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###### Department of Transportation

###### Federal Aviation Administration

          - 14 CFR Part 39
          - [Docket No. FAA-2023-2238; Project Identifier MCAI-2023-00698-R; Amendment 39-22803; AD 2024-15-11]
          - RIN 2120-AA64

# AGENCY:

Federal Aviation Administration (FAA), DOT.

# ACTION:

Final rule.

# SUMMARY:

The FAA is adopting a new airworthiness directive (AD) for all Leonardo S.p.a. Model A109C, A109E, A109K2, A109S, and AW109SP helicopters. This AD was prompted by reports of loose tail rotor duplex bearing locking nuts, possibly caused by improper installation. This AD requires disassembling certain tail rotor duplex bearings and reassembling them in accordance with updated procedures. This AD also prohibits installing certain tail rotor duplex bearing housings and pitch change slider assemblies. These actions are specified in a European Union Aviation Safety Agency (EASA) AD, which is incorporated by reference. The FAA is issuing this AD to address the unsafe condition on these products.

# DATES:

This AD is effective October 21, 2024.

The Director of the Federal Register approved the incorporation by reference of a certain publication listed in this AD as of October 21, 2024.

# ADDRESSES:

*AD Docket:*                         You may examine the AD docket at                         *regulations.gov*                         under Docket No. FAA-2023-2238; 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.                    

*Material Incorporated by Reference:*
      - 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. 
      - 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. It is also available at regulations.gov                          under Docket No. FAA-2023-2238.                    

# FOR FURTHER INFORMATION CONTACT:

                        William McCully, Aviation Safety Engineer, FAA, International Validation Branch, FAA, 1600 Stewart Ave. Suite 410, Westbury, NY 11590; phone: (404) 474-5548; email:                         *william.mccully@faa.gov.*

# SUPPLEMENTARY INFORMATION:

## Background

EASA, which is the Technical Agent for the Member States of the European Union, has issued EASA AD 2023-0105, dated May 23, 2023 (EASA AD 2023-0105), to correct an unsafe condition on Leonardo S.p.A. Model A109C, A109E, A109K2, A109LUH, A109S, and AW109SP helicopters.

                    The FAA issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 by adding an AD that would apply to all Leonardo S.p.a. Model A109C, A109E, A109K2, A109S, and AW109SP helicopters. The NPRM published in the                     **Federal Register**                     on December 11, 2023 (88 FR 85856). The                           ( print page 75473)                        NPRM was prompted by reports of loose tail rotor duplex bearing locking nuts. Investigations identified incorrect accomplishment of the assembly and continued maintenance instructions of the tail rotor duplex bearing housing and slider group as the most likely root cause of that loosening. Accordingly, the NPRM proposed to require disassembling certain tail rotor duplex bearing housings and pitch change slider assemblies and reassembling them in accordance with updated procedures. The NPRM also proposed to prohibit installing certain tail rotor duplex bearing housings and pitch change slider assemblies. These actions are specified in EASA AD 2023-0105.                

The FAA is issuing this AD to detect and address the incorrect assembly of the tail rotor duplex bearing. This unsafe condition, if not addressed, could lead to failure of the tail rotor function, possibly resulting in loss of control of the helicopter. See EASA AD 2023-0105 for additional background information.

## Discussion of Final Airworthiness Directive

## Comments

The FAA received comments from one commenter, Air Methods. The following presents the comments received on the NPRM and the FAA's response to each comment.

## Comments Regarding Compliance With Updated Maintenance Procedures

                    Air Methods commented that, upon review of the ASB [alert service bulletin] and the existing MM [maintenance manual], changes to the MM appear to be relatively minor between the existing MM procedures and the updated maintenance procedures (defined in EASA AD 2023-0105 as “the updated procedure” and that are included in the alert service bulletins [1]                                          that are referenced for compliance). Air Methods also requested the FAA to advise of the reasoning behind the proposed AD requirement when the maintenance procedures should get updated to accurately reflect the new work steps and this area has a 180-day recurrent inspection.                

The FAA infers that Air Methods is requesting justification of the proposed requirement in the NPRM to replace an affected part, as defined in EASA AD 2023-0105, with a serviceable part, as defined in EASA AD 2023-0105, which may be done by following certain maintenance procedures to disassemble the affected part and updated maintenance procedures to reassemble the affected part, instead of allowing for accomplishment of anticipated updated maintenance procedures to address the unsafe condition without an AD. The FAA cannot require a manufacturer to revise its maintenance publications and, operators are subject to the specific manufacturer's maintenance procedures at time of delivery, which may vary. Therefore, to mandate specific procedures when an unsafe condition has been determined, the FAA must issue an AD to address and correct that unsafe condition. Lastly, compliance times in AD actions commonly specify multiple compliance time units to capture varying usage of the fleet and various factors related to the unsafe condition. The compliance time proposed by the NPRM to accomplish the replacement is within 100 hours time-in-service or 6 months, whichever occurs first. The purpose of the “within 100 hours time-in-service” compliance time unit is to capture high usage helicopters, which have an increased likeliness of occurrence of a failure, that a 180-day compliance time alone would not capture to an acceptable level of safety.

## Comments Regarding Compliance With Future Revisions of the Updated Maintenance Procedures

Air Methods stated that there are three levels of documents to comply with to accomplish the proposed AD; EASA AD 2023-0105, the ASB [alert service bulletins] (that are referred to as “the ASB” and referenced in EASA AD 2023-0105 for compliance), and MM [maintenance manual] (particularly, maintenance procedures, that are referenced in the alert service bulletins for compliance and are normally available in maintenance publications). Air Methods also stated that the proposed AD does not address future revisions of the updated maintenance procedures identified in EASA AD 2023-0105 (defined in EASA AD 2023-0105 as “the updated procedure”) and the alert service bulletins.

The NPRM proposed to require accomplishing the required actions and compliance times specified in EASA AD 2023-0105 with certain exceptions. Through that incorporation, the NPRM proposed to allow using future revisions of the maintenance procedures because EASA AD 2023-0105 defines “the updated procedure” by identifying certain revisions of the maintenance procedures for the applicable model helicopters and explicitly states “or later revisions;” and, the NPRM did not propose an exception to prohibit using later revisions of the updated maintenance procedures. The NPRM did not propose compliance with part II of the alert service bulletins.

Air Methods asked if the FAA intends to require an AD logbook signoff each time this area is disassembled/reassembled after the initial task compliance. Air Methods also asked if the signoff with the “the updated procedure” as identified in EASA AD 2023-0105, or later, is sufficient for future maintenance as it is impossible to forecast unplanned maintenance and the current version of the maintenance procedures would be used for this maintenance.

The requirements proposed in the NPRM do not require an AD logbook signoff each time the tail rotor duplex bearing housing or pitch change slider assembly are disassembled and reassembled. The NPRM proposed to require a one-time replacement, and compliance must be entered into the helicopter maintenance records in accordance with 14 CFR 43.9(a) and 91.417(a)(2)(v) for that one-time replacement. Thereafter, the NPRM proposed to prohibit installing any tail rotor duplex bearing housing part number (P/N) 109-0130-94-XXX and any pitch change slider assembly P/N 109-0130-91-XXX (with “XXX” representing any numerical sequence) that has been disassembled and (re)assembled in service using maintenance procedures issued prior to the updated procedure, as defined in EASA AD 2023-0105. There is no logbook entry for part installation prohibitions because the identified parts must not be installed on any helicopters.

## Additional Changes Since the NPRM Was Issued

                    Since the FAA issued the NPRM, two errors in EASA AD 2023-0105 have been identified. EASA AD 2023-0105 inadvertently omits “MM Paragraph 64-31-6 Rev. 6” (for certain serial-numbered Model A109K2 helicopters) in its definition of “the updated procedure” and inadvertently identifies the updated procedures as “(as referenced in Annex A of the ASB).”                           ( print page 75474)                        The FAA is correcting the omission by adding an exception to revise the definition of “the updated procedure” and is correcting the misidentification by adding an exception to replace that text with “(as referenced in Annex A or B of the ASB, as applicable).” These corrections are relieving as they reduce the population of “affected parts” as defined in EASA AD 2023-0105.                

## Conclusion

These helicopters have been approved by EASA and are approved for operation in the United States. Pursuant to the FAA's bilateral agreement with the European Union, EASA has notified the FAA about the unsafe condition described in its AD. The FAA reviewed the relevant data, considered the comments received, and determined that air safety requires adopting this AD as proposed. Accordingly, the FAA is issuing this AD to address the unsafe condition on these helicopters. Except for the changes described previously and minor editorial changes, this AD is adopted as proposed in the NPRM. None of the changes will increase the economic burden on any operator.

## Material Incorporated by Reference Under 1 CFR Part 51

EASA AD 2023-0105 requires replacing certain parts through the disassembly and reassembly of the tail rotor duplex bearing and the pitch change slider assembly. EASA AD 2023-0105 also prohibits installing certain parts on any helicopter.

                    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.                

## Differences Between This AD and the EASA

EASA AD 2023-0105 applies to Model A109LUH helicopters, whereas this AD does not because that model is not FAA type-certificated.

## Costs of Compliance

The FAA estimates that this AD affects 160 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 AD.

Disassembly and reassembly of the tail rotor housing and slider assembly will take approximately 8 work-hours for an estimated cost of $680 per helicopter and $108,800 for the U.S. fleet.

## 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

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

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

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

§ 39.13

2. The FAA amends § 39.13 by adding the following new airworthiness directive: 

**2024-15-11 Leonardo S.p.a.:**                             Amendment 39-22803; Docket No. FAA-2023-2238; Project Identifier MCAI-2023-00698-R.                        

## (a) Effective Date

This airworthiness directive (AD) is effective October 21, 2024.

## (b) Affected ADs

None.

## (c) Applicability

This AD applies to all Leonardo S.p.a. Model A109C, A109E, A109K2, A109S, and AW109SP helicopters, certificated in any category.

## (d) Subject

Joint Aircraft Service Component (JASC) Code: 6400, Tail Rotor System.

## (e) Unsafe Condition

This AD was prompted by reports of loose tail rotor duplex bearing locking nuts, possibly caused by improper installation. The FAA is issuing this AD to detect and address the incorrect assembly of the tail rotor duplex bearing. The unsafe condition, if not addressed, could lead to failure of the tail rotor function, possibly resulting in loss of 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 (EASA) AD 2023-0105, dated May 23, 2023 (EASA AD 2023-0105).

## (h) Exceptions to EASA AD 2023-0105

(1) Where EASA AD 2023-0105 defines the updated procedure as “Paragraph 64-30-3 Rev. 5 (for A109C helicopters), MM Paragraph 64-31-6 Rev. 16 (for A109E helicopters), MM Paragraph 64-30-5 Rev. 5 (for A109K2 helicopters), AM DM 64-31-10-00A-710A-B Issue 13 (for A109LUH helicopters) or AMP DM 0B-A-64-31-06-00A-710A-B Issue 13 (for A109S and AW109SP helicopters), as applicable, or later revisions;” for this AD, replace that text with “Paragraph 64-30-3 Rev. 5 (for A109C helicopters), MM Paragraph 64-31-6 Rev. 16 (for A109E helicopters), MM Paragraph 64-30-5 Rev. 5 or MM Paragraph 64-31-6 Rev. 6, as applicable (for A109K2 helicopters), or AMP DM 0B-A-64-31-06-00A-710A-B Issue 13 (for A109S and AW109SP helicopters), as applicable, or later revisions.”

(2) Where EASA AD 2023-0105 states “Annex A of the ASB;” for this AD, replace that text with “Annex A or B of the ASB, as applicable.”

(3) Where EASA AD 2023-0105 requires compliance in terms of flight hours, this AD requires using hours time-in-service.

                            (4) Where EASA AD 2023-0105 refers to its effective date, this AD requires using the effective date of this AD.                                  ( print page 75475)    

(5) Where the material referenced in EASA AD 2023-0105 specifies to “discard” parts; for this AD, replace that text with “remove from service.”

(6) This AD does not adopt the “Remarks” section of EASA AD 2023-0105.

## (i) No Reporting Requirement

Although the material referenced in EASA AD 2023-0105 specifies to submit certain information to the manufacturer, this AD does not include that requirement.

## (j) 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 (k) of this AD. Information may be emailed to:                             *9-AVS-AIR-730-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.

## (k) Related Information

                            For more information about this AD, contact William McCully, Aviation Safety Engineer, FAA, International Validation Branch, FAA, 1600 Stewart Ave., Suite 410, Westbury, NY 11590; phone: (404) 474-5548; email:                             *william.mccully@faa.gov.*

## (l) 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 this AD specifies otherwise.

(i) European Union Aviation Safety Agency (EASA) AD 2023-0105, dated May 23, 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-locationsoremailfr.inspection@nara.gov.*

Issued on September 10, 2024.

Victor Wicklund,

Deputy Director, Compliance & Airworthiness Division, Aircraft Certification Service.

# Footnotes

1.                             Leonardo Helicopters Alert Service Bulletin (ASB) No. 109-158, ASB No. 109EP-180, ASB No. 109K-076, ASB No. 109S-115, and ASB No. 109SP-154, each dated March 21, 2023, contain updated maintenance procedures (referenced as “Annex A” or “Annex B” in the ASBs, as applicable) for assembling the tail rotor housing and slider assembly. The updated maintenance procedures are MM Paragraph 64-30-3 Revision 5, MM Paragraph 64-31-6 Revision 16, MM Paragraph 64-30-5 Revision 5, MM Paragraph 64-31-6 Rev. 6, and AMP DM 0B-A-64-31-06-00A-710A-B Issue 13, as applicable. The identified ASBs are referenced in EASA AD 2023-0105 for compliance and will be available at                         *regulations.gov*                         under Docket No. FAA-2023-2238 after this FAA final rule is published.                    
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[FR Doc. 2024-20969 Filed 9-13-24; 8:45 am]

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