Airworthiness Directives; General Electric Company Engines

<RULE> DEPARTMENT OF TRANSPORTATION <SUBAGY>Federal Aviation Administration</SUBAGY> <CFR>14 CFR Part 39</CFR> <DEPDOC>[Docket No. FAA-2025-0015; Project Identifier AD-2024-00615-E; Amendment 39-23049; AD 2025-11-03]</DEPDOC> <RIN>RIN 2120-AA64</RIN> <SUBJECT>Airworthiness Directives; General Electric Company Engines</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 General Electric Company (GE) Model GEnx-1B64, GEnx-1B64/P1, GEnx-1B64/P2, GEnx-1B67, GEnx-1B67/P1, GEnx-1B67/P2, GEnx-1B70, GEnx-1B70/75/P1, GEnx-1B70/75/P2, GEnx-1B70/P1, GEnx-1B70/P2, GEnx-1B70C/P1, GEnx-1B70C/P2, GEnx-1B74/75/P1, GEnx-1B74/75/P2, GEnx-1B76/P2, GEnx-1B76A/P2, and GEnx-2B67/P engines. This AD was prompted by a manufacturer's investigation that revealed certain high-pressure turbine (HPT) stage 1 and HPT stage 2 disks were manufactured from powder metal material suspected to contain iron inclusion. This AD requires replacement of affected HPT stage 1 and HPT stage 2 disks with parts eligible for installation. 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 July 8, 2025. The Director of the Federal Register approved the incorporation by reference of certain publications listed in this AD as of July 8, 2025. </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-2025-0015; 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 GE material identified in this AD, contact GE, 1 Neumann Way, Cincinnati, OH 45215; phone: (513) 552-3272; email: <E T="03">aviation.fleetsupport@ge.com;</E> website: <E T="03">ge.com</E> . • You may view this material at the FAA, Airworthiness Products Section, Operational Safety Branch, 1200 District Avenue, Burlington, MA 01803. For information on the availability of this material at the FAA, call (817) 222-5110. It is also available at <E T="03">regulations.gov</E> under Docket No. FAA-2025-0015. <FURINF> <HD SOURCE="HED">FOR FURTHER INFORMATION CONTACT:</HD> Alexei Marqueen, Aviation Safety Engineer, FAA, 2200 South 216th Street, Des Moines, WA 98198; phone: (781) 238-7178; email: <E T="03">alexei.t.marqueen@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 GE Model GEnx-1B64, GEnx-1B64/P1, GEnx-1B64/P2, GEnx-1B67, GEnx-1B67/P1, GEnx-1B67/P2, GEnx-1B70, GEnx-1B70/75/P1, GEnx-1B70/75/P2, GEnx-1B70/P1, GEnx-1B70/P2, GEnx-1B70C/P1, GEnx-1B70C/P2, GEnx-1B74/75/P1, GEnx-1B74/75/P2, GEnx-1B76/P2, GEnx-1B76A/P2, and GEnx-2B67/P engines. The NPRM was published in the <E T="04">Federal Register</E> on January 31, 2025 (90 FR 8687). The NPRM was prompted by a manufacturer's investigation that revealed the detection of iron inclusion in turbine disks manufactured from the same powder metal material used to manufacture certain HPT stage 1 and HPT stage 2 disks for the above-referenced engines. Further investigation by the manufacturer revealed that the iron inclusion is attributed to deficiencies in the manufacturing process and may cause reduced material properties and a lower fatigue life capability, which may result in premature fracture and uncontained failure. The manufacturer also informed the FAA that additional risk assessments determined that there were no failed events associated with the discovery of this iron inclusion material; however, concluded that replacement of the affected HPT stage 1 and HPT stage 2 disks is necessary to prevent any future failed events. In the NPRM, the FAA proposed to require replacement of affected HPT stage 1 and HPT stage 2 disks with parts eligible for installation. The FAA is issuing this AD to address the unsafe condition on these products. <HD SOURCE="HD1">Discussion of Final Airworthiness Directive</HD> <HD SOURCE="HD1">Comments</HD> The FAA received comments from six commenters. The commenters were the Air Line Pilots Association, International (ALPA), The Boeing Company (Boeing), Cathay Pacific Airways, Thai Airways, United Airlines, and an individual commenter. ALPA and Boeing supported the NPRM without change. The following presents the comments received from Cathay Pacific Airways, Thai Airways, United Airlines, and the individual commenter and the FAA's response. <HD SOURCE="HD1">Request To Clarify Reinstallation of Affected Part</HD> Cathay Pacific Airways requested that the FAA clarify whether the affected part may be reinstalled after being removed from an engine if the part has not reached the cyclic removal threshold identified in GE GEnx-1B Service Bulletin 72-0542 R00, dated April 15, 2024 (GE GEnx-1B SB 72-0542 R00) and GE GEnx-2B SB 72-0471 R00, dated April 15, 2024 (GE GEnx-2B Service Bulletin 72-0471 R00). The FAA agrees to clarify. Because the compliance time of this final rule is at a certain number of cycles or at the next piece part exposure after the effective date of the AD, whichever occurs first, the affected part must be removed from service and is not eligible to be re-installed during piece part exposure. The FAA did not change this AD as a result of this comment. <HD SOURCE="HD1">Request To Clarify Affected Engines</HD> Thai Airways noted that GE Model GEnx-1b engines with engine serial numbers 958136, 958164, and 958949 are not affected by GE GEnx-1B SB 72-0542 R00. The FAA clarifies that the applicability for this AD is not designated by engine serial number, but it is designated by specific part numbers and serial numbers of affected parts. The FAA did not change this AD as a result of this comment. <HD SOURCE="HD1">Request To Update Proposed AD Requirements</HD> United Airlines requested that the FAA update the language in the “Proposed AD Requirements in This NPRM” paragraph of the proposed AD to the following: “Depending on the part numbers and serial numbers of the affected HPT stage 1 disks and HPT stage 2 disks, this NPRM proposes to require these actions to be accomplished at the next piece-part exposure after the effective date of this proposed AD or before the affected HPT stage 1 disks and HPT stage 2 disks reach the cyclic removal threshold of up to 10,100 cycles since new, whichever occurs first.” The FAA agrees with the content in the requested language. However, this section is not included in the final rule. Therefore, the FAA did not change this AD as a result of this comment. <HD SOURCE="HD1">Request for New Part Design Details</HD> An individual commenter requested that the FAA provide information on what material the new HPT stage 1 and HPT stage 2 disks that are eligible for installation will be composed of, how long these parts will take to deteriorate, and how these new parts will be tested to assure they will be more viable than the affected HPT stage 1 and HPT stage 2 disks. The FAA clarifies that the design of the HPT stage 1 and HPT stage 2 disks is unchanged by this AD. The iron inclusions are a result of a deficiency in the manufacturing process, which has since been addressed by the manufacturer. The FAA did not change this AD as a result of this comment. <HD SOURCE="HD1">Conclusion</HD> The FAA reviewed the relevant data, considered any comments received, and determined that air safety requires adopting this AD as proposed. Accordingly, the FAA is issuing this AD to address the unsafe condition on these products. Except for minor editorial changes, this AD is adopted as proposed in the NPRM. None of the changes will increase the economic burden on any operator. <HD SOURCE="HD1">Material Incorporated by Reference Under 1 CFR Part 51</HD> The FAA reviewed GE GEnx-1B SB 72-0542 R00. The FAA also reviewed GE GEnx-2B SB 72-0471 R00. This material specifies the affected part numbers, serial numbers, and cyclic removal thresholds for the HPT stage 1 and HPT stage 2 disks. This material is reasonably available because the interested parties have access to it through their normal course of business or by the means identified in the <E T="02">ADDRESSES</E> section. <HD SOURCE="HD1">Costs of Compliance</HD> The FAA estimates that this AD affects one engine installed on an airplane of U.S. registry. The FAA estimates that no engines installed on airplanes of U.S. registry require replacement of the HPT stage 2 disk. The FAA estimates the following costs to comply with this AD: <GPOTABLE COLS="5" OPTS="L2,nj,i1" CDEF="s50,r50,xs90,10,12"> <TTITLE>Estimated Costs</TTITLE> <CHED H="1">Action</CHED> <CHED H="1">Labor cost</CHED> <CHED H="1">Parts cost</CHED> Cost on U.S. operators </CHED> <ROW> <ENT I="01">Replace HPT stage 1 disk</ENT> <ENT>8 work-hours × $85 per hour = $680</ENT> <ENT>$757,416 (prorated)</ENT> <ENT>$758,096</ENT> <ENT>$758,096</ENT> </ROW> <ROW> <ENT I="01">Replace HPT stage 2 disk</ENT> <ENT>8 work-hours × $85 per hour = $680</ENT> <ENT>$278,101 (prorated)</ENT> <ENT>278,781</ENT> <ENT>0</ENT> </ROW> </GPOTABLE> <HD SOURCE="HD1">Authority for This Rulemaking</HD> Title 49 of the United States Code specifies the FAA's authority to issue rules on aviation safety. Subtitle I, section 106, describes the aut ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ Preview showing 10k of 19k characters. 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