[Federal Register Volume 90, Number 64 (Friday, April 4, 2025)]
[Rules and Regulations]
[Pages 14723-14726]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2025-05781]


-----------------------------------------------------------------------

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2024-2419; Project Identifier MCAI-2023-00366-R; 
Amendment 39-22992; AD 2025-06-04]
RIN 2120-AA64


Airworthiness Directives; Airbus Helicopters

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule.

-----------------------------------------------------------------------

SUMMARY: The FAA is adopting a new airworthiness directive (AD) for all 
Airbus Helicopters (Airbus) Model AS350B, AS350B1, AS350B2, AS350B3, 
AS350BA, AS350D, AS355E, AS355F, AS355F1, AS355F2, AS355N, AS355NP, 
EC130B4, and EC130T2 helicopters. This AD was prompted by a 
manufacturer assessment that determined additional actions are 
necessary to improve particle detection for main gearboxes (MGBs) with 
certain planet gear bearings installed. This AD requires repetitively 
inspecting the MGB bevel wheel and the MGB magnetic plug for particles 
and prohibits installing an affected MGB unless certain requirements 
are met. 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 May 9, 2025.
    The Director of the Federal Register approved the incorporation by 
reference of a certain publication listed in this AD as of May 9, 2025.

ADDRESSES: 
    AD Docket: You may examine the AD docket at regulations.gov under 
Docket No. FAA-2024-2419; 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 EASA AD, 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: [email protected]. 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 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-2024-2419.

FOR FURTHER INFORMATION CONTACT: Dan McCully, Aviation Safety Engineer, 
FAA, 1600 Stewart Avenue, Suite 410, Westbury, NY 11590; phone: (404) 
474-5548; email: [email protected].

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 Model 
AS350B, AS350B1, AS350B2, AS350B3, AS350BA, AS350D, AS355E, AS355F, 
AS355F1, AS355F2, AS355N, AS355NP, EC130B4, and EC130T2 helicopters. 
The NPRM published in the Federal Register on November 5, 2024 (89 FR 
87821). The NPRM was prompted by EASA AD 2023-0044, dated February 28, 
2023, (EASA AD 2023-0044), issued by EASA, which is the Technical Agent 
for the Member States of the European Union. EASA advises that after a 
fleet design review for detection of particles in the MGB, it was 
determined that additional maintenance actions are necessary to improve 
detection of particles in the MGB.
    In the NPRM, the FAA proposed to require repetitively inspecting 
the MGB bevel wheel for the presence of particles, repetitively 
inspecting the MGB magnetic plug for particles, close monitoring of the 
MGB magnetic plug if it has particles, and replacing the epicyclic 
module if necessary. The NPRM also proposed to prohibit installing an 
affected MGB unless certain requirements are met. The FAA is issuing 
this AD to detect and correct the presence of particles in the MGB, 
which if not addressed, could result in reduced or loss of control of 
the helicopter.
    You may examine EASA AD 2023-0044 in the AD docket at 
regulations.gov under Docket No. FAA-2024-2419.

Discussion of Final Airworthiness Directive

Comments

    The FAA received no comments on the NPRM or on the determination of 
the costs.

Conclusion

    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 EASA AD referenced above. The FAA reviewed the relevant data 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

    EASA AD 2023-0044 requires repetitive borescope visual inspections 
of the bevel wheel of the affected MGB for particles, collecting and 
analyzing any found particles, and depending on the results, further 
actions, accomplishing corrective action in accordance with the ASB 
defined within, or contacting AH [Airbus Helicopters] for further 
corrective action. EASA AD 2023-0044 also requires accomplishing a 
borescope visual inspection of the bevel wheel of the affected MGB for 
particles following the detection of any particles at the MGB magnetic 
plug during accomplishment of certain maintenance tasks and depending 
on the results, taking corrective action. Lastly, EASA AD 2023-0044 
prohibits installing an affected MGB on any helicopter unless it is a 
serviceable part as defined within and certain requirements are met.
    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 EASA AD 2023-0044

    EASA AD 2023-0044 applies to Model AS350BB helicopters, whereas 
this AD does not because that model is not FAA-type certificated.
    Where Note 1 in the material referenced in EASA AD 2023-0044 
specifies the option of 1 mechanical technician and 1 crew member, for 
this

[[Page 14724]]

AD, the pilot is only permitted to turn the tail rotor (b) because the 
other actions specified in the note must be accomplished by persons 
authorized under 14 CFR 43.3. Therefore, for the purpose of this AD, 
the owner/operator (pilot) may turn the tail rotor (b) and must enter 
compliance with the applicable paragraph of this AD in the helicopter 
maintenance records in accordance with 14 CFR 43.9(a) and 
91.417(a)(2)(v). The pilot may perform this action because it only 
involves turning the tail rotor (b). This action can be performed 
equally well by a pilot or a mechanic. This action is an exception to 
the FAA's standard maintenance regulations.
    This AD does not require complying with paragraph (2) of EASA AD 
2023-0044. Instead, this AD requires repetitively inspecting the MGB 
magnetic plug for particles and, if there is any particle, 
accomplishing a borescope visual inspection, as specified in paragraphs 
(h)(6)(i) and (ii) of this AD.
    Where the material referenced in EASA AD 2023-0044 specifies 
contacting Airbus Helicopters for a certain action, this AD requires 
accomplishing action in accordance with a method approved the FAA, 
EASA, or Airbus Helicopters' EASA Design Organization Approval.

Costs of Compliance

    The FAA estimates that this AD affects 522 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.
    A repetitive visual borescope inspection of the MGB bevel wheel 
will take 1 work-hour for an estimated cost of $85 per helicopter and 
$44,370 for the U.S. fleet, per inspection cycle.
    If necessary, collecting and performing a metallurgical analysis of 
the detected particles will take 6 work-hours for an estimated cost of 
$510 per helicopter, per analysis.
    Repetitively inspecting the magnetic plugs of the MGB will take 1 
work-hour for an estimated cost of $85 per helicopter and $44,370 for 
the U.S. fleet, per inspection cycle.
    If required, close monitoring will take 2 work-hours for an 
estimated cost of $170 per helicopter, per close monitoring cycle.
    Accomplishing a visual borescope inspection of the MGB bevel wheel 
as a result of an MGB magnetic plug inspection will take 1 work-hour 
for an estimated cost of $85 per helicopter.
    If necessary, replacing an epicyclic module will take 56 work-hours 
and parts will cost $50,524 (overhauled) for an estimated cost of 
$55,284 per module.
    If necessary, replacing a bevel reduction module will take 56 work-
hours and parts will cost $18,500 (overhaled) for an estimated cost of 
$23,260 per module.
    Certain corrective action could vary significantly from helicopter 
to helicopter. The FAA has no data to determine the costs to accomplish 
the corrective action.

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:

2025-06-04 Airbus Helicopters: Amendment 39-22992; Docket No. FAA-
2024-2419; Project Identifier MCAI-2023-00366-R.

(a) Effective Date

    This airworthiness directive (AD) is effective May 9, 2025.

(b) Affected ADs

    None.

(c) Applicability

    This AD applies to all Airbus Helicopters Model AS350B, AS350B1, 
AS350B2, AS350B3, AS350BA, AS350D, AS355E, AS355F, AS355F1, AS355F2, 
AS355N, AS355NP, EC130B4, and EC130T2 helicopters, certificated in 
any category.

(d) Subject

    Joint Aircraft System Component (JASC) Code: 6320, Main Rotor 
Gearbox.

(e) Unsafe Condition

    This AD was prompted by an assessment performed by the 
manufacturer which determined that additional actions are necessary 
to improve particle detection for main gearboxes (MGBs) with certain 
part-numbered planet gear bearings installed. The FAA is issuing 
this AD to detect and correct particles in the MGB. The unsafe 
condition, if not addressed, could result in reduced or 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 AD 2023-0044, 
dated February 28, 2023 (EASA AD 2023-0044).

(h) Exceptions to EASA AD 2023-0044

    (1) Where EASA AD 2023-0044 defines ``serviceable MGB'' as ``An 
affected MGB which has accumulated less than 330 flight hours (FH) 
since new (first installation on a helicopter), or since an 
overhaul, or since an inspection in accordance with the instructions 
of the ASB,'' this AD requires replacing that text with ``An 
affected MGB which has accumulated less than 330 total hours time-
in-service since new (zero total hours time-in-service), since last 
overhaul if

[[Page 14725]]

an overhaul has been accomplished, or since last inspection and any 
specified corrective action in accordance with the instructions of 
the ASB if an inspection and any specified corrective action by 
following the instructions of the ASB have been accomplished.''
    (2) Where EASA AD 2023-0044 requires compliance in terms of 
flight hours, this AD requires using hours time-in-service (TIS).
    (3) Where EASA AD 2023-0044 refers to its effective date, this 
AD requires using the effective date of this AD.
    (4) Where Note 1 in the material referenced in paragraph (1) of 
EASA AD 2023-0044 specifies the option of 1 mechanical technician 
and 1 crew member, for this AD, the pilot is only permitted to turn 
the tail rotor (b). The owner/operator (pilot) holding at least a 
private pilot certificate may turn the tail rotor (b) and must enter 
compliance with paragraph (g) of this AD in 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 135.43. All other actions specified in Note 1 in 
the material referenced in paragraph (1) of EASA AD 2023-0044 must 
be accomplished by persons authorized under 14 CFR 43.3.
    (5) Where Note 2 in the material referenced in paragraph (1) of 
EASA AD 2023-0044 specifies contacting Airbus Helicopters for 
further instructions if the bottom of the radius (a6) of the bevel 
wheel (a3) or head screws (a4) (see Figure 2) are not clearly 
visible, this AD requires, before further flight, accomplishing 
action in accordance with a method approved by the FAA, EASA, or 
Airbus Helicopters' EASA Design Organization Approval (DOA). If 
approved by the DOA, the approval must include the DOA-authorized 
signature.
    (6) Instead of complying with paragraph (2) of EASA AD 2023-
0044, comply with the actions required by paragraphs (h)(6)(i) and 
(ii) of this AD.
    (i) After the effective date of this AD, and within the 
compliance time intervals specified table 1 to paragraph (h)(6)(i) 
of this AD, visually inspect the MGB magnetic plug for particles.
    Note 1 to paragraph (h)(6)(i): Aircraft Maintenance Manual (AMM) 
task 60-00-00, 6-2A, or AMM task 60-00-00, 6-2, or work card 60-00-
00-602, as applicable, provides information regarding inspecting the 
MGB magnetic plug.

                          Table 1 to Paragraph (h)(6)(i)--MGB Magnetic Plug Inspections
----------------------------------------------------------------------------------------------------------------
                                                     Initial compliance times (after
               Helicopter model(s)                   the effective date of this AD)    Interval compliance times
                                                               (hours TIS)              (thereafter) (hours TIS)
----------------------------------------------------------------------------------------------------------------
AS350B, AS350B1, AS350BA, and AS350D.............                                   5                         30
AS355E, AS355F, AS355F1, AS355F2, AS355N, and                                       5                         30
 AS355NP.........................................
AS350B2 and AS350B3..............................                                  10                        100
EC130B4..........................................                                   5                        150
EC130T2..........................................                                   5                        150
----------------------------------------------------------------------------------------------------------------

    (ii) If there is any particle as a result of any MGB magnetic 
plug inspection required by paragraph (h)(6)(i) of this AD, before 
further flight, borescope inspect the bevel wheel of the affected 
MGB for particles as required by paragraph (1) of EASA AD 2023-0044. 
If there is any particle as a result of the borescope inspection of 
the bevel wheel, before further flight, collect and analyze the 
particles as required by paragraph (3) of EASA AD 2023-0044.
    (7) Where paragraph (3) of EASA AD 2023-0044 specifies ``If, 
during any inspection as required by paragraph (1) or (2) of this 
AD,'' this AD requires replacing that text with ``If, during any 
inspection as required by paragraph (1) of this AD.''
    (8) Where the material referenced in paragraph (3) of EASA AD 
2023-0044 specifies performing a metallurgical analysis and 
contacting Airbus Helicopters if collected particles cannot be 
characterized with Work Card 20-08-01-601, this AD does not require 
contacting Airbus Helicopter but does require performing the 
metallurgical analysis.
    (9) This AD does not allow the ferry flight provision specified 
in the material referenced in paragraph (3) of EASA AD 2023-0044; 
for this AD, refer to paragraph (j) of this AD.
    (10) Where the material referenced in paragraph (3) of EASA AD 
2023-0044 specifies contacting Airbus Helicopters if the damaged 
module cannot be identified, this AD requires, before further 
flight, accomplishing action in accordance with a method approved by 
the FAA, EASA, or Airbus Helicopters' EASA DOA. If approved by the 
DOA, the approval must include the DOA-authorized signature.
    (11) Where paragraph (5) of EASA AD 2023-0044 states ``to 
contact AH for corrective action(s) instructions, and within the 
compliance time specified therein, to accomplish those instructions 
accordingly,'' this AD requires replacing that text with 
``accomplishing corrective actions in accordance with a method 
approved by the FAA, EASA, or Airbus Helicopters' EASA DOA. If 
approved by the DOA, the approval must include the DOA-authorized 
signature.''
    (12) Where paragraph (7) of EASA AD 2023-0044 states ``since new 
(first installation a helicopter), or since an overhaul, or since an 
inspection in accordance with the instructions of the ASB, as 
applicable, and, thereafter, as required by this AD,'' this AD 
requires replacing that text with ``since new (zero total hours 
time-in-service), or since last overhaul if an overhaul has been 
accomplished, or since last inspection and any specified corrective 
action in accordance with the instructions of the ASB if an 
inspection and any specified corrective action by following the 
instructions of the ASB have been accomplished, and thereafter as 
required by this AD.''
    (13) This AD does not adopt the ``Remarks'' section of EASA AD 
2023-0044.

(i) No Reporting Requirement

    Although the material referenced in EASA AD 2023-0044 specifies 
to submit certain information to the manufacturer, this AD does not 
require that action.

(j) Special Flight Permits

    A special flight permit may be issued in accordance with 14 CFR 
21.197 and 21.199 to permit a one-time, non-revenue flight to a 
location where the actions required by this AD can be accomplished. 
This flight must be performed with only essential flight crew.

(k) 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 (l) of 
this AD. Information may be emailed to: [email protected].
    (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.

(l) Related Information

    For more information about this AD, contact Dan McCully, 
Aviation Safety Engineer, FAA, 1600 Stewart Avenue, Suite 410, 
Westbury, NY 11590; phone: (404) 474-5548; email: 
[email protected].

(m) 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 2023-0044, 
dated February 28, 2023.
    (ii) [Reserved]
    (3) For EASA material identified in this AD, contact EASA, 
Konrad-Adenauer-Ufer 3,

[[Page 14726]]

50668 Cologne, Germany; phone: +49 221 8999 000; email: 
[email protected]; 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 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 www.archives.gov/federal-register/cfr/ibr-locations or email [email protected].

    Issued on March 28, 2025.
Paul R. Bernado,
Acting Director, Compliance & Airworthiness Division, Aircraft 
Certification Service.
[FR Doc. 2025-05781 Filed 4-3-25; 8:45 am]
BILLING CODE 4910-13-P