[Federal Register Volume 90, Number 240 (Wednesday, December 17, 2025)]
[Proposed Rules]
[Pages 58515-58518]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2025-23103]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2025-5389; Project Identifier MCAI-2024-00716-R]
RIN 2120-AA64
Airworthiness Directives; Airbus Helicopters
AGENCY: Federal Aviation Administration (FAA), DOT.
ACTION: Notice of proposed rulemaking (NPRM).
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SUMMARY: The FAA proposes to supersede Airworthiness Directive (AD)
2020-09-15, which applies to certain Airbus Helicopters Model AS332C,
AS332C1, AS332L, and AS332L1 helicopters. AD 2020-09-15 requires
removing the removable parts of the dual hoist installation or removing
the de-icing system and allows, for certain helicopters, revising the
rotorcraft flight manual (RFM) for the helicopter and installing a
placard as an optional method of compliance. Since the FAA issued AD
2020-09-15, analysis revealed that additional vibration level
measurements are necessary. This proposed AD would retain all the
requirements of AD 2020-09-15 and would require for certain helicopters
repetitively measuring vibration levels in-flight, and depending on the
results, performing corrective actions. The FAA is proposing this AD to
address the unsafe condition on these products.
DATES: The FAA must receive comments on this NPRM by February 2, 2026.
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-2025-5389; 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 Airbus Helicopters material identified in this AD,
contact Airbus Helicopters, 2701 North Forum Drive, Grand Prairie, TX
75052; phone: (972) 641-0000 or (800) 232-0323; fax: (972) 641-3775; or
at airbus.com/en/products-services/helicopters/hcare-services/airbusworld.
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
regulations.gov under Docket No. FAA-2025-5389.
FOR FURTHER INFORMATION CONTACT: Matthew Williams, Aviation Safety
Engineer, FAA, 1600 Stewart Avenue, Suite 410, Westbury, NY 11590;
phone: (316) 946-4134; email: [email protected].
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-2025-5389;
Project Identifier MCAI-2024-00716-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 the 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
[[Page 58516]]
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 Matthew Williams, Aviation
Safety Engineer, FAA, 1600 Stewart Avenue, Suite 410, Westbury, NY
11590. Any commentary that the FAA receives which is not specifically
designated as CBI will be placed in the public docket for this
rulemaking.
Background
The FAA issued AD 2020-09-15, Amendment 39-19911 (85 FR 30589, May
20, 2020) (AD 2020-09-15), for Airbus Helicopters Model AS332C,
AS332C1, AS332L, and AS332L1 helicopters equipped with a dual hoist
installation and de-icing system, except those that have Airbus
Helicopters modification 0722907 installed in production. AD 2020-09-15
was prompted by an MCAI originated by the European Union Aviation
Safety Agency (EASA), which is the Technical Agent for the Member
States of the European Union. EASA issued AD 2018-0142R1, dated
December 9, 2019 (EASA AD 2018-0142R1) to address vibrations around the
12Hz frequency. EASA AD 2018-0142R1 states that during the first flight
of an Airbus Helicopters Model AS332L helicopter after a retrofit that
re-installed the deicing system, vibrations around the 12Hz frequency
were observed. Subsequent flight tests and analysis determined that
this vibration is due to the specific helicopter configuration. Factors
that contributed to the vibration included simultaneous installation of
riveted main frames X3855 and X5295 (pre-Airbus Helicopter modification
0722907), additional weight created by parts of the rotor de-icing
system on the main rotor head (the distributor and de-icing harnesses),
and removable parts (hoist arm and hoists) of the dual hoist
installation.
AD 2020-09-15 requires removing the removable parts of the dual
hoist installation or removing the de-icing system, and allows, for
certain helicopters, revising the RFM for the helicopter and installing
a placard as an optional method of compliance. The FAA issued AD 2020-
09-15 to address vibrations around the 12Hz frequency. The unsafe
condition, if not addressed, could generate divergent aeromechanic
coupling between the helicopter structure and the rotor, possibly
resulting in mechanical failure of structural parts and loss of control
of the helicopter.
Actions Since AD 2020-09-15 Was Issued
Since the FAA issued AD 2020-09-15, EASA issued EASA AD 2024-0100,
dated May 10, 2024 (EASA AD 2024-0100), which superseded EASA AD 2018-
0142R1. EASA AD 2024-0100 stated that the same occurrence of the 12Hz
vibratory condition was reported on a helicopter with Airbus
Helicopters modification 0722907 embodied and that it was necessary for
all helicopters with this modification to measure vibrations in-flight,
interpret the results, and depending on the results, send the vibration
levels to Airbus Helicopters or modify the helicopter configuration.
After EASA issued EASA AD 2024-0100, EASA superseded EASA AD 2024-
0100 and issued EASA AD 2024-0233, dated December 5, 2024 (EASA AD
2024-0233) (also referred to as the MCAI). The MCAI states that since
EASA AD 2024-0100 was issued, it was determined that further vibration
level measurements were necessary after performing certain maintenance
tasks. The MCAI further states that EASA AD 2024-0233 is considered to
be an interim action.
This condition, if not addressed, could generate divergent
aeromechanic coupling between the helicopter structure and the rotor,
possibly resulting in mechanical failure of structural parts and loss
of control of the helicopter.
You may examine the MCAI in the AD docket at regulations.gov under
Docket No. FAA-2025-5389.
Material Incorporated by Reference Under 1 CFR Part 51
The FAA reviewed Airbus Helicopters Alert Service Bulletin AS332-
04-00-0001 Issue 002, dated December 4, 2024 (ASB AS332-04-00-0001),
which specifies procedures for installing the accelerometer in the
cockpit of the helicopter, repetitively inspecting the vibration level
at 12 Hz each time a specific maintenance task is completed, and
interpreting the results. Depending on the results of this inspection,
ASB AS332-04-00-0001 specifies procedures for corrective actions, which
include changing the configuration by either removing the dual hoist
system or removing the de-icing harness and contacting Airbus
Helicopters for further instructions.
This proposed AD would also require Airbus Helicopters Emergency
Alert Service Bulletin (EASB) No. 01.00.91 Revision 1 (EASB 01.00.91
Rev 1) for Model AS332C, and AS332C1 helicopters, and EASB No. 01.00.96
Revision 0 (EASB 01.00.96) for Model AS332L and AS332L1 helicopters,
both dated December 4, 2019. EASB 01.00.91 Rev 1 specifies procedures
for removing parts of the dual hoist installation or removing the de-
icing system. EASB 01.00.96 describes procedures for amending the RFM
of Airbus Helicopters Model AS332L and AS332L1 helicopters to limit the
flight envelope and the Vne and installing a placard. EASB 01.00.96
also describes procedures for removing parts of the dual hoist
installation or removing the de-icing system. The Director of the
Federal Register approved EASB 01.00.91 Rev 1 and EASB 01.00.96 for
incorporation by reference as of May 20, 2020 (85 FR 30589, May 20,
2020).
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
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 the same type design.
Proposed AD Requirements in This NPRM
This proposed AD would retain all the requirements of AD 2020-09-15
and would require repetitively measuring the vibration level,
interpreting the results, and depending on the results, removing
certain parts and further inspections. This proposed AD would also
allow an alternative to removing parts by placing a placard and
revising the RFM for the helicopter.
Measuring the vibration levels in-flight and revising the existing
RFM for the helicopter may be performed by the owner/operator (pilot)
holding at least a private pilot certificate and must be entered into
the aircraft records showing compliance with this action in accordance
with 14 CFR 43.9(a) and 91.417(a)(2)(v). The pilot may perform these
actions because they only involve recording data in-flight and revising
the existing RFM by inserting pages, which are not considered
maintenance actions. This proposed AD would also prohibit installing
the de-icing system and the
[[Page 58517]]
dual hoist unless certain requirements are accomplished.
Interim Action
The FAA considers that this proposed AD would be an interim action.
If final action is later identified, the FAA might consider further
rulemaking.
Costs of Compliance
The FAA estimates that this AD, if adopted as proposed, would
affect five helicopters of U.S. registry.
The FAA estimates the following costs to comply with this proposed
AD.
Estimated Costs
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Cost on U.S.
Action Labor cost Parts cost Cost per product operators
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Remove the removable parts of the 12 work-hours x $85 $0 $1,020..................... $5,100
dual hoist. per hour = $1,020
per helicopter.
Remove the de-icing system....... 12 work-hours x $85 0 $1,020..................... 5,100
per hour = $1,020
per helicopter.
Measure vibrations to include 7 work-hours x $85 0 $595 per cycle............. 2,975
interpreting results. per hour = $595.
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The FAA estimates the following costs to do any repairs/
replacements that would be required based on the results of the
inspection. The agency has no way of determining the number of
helicopters that might need these repairs or replacements:
On-Condition Costs
----------------------------------------------------------------------------------------------------------------
Action Labor cost Parts cost Cost per product
----------------------------------------------------------------------------------------------------------------
Revise the RFM............................. 1 work-hour x $85 per hour = $85.. $0 $85
Install a placard.......................... 1 work-hour x $85 per hour = $85.. 0 85
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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 that the 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
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:
0
a. Removing Airworthiness Directive 2020-09-15, Amendment 39-19911 (85
FR 30589, May 20, 2020); and
0
b. Adding the following new airworthiness directive:
Airbus Helicopters: Docket No. FAA-2025-5389; Project Identifier
MCAI-2024-00716-R.
(a) Comments Due Date
The FAA must receive comments on this airworthiness directive
(AD) by February 2, 2026.
(b) Affected ADs
This AD replaces AD 2020-09-15, Amendment 39-19911 (85 FR 30589,
May 20, 2020).
(c) Applicability
This AD applies to Airbus Helicopters Model AS332C, AS332C1,
AS332L, and AS332L1 helicopters, certificated in any category,
equipped with a dual hoist installation and de-icing system.
(d) Subject
Joint Aircraft System Component (JASC) Code 1810, Helicopter
vibration analysis.
(e) Unsafe Condition
This AD was prompted by a report of vibrations around the 12 Hz
frequency due to the specific helicopter configuration and
determination that additional vibration level measurements are
necessary. The FAA is issuing this AD to prevent divergent
aeromechanic coupling between the helicopter structure and rotor.
The unsafe condition, if not addressed, could result in mechanical
failure of structural parts and consequent loss of control of the
helicopter.
(f) Compliance
Comply with this AD within the compliance times specified,
unless already done.
[[Page 58518]]
(g) Required Actions
(1) For helicopters without Airbus Helicopters modification
0722907 installed, within 7 days after May 20, 2020 (the effective
date of AD 2020-09-15): Remove the removable parts of the dual hoist
installation or remove the de-icing system in accordance with the
instructions of section 3.B of Airbus Helicopters Emergency Alert
Service Bulletin (EASB) AS332 01.00.91, Revision 1, dated December
4, 2019 (EASB AS32 01.00.91 Rev 1), or Section 3.B.2 of Airbus
Helicopters EASB AS332 01.00.96, Revision 0, dated December 4, 2019
(EASB AS332 01.00.96), as applicable to the helicopter, except you
are not required to contact Airbus Helicopters.
(2) For helicopters with Airbus Helicopters modification 0722907
installed, within 110 hours time-in-service (TIS) or 30 days
whichever occurs first after the effective date of this AD and
thereafter, during the first flight after each time any of the
maintenance tasks identified in the COMPLIANCE: MANDATORY section of
Airbus Helicopters Alert Service Bulletin (ASB) AS332-04-00-0001
Issue 002, dated December 4, 2024 (ASB AS332-04-00-0001) is
accomplished, perform a vibration level measurement.
(i) With the accelerometer already installed, check the
measurement of the vibration level in-flight, at 12 Hz by following
figure 1 to paragraph (g)(2)(i) of this AD. The owner/operator
(pilot) holding at least a private pilot certificate may perform
this check and must enter compliance with these paragraphs into the
helicopter maintenance records in accordance with 14 CFR 43.9(a) and
91.417(a)(2)(v). The record must be maintained as required by 14 CFR
91.417, 121.380, or 135.439.
Figure 1 to Paragraph (g)(2)(i)--Method of Measurement
[GRAPHIC] [TIFF OMITTED] TP17DE25.076
(ii) Interpret the results in accordance with the instructions
in Section 4.4 of ASB AS332-04-00-0001 except you are not required
to send any information to Airbus Helicopters. If the vibration
level between 11.7 Hz and 12.7 Hz is more than 0.08g (0.40 IPS),
before further flight, revise the helicopter configuration by
removing the dual hoist system or removing the blade de-icing
harnesses in accordance with instructions of section 4.5 through
4.5.2.1 of ASB AS332-04-00-0001.
(h) Optional Method of Compliance
For helicopters without Airbus Helicopters modification 0722907
installed: Revising the rotorcraft flight manual for your helicopter
by inserting the information specified in Appendix 4A, 4B, or 4C of
EASB AS332 01-00.96, as applicable to your helicopter model and
configuration, and installing a locally made placard on the
instrument panel, in accordance with the instructions of section
3.B.1 of EASB AS332 01-00.96, is an acceptable method for compliance
with the requirements of paragraph (g)(1) of this AD.
(i) 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 responsible Flight
Standards 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 (j) of this AD and
email to: [email protected].
(2) Before using any approved AMOC, notify your appropriate
principal inspector, or lacking a principal inspector, the manager
of the responsible Flight Standards Office.
(j) Additional Information
For more information about this AD, contact Matthew Williams,
Aviation Safety Engineer, FAA, 1600 Stewart Avenue, Suite 410,
Westbury, NY 11590; phone: (316) 946-4134; email:
[email protected].
(k) Material Incorporated by Reference
(1) The Director of the Federal Register approved the
incorporation by reference (IBR) 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.
(3) The following material was approved for IBR on [DATE 35 DAYS
AFTER PUBLICATION OF THE FINAL RULE].
(i) Airbus Helicopters Alert Service Bulletin AS332-04-00-0001
Issue 002, dated December 4, 2024.
(ii) [Reserved]
(4) The following material was approved for IBR on May 20, 2020,
(85 FR 30589, May 20, 2020).
(i) Airbus Helicopters Emergency Alert Service Bulletin No.
01.00.91 Revision 1, dated December 4, 2019.
(ii) Airbus Helicopters Emergency Alert Service Bulletin No.
01.00.96 Revision 0, dated December 4, 2019.
(5) For Airbus material identified in this AD, contact Airbus
Helicopters, 2701 North Forum Drive, Grand Prairie, TX 75052; phone:
(972) 641-0000 or (800) 232-0323; fax: (972) 641-3775; or at
airbus.com/en/products-services/helicopters/hcare-services/airbusworld.
(6) 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.
(7) 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 [email protected].
Issued on December 12, 2025.
Steven W. Thompson,
Acting Deputy Director, Compliance & Airworthiness Division, Aircraft
Certification Service.
[FR Doc. 2025-23103 Filed 12-16-25; 8:45 am]
BILLING CODE 4910-13-P