Discussion \n\n\n\tThe European Union Aviation Safety Agency (EASA), which is the Technical Agent for the Member States of the European Community, has issued EASA AD 2020-0010R2, dated March 4, 2020 (referred to after this as ''the MCAI''), to address an unsafe condition for the specified products. The MCAI states: \n\n\n\tOccurrences have been reported of engine surges on certain Trent 1000 engines, particularly those that have accumulated a high number of flight hours (FH) and engine flight cycles (EFC). The investigation into the cause(s) of these events is on-going. This condition, if not corrected, could lead to a dual engine surge, possibly resulting in a dual engine in-flight shut-down and consequent reduced control of the aeroplane. \n\tTo address this potential unsafe condition, Rolls-Royce published the NMSB to provide de-pairing instructions, reducing the risk of a dual surge event. Instructions for in-shop performance recovery are being developed. Prompted by some errors detected in Table 1 of the NMSB, Appendix 1 of this (EASA) AD must be used instead. Rolls-Royce will revise the NMSB to correct those errors. \n\tFor the reasons described above, EASA issued AD 2020-0010 (later revised) to require de-pairing of the affected engines. \n\tSince EASA AD 2020-0010R1 was issued, Rolls-Royce issued NMSB TRENT 1000 72-K494, providing instructions for in-shop action to restore the surge margin. Embodiment of Part B of this NMSB allows relaxation of the de-pairing actions as required by this (EASA) AD. Rolls-Royce have revised NMSB TRENT 1000 72-AK468 accordingly, including a new Table 1, defining de-pairing upper and lower thresholds (pre- and post-NMSB 72-K494 embodied) and Table 2 (which was Table 1 in the NMSB 72-AK468 at original issue) for de-pairing when one engine has embodied Part B of NMSB TRENT 1000 72-K494, and when both engines have embodied Part B of NMSB TRENT 1000 72-K494. \n\tConsequently, this (EASA) AD is revised to include references to NMSB TRENT 1000 72-K494 and to NMSB TRENT 1000 72-AK468 Revision 1, and Table 2 thereof. \n\n\n\tYou may obtain further information by examining the MCAI in the AD docket on the internet at https://www.regulations.gov by searching for and locating Docket No. FAA-2020-0638. \n\nRelated Service Information Under 1 CFR Part 51 \n\n\n\tThe FAA reviewed Rolls-Royce plc (RR) Alert Non-Modification Service Bulletin (NMSB) Trent 1000 72-AK468, Revision 1, dated March 3, 2020. The Alert NMSB describes compliant and non-compliant engine pairing combinations based on IPC module flight HSN or CSN. This service information is reasonably available because the interested parties have access to it through their normal course of business or by the means identified in the ADDRESSES section. \n\n((Page 40874)) \n\nRelated Service Information \n\n\n\tThe FAA reviewed RR NMSB Trent 1000 72-K494, Initial Issue, dated March 3, 2020. The NMSB describes procedures for the inspection, repair, and replacement of specified IPC module components to restore surge margin and recover IPC performance. \n\nFAA's Determination \n\n\n\tThis product has been approved by EASA and is approved for operation in the United States. Pursuant to our bilateral agreement with the European Community, EASA has notified us of the unsafe condition described in the MCAI. The FAA is issuing this AD because it evaluated all the relevant information provided by EASA and determined the unsafe condition described previously is likely to exist or develop in other products of the same type design. \n\nAD Requirements \n\n\n\tThis AD requires removing and replacing one or both affected engines, depending on whether the engine pairing combinations are compliant or non-compliant, as described in the Accomplishment Instructions of RR Alert NMSB Trent 1000 72-AK468, Revision 1, dated March 3, 2020. \n\nJustification for Immediate Adoption and Determination of the Effective Date \n\n\n\tSection 553(b)(3)(B) of the Administrative Procedure Act (APA) (5 U.S.C.) authorizes agencies to dispense with notice and comment procedures for rules when the agency, for ''good cause,'' finds that those procedures are ''impracticable, unnecessary, or contrary to the public interest.'' Under this section, an agency, upon finding good cause, may issue a final rule without seeking comment prior to the rulemaking. Similarly, Section 553(d) of the APA authorizes agencies to make rules effective in less than 30 days, upon a finding of good cause. \n\tThe FAA has found the risk to the flying public justifies waiving notice and comment prior to adoption of this rule because no domestic operators use this product. It is unlikely that the FAA will receive any adverse comments or useful information about this AD from U.S. operators. Therefore, the FAA finds good cause that notice and opportunity for prior public comment are unnecessary. In addition, for this same reason, the FAA finds that good cause exists for making this amendment effective in less than 30 days. \n\nComments Invited \n\n\n\tThis AD is a final rule that involves requirements affecting flight safety and was not preceded by notice and an opportunity for public comment. However, the FAA invites you to send any written data, views, or arguments about this final rule. Send your comments to an address listed under the ADDRESSES section. Include the docket number FAA-2020- 0638 and Project Identifier MCAI-2020-00308-E at the beginning of your comments. The FAA specifically invites comments on the overall regulatory, economic, environmental, and energy aspects of this final rule. The FAA will consider all comments received by the closing date and may amend this final rule because of those comments. \n\tExcept for Confidential Business Information (CBI) as described in the following paragraph, and other information as described in 14 CFR 11.35, the FAA will post all comments received, without change, to https://www.regulations.gov, including any personal information you provide. The FAA will also post a report summarizing each substantive verbal contact received about this final rule. \n\nConfidential Business Information \n\n\n\tConfidential Business Information (CBI) is commercial or financial information that is both customarily and actually treated as private by its owner. Under the Freedom of Information Act (FOIA) (5 U.S.C. 552), CBI is exempt from public disclosure. If your comments responsive to this final rule contain commercial or financial information that is customarily treated as private, that you actually treat as private, and that is relevant or responsive to this final rule, it is important that you clearly designate the submitted comments as CBI. Please mark each page of your submission containing CBI as ''PROPIN.'' The FAA will treat such marked submissions as confidential under the FOIA, and they will not be placed in the public docket of this final rule. Submissions containing CBI should be sent to Stephen Elwin, Aerospace Engineer, ECO Branch, FAA, 1200 District Avenue, Burlington, MA 01803. Any commentary that the FAA receives which is not specifically designated as CBI will be placed in the public docket for this rulemaking. \n\nRegulatory Flexibility Act \n\n\n\tThe requirements of the Regulatory Flexibility Act (RFA) do not apply when an agency finds good cause pursuant to 5 U.S.C. 553 to adopt a rule without prior notice and comment. Because the FAA has determined that it has good cause to adopt this rule without notice and comment, RFA analysis is not required. \n\nCosts of Compliance \n\n\n\tThe FAA estimates that this AD affects 0 engines installed on airplanes of U.S. registry. \n\tThe FAA estimates the following costs to comply with this AD: \n\n\n\tEstimated Costs ---------------------------------------------------------------------------------------------------------------- \n\tCost per Cost on U.S. \n\tAction Labor cost Parts cost product operators ---------------------------------------------------------------------------------------------------------------- Remove and replace engine........... 48 work-hours x $85 per $0 $4,080 $0 \n\thour = $4,080. ---------------------------------------------------------------------------------------------------------------- \n\n\n\tAccording to the manufacturer, some of the costs of this AD may be covered under warranty, thereby reducing the cost impact on affected individuals. The FAA does not control warranty coverage for affected individuals. As a result, the FAA has included all costs in our estimate. \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 \n\n((Page 40875)) \n\nthat 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 this AD: \n\t(1) Is not a ''significant regulatory action'' under Executive Order 12866, and \n\t(2) Will not affect intrastate aviation in Alaska. \n\nList of Subjects in 14 CFR Part 39 \n\n\n\tAir transportation, Aircraft, Aviation safety, Incorporation by reference, Safety.