DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2024-1297; Project Identifier MCAI-2022-00736-R; 
Amendment 39-22833; AD 2024-17-08]
RIN 2120-AA64

Airworthiness Directives; Airbus 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 
Airbus Helicopters Model EC225LP helicopters. This AD was prompted by a 
report of water in the oil of a main gearbox (MGB). This AD requires 
replacing certain main rotor (M/R) mast upper stops assembly screws. 
This AD also requires inspecting certain M/R mast cover plates and 
accomplishing MGB oil analyses and, depending on the results, taking 
corrective action. This AD prohibits installing certain M/R mast upper 
stops assembly screws, M/R masts with an affected M/R mast upper stops 
assembly screw installed, and used M/R mast cover plates on any 
helicopter. Lastly, this AD prohibits installing affected M/R masts 
unless the inspections are done. 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 November 7, 2024.

    The Director of the Federal Register approved the incorporation by 
reference of a certain publication listed in this AD as of November 7, 2024.

ADDRESSES: 

    AD Docket: You may examine the AD docket at regulations.gov under 
Docket No. FAA-2024-1297; 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: 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-2024-1297.

    Other Related material: 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 also view this material at the FAA 
contact information under Material Incorporated by Reference above.

FOR FURTHER INFORMATION CONTACT: Dan McCully, Aviation Safety Engineer, 
FAA, 1600 Stewart Avenue, Suite 410, Westbury, NY 11590; phone: (404) 
474-5548; email: william.mccully@faa.gov.

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 
Model EC225LP helicopters. The NPRM published in the Federal Register 
on May 16, 2024 (89 FR 42820).

    The NPRM was prompted by a report of water in the oil of an MGB, 
due to an incorrect installation of the upper M/R mast cover plate. In 
the NPRM, the FAA proposed to require replacing certain M/R mast upper 
stops assembly screws. The NPRM also proposed to require inspecting 
certain M/R mast cover plates and accomplishing MGB oil analyses and, 
depending on the results, replacing the M/R mast cover plate, 
accomplishing an additional inspection, or replacing the MGB. The NPRM 
proposed to prohibit installing certain M/R mast upper stops assembly 
screws, M/R masts with an affected M/R mast upper stops assembly screw 
installed, and used M/R mast cover plates on any helicopter. Lastly, 
the NPRM proposed to prohibit installing affected M/R masts unless the 
inspections are done. These actions are specified in EASA AD 2022-0104, 
dated June 9, 2022 (EASA AD 2022-0104).

    The FAA is issuing this AD to prevent water in the MGB oil, which, 
if not addressed, could result in corrosion of the M/R mast and inside 
the MGB, degradation of the MGB, degradation of the upper stops 
assembly, failure of a critical part, and subsequent loss of control of 
the helicopter. You may examine EASA AD 2022-0104 in the AD docket at 
regulations.gov under Docket No. FAA-2024-1297.

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 
its 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.

Material Incorporated by Reference Under 1 CFR Part 51

    EASA AD 2022-0104 requires replacing each M/R mast upper stops 
assembly screw, except those marked with "BC" on the screw head. For 
certain helicopters, EASA AD 2022-0104 requires inspecting a certain 
part-numbered M/R mast cover plate and depending on the results, replacing 
the cover plate and accomplishing an additional inspection. For those 
same certain helicopters, EASA AD 2022-0104 also requires accomplishing 
MGB oil analyses and, depending on the results, accomplishing an 
additional inspection. Depending on the results of the additional 
inspection following the M/R mast cover plate inspection or MGB oil 
analyses, EASA AD 2022-0104 requires replacing the MGB. As an option, 
EASA AD 2022-0104 allows replacing the MGB as an acceptable alternative 
method to comply with the required MGB oil sample analyses.

    Lastly, EASA AD 2022-0104 prohibits installing M/R mast upper stops 
assembly screws--except those marked with "BC" on the screw head, M/R 
masts with an affected M/R mast upper stops assembly screw installed, 
and used M/R mast cover plates on any helicopter. EASA AD 2022-0104 
also prohibits installing an affected M/R mast unless its required 
inspections are done.

    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 Material

    The FAA also reviewed Airbus Helicopters Alert Service Bulletin No. 
EC225-62A016, Revision 1, dated February 28, 2023. This material 
specifies procedures for inspecting the M/R mast upper stops assembly 
screws to determine if they're marked with "BC" on the screw head and 
depending on the results, replacing those screws one by one. This 
material also specifies procedures for checking the flatness of the M/R 
mast cover plate and, depending on the results, removing and discarding 
that cover plate, installing a flat cover plate, draining the MGB, 
writing to Airbus Helicopters to do a detailed MGB inspection, and 
removing the M/R mast. Depending on the detailed MGB inspection 
results, this material specifies filling the MGB with oil and 
installing the M/R mast; or replacing the MGB with an airworthy MGB, 
sending the removed MGB to an approved D-level center for repair, and 
installing the M/R mast.

    This material also specifies procedures for collecting an MGB oil 
sample and sending the sample to an Airbus Helicopters approved 
laboratory for water content analysis. Depending on the analysis 
results, this material specifies draining the MGB, writing to Airbus 
Helicopters to do a detailed MGB inspection, and removing the M/R mast. 
Depending on the detailed MGB inspection results, this material 
specifies filling the MGB with oil and installing the M/R mast; or 
replacing the MGB with an airworthy MGB, sending the removed MGB to an 
approved D-level center for repair, and installing the M/R mast.

Differences Between This AD and the EASA AD

    For certain helicopters, EASA AD 2022-0104 specifies sending oil 
samples to an Airbus Helicopters approved laboratory for an analysis of 
the water content, whereas this AD requires sending the main gearbox 
oil sample for water content analysis. Additionally, for those 
helicopters, EASA AD 2022-0104 specifies taking and analyzing the 
second MGB oil sample within 110 FH or 3 months after the initial oil 
sample, whereas this AD requires collecting the second main gearbox oil 
sample and sending it for water content analysis within 110 hours time-
in-service or 3 months after accomplishing the initial instance of 
those actions, whichever occurs later. Depending on the results of the 
cover plate inspection or an oil sample analysis, EASA AD 2022-0104 
specifies contacting Airbus Helicopters to request to accomplish a 
detailed inspection, which shall be accomplished by authorized Airbus 
Helicopters staff and the Airbus Helicopters qualified staff identify 
any discrepancies, whereas this AD requires a detailed inspection, 
which must define what is considered a discrepancy and be done in 
accordance with a method approved by the FAA, EASA, or Airbus 
Helicopters' EASA Design Organization Approval.

Costs of Compliance

    The FAA estimates that this AD affects 32 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.

    Replacing the M/R mast upper stops assembly screws (up to 10 
screws) takes up to approximately 0.5 work-hour and parts cost up to 
approximately $250 (for 10 screws) for an estimated cost of up to $293 
per helicopter and $9,376 for the U.S. fleet.

    For certain helicopters, inspecting the M/R mast cover plate takes 
approximately 0.5 work-hour for an estimated cost of $43 per helicopter 
and up to $1,376 for the U.S. fleet. Collecting an MGB oil sample and 
sending the MGB oil sample for water content analysis, which is 
considered a reporting requirement in this AD, takes approximately 1.5 
work-hours (0.5 work-hour for collecting and 1 work-hour for sending) 
for an estimated cost of $128 per helicopter and up to $4,096 for the 
U.S. fleet, per instance.

    If required, replacing the M/R mast cover plate takes approximately 
2 work-hours and parts cost approximately $276 for an estimated cost of 
$446 per helicopter. The detailed inspection that may be needed could 
vary significantly from helicopter to helicopter. The FAA has no data 
to determine the costs to accomplish the detailed inspection or the 
number of helicopters that may need it. Replacing an MGB takes 
approximately 40 work-hours and parts cost approximately $998,595 
(overhauled) for an estimated cost of $1,001,995 per helicopter.

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 1.5 hours 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

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: