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

Airworthiness Directives; Leonardo S.p.a. Helicopters

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule.

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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 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.

\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.

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)."

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.

Sec. 39.13 [Amended]

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