90 FR 79 pgs. 17352-17355 - Airworthiness Directives; Airbus Helicopters Deutschland GmbH (AHD) Helicopters
Type: PRORULEVolume: 90Number: 79Pages: 17352 - 17355
Pages: 17352, 17353, 17354, 17355Docket number: [Docket No. FAA-2025-0629; Project Identifier MCAI-2023-01183-R]
FR document: [FR Doc. 2025-07111 Filed 4-24-25; 8:45 am]
Agency: Transportation Department
Sub Agency: Federal Aviation Administration
Official PDF Version: PDF Version
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2025-0629; Project Identifier MCAI-2023-01183-R]
RIN 2120-AA64
Airworthiness Directives; Airbus Helicopters Deutschland GmbH (AHD) Helicopters
AGENCY:
Federal Aviation Administration (FAA), DOT.
ACTION:
Notice of proposed rulemaking (NPRM).
SUMMARY:
[top] The FAA proposes to adopt a new airworthiness directive (AD) for all Airbus Helicopters Deutschland GmbH (AHD) Model EC135P1, EC135P2,
DATES:
The FAA must receive comments on this NPRM by June 9, 2025.
ADDRESSES:
You may send comments, using the procedures found in 14 CFR 11.43 and 11.45, by any of the following methods:
• Federal eRulemaking Portal: Go to regulations.gov . Follow the instructions for submitting comments.
• Fax: (202) 493-2251.
• Mail: U.S. Department of Transportation, Docket Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New Jersey Avenue SE, Washington, DC 20590.
• Hand Delivery: Deliver to Mail address above between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays.
AD Docket: You may examine the AD docket at regulations.gov under Docket No. FAA-2025-0629; 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 NPRM, the mandatory continuing airworthiness information (MCAI), any comments received, and other information. The street address for Docket Operations is listed above.
Material Incorporated by Reference:
• For EASA material identified in this proposed AD, contact EASA, Konrad-Adenauer-Ufer 3, 50668 Cologne, Germany; phone: +49 221 8999 000; email: ADs@easa.europa.eu ; website: easa.europa.eu . You may find the EASA material on the EASA website at ad.easa.europa.eu .
• You may view this material at the FAA, Office of the Regional Counsel, Southwest Region, 10101 Hillwood Parkway, Room 6N-321, Fort Worth, TX 76177. For information on the availability of this material at the FAA, call (817) 222-5110. The EASA material is also available at regulations.gov under Docket No. FAA-2025-0629.
FOR FURTHER INFORMATION CONTACT:
Aaron Nguyen, Aviation Safety Engineer, FAA, 1600 Stewart Avenue, Suite 410, Westbury, NY 11590; phone: (817) 222-5134; email: Aaron.T.Nguyen@faa.gov .
SUPPLEMENTARY INFORMATION:
Comments Invited
The FAA invites you to send any written relevant data, views, or arguments about this proposal. Send your comments to an address listed under the ADDRESSES section. Include "Docket No. FAA-2025-0629; Project Identifier MCAI-2023-01183-R" at the beginning of your comments. The most helpful comments reference a specific portion of the proposal, explain the reason for any recommended change, and include supporting data. The FAA will consider all comments received by the closing date and may amend this proposal because of those comments.
Except 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 regulations.gov, including any personal information you provide. The agency will also post a report summarizing each substantive verbal contact received about this NPRM.
Confidential 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 NPRM 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 NPRM, 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 NPRM. Submissions containing CBI should be sent to Aaron Nguyen, Aviation Safety Engineer, FAA, 1600 Stewart Avenue, Suite 410, Westbury, NY 11590; phone: (817) 222-5134; email: Aaron.T.Nguyen@faa.gov . Any commentary that the FAA receives which is not specifically designated as CBI will be placed in the public docket for this rulemaking.
Background
EASA, which is the Technical Agent for the Member States of the European Union, has issued EASA AD 2023-0197, dated November 10, 2023 (EASA AD 2023-0197) (also referred to as the MCAI), to correct an unsafe condition on Airbus Helicopters Deutschland GmbH Model EC135 P1, EC135 P2, EC135 P2+, EC135 P3, EC135 T1, EC135 T2, EC135 T2+, EC135 T3, EC635 P2+, EC635 P3, EC635 T1, EC635 T2+, and EC635 T3 helicopters. The MCAI advises of reports of ruptured and deformed flexible couplings, and that investigations determined that a flexible coupling installed with high axial displacement causes increased stresses and friction between its sheets. The MCAI states that this unsafe condition, if not detected and corrected, could lead to cracks and extensive deformation of flexible couplings and consequent high vibration of the tail rotor drive shaft, possibly resulting in reduced control of the helicopter. The FAA is proposing this AD to address the unsafe condition on these helicopters.
You may examine the MCAI in the AD docket at regulations.gov under Docket No. FAA-2025-0629.
Material Incorporated by Reference Under 1 CFR Part 51
The FAA reviewed EASA AD 2023-0197, which requires a one-time inspection of the flexible coupling for axial displacement and, depending on the results, replacing both flexible couplings and correcting the axial displacement, or inspecting the flexible couplings, replacing each flexible coupling having a discrepancy, and correcting the axial displacement. For certain flexible couplings not replaced based on the results of the flexible coupling inspection, EASA AD 2023-0197 requires replacing the flexible couplings within a longer compliance time. EASA AD 2023-0197 also prohibits installing a tail rotor drive shaft on any helicopter unless certain procedures are followed. This material 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.
FAA's Determination
[top] These products have been approved by the aviation authority of another country and are approved for operation in the United States. Pursuant to the FAA's bilateral agreement with this State of Design Authority, it has notified the FAA of the unsafe condition described in the MCAI referenced above. The FAA is issuing this NPRM after determining that the unsafe condition described previously is likely to exist or develop on other products of these same type designs.
Proposed AD Requirements in This NPRM
This proposed AD would require accomplishing the actions specified in EASA AD 2023-0197, described previously, as incorporated by reference, except for any differences identified as exceptions in the regulatory text of this proposed AD and except as discussed under "Differences Between this Proposed AD and the MCAI."
Explanation of Required Compliance Information
In the FAA's ongoing efforts to improve the efficiency of the AD process, the FAA developed a process to use some civil aviation authority (CAA) ADs as the primary source of information for compliance with requirements for corresponding FAA ADs. The FAA has been coordinating this process with manufacturers and CAAs. As a result, the FAA proposes to incorporate EASA AD 2023-0197 by reference in the FAA final rule. This proposed AD would, therefore, require compliance with EASA AD 2023-0197 in its entirety through that incorporation, except for any differences identified as exceptions in the regulatory text of this proposed AD. Using common terms that are the same as the heading of a particular section in EASA AD 2023-0197 does not mean that operators need comply only with that section. For example, where the AD requirement refers to "all required actions and compliance times," compliance with this AD requirement is not limited to the section titled "Required Action(s) and Compliance Time(s)" in EASA AD 2023-0197. Material referenced in EASA AD 2023-0197 for compliance will be available at regulations.gov by searching for and locating Docket No. FAA-2025-0629 after the FAA final rule is published.
Differences Between This Proposed AD and the MCAI
The MCAI applies to Model EC635 P2+, EC635 P3, EC635 T1, and EC635 T3 helicopters, whereas this proposed AD would not because these model helicopters are not FAA type-certificated.
Costs of Compliance
The FAA estimates that this AD, if adopted as proposed, would affect 69 helicopters of U.S. registry. Labor rates are estimated at $85 per work-hour. Based on these numbers, the FAA estimates the following costs to comply with this proposed AD.
Inspecting both flexible couplings for axial displacement would take 8 work-hours for an estimated cost of $680 per helicopter and $46,920 for the U.S. fleet.
If required, replacing both flexible couplings would take 2 work-hours and parts would cost $4,100 for an estimated cost of $4,270 per helicopter. Replacing one flexible coupling would take 1 work-hour and parts would cost $2,050 for an estimated cost of $2,135 per flexible coupling.
If required, correcting the axial displacement of the flexible couplings would take 5 work-hours for an estimated cost of $425 per helicopter.
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 determined that this proposed AD would not have federalism implications under Executive Order 13132. This proposed AD would 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 this proposed regulation:
(1) Is not a "significant regulatory action" under Executive Order 12866,
(2) Would not affect intrastate aviation in Alaska, and
(3) Would 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 Proposed Amendment
Accordingly, under the authority delegated to me by the Administrator, the FAA proposes to amend 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(f), 40113, 44701.
§?39.13 [Amended]
2. The FAA amends §?39.13 by adding the following new airworthiness directive:
Airbus Helicopters Deutschland GmbH (AHD): Docket No. FAA-2025-0629; Project Identifier MCAI-2023-01183-R.
(a) Comments Due Date
The FAA must receive comments on this airworthiness directive (AD) by June 9, 2025.
(b) Affected ADs
None.
(c) Applicability
This AD applies to Airbus Helicopters Deutschland GmbH (AHD) Model EC135P1, EC135P2, EC135P2+, EC135P3, EC135T1, EC135T2, EC135T2+, EC635T2+, and EC135T3 helicopters, certificated in any category.
Note 1 to paragraph (c): Helicopters with an EC135P3H designation are Model EC135P3 helicopters and helicopters with an EC135T3H designation are Model EC135T3 helicopters.
(d) Subject
Joint Aircraft System Component (JASC) Code 6510, Tail Rotor Drive Shaft.
(e) Unsafe Condition
This AD was prompted by reports of ruptured and deformed flexible couplings. The FAA is issuing this AD to detect axial displacement of the tail rotor drive shaft that exceeds allowable limits. The unsafe condition, if not addressed, could result in cracks and extensive deformation of flexible couplings, high vibration of the tail rotor drive shaft, and subsequent reduced control of the helicopter.
(f) Compliance
Comply with this AD within the compliance times specified, unless already done.
(g) Requirements
Except as specified in paragraphs (h) and (i) of this AD: Comply with all required actions and compliance times specified in, and in accordance with, European Union Aviation Safety Agency AD 2023-0197, dated November 10, 2023 (EASA AD 2023-0197).
(h) Exceptions to EASA AD 2023-0197
[top] (1) Where EASA AD 2023-0197 requires compliance in terms of flight hours, this AD requires using hours time-in-service.
(2) Where EASA AD 2023-0197 refers to its effective date, this AD requires using the effective date of this AD.
(3) Where the material referenced in EASA AD 2023-0197 specifies sending flexible couplings to Airbus Helicopters, this AD requires removing those parts from service.
(4) Where paragraphs (2) and (6) of EASA AD 2023-0197 state "new," this AD requires replacing each instance of that text with "new (zero hours time-in-service)."
(5) Where paragraph (4) of EASA AD 2023-0197 states "any discrepancy," for the purpose of this AD, discrepancy may be indicated by cracks, mechanical damage, deformation, delamination, corrosion, loose rivets, or damaged surface protection, where these discrepancies exceed the allowable limits as defined in the material referenced in the ASB.
(6) Where paragraph (4) of EASA AD 2023-0197 states "replace that flexible coupling," this AD requires replacing that text with "replace that flexible coupling with a new (zero hours time-in-service) flexible coupling."
(7) This AD does not adopt paragraph (7) or the "Remarks" section of EASA AD 2023-0197.
(i) No Reporting Requirement
Although the material referenced in EASA AD 2023-0197 specifies to submit certain information to the manufacturer, this AD does not require that action.
(j) Special Flight Permits
Special flight permits are prohibited.
(k) Alternative Methods of Compliance (AMOCs)
(1) The Manager, International Validation 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 International Validation Branch, send it to the attention of the person identified in paragraph (l) of this AD. Information may be emailed to: 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.
(l) Additional Information
For more information about this AD, contact Aaron Nguyen, Aviation Safety Engineer, FAA, 1600 Stewart Avenue, Suite 410, Westbury, NY 11590; phone: (817) 222-5134; email: Aaron.T.Nguyen@faa.gov .
(m) Material Incorporated by Reference
(1) The Director of the Federal Register approved the incorporation by reference of the material listed in this paragraph under 5 U.S.C. 552(a) and 1 CFR part 51.
(2) You must use this material as applicable to do the actions required by this AD, unless the AD specifies otherwise.
(i) European Union Aviation Safety Agency (EASA) AD 2023-0197, dated November 10, 2023.
(ii) [Reserved]
(3) For EASA material identified in this AD, contact EASA, Konrad-Adenauer-Ufer 3, 50668 Cologne, Germany; phone: +49 221 8999 000; email: ADs@easa.europa.eu ; website: easa.europa.eu . You may find the EASA material on the EASA website at ad.easa.europa.eu .
(4) You may view this material at the FAA, Office of the Regional Counsel, Southwest Region, 10101 Hillwood Pkwy., Room 6N-321, Fort Worth, TX 76177. For information on the availability of this material at the FAA, call (817) 222-5110.
(5) You may view this material at the National Archives and Records Administration (NARA). For information on the availability of this material at NARA, visit www.archives.gov/federal-register/cfr/ibr-locations or email fr.inspection@nara.gov .
Issued on April 21, 2025.
Steven W. Thompson,
Acting Deputy Director, Compliance & Airworthiness Division, Aircraft Certification Service.
[FR Doc. 2025-07111 Filed 4-24-25; 8:45 am]
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