Airworthiness Directives; The Boeing Company Airplanes

<RULE> DEPARTMENT OF TRANSPORTATION <SUBAGY>Federal Aviation Administration</SUBAGY> <CFR>14 CFR Part 39</CFR> <DEPDOC>[Docket No. FAA-2023-1046; Project Identifier AD-2023-00253-T; Amendment 39-22700; AD 2024-05-09]</DEPDOC> <RIN>RIN 2120-AA64</RIN> <SUBJECT>Airworthiness Directives; The Boeing Company Airplanes</SUBJECT> <HD SOURCE="HED">AGENCY:</HD> Federal Aviation Administration (FAA), DOT. <HD SOURCE="HED">ACTION:</HD> Final rule. <SUM> <HD SOURCE="HED">SUMMARY:</HD> The FAA is adopting a new airworthiness directive (AD) for certain The Boeing Company Model 757-200, -200CB, and -300 series airplanes. This AD was prompted by a report of a crack at fuselage station (STA) 1640 frame web common to the lower hinge intercostal tee clip center hole of the upper fastener row. This AD requires a maintenance records check for existing repairs at STA 1640, repetitive ultrasonic (UT) inspections for cracking of the frame web, and applicable on-condition actions. The FAA is issuing this AD to address the unsafe condition on these products. </SUM> <EFFDATE> <HD SOURCE="HED">DATES:</HD> This AD is effective May 8, 2024. The Director of the Federal Register approved the incorporation by reference of a certain publication listed in this AD as of May 8, 2024. </EFFDATE> <HD SOURCE="HED">ADDRESSES:</HD> <E T="03">AD Docket:</E> You may examine the AD docket at <E T="03">regulations.gov</E> under Docket No. FAA-2023-1046; or in person at Docket Operations between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The AD docket contains this final rule, any comments received, and other information. The address for Docket Operations is U.S. Department of Transportation, Docket Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New Jersey Avenue SE, Washington, DC 20590. <E T="03">Material Incorporated by Reference:</E> • For material identified in this final rule, contact Boeing Commercial Airplanes, Attention: Contractual & Data Services (C&DS), 2600 Westminster Boulevard, MC 110-SK57, Seal Beach, CA 90740-5600; telephone 562-797-1717; website: <E T="03">myboeingfleet.com.</E> • You may view this material that is incorporated by reference at the FAA, Airworthiness Products Section, Operational Safety Branch, 2200 South 216th St., Des Moines, WA. For information on the availability of this material at the FAA, call 206-231-3195. It is also available at <E T="03">regulations.gov</E> under Docket No. FAA-2023-1046. <FURINF> <HD SOURCE="HED">FOR FURTHER INFORMATION CONTACT:</HD> Wayne Ha, Aviation Safety Engineer, Continued Operational Safety Branch, FAA, 2200 South 216th Street, Des Moines, WA 98198; phone: 562-627-5238; email: <E T="03">wayne.ha@faa.gov.</E> </FURINF> <SUPLINF> <HD SOURCE="HED">SUPPLEMENTARY INFORMATION:</HD> <HD SOURCE="HD1">Background</HD> The FAA issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 by adding an AD that would apply to certain The Boeing Company Model 757-200, -200CB, and -300 series airplanes. The NPRM published in the <E T="04">Federal Register</E> on June 1, 2023 (88 FR 35783). The NPRM was prompted by a report of a crack at fuselage STA 1640 frame web common to the lower hinge intercostal tee clip center hole of the upper fastener row. In the NPRM, the FAA proposed to require a maintenance records check for existing repairs at STA 1640, repetitive UT inspections for cracking of the frame web, and applicable on-condition actions. The FAA is issuing this AD to address possible undetected cracking in the STA 1640 frame web common to the lower hinge intercostal tee clip center hole of the upper fastener row. Such cracking, if not addressed, could result in the inability of a principal structural element to sustain limit loads which could adversely affect the structural integrity of the airplane. <HD SOURCE="HD1">Discussion of Final Airworthiness Directive</HD> <HD SOURCE="HD1">Comments</HD> The FAA received comments from Air Line Pilots Association, International, who supported the NPRM without change. The FAA received additional comments from seven commenters, including Aviation Partners Boeing (APB), Boeing, Delta Air Lines (DAL), European Air Transport GmbH (DHL), FedEx Express, United Airlines (UAL), and VT Mobile Aerospace Engineering, Inc. (VT MAE). The following presents the comments received on the NPRM and the FAA's response to each comment. <HD SOURCE="HD1">Request To Correct the Location of the Unsafe Condition</HD> Boeing requested that the location of the cracking be corrected from “inboard and center holes” to “center hole” of the upper fastener row in the Summary and Background of the NPRM, and paragraph (e) of the proposed AD. Boeing said that cracking was found only in the center hole. The FAA agrees. The correction has been made in the specified sections of this AD. <HD SOURCE="HD1">Request To Change Inspection Requirement for Certain Converted Airplanes</HD> VT MAE proposed that no additional inspection be required other than the inspection specified in VT MAE 15-Pallet Maintenance Planning Data (MPD) Supplement 757SF-MPD-01 for airplanes converted per VT MAE Supplemental Type Certificate (STC) ST04242AT. VT MAE asserted that Boeing has performed analysis of the modified airplanes, including the new STA 1640 frame, which is inspected as part of the VT MAE MPD Supplement 757SF-MPD-01. The FAA disagrees with the commenter's request because sufficient data was not submitted to substantiate that the inspections specified in VT MAE MPD Supplement 757SF-MPD-01 would provide an acceptable level of safety. Under the provisions of paragraph (i) of this AD, however, the FAA will consider requests for approval of alternative actions and compliance times if sufficient data are submitted to substantiate that the change would provide an acceptable level of safety. The FAA has not changed this AD in this regard. <HD SOURCE="HD1">Request To Clarify a Certain Exception</HD> DAL requested that paragraph (h)(3) of the proposed AD be amended or revised to clarify whether aircraft configured with STC ST01518SE but without winglets require the specified reduction in applicable compliance times and repeat intervals. DAL stated that this approved configuration was not clearly addressed in the proposed AD. The FAA agrees to clarify. Because a longer compliance time for the identified configuration (STC ST01518SE without winglets) has not been evaluated, all configurations with the STC ST01518SE modification must be included in the requirement. The FAA has revised paragraph (h)(3) of this AD to specify that airplanes modified in accordance APB STC ST01518SE, with or without blended or scimitar blended winglets installed, have the reduced compliance time. However, as specified in paragraph (i) of this AD, the FAA will consider requests for approval of alternative actions and compliance times if sufficient data are submitted to substantiate that the change would provide an acceptable level of safety. <HD SOURCE="HD1">Request To Clarify What Prompted the NPRM</HD> Boeing requested that the Background section of the NPRM be revised to clarify the sequence of events and the associated service documents that led to detection of the cracking that prompted the NPRM. Boeing asserted that the NPRM indicated that the crack was found as a result of inspections required by AD 2020-20-10, Amendment 39-21266 (85 FR 63002, October 6, 2020) (AD 2020-20-10), but the crack was actually found as a result of inspections required by AD 2018-06-07, Amendment 39-19227 (83 FR 13398, March 29, 2018) (AD 2018-06-07). The FAA agrees that the AD number reference in the Background section of the NPRM described by Boeing should have been AD 2018-06-07 (which was superseded by AD 2020-20-10). However, since that portion of the Background section does not reappear in the final rule, no change to the final rule is necessary. <HD SOURCE="HD1">Request To Extend Compliance Time</HD> APB, DAL, and DHL proposed that APB Service Bulletin AP757-53-005 be incorporated into the final rule. APB, DAL, DHL, and UAL suggested that paragraph (h)(3) of the proposed AD be revised to extend the required time for compliance. APB explained that APB Service Bulletin AP757-53-005 is currently in approval review by an independent DER (Designated Engineering Representative) for submittal to the FAA, and this service information proposes less restrictive compliance times than specified by paragraphs (g) and (h)(3) of the proposed AD. DHL added that halving the compliance time for the initial inspection is more burdensome than halving the time for repetitive inspections, which can still be accomplished during base maintenance events. DAL and UAL added that the reduced initial inspection time would mean that the inspection could not occur during a regularly scheduled check, resulting in extended unscheduled ground time and increased costs for operators. The FAA does not agree. Waiting for the review and approval of APB Service Bulletin AP757-53-005 would delay the rulemaking process. The urgency of the unsafe condition warrants issuing this AD as proposed because it adequately addresses the unsafe condition. Until APB completes its evaluation of airplanes with APB STC ST01518SE installed to determine an appropriate compliance time for the inspection, the conservative factor of 2 will apply to these airplanes. Under the provisions of paragraph (i) of this AD, however, the FAA will consider requests for approval of alternative compliance times if sufficient data are submitted to substantiate that the change would provide an acceptable level of safety. The FAA has not changed this AD in this regard. <HD SOURCE="HD1">Request for Clarification on Credit for Certain Airplanes</HD> UAL requested clarification on the NPRM as it does not give operators credit for airplanes on which the re ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ Preview showing 10k of 27k characters. Full document text is stored and available for version comparison. ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━