for that frame.
(1) Do detailed and eddy current inspections of the frame at stations 328, 344, and 360, as applicable, for cracking or a severed frame web.
(2) Do detailed and eddy current inspections of the frame at stations 328, 344, and 360, as applicable, for cracking or a severed frame web; and external detailed and eddy current inspections of the fuselage skin for cracking.
For airplanes identified as Group 7 in Boeing Alert Service Bulletin 737-53A1323, dated December 6, 2013: At the applicable time specified in table 6 of paragraph 1.E., “Compliance,” of Boeing Alert Service Bulletin 737-53A1323, dated December 6, 2013, except as provided by paragraph (n)(1) of this AD, do a detailed inspection and eddy current inspection of the frame at station 328 for cracking or a severed frame web; and do all applicable related investigative and corrective actions; in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 737-53A1323, dated December 6, 2013, except as specified in paragraph (n)(2) of this AD. Do all applicable related investigative and corrective actions before further flight. Repeat the inspections specified in this paragraph thereafter at the applicable time and intervals specified in paragraph 1.E., “Compliance,” of Boeing Alert Service Bulletin 737-53A1323, dated December 6, 2013. Operators may do the repair of the frame at station 328, as specified in paragraph (m) of this AD, as an optional preventive modification for that frame.
For airplanes identified as Groups 2 through 5 in Boeing Alert Service Bulletin 737-53A1323, dated December 6, 2013: At the applicable time specified in tables 9 and 10 of paragraph 1.E., “Compliance,” of Boeing Alert Service Bulletin 737-53A1323, dated December 6, 2013, except as provided by paragraph (n)(1) of this AD, do detailed and eddy current inspections of the frame at station 380 for cracking or a severed frame web; and do all applicable corrective actions; in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 737-53A1323, dated December 6, 2013, except as specified in paragraph (n)(2) of this AD. Do all applicable corrective actions before further flight. Repeat the inspections specified in this paragraph thereafter at the applicable time and intervals specified in paragraph 1.E., “Compliance,” of Boeing Alert Service Bulletin 737-53A1323, dated December 6, 2013.
(1) For airplanes identified as Groups 2, 3, 4, 5, and 7 in Boeing Alert Service Bulletin 737-53A1323, dated December 6, 2013: Accomplishing the repair or preventive modification of the frame at station 328, in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 737-53A1323, dated December 6, 2013, except as required by paragraph (n)(2) of this AD, terminates the inspections of that frame required by paragraphs (i), (j), and (k) of this AD.
(2) For airplanes identified as Groups 2, 3, 4, and 5 in Boeing Alert Service Bulletin 737-53A1323, dated December 6, 2013: Accomplishing the repair or preventive modification of the frame at station 328 and the preventive modification of the frame at station 360, in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 737-53A1323, dated December 6, 2013, except as required by paragraph (n)(2) of this AD, terminates the inspections of the frame at station 344 and the fuselage skin inspections required by paragraphs (i) and (j) of this AD.
(3) For airplanes identified as Groups 2, 3, 4, and 5 in Boeing Alert Service Bulletin 737-53A1323, dated December 6, 2013: Accomplishing the repair or preventive modification of the frame at station 360, in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 737-53A1323, dated December 6, 2013, except as required by paragraph (n)(2) of this AD, terminates the inspections of that frame required by paragraphs (i) and (j) of this AD.
(4) For airplanes identified as Group 6 in Boeing Alert Service Bulletin 737-53A1323, dated December 6, 2013: Accomplishing the repair or preventive modification of the frame at station 328, in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 737-53A1323, dated December 6, 2013, except as required by paragraph (n)(2) of this AD, terminates the fuselage skin inspections and the station 328 frame inspections required by paragraphs (i) and (j) of this AD.
(1) Where Boeing Alert Service Bulletin 737-53A1323, dated December 6, 2013, specifies a compliance time after the “original issue date of this service bulletin,” this AD requires compliance within the specified compliance time after the effective date of this AD.
(2) If any cracking is found during any inspection required by this AD, and Boeing Alert Service Bulletin 737-53A1323, dated December 6, 2013, specifies to contact Boeing for appropriate action: Before further flight, repair the cracking using a method approved in accordance with the procedures specified in paragraph (q) of this AD.
(3) The Condition column of Tables 4, 5, 7, and 8 in paragraph 1.E., “Compliance,” of Boeing Alert Service Bulletin 737-53A1323, dated December 6, 2013, refers to total flight cycles “at the original issue date of this service bulletin.” This AD, however, applies to the airplanes with the specified total flight cycles as of the effective date of this AD.
(1) The post-repair and post-modification inspections specified in tables 13 through 15 of paragraph 1.E., “Compliance,” of Boeing Alert Service Bulletin 737-53A1323, dated December 6, 2013, are not required by this AD.
(2) The post-repair and post-modification inspections specified in Tables 13 through 15 of paragraph 1.E., “Compliance,” of Boeing Alert Service Bulletin 737-53A1323, dated December 6, 2013, may be used in support of compliance with section 121.1109(c)(2) or 129.109(b)(2) of the Federal Aviation Regulations (14 CFR 121.1109(c)(2) or 14 CFR 129.109(b)(2)). The corresponding actions specified in the Accomplishment Instructions of Boeing Alert Service Bulletin 737-53A1323, dated December 6, 2013, are not required by this AD.
