DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2024-1002; Project Identifier MCAI-2022-01574-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 adopt a new airworthiness directive (AD)
for all Airbus Helicopters Model AS350B, AS350BA, AS350B1, AS350B2,
AS350D, AS355E, AS355F, AS355F1, AS355F2, and AS355N helicopters. This
proposed AD was prompted by reports of debonding on the leading edge
protection of certain part-numbered main rotor blades (MRBs). This
proposed AD would require repetitively tap inspecting the MRB and,
depending on the results, taking corrective action. This proposed AD
would also prohibit installing an affected MRB on any helicopter unless
its requirements are met. These actions are specified in a European
Union Aviation Safety Agency (EASA) AD, which is proposed for
incorporation by reference. The FAA is proposing this AD to address the
unsafe condition on these products.

DATES: The FAA must receive comments on this proposed AD by May 31,
2024.

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-2024-1002; 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 EASA AD, any comments received, and
other information. The street address for Docket Operations is listed
above.
Material Incorporated by Reference:
For EASA material, contact EASA, Konrad-Adenauer-Ufer 3,
50668 Cologne, Germany; telephone +49 221 8999 000; email
ADs@easa.europa.eu. You may find the EASA material on the EASA website
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-2024-1002.
Other Related Service Information: For Airbus Helicopters service
information identified in this NPRM, 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 also view this
service information at the FAA contact information under Material
Incorporated by Reference above.

FOR FURTHER INFORMATION CONTACT: Dan McCully, Aviation Safety Engineer,
FAA, 1600 Stewart Ave., Suite 410, Westbury, NY 11590; telephone (404)
474-5548; email william.mccully@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 ADDRESSES. Include ``Docket No. FAA-2024-1002; Project Identifier
MCAI-2022-01574-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 Dan
McCully, Aviation Safety Engineer, FAA, 1600 Stewart Ave., Suite 410,
Westbury, NY 11590; telephone (404) 474-5548; email
william.mccully@faa.gov. Any commentary that the FAA receives that 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 2022-0246, dated December 12, 2022
(EASA AD 2022-0246), to correct an unsafe condition for all Airbus
Helicopters Model AS 350 B, AS 350 BA, AS 350 B1, AS 350 B2, AS 350 BB,
AS 350 D, AS 355 E, AS 355 F, AS 355 F1, AS 355 F2, and AS 355 N
helicopters.
This proposed AD was prompted by reports of debonding on the
stainless steel leading edge protection of certain part-numbered MRBs.
The FAA is proposing this AD to address the debonding of the MRB leading edge
protection. The unsafe condition, if not detected and corrected, could
lead to significant unbalance of the main rotor, a high level of
vibration, failure of the main rotor, failure of the main gearbox, and
subsequent loss of control of the helicopter.

Related Service Information Under 1 CFR Part 51

EASA AD 2022-0246 requires repetitively tap inspecting affected
MRBs and, depending on findings, either repairing or replacing the MRB.
For certain helicopters, EASA AD 2022-0246 prohibits installing an
affected MRB unless it is a serviceable part as defined within and is
inspected following installation. For other certain helicopters, EASA
AD 2022-0246 prohibits installing an affected MRB.
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.

Other Related Service Information

The FAA also reviewed Airbus Helicopters Alert Service Bulletin No.
AS350-05.01.07 and No. AS355-05.00.91, both Revision 0 and dated
December 6, 2022. This service information specifies procedures for tap
inspecting the stainless steel leading edge protection of the MRB and,
depending on the results, repairing or sending the MRB for repair to
Airbus Helicopters. The service information also specifies sending
certain information to Airbus Helicopters.

FAA's Determination

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 is proposing this AD
after evaluating all known relevant information and determining that
the unsafe condition described previously is likely to exist or develop
on other helicopters of these same type designs.

Proposed AD Requirements in This NPRM

This proposed AD would require accomplishing the actions specified
in EASA AD 2022-0246, 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 EASA AD.''

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 2022-0246 by reference in the FAA
final rule. This proposed AD would, therefore, require compliance with
EASA AD 2022-0246 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 2022-0246 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 2022-
0246. Service information referenced in EASA AD 2022-0246 for
compliance will be available at regulations.gov under Docket No. FAA-
2024-1002 after the FAA final rule is published.

Differences Between This Proposed AD and the EASA AD

EASA AD 2022-0246 applies to Model AS350BB helicopters, whereas
this proposed AD would not because that model is not FAA-type
certificated.

Costs of Compliance

The FAA estimates that this AD, if adopted as proposed, would
affect 405 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.
Tap inspecting affected MRBs for disbonding would take up to
approximately 1 work-hour (up to three MRBs per helicopter) for an
estimated cost of up to $85 per helicopter and $34,425 for the U.S.
fleet, per inspection cycle. Replacing a blade would take approximately
6 work-hours and parts would cost up to approximately $84,000 for an
estimated cost of up to $84,510 per MRB. The FAA has no data to
determine the cost of or the number of helicopters that might need the
MRB repaired.

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(g), 40113, 44701.

Sec. 39.13 [Amended]

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