AD 2020-21-13

The FAA is adopting a new airworthiness directive (AD) for certain General Electric Company (GE) GE90-110B1 and GE90-115B model turbofan engines. This AD was prompted by the detection of melt-related freckles in the billet, which may reduce the life limits of certain high-pressure turbine (HPT) rotor stage 2 disks and certain rotating compressor discharge pressure (CDP) HPT seals. This AD requires the replacement of the affected HPT rotor stage 2 disks and rotating CDP HPT seals. The FAA is issuing this AD to address the unsafe condition on these products.

Final rule.

The Amendment \n\n\n\tAccordingly, under the authority delegated to me by the Administrator, the FAA amends 14 CFR part 39 as follows: \n\nPART 39--AIRWORTHINESS DIRECTIVES \n\n0 1. The authority citation for part 39 continues to read as follows: \n\n\n\tAuthority: 49 U.S.C. 106(g), 40113, 44701. \n\n\n\nSec. 39.13 (Amended) \n\n0 2. The FAA amends Sec. 39.13 by adding the following new airworthiness directive (AD): \n\n2020-21-13 General Electric Company: Amendment 39-21286; Docket No. FAA-2020-0733; Project Identifier AD-2020-00990-E. \n\n(a) Effective Date \n\n\n\tThis AD is effective November 17, 2020. \n\n(b) Affected ADs \n\n\n\tNone. \n\n(c) Applicability \n\n\n\tThis AD applies to General Electric Company GE90-110B1 and GE90- 115B model turbofan engines with: \n\t(1) A high-pressure turbine (HPT) rotor stage 2 disk, part number (P/N) 2505M73P03, and serial number (S/N) TMT1BA38 or TMT1BA41, installed; or \n\t(2) A rotating compressor discharge pressure (CDP) HPT seal, P/N 2479M03P01, and S/N GEE1H7GH or GEE1H7JJ, installed. \n\n(d) Subject \n\n\n\tJoint Aircraft System Component (JASC) Code 7250, Turbine Section. \n\n(e) Unsafe Condition \n\n\n\tThis AD was prompted by the detection of melt-related freckles in the billet, which may reduce the life limits of certain HPT rotor stage 2 disks and certain rotating CDP HPT seals. The FAA is issuing this AD to prevent uncontained release of both the HPT rotor stage 2 disk and the rotating CDP HPT seal. The unsafe condition, if not addressed, could result in damage to the engine and damage to the aircraft. \n\n(f) Compliance \n\n\n\tComply with this AD within the compliance times specified, unless already done. \n\n(g) Required Actions \n\n\n\t(1) Before the affected HPT rotor stage 2 disk or the rotating CDP HPT seal listed in Table 1 to paragraph (g) of this AD (''Table 1'') accumulates the cycles since new (CSN) threshold in Table 1, or at the next engine shop visit, whichever occurs first after the effective date of this AD, remove the affected part from service and replace it with a part eligible for installation. \n\t(2) If the affected HPT rotor stage 2 disk or rotating CDP HPT seal has already exceeded the CSN threshold in Table 1, remove the affected part before further flight and replace with a part eligible for installation. (GRAPHIC) (TIFF OMITTED) TR13OC20.005 \n\n(h) Definitions \n\n\n\t(1) For the purpose of this AD, a part eligible for installation is any HPT stage 2 disk or rotating CDP HPT seal with an S/N that is not listed in Table 1. \n\t(2) For the purpose of this AD, an engine shop visit is the induction of an engine into the shop for maintenance involving the separation of pairs of major mating engine flanges, except that the separation of engine flanges solely for the purposes of transportation of the engine without subsequent engine maintenance does not constitute an engine shop visit. \n\n(i) Alternative Methods of Compliance (AMOCs) \n\n\n\t(1) The Manager, ECO Branch, FAA, hasthe authority to approve AMOCs for this AD, if requested using the procedures found in 14 CFR 39.19. In accordance with 14 CFR 39.19, send your request to your principal inspector or local Flight Standards District Office, as appropriate. If sending information directly to the manager of the certification office, send it to the attention of the person identified in paragraph (j) of this AD. You may email your request to: ANE-AD-AMOC@faa.gov. \n\t(2) Before using any approved AMOC, notify your appropriate principal inspector, or lacking a principal inspector, the manager \n\n((Page 64377)) \n\nof the local flight standards district office/certificate holding district office. \n\n(j) Related Information \n\n\n\tFor more information about this AD, contact Mehdi Lamnyi, Aerospace Engineer, ECO Branch, FAA, 1200 District Avenue, Burlington, MA 01803; phone: 781-238-7743; fax: 781-238-7199; email: Mehdi.Lamnyi@faa.gov. \n\n(k) Material Incorporated by Reference \n\n\n\tNone. \n\n\n\tIssued on October 6, 2020. Lance T. Gant, Director, Compliance & Airworthiness Division, Aircraft Certification Service. (FR Doc. 2020-22505 Filed 10-9-20; 8:45 am) BILLING CODE 4910-13-P

Discussion \n\n\n\tThe FAA issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 by adding an AD that would apply to certain GE GE90-110B1 and GE90-115B model turbofan engines. The NPRM published in the Federal Register on August 13, 2020 (85 FR 49322). The NPRM was prompted by the detection of melt-related freckles in the billet, which may reduce the life limits of certain HPT rotor stage 2 disks and certain rotating CDP HPT seals. The NPRM proposed to require the replacement of certain HPT rotor stage 2 disks and certain rotating CDP HPT seals. The FAA is issuing this AD to address the unsafe condition on these products. \n\nComments \n\n\n\tThe FAA gave the public the opportunity to participate in developing this final rule. The FAA has considered the comments received. Boeing Commercial Airplanes supported the NPRM. The Air Line Pilots Association and United Airlines reviewed the NPRM and have no objections. \n\nConclusion \n\n\n\tThe FAAreviewed the relevant data, considered the comments received, and determined that air safety and the public interest require adopting this final rule as proposed. \n\nRelated Service Information \n\n\n\tThe FAA reviewed GE Service Bulletin GE90-100 S/B 72-0845, Revision 1, dated July 17, 2020. The service information describes procedures for the removal of affected HPT rotor stage 2 disks and rotating CDP HPT seals from service. \n\nInterim Action \n\n\n\tThe FAA considers this AD an interim action. This issue is still under investigation by the manufacturer and, depending on the results of that investigation, the FAA may consider further rulemaking action. \n\nCosts of Compliance \n\n\n\tThe FAA estimates that this AD will affect 1 engine installed on an airplane of U.S. registry. \n\tThe FAA estimates the following costs to comply with this AD: \n\n\n\tEstimated Costs ---------------------------------------------------------------------------------------------------------------- \n\tCostper Cost on U.S. \n\tAction Labor cost Parts cost product operators ---------------------------------------------------------------------------------------------------------------- Remove and replace the HPT rotor stage 1,500 work-hours x $85 $565,600 $693,100 $693,100 \n\t2 disk. per hour = $127,500. Remove and replace the rotating CDP 600 work-hours x $85 per 209,900 260,900 0 \n\tHPT Seal. hour = $51,000. ---------------------------------------------------------------------------------------------------------------- \n\n\n\n((Page 64376)) \n\nAuthority for This Rulemaking \n\n\n\tTitle 49 of the United States Code specifies the FAA's authority to issue rules on aviation safety. Subtitle I, section 106, describes the authority of the FAA Administrator. Subtitle VII: Aviation Programs, describes in more detail the scope of the Agency's authority. \n\tThe FAA is issuing this rulemaking under the authority described in Subtitle VII, Part A, Subpart III, Section 44701: ''General requirements.'' Under that section, Congress charges the FAA with promoting safe flight of civil aircraft in air commerce by prescribing regulations for practices, methods, and procedures the Administrator finds necessary for safety in air commerce. This regulation is within the scope of that authority because it addresses an unsafe condition that is likely to exist or develop on products identified in this rulemaking action. \n\nRegulatory Findings \n\n\n\tThis AD will not have federalism implications under Executive Order 13132. This AD will not have a substantial direct effect on the States, on the relationship between the national government and the States, or on the distribution of power and responsibilities among the various levels of government. \n\tFor the reasons discussed above, I certify that this AD: \n\t(1) Is not a ''significant regulatory action'' under Executive Order 12866, \n\t(2) Will not affect intrastate aviation in Alaska, and \n\t(3) Will not have a significant economic impact, positive or negative, on a substantial number of small entities under the criteria of the Regulatory Flexibility Act. \n\nList of Subjects in 14 CFR Part 39 \n\n\n\tAir transportation, Aircraft, Aviation safety, Incorporation by reference, Safety.