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Rule2025-22217

Airworthiness Directives; Airbus Helicopters Deutschland GmbH

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Published

December 8, 2025

Effective

January 12, 2026

Issuing agencies

Transportation DepartmentFederal Aviation Administration

Abstract

The FAA is adopting a new airworthiness directive (AD) for all Airbus Helicopters Deutschland GmbH Model MBB-BK 117 C-2 and MBB-BK 117 D-2 helicopters. This AD was prompted by reports of significant wear of the spherical bearings of the control rod assembly and pitch link assembly. This AD requires measuring the radial play of certain spherical bearings of control rod assemblies and pitch link assemblies, reporting the results, and depending on the results, taking corrective action. This AD also prohibits installing certain control rod assemblies and pitch link assemblies unless certain requirements are met. The FAA is issuing this AD to address the unsafe condition on these products.

Full Text

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<title>Federal Register, Volume 90 Issue 233 (Monday, December 8, 2025)</title>
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[Federal Register Volume 90, Number 233 (Monday, December 8, 2025)]
[Rules and Regulations]
[Pages 56663-56666]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 2025-22217]

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2025-0214; Project Identifier MCAI-2024-00391-R;
Amendment 39-23099; AD 2025-16-02]
RIN 2120-AA64

Airworthiness Directives; Airbus Helicopters Deutschland GmbH

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
Airbus Helicopters Deutschland GmbH Model MBB-BK 117 C-2 and MBB-BK 117
D-2 helicopters. This AD was prompted by reports of significant wear of
the spherical bearings of the control rod assembly and pitch link
assembly. This AD requires measuring the radial play of certain
spherical bearings of control rod assemblies and pitch link assemblies,
reporting the results, and depending on the results, taking corrective
action. This AD also prohibits installing certain control rod
assemblies and pitch link assemblies unless certain requirements are
met. The FAA is issuing this AD to address the unsafe condition on
these products.

DATES: This AD is effective January 12, 2026.
The Director of the Federal Register approved the incorporation by
reference of a certain publication listed in this AD as of January 12,
2026.

ADDRESSES:
AD Docket: You may examine the AD docket at <a href="http://regulations.gov">regulations.gov</a> under
Docket No. FAA-2025-0214; 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, the mandatory continuing airworthiness
information (MCAI), 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:
<bullet> For European Union Aviation Safety Agency (EASA) material
identified in this AD, contact EASA, Konrad-Adenauer-Ufer 3, 50668
Cologne, Germany; phone: +49 221 8999 000; email: <a href="/cdn-cgi/l/email-protection#7f3e3b0c3f1a1e0c1e511a0a0d100f1e511a0a">[email&#160;protected]</a>;
website: easa.europa.eu. You may find the EASA material on the EASA
website at ad.easa.europa.eu.
<bullet> 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. It is also available at
<a href="http://regulations.gov">regulations.gov</a> under Docket No. FAA-2025-0214.

FOR FURTHER INFORMATION CONTACT: Michael Mueller, Aviation Safety
Engineer, FAA, 1600 Stewart Avenue Suite 410, Westbury, NY 11590;
phone: (847) 294-7543; email: <a href="/cdn-cgi/l/email-protection#660b0f050e07030a480c480b13030a0a03142600070748010910">[email&#160;protected]</a>.

SUPPLEMENTARY INFORMATION:

Background

The FAA issued a notice of proposed rulemaking (NPRM) to amend 14
CFR part 39 by adding an AD that would apply to all Airbus Helicopters
Deutschland GmbH Model MBB-BK 117 C-2 and MBB-BK 117 D-2 helicopters.
The NPRM was published in the Federal Register on February 26, 2025 (90
FR 10705). The NPRM was prompted by AD 2024-0131, dated July 8, 2024
(EASA AD 2024-0131) (also referred to as the MCAI), issued by EASA,
which is the Technical Agent for the Member States of the European
Union. The MCAI states there have been reports of significant wear of
the spherical bearings of control rod assemblies and pitch link
assemblies having part number 105-13122, B623M3001101, D623M3201101, or
D623M3201102. This condition, if not detected and corrected, could lead
to erroneous pitch and oscillations of the main rotor blades and
consequent loss of control of the helicopter.
In the NPRM, the FAA proposed to require measuring the radial play
of certain spherical bearings of control rod assemblies and pitch link
assemblies, reporting the results, and depending on the results, taking
corrective action. The NPRM also prohibited installing certain control
rod assemblies and pitch link assemblies unless certain requirements
are met. The FAA is issuing this AD to address the unsafe condition on
these products.
You may examine the MCAI in the AD docket at <a href="http://regulations.gov">regulations.gov</a> under
Docket No. FAA-2025-0214.

Discussion of Final Airworthiness Directive

Comments

The FAA received comments from two commenters. The commenters were
an individual and the Air Medical Mechanics Organization (AMMO). The
individual commenter expressed support for the proposed AD as written.
The following presents the comments received on the NPRM and the FAA's
response to the comments.

Request To Incorporate Requirements Directly Into the AD

AMMO commented that the practice of relying on manufacturer-issued
and foreign regulatory documents that are not fully integrated into the
rule text creates ambiguity, enforcement concerns, and procedural
noncompliance under Section 14 of the Code of Federal Regulations (14
CFR) Part 39 and the Administrative Procedure Act. The commenter
requested that the FAA incorporate the complete inspection method,
measurable thresholds, and response actions directly into the AD text.
The commenter also requested that the FAA provide FAA-originated
inspection criteria and field-level illustrations.
The FAA disagrees with the request. 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 ADs as the primary source of
information for compliance with requirements for corresponding FAA ADs.
This AD incorporates EASA AD 2024-0131 by reference. Incorporation by
reference (IBR) allows Federal agencies to comply with the requirement
to publish rules in the Federal Register by referring to materials
already published elsewhere. The legal effect of IBR is that the

[[Page 56664]]

material is treated as if it were published in the Federal Register.
This AD would, therefore, require compliance with EASA AD 2024-0131 in
its entirety through that incorporation, except for any differences
identified as exceptions in the regulatory text of this AD. The
complete inspection method, measurable thresholds, and corrective
actions are included in EASA AD 2024-0131 and the material referenced
in EASA AD 2024-0131. Material referenced in EASA AD 2024-0131 for
compliance will be available at <a href="http://regulations.gov">regulations.gov</a> under Docket No. FAA-
2025-0214. This material, like any other properly issued rule, has the
force and effect of law, thus preventing any ambiguity, enforcement
concerns, and procedural noncompliance issues under 14 CFR 39 and the
Administrative Procedure Act. In addition, Congress authorized IBR in
the Freedom of Information Act (5 U.S.C. 552), in part, to reduce the
volume of material published in the Federal Register and the CFR. The
FAA has not changed this AD in this regard.

Request To Provide Standardized Terminology

AMMO stated that certain words used in the EASA AD and the material
referenced in the EASA AD are ambiguous and not standardized FAA
terminology. It requested that the FAA provide standardized FAA
terminology for field-observed symptoms such as ``play'' or
``clicking.''
The FAA agrees that there could be certain words in the EASA AD and
the material referenced in the EASA AD that are ambiguous. In these
instances, the FAA writes exceptions to eliminate such ambiguity. For
example, the term ``play,'' specified in EASA AD 2024-0131, is
subjective. In paragraph (h)(2) of this AD, the FAA specifies that this
AD does not adopt paragraph (1) and (2) of EASA AD 2024-0131. This
exception removes the ambiguous term ``play'' from the requirements of
this AD. In addition, in paragraph (h)(2) of this AD the FAA requires
measurement of the radial play of the two spherical bearings of each
affected part. The service bulletin then specifies actions based on the
radial play measurements. By requiring these measurements, the term
``play'' is unambiguous in this AD. The term ``clicking'' referenced in
the service bulletin is not part of the required actions. The FAA has
not changed this AD in this regard.

Request for Alternate Means of Reporting

AMMO claimed that a line mechanic cannot be expected to navigate
Original Equipment Manufacturer (OEM) reporting portals and requested
that the FAA avoid exclusive reliance on OEM digital platforms for
compliance reporting in the proposed AD.
The FAA disagrees with the request. EASA AD 2024-0131 identifies
the on-line questionnaire referenced in the Alert Service Bulletin
(ASB) as an acceptable method to comply with the reporting requirement,
but it does not specify that it is the only acceptable method to comply
with the reporting requirement. EASA AD 2024-0131 provides the website
address for Airbus Helicopters Deutschland GmbH, which identifies
contact information for the appropriate service area. The FAA has not
changed this AD in this regard.

Request To Coordinate With Flight Standards Field Personnel

AMMO stated that the FAA did not coordinate with Flight Standards
field personnel to validate the AD's practical executability, as
required by FAA's internal policy. The commenter suggested that the FAA
coordinate the proposed AD with Flight Standards to validate the AD's
practical executability.
The FAA disagrees with the implication that Flight Standards did
not review the proposed AD. The FAA coordinates all AD actions with the
appropriate Flight Standards Office before issuance. The FAA has not
changed this AD in this regard.

Request To Ensure All Referenced Documents Are Available

AMMO stated that EASA AD 2024-0131 and Airbus ASB MBB-BK117-62-33-
0001 are not FAA-certified documents and are therefore subject to
unilateral revision by external entities, not docketed for permanent
public access, and inaccessible without subscriptions or OEM login
credentials. The commenter requested that the FAA ensure that all
referenced documents are docketed, publicly accessible, and version-
locked.
The FAA disagrees with the commenter's statements about the
referenced material. The FAA reviewed EASA AD 2024-0131 and Airbus ASB
MBB-BK117-62-33-0001 before issuing the NPRM and found them to be
acceptable and locked. After this final rule is published, EASA AD
2024-0131 and the referenced material specified in EASA AD 2024-0131
that is required for compliance will be docketed and publicly
accessible as they will be able to be found at <a href="http://regulations.gov">regulations.gov</a> by
locating Docket No. FAA 2025-0214. Additionally, as stated in the NPRM,
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. The FAA has not changed this
AD in this regard.

Conclusion

These products have been approved by the civil 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, that authority has notified the FAA of the unsafe condition
described in the MCAI referenced above. The FAA reviewed the relevant
data, considered any 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 products. Except for
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

The FAA reviewed EASA AD 2024-0131, which specifies procedures for
a one-time inspection of the spherical bearings of the control rod
assemblies and pitch link assemblies for radial play and, depending on
the results, measuring the radial play of the spherical bearings of the
control rod assembly and pitch link assembly. Depending on the
measurement results, EASA AD 2024-0131 specifies replacing the control
rod end and reporting all measurement results to AH (Airbus
Helicopters). 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 MCAI

This AD does not require inspecting the spherical bearings of the
control rod assemblies and pitch link assemblies for play as specified
in the MCAI since that action is subjective and could vary from
mechanic to mechanic. Instead, this AD requires measuring the radial
play of the spherical bearings of the control rod assembly and pitch
link assembly. This AD also prohibits installing an affected control
rod assembly or pitch link assembly unless the radial play of the
assembly's two spherical bearings is measured and the radial play of
each spherical bearing is equal to or less than 0.10 mm, whereas the
MCAI does not require that installation limitation.

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Interim Action

The FAA considers that this AD is an interim action. If final
action is later identified, the FAA might consider further rulemaking
then.

Costs of Compliance

The FAA estimates that this AD affects 180 helicopters of U.S.
registry. Labor costs are estimated at $85 per hour. Based on these
numbers, the FAA estimates the following costs to comply with this AD.
Measuring the axial play takes 1 work-hour and reporting the
results takes 1 work-hour, for an estimated cost of $170 per helicopter
and $30,600 for the U.S. fleet. If required, replacing a control rod or
pitch link assembly takes 1 work-hour and parts cost $1,650 for an
estimated cost of $1,735 per control rod or pitch link assembly
replacement.

Paperwork Reduction Act

A federal agency may not conduct or sponsor, and a person is not
required to respond to, nor shall a person be subject to a penalty for
failure to comply with a collection of information subject to the
requirements of the Paperwork Reduction Act unless that collection of
information displays a currently valid OMB Control Number. The OMB
Control Number for this information collection is 2120-0056. Public
reporting for this collection of information is estimated to take
approximately 1 hour per response, including the time for reviewing
instructions, searching existing data sources, gathering and
maintaining the data needed, and completing and reviewing the
collection of information. All responses to this collection of
information are mandatory. Send comments regarding this burden estimate
or any other aspect of this collection of information, including
suggestions for reducing this burden, to: Information Collection
Clearance Officer, Federal Aviation Administration, 10101 Hillwood
Parkway, Fort Worth, TX 76177-1524.

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

0
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]

0
2. The FAA amends Sec. 39.13 by adding the following new airworthiness
directive:

2025-16-02 Airbus Helicopters Deutschland GmbH: Amendment 39-23099;
Docket No. FAA-2025-0214; Project Identifier MCAI-2024-00391-R.

(a) Effective Date

This airworthiness directive (AD) is effective January 12, 2026.

(b) Affected ADs

None.

This AD applies to Airbus Helicopters Deutschland GmbH Model
MBB-BK 117 C-2 and MBB-BK 117 D-2 helicopters, certificated in any
category.
Note 1 to paragraph (c): Helicopters with an MBB-BK 117 C-2e
designation are Model MBB-BK 117 C-2 helicopters.

(d) Subject

Joint Aircraft System Component (JASC) Code 6230, Main Rotor
Mast/Swashplate.

(e) Unsafe Condition

This AD was prompted by reports of significant wear of the
spherical bearings of the control rod assembly and pitch link
assembly. The FAA is issuing this AD to detect and address wear of
the spherical bearings of the control rod assembly and pitch link
assembly. The unsafe condition, if not addressed, could result in
erroneous pitch and oscillations of the main rotor blades, and
consequent 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 paragraph (h) of this AD: Comply with all
required actions and compliance times specified in, and in
accordance with, European Union Aviation Safety Agency AD 2024-0131,
dated July 8, 2024 (EASA AD 2024-0131).

(h) Exceptions to EASA AD 2024-0131

(1) Where EASA AD 2024-0131 requires compliance in terms of
flight hours, this AD requires using hours time-in-service.
(2) Instead of complying with paragraphs (1) and (2) of EASA AD
2024-0131, within 100 hours time-in-service after the effective date
of this AD, measure the radial play of the two spherical bearings of
each affected part, as defined in EASA AD 2024-0131, in accordance
with the instructions of the ASB, as defined in EASA AD 2024-0131.
(3) Where paragraph (5) of EASA AD 2024-0131 specifies reporting
measurement results to AH (Airbus Helicopters) within a certain
compliance time, for this AD, report those measurement results at
the applicable time specified in paragraph (h)(3)(i) or (ii) of this
AD.
(i) If the measurement was done on or after the effective date
of this AD: Submit the report within 30 days after the measurement.
(ii) If the inspection was done before the effective date of
this AD: Submit the report within 30 days after the effective date
of this AD.
(4) This AD does not adopt the ``Remarks'' section of EASA AD
2024-0131.

(i) Parts Installation Limitation

As of the effective date of this AD, do not install an affected
part, as defined in EASA AD 2024-0131, on any helicopter unless the
radial play of the two spherical bearings of that affected part is
measured by following the actions required by paragraph (2) of EASA
AD 2024-0131 and the radial play of each spherical bearing is equal
to or less than 0.10 mm.

(j) Alternative Methods of Compliance (AMOCs)

(1) The Manager, International Validation Branch, FAA, has the
authority to approve

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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 and email to:
<a href="/cdn-cgi/l/email-protection#c1808c8e8281a7a0a0efa6aeb7">[email&#160;protected]</a>.
(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) Additional Information

For more information about this AD, contact Michael Mueller,
Aviation Safety Engineer, FAA, 1600 Stewart Avenue, Suite 410,
Westbury, NY 11590; phone: (847) 294-7543; email:
<a href="/cdn-cgi/l/email-protection#91fcf8f2f9f0f4fdbffbbffce4f4fdfdf4e3d1f7f0f0bff6fee7">[email&#160;protected]</a>.

(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 the AD specifies otherwise.
(i) European Union Aviation Safety Agency (EASA) AD 2024-0131,
dated July 8, 2024.
(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: <a href="/cdn-cgi/l/email-protection#6e2f2a1d2e0b0f1d0f400b1b1c011e0f400b1b">[email&#160;protected]</a>; website: easa.europa.eu. You may
find this 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 Parkway, 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 <a href="http://www.archives.gov/federal-register/cfr/ibr-locations">www.archives.gov/federal-register/cfr/ibr-locations</a> or email <a href="/cdn-cgi/l/email-protection#7e180c5017100d0e1b1d0a1711103e101f0c1f50191108">[email&#160;protected]</a>.

Issued on November 19, 2025.
Steven W. Thompson,
Acting Deputy Director, Compliance & Airworthiness Division, Aircraft
Certification Service.
[FR Doc. 2025-22217 Filed 12-5-25; 8:45 am]
BILLING CODE 4910-13-P

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