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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. FAA20200700; Project Identifier AD202000238E; Amendment 3921461; AD 20210518
RIN 2120AA64

Airworthiness Directives; International Aero Engines AG Turbofan Engines Federal Aviation Administration FAA, DOT.
ACTION: Final rule.
AGENCY:

The FAA is superseding Airworthiness Directive AD 201906
06 for all International Aero Engines AG
IAE V2500A1, V2522A5, V2524A5, V2525D5, V2527A5, V2527EA5, V2527MA5, V2528D5, V2530A5, and V2533A5 model turbofan engines.
AD 20190606 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 5650140; email: help24@
pw.utc.com; website: http
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. FAA2020
0700.
DATES:

Examining the AD Docket You may examine the AD docket at https www.regulations.gov by searching for and locating Docket No.
FAA20200700; 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
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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 W12140, 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 2387742; 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 20190606, Amendment 3919604 84 FR 11642, March 28, 2019, AD 20190606. AD
20190606 applied to all IAE V2500
A1, V2522A5, V2524A5, V2525D5, V2527A5, V2527EA5, V2527MA5, V2528D5, V2530A5, and V2533A5
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 20190606, 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
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commenter requested clarification to engine shop visit. One commenter requested an update to a Note in paragraph g2 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 FAAs response to each comment.
Request To Update Applicability To Include IAE V2500E5 Model Engines IAE requested that the FAA update paragraph c, Applicability, of this AD
to include the IAE V2500E5 model turbofan engine. IAE reasoned that the V2500E5 model turbofan engine shares diffuser case assembly, P/N 2A289101, with IAE V2500A1, 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
V2531E5 model turbofan engine to the Applicability of this AD. The IAE
V2531E5 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 g1i, ii, and iii of this AD for the BSI of the M-flange to align this AD with IAE NonModification Alert Service Bulletin NMASB V2500ENG72A0706, 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 g1iii of this AD to clarify when to perform the initial
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