Airworthiness Directives; International Aero Engines AG Turbofan Engines, 15791-15795 [2021-06139]

Download as PDF Federal Register / Vol. 86, No. 56 / Thursday, March 25, 2021 / Rules and Regulations DEPARTMENT OF TRANSPORTATION Federal Aviation Administration 14 CFR Part 39 [Docket No. FAA–2020–0700; Project Identifier AD–2020–00238–E; Amendment 39–21461; AD 2021–05–18] RIN 2120–AA64 Airworthiness Directives; International Aero Engines AG Turbofan Engines Federal Aviation Administration (FAA), DOT. ACTION: Final rule. AGENCY: The FAA is superseding Airworthiness Directive (AD) 2019–06– 06 for all International Aero Engines AG (IAE) V2500–A1, V2522–A5, V2524–A5, V2525–D5, V2527–A5, V2527E–A5, V2527M–A5, V2528–D5, V2530–A5, and V2533–A5 model turbofan engines. AD 2019–06–06 required initial and repetitive borescope inspections (BSIs) of the M-flange and, if it fails the inspection, replacement of the diffuser case with a part eligible for installation. This AD requires an initial BSI of the Mflange and, if it fails the inspection, repetitive BSIs of the M-flange until replacement of the diffuser case Mflange. The FAA is issuing this AD to address the unsafe condition on these products. SUMMARY: This AD is effective April 29, 2021. The Director of the Federal Register approved the incorporation by reference of a certain publication listed in this AD as of April 29, 2021. ADDRESSES: For service information identified in this final rule, contact International Aero Engines AG, 400 Main Street, East Hartford, CT 06118; phone: (800) 565–0140; email: help24@ pw.utc.com; website: https:// fleetcare.pw.utc.com. You may view this service information 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 (781) 238– 7759. It is also available at https:// www.regulations.gov by searching for and locating Docket No. FAA–2020– 0700. DATES: Examining the AD Docket You may examine the AD docket at https://www.regulations.gov by searching for and locating Docket No. FAA–2020–0700; 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 VerDate Sep<11>2014 16:53 Mar 24, 2021 Jkt 253001 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. FOR FURTHER INFORMATION CONTACT: Nicholas Paine, Aviation Safety Engineer, ECO Branch, FAA, 1200 District Avenue, Burlington, MA 01803; phone: (781) 238–7742; fax: (781) 238– 7199; email: nicholas.j.paine@faa.gov. SUPPLEMENTARY INFORMATION: Background The FAA issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 to supersede AD 2019–06–06, Amendment 39–19604 (84 FR 11642, March 28, 2019), (AD 2019–06–06). AD 2019–06–06 applied to all IAE V2500– A1, V2522–A5, V2524–A5, V2525–D5, V2527–A5, V2527E–A5, V2527M–A5, V2528–D5, V2530–A5, and V2533–A5 model turbofan engines. The NPRM published in the Federal Register on September 9, 2020 (85 FR 55624). The NPRM was prompted by a crack found at the diffuser case M-flange during overhaul inspection. Since the FAA issued AD 2019–06–06, the manufacturer performed an updated safety risk analysis, which resulted in reducing the M-flange inspection intervals and adding the performance of a replacement of the diffuser case Mflange, which terminates the need for repetitive BSIs of the M-flange. In the NPRM, the FAA proposed to require an initial BSI of the M-flange and, if it fails the inspection, repetitive BSIs of the Mflange until replacement of the diffuser case M-flange. Discussion of Final Airworthiness Directive Comments The FAA received comments from six commenters. The commenters were Air Line Pilots Association, International (ALPA); Cathay Dragon Airways (Cathay); IAE; MTU Maintenance Hannover GmbH (MTU); Willis Lease Finance Corporation (WLFC); and United Airlines (United). Five of six commenters requested changes to this AD. One commenter requested an update to Applicability. Two commenters requested clarification when cycles are unknown or cannot be determined. Three commenters requested that the FAA reference the latest service information. One commenter requested an update to terminology. Three commenters requested credit for replacement before the effective date of this AD. One PO 00000 Frm 00013 Fmt 4700 Sfmt 4700 15791 commenter requested clarification to ‘‘engine shop visit.’’ One commenter requested an update to a Note in paragraph (g)(2) of this AD. One commenter requested an update to include diffuser case assembly part numbers (P/Ns) after modification. One commenter supported this AD as written. The following presents the comments received on the NPRM and the FAA’s response to each comment. Request To Update Applicability To Include IAE V2500–E5 Model Engines IAE requested that the FAA update paragraph (c), Applicability, of this AD to include the IAE V2500–E5 model turbofan engine. IAE reasoned that the V2500–E5 model turbofan engine shares diffuser case assembly, P/N 2A2891–01, with IAE V2500–A1, –A5, and –D5 model turbofan engines. The FAA agrees that the IAE V2500– E5 model turbofan engine shares an affected diffuser case assembly with other affected engines, and therefore, is susceptible to the unsafe condition of this AD. The FAA added the IAE V2531–E5 model turbofan engine to the Applicability of this AD. The IAE V2531–E5 model turbofan engine is not currently installed on any airplanes of U.S. registry. Therefore, this change to applicability does not add any additional burden on U.S. operators or increase the estimated cost of this AD. Request To Clarify Compliance Time When Cycles Are Unknown or Cannot Be Determined Cathay and WLFC requested clarification when to perform the actions if the cycles since new (CSN) are unknown or cannot be determined. Cathay suggested adding the following note to paragraphs (g)(1)(i), (ii), and (iii) of this AD for the BSI of the M-flange to align this AD with IAE NonModification Alert Service Bulletin (NMASB) V2500–ENG–72–A0706, Revision 2, dated November 7, 2019 (the NMASB): ‘‘If the cycles on the diffuser case M-flange cannot be determined, you must use the total cycles on the diffuser case. If the cycles on the diffuser case cannot be determined, you must use the total engine cycles if it can be documented that the diffuser case was always with the engine.’’ WLFC asked for clarification on the compliance time for the diffuser case Mflange replacement. Although the FAA disagrees with adding the note suggested by Cathay, the FAA agrees to clarify when to perform the actions if the CSN are unknown or cannot be determined. The FAA updated paragraph (g)(1)(iii) of this AD to clarify when to perform the initial E:\FR\FM\25MRR1.SGM 25MRR1 15792 Federal Register / Vol. 86, No. 56 / Thursday, March 25, 2021 / Rules and Regulations BSI of the M-flange and added paragraph (g)(2)(ii) of this AD to clarify when to replace the diffuser case Mflange if the diffuser case M-flange CSN are unknown or cannot be determined. Request To Update Service Information IAE, MTU, and United requested that IAE Service Bulletin (SB) V2500–ENG– 72–0709, Revision 1, dated February 20, 2020 (the SB), be referenced in this AD instead of the Original Issue, dated December 13, 2019. United also requested that ‘‘IAE NMASB V2500– ENG–72–A0706, Revision 2, dated November 7, 2019,’’ be referenced. The FAA partially agrees. Revision 2 of the NMASB was already referenced in the NPRM and, therefore, no change is needed to this AD. The FAA agrees to reference Revision 1 to the SB, which was issued after publication of the NPRM. The SB provides guidance on performing the replacement of the diffuser case M-flange and is not required for compliance with the AD. Therefore, revising this AD to reference Revision 1 of the SB adds no additional burden on U.S. operators. Request To Change ‘‘Diffuser Case MFlange’’ References IAE requested that the FAA change ‘‘diffuser case M-flange’’ to ‘‘M-flange’’ when referencing inspections. IAE reasoned that inspection zone 2 includes all three flanges of the Mflange: Diffuser case M-flange, nozzle guide vane support, and the highpressure turbine (HPT) case forward flange, and all three flanges are required to be inspected. The FAA agrees. The inspections are required on all surfaces of inspection zones 1, 2, and 3 of the M-flange. The FAA changed ‘‘diffuser case M-flange’’ to ‘‘M-flange’’ when referencing inspections throughout this AD. The FAA, however, did not change ‘‘diffuser case M-flange’’ when referencing replacement. Replacement of the diffuser case M-flange is the terminating action for the repetitive BSIs of the Mflange required by this AD. Request for Credit for Diffuser Case MFlange Replacement Cathay, MTU, and WLFC requested credit for the replacement of the diffuser case M-flange if it was replaced before the effective date of this AD using TASK 72–42–11–300–028, Repair-028 (VRS3633), of the IAE V2500 Engine Manual (VRS3633 Repair-028). Cathay and WLFC reasoned that the replacement of the diffuser case Mflange resets the M-flange cycles to zero. Cathay and MTU cited the note to VRS3633 Repair-028 in the NMASB. VerDate Sep<11>2014 16:53 Mar 24, 2021 Jkt 253001 Cathay also cited the note in the NMASB that fluorescent penetrant inspection (FPI) of the diffuser case Mflange bolt holes resets the cycles since the last FPI to zero. The FAA disagrees with revising the Credit for Previous Actions section of this AD to give credit for replacement of the diffuser case M-flange using VRS3633 Repair-028. The FAA determined that it is not necessary to provide previous credit for replacement of the diffuser case M-flange because this AD does not require use of specific service information to perform this replacement. The FAA revised paragraph (i), Credit for Previous Actions, of this AD by removing references to providing credit for replacement of the diffuser case Mflange. If operators replaced the diffuser case M-flange prior to the effective date of this AD using any FAA-approved method, they meet the requirements of this AD under paragraph (f) of this AD. Request To Clarify ‘‘Major Mating Engine Flanges’’ United requested that the FAA clarify the definition of ‘‘engine shop visit’’ and ‘‘major mating engine flange.’’ United asked if ‘‘major flange’’ aligns with the NMASB, which in Figure 1 of the NMASB, identifies the engine major flanges as H through P flanges. United also asked if the ‘‘separation of pairs of major mating engine flanges’’ includes the separation of H and J flanges when replacing damaged blades in HPC stages 3 through 6 during an HPC Surgical Strike Repair. If an engine shop visit includes separating flanges when performing an HPC Surgical Strike Repair, United requested that the FAA update estimated costs of this AD to include costs associated with the teardown of modules. The FAA agrees to clarify this definition of ‘‘engine shop visit’’ in this AD. The FAA has revised the definition of ‘‘engine shop visit’’ in this AD to refer to the induction of the engine into the shop for maintenance involving the separation of pairs of major mating engine flanges, K–N. Based on this definition, separating H and J flanges during an HPC Surgical Strike Repair does not constitute an ‘‘engine shop visit.’’ The FAA disagrees with updating the estimated costs of this AD. The cost analysis in AD rulemaking actions typically includes only the costs associated with complying with the AD, and does not include secondary costs. The FAA’s cost estimate includes the work hours and parts costs to inspect and replace the parts. PO 00000 Frm 00014 Fmt 4700 Sfmt 4700 Request To Update Note to Paragraph (g)(2) MTU requested that the FAA update Note 1 to paragraph (g)(2)(i) of this AD to ‘‘Instructions on performing the replacement of the diffuser case Mflange can be found in the Accomplishment Instructions, paragraphs 1.A. and B., of IAE SB V2500–ENG–72–0709, Revision 1, dated February 20, 2020.’’ MTU reasoned that the current wording suggests that there may be alternative instructions to replace the diffuser case M-flange other than the SB. MTU suggested that there are no alternatives to using IAE SB V2500–ENG–72–0709 to replace the diffuser case M-flange. Therefore, MTU notes that the language in the NPRM may generate ambiguity. The FAA disagrees. The SB is referenced in Note 2 to paragraph (g)(2) of this AD as guidance for performing the replacement. The FAA is not mandating the use of a specific method to replace the diffuser case M-flange in this AD. The FAA did not change this AD based on this comment, but redesignated ‘‘Note 1 to paragraph (g)(2)(i)’’ in the NPRM to ‘‘Note 2 to paragraph (g)(2)’’ in this AD based on the addition of a Note earlier in paragraph (g) of this AD. Request To Include Diffuser Case Assembly P/Ns After Modification IAE requested that the FAA include the diffuser case assembly P/Ns, modified by the SB that are re-identified with new P/Ns after modification, and require replacement before the M-flange accumulates 20,000 CSN. The FAA disagrees with including the list of diffuser case assembly P/Ns. The diffuser case M-flange, regardless of P/ N, must be replaced at the next engine shop visit after the effective date of this AD or before the M-flange accumulates 20,000 CSN, whichever occurs later. Thereafter, the diffuser case M-flange must be replaced before accumulating 20,000 cycles since the previous replacement. Therefore, listing diffuser case assembly P/Ns is unnecessary. Clarification to BSI Requirement The FAA determined the need to clarify the instructions required by paragraph (g)(1)(iv) of the NPRM. The NPRM referenced paragraphs 2.A. through 2.G. of the NMASB to perform the BSI. However, paragraph 2.G. of the NMASB provides instructions to perform a FPI of the M-flange to confirm the indication as a crack. The FAA added a note to paragraph (g)(1)(iv) of this AD to clarify that paragraph 2.G. of the NMASB describes procedures for E:\FR\FM\25MRR1.SGM 25MRR1 Federal Register / Vol. 86, No. 56 / Thursday, March 25, 2021 / Rules and Regulations described previously, this AD is adopted as proposed in the NPRM. None of the changes will increase the economic burden on any operator. performing a local FPI of the M-flange if you are unable to confirm if an indication is a crack. Support for the AD ALPA expressed support for the AD as written. Conclusion The FAA reviewed the relevant data, considered any comments received, and determined that air safety requires adopting the AD as proposed. Accordingly, the FAA is issuing this AD to address the unsafe condition on these products. Except for minor editorial changes, and any other changes Related Service Information Under 1 CFR Part 51 The FAA reviewed International Aero Engines NMASB V2500–ENG–72– A0706, Revision 2, dated November 7, 2019. The NMASB describes procedures for inspecting the M-flange. 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 ADDRESSES. 15793 Other Related Service Information The FAA reviewed International Aero Engines SB V2500–ENG–72–0709, Revision 1, dated February 20, 2020. The SB identifies the diffuser case assembly P/Ns and describes procedures for replacing the diffuser case M-flange. Costs of Compliance The FAA estimates that this AD affects 1,654 engines installed on airplanes of U.S. registry. The FAA estimates the following costs to comply with this AD: ESTIMATED COSTS Action Labor cost BSI of M-flange ............................................... Replace the diffuser case M-flange ................ 2 work-hours × $85 per hour = $170 ............. 40 work-hours × $85 per hour = $3,400 ........ The FAA has included all known costs in its cost estimate. According to the manufacturer, however, some of the costs of this AD may be covered under warranty, thereby reducing the cost impact on affected operators. Authority for This Rulemaking Title 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. The 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. Regulatory Findings The FAA has determined that this 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. VerDate Sep<11>2014 16:53 Mar 24, 2021 Jkt 253001 Parts cost For the reasons discussed above, I certify that this AD: (1) Is not a ‘‘significant regulatory action’’ under Executive Order 12866, (2) Will not affect intrastate aviation in Alaska, and (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. List of Subjects in 14 CFR Part 39 Air transportation, Aircraft, Aviation safety, Incorporation by reference, Safety. The Amendment Accordingly, under the authority delegated to me by the Administrator, the FAA amends 14 CFR part 39 as follows: PART 39—AIRWORTHINESS DIRECTIVES 1. The authority citation for part 39 continues to read as follows: ■ Authority: 49 U.S.C. 106(g), 40113, 44701. § 39.13 [Amended] Cost per product $0 20,000 $170 23,400 Cost on U.S. operators $281,180 38,703,600 (a) Effective Date This airworthiness directive (AD) is effective April 29, 2021. (b) Affected ADs This AD replaces AD 2019–06–06, Amendment 39–19604 (84 FR 11642, March 28, 2019). (c) Applicability This AD applies to all International Aero Engines AG (IAE) V2500–A1, V2522–A5, V2524–A5, V2525–D5, V2527–A5, V2527E– A5, V2527M–A5, V2528–D5, V2530–A5, V2531–E5, and V2533–A5 model turbofan engines. (d) Subject Joint Aircraft System Component (JASC) Code 7250, Turbine Section. (e) Unsafe Condition This AD was prompted by a crack found at the diffuser case M-flange during overhaul inspection. The FAA is issuing this AD to prevent failure of the diffuser case. The unsafe condition, if not addressed, could result in uncontained diffuser case rupture, damage to the engine, and damage to the airplane. (f) Compliance Comply with this AD within the compliance times specified, unless already done. ■ (g) Required Actions 2021–05–18 International Aero Engines AG: Amendment 39–21461; Docket No. FAA–2020–0700; Project Identifier AD– 2020–00238–E. (1) Borescope Inspection of M-Flange For engines with a diffuser case assembly, part number 2A0051, 2A2081–01, 2A2581– 01, 2A2883–01, 2A2885–01, 2A2889–01, 2A2891–01, 2A2896–01, 2A2897–01, or 2A3132 installed, perform an initial borescope inspection (BSI) of zones 1, 2, and 3 of the M-flange as follows: (i) For engines with a diffuser case Mflange that has 19,000 or more cycles since 2. The FAA amends § 39.13 by: ■ a. Removing airworthiness directive 2019–06–06, Amendment 39–19604 (84 FR 11642, March 28, 2019); and ■ b. Adding the following new airworthiness directive: PO 00000 Frm 00015 Fmt 4700 Sfmt 4700 E:\FR\FM\25MRR1.SGM 25MRR1 15794 Federal Register / Vol. 86, No. 56 / Thursday, March 25, 2021 / Rules and Regulations new (CSN) on the effective date of this AD, perform the initial BSI of the M-flange before accumulating the ‘‘Inspect within (Cycles)’’ in Table 1 to paragraph (g)(1) of this AD. If the CSLFPI is unknown, use the CSN of the diffuser case M-flange. (ii) For engines with a diffuser case Mflange that has fewer than 19,000 CSN on the effective date of this AD, perform the initial BSI of the M-flange before accumulating 20,300 CSN. (iii) For engines with a diffuser case Mflange or diffuser case in which the CSN is unknown or cannot be determined, perform the initial BSI of the M-flange before accumulating the ‘‘Inspect within (Cycles)’’ in Table 1 to paragraph (g)(1) of this AD using one of the following options: (A) If the cycles of the diffuser case Mflange are unknown or cannot be determined, use the total cycles on the diffuser case. (B) If the cycles on the diffuser case are unknown or cannot be determined and it can be documented that the diffuser case was always installed on the engine, use total engine cycles. (C) If neither paragraph (g)(1)(iii)(A) or (B) applies, perform the BSI of the M-flange within 250 cycles after the effective date of this AD. (iv) Use the Accomplishment Instructions, paragraphs 2.A. through 2.G. of IAE NonModification Alert Service Bulletin (NMASB) V2500–ENG–72–A0706, Revision 2, dated November 7, 2019 (the NMASB), to perform the initial BSI. Note 1 to paragraph (g)(1)(iv): Paragraph 2.G. of the NMASB describes procedures for performing a local fluorescent penetrant inspection of the M-flange if you are unable to confirm if an indication is a crack. (v) If no crack is found as a result of the inspections required by paragraphs (g)(1)(i) through (iv) of this AD, repeat the BSI of zones 1, 2, and 3 of the M-flange at intervals not to exceed 2,100 cycles since the previous BSI. (vi) If a crack is found as a result of the inspections required by paragraphs (g)(1)(i) through (iv) of this AD, replace the diffuser case M-flange or repeat the BSI of zones 1, 2, and 3 of the M-flange as specified by either ‘‘Table 2: Fly on Limits’’ or ‘‘Table 4: Fly on Limits,’’ in paragraph 2.H., Accomplishment Instructions, of the NMASB as appropriate for the affected the engine model. Table 1 to paragraph (g)(l) -M-flange cycle inspection limits 30,000 and greater 250 20,000 to 29,999 500 15,000 to 19,999 1,000 1 to 14,999 1,300 0 2,100 (2) Replacement of the Diffuser Case MFlange (i) At the next engine shop visit after the effective date of this AD or before the diffuser case M-flange accumulates 20,000 CSN, whichever occurs later, replace the diffuser case M-flange. (ii) For engines with a diffuser case Mflange or diffuser case in which the CSN is unknown or cannot be determined, perform one of the following options: (A) If the cycles of the diffuser case Mflange are unknown or cannot be determined, at the next engine shop visit after the effective date of this AD or before the diffuser case accumulates 20,000 CSN, whichever occurs later, replace the diffuser case Mflange. (B) If the cycles of the diffuser case are unknown or cannot be determined, and if it can be documented that the diffuser case was always installed on the engine, at the next engine shop visit after the effective date of this AD or before the engine accumulates 20,000 CSN, whichever occurs later, replace the diffuser case M-flange. (C) If the cycles on the diffuser case Mflange are unknown or cannot be determined based on the criteria identified in paragraphs (g)(2)(ii)(A) and (B), or it cannot be shown that the diffuser case was always installed on the engine, at the next engine shop visit after the effective date of this AD, replace the diffuser case M-flange. VerDate Sep<11>2014 Inspect within (Cycles) 16:53 Mar 24, 2021 Jkt 253001 Note 2 to paragraph (g)(2)(ii): Guidance on performing the replacement of the diffuser case M-flange described in paragraphs (g)(2)(i) and (ii) can be found in the Accomplishment Instructions, paragraphs 1.A. and B., of IAE SB V2500–ENG–72–0709, Revision 1, dated February 20, 2020. (iii) Thereafter, repeat the replacement of the diffuser case M-flange before accumulating 20,000 cycles since the previous replacement. (iv) Replacement of the diffuser case Mflange is the terminating action for the repetitive BSIs required by paragraph (g)(1) of this AD. (h) Installation Prohibition After the effective date of this AD, do not install a diffuser case onto any affected engine if the diffuser case M-flange has more than 20,000 CSN. (i) Credit for Previous Actions You may take credit for the initial BSIs that are required by paragraphs (g)(1)(i) through (iii) of this AD, if you performed those actions before the effective date of this AD using IAE NMASB V2500–ENG–72–A0706, Revision 1, dated June 28, 2019, or Original Issue, dated February 14, 2019; IAE V2500 Special Instruction (SI) No. 341F–18, dated November 19, 2018; IAE V2500 SI No. 350F– 18, Rev. 1, dated December 17, 2018; IAE V2500 SI No. 356F–18, Rev. 1, dated January 9, 2019; IAE V2500 SI No. 372F–18, dated PO 00000 Frm 00016 Fmt 4700 Sfmt 4700 January 8, 2019; or IAE V2500 Special SI No. 04F–19, dated January 14, 2019. (j) Definition For the purpose of this AD, an ‘‘engine shop visit’’ is the induction of the engine into the shop for maintenance involving the separation of pairs of major mating engine flanges, K–N, except that the separation of engine flanges solely for the purposes of transportation without subsequent engine maintenance does not constitute an engine shop visit. (k) Alternative Methods of Compliance (AMOCs) (1) The Manager, ECO Branch, FAA, has the 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 Related Information. You may email your request to: ANE-AD-AMOC@ faa.gov. (2) Before using any approved AMOC, notify your appropriate principal inspector, or lacking a principal inspector, the manager of the local flight standards district office/ certificate holding district office. E:\FR\FM\25MRR1.SGM 25MRR1 ER25MR21.000</GPH> Cycles Since Last Fluorescent Penetrant Inspection (CSLFPI) Federal Register / Vol. 86, No. 56 / Thursday, March 25, 2021 / Rules and Regulations (l) Related Information For more information about this AD, contact Nicholas Paine, Aviation Safety Engineer, ECO Branch, FAA, 1200 District Avenue, Burlington, MA 01803; phone: (781) 238–7742; fax: (781) 238–7199; email: nicholas.j.paine@faa.gov. (m) Material Incorporated by Reference (1) The Director of the Federal Register approved the incorporation by reference (IBR) of the service information listed in this paragraph under 5 U.S.C. 552(a) and 1 CFR part 51. (2) You must use this service information as applicable to do the actions required by this AD, unless the AD specifies otherwise. (i) International Aero Engines (IAE) NonModification Alert Service Bulletin V2500– ENG–72–A0706, Revision 2, dated November 7, 2019. (ii) [Reserved] (3) For IAE service information identified in this AD, contact International Aero Engines AG, 400 Main Street, East Hartford, CT 06118; phone: (800) 565–0140; email: help24@pw.utc.com; website: https:// fleetcare.pw.utc.com. (4) You may view this service information at 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 (781) 238–7759. (5) You may view this service information that is incorporated by reference at the National Archives and Records Administration (NARA). For information on the availability of this material at NARA, email: fedreg.legal@nara.gov, or go to: https://www.archives.gov/federal-register/cfr/ ibr-locations.html. Issued on February 25, 2021. Gaetano A. Sciortino, Deputy Director for Strategic Initiatives, Compliance & Airworthiness Division, Aircraft Certification Service. Authority for This Rulemaking [FR Doc. 2021–06139 Filed 3–24–21; 8:45 am] BILLING CODE 4910–13–P DEPARTMENT OF TRANSPORTATION Federal Aviation Administration 14 CFR Part 71 [Docket No. FAA–2020–1186; Airspace Docket No. 20–AGL–42] RIN 2120–AA66 Amendment of Class E Airspace; Fosston and Little Falls, MN Federal Aviation Administration (FAA), DOT. ACTION: Final rule. AGENCY: This action amends the Class E airspace extending upward from 700 feet above the surface at Fosston Municipal Airport-Anderson Field, Fosston, MN, and Little Falls/Morrison SUMMARY: VerDate Sep<11>2014 16:53 Mar 24, 2021 Jkt 253001 County Airport-Lindbergh Field, Little Falls, MN. This action is the result of airspace reviews caused by the decommissioning of the Fosston and Little Falls non-federal non-directional beacons (NDBs). The names and geographic coordinates of the airports are also being updated to coincide with the FAA’s aeronautical database. DATES: Effective 0901 UTC, June 17, 2021. The Director of the Federal Register approves this incorporation by reference action under 1 CFR part 51, subject to the annual revision of FAA Order 7400.11 and publication of conforming amendments. ADDRESSES: FAA Order 7400.11E, Airspace Designations and Reporting Points, and subsequent amendments can be viewed online at https:// www.faa.gov/air_traffic/publications/. For further information, you can contact the Airspace Policy Group, Federal Aviation Administration, 800 Independence Avenue SW, Washington, DC 20591; telephone: (202) 267–8783. The Order is also available for inspection at the National Archives and Records Administration (NARA). For information on the availability of FAA Order 7400.11E at NARA, email fedreg.legal@nara.gov or go to https:// www.archives.gov/federal-register/cfr/ ibr-locations.html. FOR FURTHER INFORMATION CONTACT: Jeffrey Claypool, Federal Aviation Administration, Operations Support Group, Central Service Center, 10101 Hillwood Parkway, Fort Worth, TX 76177; telephone (817) 222–5711. SUPPLEMENTARY INFORMATION: The FAA’s authority to issue rules regarding aviation safety is found in Title 49 of the United States Code. 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. This rulemaking is promulgated under the authority described in Subtitle VII, Part A, Subpart I, Section 40103. Under that section, the FAA is charged with prescribing regulations to assign the use of airspace necessary to ensure the safety of aircraft and the efficient use of airspace. This regulation is within the scope of that authority as it amends the Class E airspace extending upward from 700 feet above the surface at Fosston Municipal Airport-Anderson Field, Fosston, MN, and Little Falls/Morrison County Airport-Lindbergh Field, Little Falls, MN, to support instrument flight rule operations at these airports. PO 00000 Frm 00017 Fmt 4700 Sfmt 4700 15795 History The FAA published a notice of proposed rulemaking in the Federal Register (86 FR 3894; January 15, 2021) for Docket No. FAA–2020–1186 to amend the Class E airspace extending upward from 700 feet above the surface at Fosston Municipal Airport-Anderson Field, Fosston, MN, and Little Falls/ Morrison County Airport-Lindbergh Field, Little Falls, MN. Interested parties were invited to participate in this rulemaking effort by submitting written comments on the proposal to the FAA. No comments were received. Class E airspace designations are published in paragraph 6005 of FAA Order 7400.11E, dated July 21, 2020, and effective September 15, 2020, which is incorporated by reference in 14 CFR 71.1. The Class E airspace designations listed in this document will be published subsequently in the Order. Availability and Summary of Documents for Incorporation by Reference This document amends FAA Order 7400.11E, Airspace Designations and Reporting Points, dated July 21, 2020, and effective September 15, 2020. FAA Order 7400.11E is publicly available as listed in the ADDRESSES section of this document. FAA Order 7400.11E lists Class A, B, C, D, and E airspace areas, air traffic service routes, and reporting points. The Rule This amendment to 14 CFR 71: Amends the Class E airspace extending upward from 700 feet above the surface to within a 6.3-mile (decreased from a 7-mile) radius of Fosston Municipal Airport-Anderson Field, Fosston, MN; adds an extension 1 mile each side of the 341° bearing from the airport extending from the 6.3mile radius to 6.5 miles north of the airport; and updates the name (previously Fosston Municipal Airport) of the airport to coincide with the FAA’s aeronautical database; And amends the Class E airspace extending upward from 700 feet above the surface to within a 6.5-mile (decreased from a 7-mile) radius of Little Falls/Morrison County AirportLindbergh Field, Little Falls, MN; and updates the name (previously Little Falls-Morrison County Airport) and geographic coordinates of the airport to coincide with the FAA’s aeronautical database. This action is the result of airspace reviews caused by the decommissioning of the Fosston and Little Falls nonfederal NDBs which provided E:\FR\FM\25MRR1.SGM 25MRR1

Agencies

[Federal Register Volume 86, Number 56 (Thursday, March 25, 2021)]
[Rules and Regulations]
[Pages 15791-15795]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2021-06139]



[[Page 15791]]

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2020-0700; Project Identifier AD-2020-00238-E; 
Amendment 39-21461; AD 2021-05-18]
RIN 2120-AA64


Airworthiness Directives; International Aero Engines AG Turbofan 
Engines

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule.

-----------------------------------------------------------------------

SUMMARY: The FAA is superseding Airworthiness Directive (AD) 2019-06-06 
for all International Aero Engines AG (IAE) V2500-A1, V2522-A5, V2524-
A5, V2525-D5, V2527-A5, V2527E-A5, V2527M-A5, V2528-D5, V2530-A5, and 
V2533-A5 model turbofan engines. AD 2019-06-06 required initial and 
repetitive borescope inspections (BSIs) of the M-flange and, if it 
fails the inspection, replacement of the diffuser case with a part 
eligible for installation. This AD requires an initial BSI of the M-
flange and, if it fails the inspection, repetitive BSIs of the M-flange 
until replacement of the diffuser case M-flange. The FAA is issuing 
this AD to address the unsafe condition on these products.

DATES: This AD is effective April 29, 2021.
    The Director of the Federal Register approved the incorporation by 
reference of a certain publication listed in this AD as of April 29, 
2021.

ADDRESSES: For service information identified in this final rule, 
contact International Aero Engines AG, 400 Main Street, East Hartford, 
CT 06118; phone: (800) 565-0140; email: [email protected]; website: 
https://fleetcare.pw.utc.com. You may view this service information 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 (781) 238-7759. It is 
also available at https://www.regulations.gov by searching for and 
locating Docket No. FAA-2020-0700.

Examining the AD Docket

    You may examine the AD docket at https://www.regulations.gov by 
searching for and locating Docket No. FAA-2020-0700; 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.

FOR FURTHER INFORMATION CONTACT: Nicholas Paine, Aviation Safety 
Engineer, ECO Branch, FAA, 1200 District Avenue, Burlington, MA 01803; 
phone: (781) 238-7742; fax: (781) 238-7199; email: 
[email protected].

SUPPLEMENTARY INFORMATION:

Background

    The FAA issued a notice of proposed rulemaking (NPRM) to amend 14 
CFR part 39 to supersede AD 2019-06-06, Amendment 39-19604 (84 FR 
11642, March 28, 2019), (AD 2019-06-06). AD 2019-06-06 applied to all 
IAE V2500-A1, V2522-A5, V2524-A5, V2525-D5, V2527-A5, V2527E-A5, 
V2527M-A5, V2528-D5, V2530-A5, and V2533-A5 model turbofan engines. The 
NPRM published in the Federal Register on September 9, 2020 (85 FR 
55624). The NPRM was prompted by a crack found at the diffuser case M-
flange during overhaul inspection. Since the FAA issued AD 2019-06-06, 
the manufacturer performed an updated safety risk analysis, which 
resulted in reducing the M-flange inspection intervals and adding the 
performance of a replacement of the diffuser case M-flange, which 
terminates the need for repetitive BSIs of the M-flange. In the NPRM, 
the FAA proposed to require an initial BSI of the M-flange and, if it 
fails the inspection, repetitive BSIs of the M-flange until replacement 
of the diffuser case M-flange.

Discussion of Final Airworthiness Directive

Comments

    The FAA received comments from six commenters. The commenters were 
Air Line Pilots Association, International (ALPA); Cathay Dragon 
Airways (Cathay); IAE; MTU Maintenance Hannover GmbH (MTU); Willis 
Lease Finance Corporation (WLFC); and United Airlines (United). Five of 
six commenters requested changes to this AD. One commenter requested an 
update to Applicability. Two commenters requested clarification when 
cycles are unknown or cannot be determined. Three commenters requested 
that the FAA reference the latest service information. One commenter 
requested an update to terminology. Three commenters requested credit 
for replacement before the effective date of this AD. One commenter 
requested clarification to ``engine shop visit.'' One commenter 
requested an update to a Note in paragraph (g)(2) of this AD. One 
commenter requested an update to include diffuser case assembly part 
numbers (P/Ns) after modification. One commenter supported this AD as 
written. The following presents the comments received on the NPRM and 
the FAA's response to each comment.

Request To Update Applicability To Include IAE V2500-E5 Model Engines

    IAE requested that the FAA update paragraph (c), Applicability, of 
this AD to include the IAE V2500-E5 model turbofan engine. IAE reasoned 
that the V2500-E5 model turbofan engine shares diffuser case assembly, 
P/N 2A2891-01, with IAE V2500-A1, -A5, and -D5 model turbofan engines.
    The FAA agrees that the IAE V2500-E5 model turbofan engine shares 
an affected diffuser case assembly with other affected engines, and 
therefore, is susceptible to the unsafe condition of this AD. The FAA 
added the IAE V2531-E5 model turbofan engine to the Applicability of 
this AD. The IAE V2531-E5 model turbofan engine is not currently 
installed on any airplanes of U.S. registry. Therefore, this change to 
applicability does not add any additional burden on U.S. operators or 
increase the estimated cost of this AD.

Request To Clarify Compliance Time When Cycles Are Unknown or Cannot Be 
Determined

    Cathay and WLFC requested clarification when to perform the actions 
if the cycles since new (CSN) are unknown or cannot be determined. 
Cathay suggested adding the following note to paragraphs (g)(1)(i), 
(ii), and (iii) of this AD for the BSI of the M-flange to align this AD 
with IAE Non-Modification Alert Service Bulletin (NMASB) V2500-ENG-72-
A0706, Revision 2, dated November 7, 2019 (the NMASB): ``If the cycles 
on the diffuser case M-flange cannot be determined, you must use the 
total cycles on the diffuser case. If the cycles on the diffuser case 
cannot be determined, you must use the total engine cycles if it can be 
documented that the diffuser case was always with the engine.'' WLFC 
asked for clarification on the compliance time for the diffuser case M-
flange replacement.
    Although the FAA disagrees with adding the note suggested by 
Cathay, the FAA agrees to clarify when to perform the actions if the 
CSN are unknown or cannot be determined. The FAA updated paragraph 
(g)(1)(iii) of this AD to clarify when to perform the initial

[[Page 15792]]

BSI of the M-flange and added paragraph (g)(2)(ii) of this AD to 
clarify when to replace the diffuser case M-flange if the diffuser case 
M-flange CSN are unknown or cannot be determined.

Request To Update Service Information

    IAE, MTU, and United requested that IAE Service Bulletin (SB) 
V2500-ENG-72-0709, Revision 1, dated February 20, 2020 (the SB), be 
referenced in this AD instead of the Original Issue, dated December 13, 
2019. United also requested that ``IAE NMASB V2500-ENG-72-A0706, 
Revision 2, dated November 7, 2019,'' be referenced.
    The FAA partially agrees. Revision 2 of the NMASB was already 
referenced in the NPRM and, therefore, no change is needed to this AD. 
The FAA agrees to reference Revision 1 to the SB, which was issued 
after publication of the NPRM. The SB provides guidance on performing 
the replacement of the diffuser case M-flange and is not required for 
compliance with the AD. Therefore, revising this AD to reference 
Revision 1 of the SB adds no additional burden on U.S. operators.

Request To Change ``Diffuser Case M-Flange'' References

    IAE requested that the FAA change ``diffuser case M-flange'' to 
``M-flange'' when referencing inspections. IAE reasoned that inspection 
zone 2 includes all three flanges of the M-flange: Diffuser case M-
flange, nozzle guide vane support, and the high-pressure turbine (HPT) 
case forward flange, and all three flanges are required to be 
inspected.
    The FAA agrees. The inspections are required on all surfaces of 
inspection zones 1, 2, and 3 of the M-flange. The FAA changed 
``diffuser case M-flange'' to ``M-flange'' when referencing inspections 
throughout this AD. The FAA, however, did not change ``diffuser case M-
flange'' when referencing replacement. Replacement of the diffuser case 
M-flange is the terminating action for the repetitive BSIs of the M-
flange required by this AD.

Request for Credit for Diffuser Case M-Flange Replacement

    Cathay, MTU, and WLFC requested credit for the replacement of the 
diffuser case M-flange if it was replaced before the effective date of 
this AD using TASK 72-42-11-300-028, Repair-028 (VRS3633), of the IAE 
V2500 Engine Manual (VRS3633 Repair-028). Cathay and WLFC reasoned that 
the replacement of the diffuser case M-flange resets the M-flange 
cycles to zero. Cathay and MTU cited the note to VRS3633 Repair-028 in 
the NMASB. Cathay also cited the note in the NMASB that fluorescent 
penetrant inspection (FPI) of the diffuser case M-flange bolt holes 
resets the cycles since the last FPI to zero.
    The FAA disagrees with revising the Credit for Previous Actions 
section of this AD to give credit for replacement of the diffuser case 
M-flange using VRS3633 Repair-028. The FAA determined that it is not 
necessary to provide previous credit for replacement of the diffuser 
case M-flange because this AD does not require use of specific service 
information to perform this replacement. The FAA revised paragraph (i), 
Credit for Previous Actions, of this AD by removing references to 
providing credit for replacement of the diffuser case M-flange. If 
operators replaced the diffuser case M-flange prior to the effective 
date of this AD using any FAA-approved method, they meet the 
requirements of this AD under paragraph (f) of this AD.

Request To Clarify ``Major Mating Engine Flanges''

    United requested that the FAA clarify the definition of ``engine 
shop visit'' and ``major mating engine flange.'' United asked if 
``major flange'' aligns with the NMASB, which in Figure 1 of the NMASB, 
identifies the engine major flanges as H through P flanges. United also 
asked if the ``separation of pairs of major mating engine flanges'' 
includes the separation of H and J flanges when replacing damaged 
blades in HPC stages 3 through 6 during an HPC Surgical Strike Repair. 
If an engine shop visit includes separating flanges when performing an 
HPC Surgical Strike Repair, United requested that the FAA update 
estimated costs of this AD to include costs associated with the 
teardown of modules.
    The FAA agrees to clarify this definition of ``engine shop visit'' 
in this AD. The FAA has revised the definition of ``engine shop visit'' 
in this AD to refer to the induction of the engine into the shop for 
maintenance involving the separation of pairs of major mating engine 
flanges, K-N. Based on this definition, separating H and J flanges 
during an HPC Surgical Strike Repair does not constitute an ``engine 
shop visit.''
    The FAA disagrees with updating the estimated costs of this AD. The 
cost analysis in AD rulemaking actions typically includes only the 
costs associated with complying with the AD, and does not include 
secondary costs. The FAA's cost estimate includes the work hours and 
parts costs to inspect and replace the parts.

Request To Update Note to Paragraph (g)(2)

    MTU requested that the FAA update Note 1 to paragraph (g)(2)(i) of 
this AD to ``Instructions on performing the replacement of the diffuser 
case M-flange can be found in the Accomplishment Instructions, 
paragraphs 1.A. and B., of IAE SB V2500-ENG-72-0709, Revision 1, dated 
February 20, 2020.'' MTU reasoned that the current wording suggests 
that there may be alternative instructions to replace the diffuser case 
M-flange other than the SB. MTU suggested that there are no 
alternatives to using IAE SB V2500-ENG-72-0709 to replace the diffuser 
case M-flange. Therefore, MTU notes that the language in the NPRM may 
generate ambiguity.
    The FAA disagrees. The SB is referenced in Note 2 to paragraph 
(g)(2) of this AD as guidance for performing the replacement. The FAA 
is not mandating the use of a specific method to replace the diffuser 
case M-flange in this AD. The FAA did not change this AD based on this 
comment, but redesignated ``Note 1 to paragraph (g)(2)(i)'' in the NPRM 
to ``Note 2 to paragraph (g)(2)'' in this AD based on the addition of a 
Note earlier in paragraph (g) of this AD.

Request To Include Diffuser Case Assembly P/Ns After Modification

    IAE requested that the FAA include the diffuser case assembly P/Ns, 
modified by the SB that are re-identified with new P/Ns after 
modification, and require replacement before the M-flange accumulates 
20,000 CSN.
    The FAA disagrees with including the list of diffuser case assembly 
P/Ns. The diffuser case M-flange, regardless of P/N, must be replaced 
at the next engine shop visit after the effective date of this AD or 
before the M-flange accumulates 20,000 CSN, whichever occurs later. 
Thereafter, the diffuser case M-flange must be replaced before 
accumulating 20,000 cycles since the previous replacement. Therefore, 
listing diffuser case assembly P/Ns is unnecessary.

Clarification to BSI Requirement

    The FAA determined the need to clarify the instructions required by 
paragraph (g)(1)(iv) of the NPRM. The NPRM referenced paragraphs 2.A. 
through 2.G. of the NMASB to perform the BSI. However, paragraph 2.G. 
of the NMASB provides instructions to perform a FPI of the M-flange to 
confirm the indication as a crack. The FAA added a note to paragraph 
(g)(1)(iv) of this AD to clarify that paragraph 2.G. of the NMASB 
describes procedures for

[[Page 15793]]

performing a local FPI of the M-flange if you are unable to confirm if 
an indication is a crack.

Support for the AD

    ALPA expressed support for the AD as written.

Conclusion

    The FAA reviewed the relevant data, considered any comments 
received, and determined that air safety requires adopting the AD as 
proposed. Accordingly, the FAA is issuing this AD to address the unsafe 
condition on these products. Except for minor editorial changes, and 
any other changes described previously, this AD is adopted as proposed 
in the NPRM. None of the changes will increase the economic burden on 
any operator.

Related Service Information Under 1 CFR Part 51

    The FAA reviewed International Aero Engines NMASB V2500-ENG-72-
A0706, Revision 2, dated November 7, 2019. The NMASB describes 
procedures for inspecting the M-flange. 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 
ADDRESSES.

Other Related Service Information

    The FAA reviewed International Aero Engines SB V2500-ENG-72-0709, 
Revision 1, dated February 20, 2020. The SB identifies the diffuser 
case assembly P/Ns and describes procedures for replacing the diffuser 
case M-flange.

Costs of Compliance

    The FAA estimates that this AD affects 1,654 engines installed on 
airplanes of U.S. registry.
    The FAA estimates the following costs to comply with this AD:

                                                 Estimated Costs
----------------------------------------------------------------------------------------------------------------
                                                                                     Cost per      Cost on U.S.
                Action                         Labor cost           Parts cost        product        operators
----------------------------------------------------------------------------------------------------------------
BSI of M-flange.......................  2 work-hours x $85 per                $0            $170        $281,180
                                         hour = $170.
Replace the diffuser case M-flange....  40 work-hours x $85 per           20,000          23,400      38,703,600
                                         hour = $3,400.
----------------------------------------------------------------------------------------------------------------

    The FAA has included all known costs in its cost estimate. 
According to the manufacturer, however, some of the costs of this AD 
may be covered under warranty, thereby reducing the cost impact on 
affected operators.

Authority for This Rulemaking

    Title 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.
    The 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.

Regulatory Findings

    The FAA has determined that this 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.
    For the reasons discussed above, I certify that this AD:
    (1) Is not a ``significant regulatory action'' under Executive 
Order 12866,
    (2) Will not affect intrastate aviation in Alaska, and
    (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.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Incorporation by 
reference, Safety.

The Amendment

    Accordingly, under the authority delegated to me by the 
Administrator, the FAA amends 14 CFR part 39 as follows:

PART 39--AIRWORTHINESS DIRECTIVES

0
1. The authority citation for part 39 continues to read as follows:

    Authority: 49 U.S.C. 106(g), 40113, 44701.


Sec.  39.13  [Amended]

0
2. The FAA amends Sec.  39.13 by:
0
a. Removing airworthiness directive 2019-06-06, Amendment 39-19604 (84 
FR 11642, March 28, 2019); and
0
b. Adding the following new airworthiness directive:

2021-05-18 International Aero Engines AG: Amendment 39-21461; Docket 
No. FAA-2020-0700; Project Identifier AD-2020-00238-E.

(a) Effective Date

    This airworthiness directive (AD) is effective April 29, 2021.

(b) Affected ADs

    This AD replaces AD 2019-06-06, Amendment 39-19604 (84 FR 11642, 
March 28, 2019).

(c) Applicability

    This AD applies to all International Aero Engines AG (IAE) 
V2500-A1, V2522-A5, V2524-A5, V2525-D5, V2527-A5, V2527E-A5, V2527M-
A5, V2528-D5, V2530-A5, V2531-E5, and V2533-A5 model turbofan 
engines.

(d) Subject

    Joint Aircraft System Component (JASC) Code 7250, Turbine 
Section.

(e) Unsafe Condition

    This AD was prompted by a crack found at the diffuser case M-
flange during overhaul inspection. The FAA is issuing this AD to 
prevent failure of the diffuser case. The unsafe condition, if not 
addressed, could result in uncontained diffuser case rupture, damage 
to the engine, and damage to the airplane.

(f) Compliance

    Comply with this AD within the compliance times specified, 
unless already done.

(g) Required Actions

(1) Borescope Inspection of M-Flange

    For engines with a diffuser case assembly, part number 2A0051, 
2A2081-01, 2A2581-01, 2A2883-01, 2A2885-01, 2A2889-01, 2A2891-01, 
2A2896-01, 2A2897-01, or 2A3132 installed, perform an initial 
borescope inspection (BSI) of zones 1, 2, and 3 of the M-flange as 
follows:
    (i) For engines with a diffuser case M-flange that has 19,000 or 
more cycles since

[[Page 15794]]

new (CSN) on the effective date of this AD, perform the initial BSI 
of the M-flange before accumulating the ``Inspect within (Cycles)'' 
in Table 1 to paragraph (g)(1) of this AD. If the CSLFPI is unknown, 
use the CSN of the diffuser case M-flange.
    (ii) For engines with a diffuser case M-flange that has fewer 
than 19,000 CSN on the effective date of this AD, perform the 
initial BSI of the M-flange before accumulating 20,300 CSN.
    (iii) For engines with a diffuser case M-flange or diffuser case 
in which the CSN is unknown or cannot be determined, perform the 
initial BSI of the M-flange before accumulating the ``Inspect within 
(Cycles)'' in Table 1 to paragraph (g)(1) of this AD using one of 
the following options:
    (A) If the cycles of the diffuser case M-flange are unknown or 
cannot be determined, use the total cycles on the diffuser case.
    (B) If the cycles on the diffuser case are unknown or cannot be 
determined and it can be documented that the diffuser case was 
always installed on the engine, use total engine cycles.
    (C) If neither paragraph (g)(1)(iii)(A) or (B) applies, perform 
the BSI of the M-flange within 250 cycles after the effective date 
of this AD.
    (iv) Use the Accomplishment Instructions, paragraphs 2.A. 
through 2.G. of IAE Non-Modification Alert Service Bulletin (NMASB) 
V2500-ENG-72-A0706, Revision 2, dated November 7, 2019 (the NMASB), 
to perform the initial BSI.

    Note 1 to paragraph (g)(1)(iv): Paragraph 2.G. of the NMASB 
describes procedures for performing a local fluorescent penetrant 
inspection of the M-flange if you are unable to confirm if an 
indication is a crack.

    (v) If no crack is found as a result of the inspections required 
by paragraphs (g)(1)(i) through (iv) of this AD, repeat the BSI of 
zones 1, 2, and 3 of the M-flange at intervals not to exceed 2,100 
cycles since the previous BSI.
    (vi) If a crack is found as a result of the inspections required 
by paragraphs (g)(1)(i) through (iv) of this AD, replace the 
diffuser case M-flange or repeat the BSI of zones 1, 2, and 3 of the 
M-flange as specified by either ``Table 2: Fly on Limits'' or 
``Table 4: Fly on Limits,'' in paragraph 2.H., Accomplishment 
Instructions, of the NMASB as appropriate for the affected the 
engine model.
[GRAPHIC] [TIFF OMITTED] TR25MR21.000

(2) Replacement of the Diffuser Case M-Flange

    (i) At the next engine shop visit after the effective date of 
this AD or before the diffuser case M-flange accumulates 20,000 CSN, 
whichever occurs later, replace the diffuser case M-flange.
    (ii) For engines with a diffuser case M-flange or diffuser case 
in which the CSN is unknown or cannot be determined, perform one of 
the following options:
    (A) If the cycles of the diffuser case M-flange are unknown or 
cannot be determined, at the next engine shop visit after the 
effective date of this AD or before the diffuser case accumulates 
20,000 CSN, whichever occurs later, replace the diffuser case M-
flange.
    (B) If the cycles of the diffuser case are unknown or cannot be 
determined, and if it can be documented that the diffuser case was 
always installed on the engine, at the next engine shop visit after 
the effective date of this AD or before the engine accumulates 
20,000 CSN, whichever occurs later, replace the diffuser case M-
flange.
    (C) If the cycles on the diffuser case M-flange are unknown or 
cannot be determined based on the criteria identified in paragraphs 
(g)(2)(ii)(A) and (B), or it cannot be shown that the diffuser case 
was always installed on the engine, at the next engine shop visit 
after the effective date of this AD, replace the diffuser case M-
flange.

    Note 2 to paragraph (g)(2)(ii): Guidance on performing the 
replacement of the diffuser case M-flange described in paragraphs 
(g)(2)(i) and (ii) can be found in the Accomplishment Instructions, 
paragraphs 1.A. and B., of IAE SB V2500-ENG-72-0709, Revision 1, 
dated February 20, 2020.

    (iii) Thereafter, repeat the replacement of the diffuser case M-
flange before accumulating 20,000 cycles since the previous 
replacement.
    (iv) Replacement of the diffuser case M-flange is the 
terminating action for the repetitive BSIs required by paragraph 
(g)(1) of this AD.

(h) Installation Prohibition

    After the effective date of this AD, do not install a diffuser 
case onto any affected engine if the diffuser case M-flange has more 
than 20,000 CSN.

(i) Credit for Previous Actions

    You may take credit for the initial BSIs that are required by 
paragraphs (g)(1)(i) through (iii) of this AD, if you performed 
those actions before the effective date of this AD using IAE NMASB 
V2500-ENG-72-A0706, Revision 1, dated June 28, 2019, or Original 
Issue, dated February 14, 2019; IAE V2500 Special Instruction (SI) 
No. 341F-18, dated November 19, 2018; IAE V2500 SI No. 350F-18, Rev. 
1, dated December 17, 2018; IAE V2500 SI No. 356F-18, Rev. 1, dated 
January 9, 2019; IAE V2500 SI No. 372F-18, dated January 8, 2019; or 
IAE V2500 Special SI No. 04F-19, dated January 14, 2019.

(j) Definition

    For the purpose of this AD, an ``engine shop visit'' is the 
induction of the engine into the shop for maintenance involving the 
separation of pairs of major mating engine flanges, K-N, except that 
the separation of engine flanges solely for the purposes of 
transportation without subsequent engine maintenance does not 
constitute an engine shop visit.

(k) Alternative Methods of Compliance (AMOCs)

    (1) The Manager, ECO Branch, FAA, has the 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 Related Information. You may email your request to: 
[email protected].
    (2) Before using any approved AMOC, notify your appropriate 
principal inspector, or lacking a principal inspector, the manager 
of the local flight standards district office/certificate holding 
district office.

[[Page 15795]]

(l) Related Information

    For more information about this AD, contact Nicholas Paine, 
Aviation Safety Engineer, ECO Branch, FAA, 1200 District Avenue, 
Burlington, MA 01803; phone: (781) 238-7742; fax: (781) 238-7199; 
email: [email protected].

(m) Material Incorporated by Reference

    (1) The Director of the Federal Register approved the 
incorporation by reference (IBR) of the service information listed 
in this paragraph under 5 U.S.C. 552(a) and 1 CFR part 51.
    (2) You must use this service information as applicable to do 
the actions required by this AD, unless the AD specifies otherwise.
    (i) International Aero Engines (IAE) Non-Modification Alert 
Service Bulletin V2500-ENG-72-A0706, Revision 2, dated November 7, 
2019.
    (ii) [Reserved]
    (3) For IAE service information identified in this AD, contact 
International Aero Engines AG, 400 Main Street, East Hartford, CT 
06118; phone: (800) 565-0140; email: [email protected]; website: 
https://fleetcare.pw.utc.com.
    (4) You may view this service information at 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 (781) 238-7759.
    (5) You may view this service information that is incorporated 
by reference at the National Archives and Records Administration 
(NARA). For information on the availability of this material at 
NARA, email: [email protected], or go to: https://www.archives.gov/federal-register/cfr/ibr-locations.html.

    Issued on February 25, 2021.
Gaetano A. Sciortino,
Deputy Director for Strategic Initiatives, Compliance & Airworthiness 
Division, Aircraft Certification Service.
[FR Doc. 2021-06139 Filed 3-24-21; 8:45 am]
BILLING CODE 4910-13-P

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