AD 2019-12-05

The FAA is adopting a new airworthiness directive (AD) for certain CFM International S.A. (CFM) CFM56-5B, CFM56-5C, and CFM56-7B model turbofan engines with a certain rotating air high-pressure turbine (HPT) front seal. This AD requires replacement of the affected rotating air HPT front seal with a part eligible for installation. This AD was prompted by cracks found in the rotating air HPT front seal. The FAA is issuing this AD to address the unsafe condition on these products.

Final rule; request for comments.

Adoption of 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\n2019-12-05 CFM International S.A.: Amendment 39-19660; Docket No. FAA-2019-0212; Product Identifier 2019-NE-05-AD. \n\n(a) Effective Date \n\n\n\tThis AD is effective July 5, 2019. \n\n(b) Affected ADs \n\n\n\tNone. \n\n(c) Applicability \n\n\n\tThis AD applies to: \n\t(1) CFM International S.A. (CFM) CFM56-5B1, -5B2, -5B4, -5B5, - 5B6, -5B7, -5B1/P, -5B2/P, -5B3/P, -5B4/P, -5B5/P, -5B6/P, -5B7/P, - 5B8/P, -5B9/P, -5B3/P1, -5B4/P1, -5B1/2P, -5B2/2P, -5B3/2P, -5B4/2P, -5B6/2P, -5B9/2P, -5B3/2P1, -5B4/2P1, -7B20, -7B22, -7B24, -7B26, - 7B27, -7B22/B1, -7B24/B1,-7B26/B1, -7B26/B2, -7B27/B1, -7B27/B3, - 7B20/2, -7B22/2, -7B24/2, -7B26/2, -7B27/2, -7B27A model turbofan engines with a: \n\t(i) rotating air high-pressure turbine (HPT) front seal: \n\t(A) with part number (P/N) 1795M36P01 or P/N 1795M36P02 and serial numbers (S/Ns) GWNDN949 through GWNSE969 or S/Ns GWN000CE through GWN0990L, not including S/Ns GWN08ND7, GWN0923A, GWN0971E, GWN098A1, GWN098W6, GWN098W8, GWN098WA, and GWN0990G, installed; \n\t(B) that has been removed from the original HPT disk and re- assembled to a different HPT disk; and \n\t(C) that has 6,001 or more cycles since being reconfigured. \n\t(ii) (Reserved) \n\t(2) CFM CFM56-5C2, -5C2/4, -5C2/F, -5C2/F4, -5C2/G, -5C2/G4, - 5C2/P, -5C3/F, -5C3/F4, -5C3/G, -5C3/G4, -5C3/P, -5C4, -5C4/1, -5C4/ P, -5C4/1P model turbofan engines with a: \n\t(i) rotating air HPT front seal: \n\t(A) with P/N 1795M36P01 or P/N 1795M36P02 and S/Ns GWNDN949 through GWNSE969 or S/Ns GWN000CE through GWN0990L, not including S/ Ns GWN08ND7, GWN0923A, GWN0971E, GWN098A1, GWN098W6, GWN098W8, GWN098WA, and GWN0990G, installed; \n\n((Page 28719)) \n\n\n\t(B) that has been removed from the original HPT disk and re- assembled to a different HPT disk; and \n\t(C) that has 3,751 or more cycles since being reconfigured. \n\t(ii) (Reserved) \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 cracks found in the rotating air HPT front seal. The FAA is issuing this AD to prevent failure of the rotating air HPT front seal. The unsafe condition, if not addressed, could result in the uncontained release of the rotating air HPT front seal, damage to the engine, and damage to the airplane. \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) For all affected CFM CFM56-5B and CFM56-7B model turbofan engines: \n\t(i) If, on the effective date of this AD, the rotating air HPT front seal has 7,000 cycles or greater since being reconfigured, remove the part from service within 50 cycles after the effective date of this AD and replace with a part eligible for installation. \n\t(ii) If, on the effective date of this AD, the rotating air HPT front seal has between 6,001 and 6,999 cycles, inclusive, since being reconfigured, remove the part from service within 500 cycles after the effective date of this AD, but not to exceed 7,050 cycles since being reconfigured, and replace with a part eligible for installation. \n\t(2) For all affected CFM CFM56-5C model turbofan engines: \n\t(i) If, on the effective date of this AD, the rotating air HPT front seal has 4,250 cycles or greater since being reconfigured, remove the part from service within 25 cycles after the effective date of this AD, or within 1,500 cycles since the last fluorescent penetrant inspection (FPI) of the rotating air HPT front seal, whichever occurs later, and replace with a part eligible for installation. \n\t(ii) If, on the effective date of this AD, the rotating air HPT front seal has between 3,751 and 4,249 cycles, inclusive, since being reconfigured, remove the part from service within 250 cycles after the effective date of this AD, before accumulating 4,275 cycles since being reconfigured, or within 1,500 cycles since the last FPI of the rotating air HPT front seal, whichever occurs later, and replace with a part eligible for installation. \n\n(h) Definition \n\n\n\tFor the purpose of this AD, reconfigured is when a rotating air HPT front seal has been removed from the original HPT disk and re- assembled to a different HPT disk. \n\n(i) Alternative Methods of Compliance (AMOCs) \n\n\n\t(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 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 of 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 Christopher McGuire, Aerospace Engineer, ECO Branch, FAA, 1200 District Avenue, Burlington, MA 01803; phone: 781-238-7120; fax: 781-238-7199; email: chris.mcguire@faa.gov. \n\n(k) Material Incorporated by Reference \n\n\n\tNone.

Discussion \n\n\n\tThe FAA received reports that cracks were found in the rotating air HPT front seal on CFM56-5B model turbofan engines during a scheduled shop visit. After further analysis, CFM determined that when a single rotating air HPT front seal is mated to more than one HPT disk some seals develop microcracks. These cracks resulted from variations in the geometry of the parts being mated. \n\tThis AD pertains to the highest risk engines and therefore addresses certain CFM CFM56-5B, CFM56-5C, and CFM56-7B model turbofan engines with an affected rotating air HPT front seal that has a specified number of cycles since being reconfigured. The FAA expects to propose future rulemaking for additional CFM CFM56-5B, CFM56-5C, and CFM56-7B model turbofan engines with this same rotating air HPT front seal that have fewer cycles since being reconfigured. These engines have the same unsafe condition as the engines affected by this AD but represent a lower safetyrisk due to the lower number of cycles since being reconfigured on the affected rotating air HPT front seal. \n\tThis condition, if not addressed, could result in the uncontained release of the rotating air HPT front seal, damage to the engine, and damage to the airplane. The FAA is issuing this AD to address the unsafe condition on these products. \n\nRelated Service Information \n\n\n\tThe FAA reviewed CFM Service Bulletin (SB) CFM56-5B S/B 72-1074, Revision 01, dated December 5, 2018; CFM SB CFM56-5C S/B 72-0794, Revision 01, dated January 2, 2019; and CFM SB CFM56-7B S/B 72-1042, Revision 01, dated January 2, 2019. CFM SB CFM56-5B S/B 72-1074, Revision 01, describes procedures for replacement of the affected rotating air HPT front seal on CFM CFM56-5B turbofan engines. CFM SB CFM56-5C S/B 72-0794, Revision 01, describes procedures for replacement of the affected rotating air HPT front seal on CFM CFM56-5C turbofan engines. CFM SB CFM56-7B S/B 72-1042, Revision 01, describes procedures for replacement of the affected rotating air HPT front seal on CFM CFM56-7B turbofan engines. \n\nFAA's Determination \n\n\n\tThe FAA is issuing this AD because it evaluated all the relevant information 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 replacement of the affected rotating air HPT front seal with a part eligible for installation. \n\nFAA's Justification and Determination of the Effective Date \n\n\n\tNo domestic operators use the affected higher risk CFM CFM56-5B, CFM56-5C, and CFM56-7B model turbofan engines. Therefore, the FAA finds good cause that notice and opportunity for prior public comment \n\n((Page 28718)) \n\nare impracticable. In addition, for the reason stated above, 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-2019- 0212 and Product Identifier 2019-NE-05-AD 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\tThe FAA will post all comments received, without change, to http://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\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 no 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 ---------------------------------------------------------------------------------------------------------------- Replace the rotating air HPT front 1 work-hour x $85 per $344,600 $344,685 $0 \n\tseal. hour = $85. ---------------------------------------------------------------------------------------------------------------- \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\tThis AD is issued in accordance with authority delegatedby the Executive Director, Aircraft Certification Service, as authorized by FAA Order 8000.51C. In accordance with that order, issuance of ADs is normally a function of the Compliance and Airworthiness Division, but during this transition period, the Executive Director has delegated the authority to issue ADs applicable to engines, propellers, and associated appliances to the Manager, Engine and Propeller Standards Branch, Policy and Innovation Division. \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, and \n\t(2) Will not affect intrastate aviation in Alaska. \n\nList ofSubjects in 14 CFR Part 39 \n\n\n\tAir transportation, Aircraft, Aviation safety, Incorporation by reference, Safety.