DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2017-1036; Product Identifier 2018-SW-015-AD; Amendment
39-21593; AD 2021-12-06]
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
Airbus Helicopters Model AS-365N2, AS 365 N3, SA-365N, and SA-365N1
helicopters. This AD requires replacing the main gearbox (MGB), or as
an alternative, replacing the epicyclic reduction gear module for
certain serial numbered planet gear assemblies installed on the MGB.
This AD also requires inspecting the MGB magnetic plugs and oil filter
for particles. Depending on the outcome of the inspections, this AD
requires further inspections and replacing certain parts. This AD was
prompted by failure of an MGB second stage planet gear. The FAA is
issuing this AD to correct an unsafe condition on these products.
DATES: This AD is effective July 20, 2021.
The Director of the Federal Register approved the incorporation by
reference of certain documents listed in this AD as of July 20, 2021.
ADDRESSES: For service information identified in this final rule,
contact Airbus Helicopters, 2701 N Forum Drive, Grand Prairie, TX
75052; telephone 972-641-0000 or 800-232-0323; fax 972-641-3775; or at
https://www.airbus.com/helicopters/services/technical-support.html. You
may view the referenced service information at the FAA, Office of the
Regional Counsel, Southwest Region, 10101 Hillwood Pkwy., Room 6N-321,
Fort Worth, TX 76177. Service information that is incorporated by
reference is also available at https://www.regulations.gov by searching
for and locating Docket No. FAA-2017-1036.
Examining the AD Docket
You may examine the AD docket at https://www.regulations.gov by
searching for and locating Docket No. FAA-2017-1036; 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
European Aviation Safety Agency (now European Union Aviation Safety
Agency) (EASA) AD, any comments received, and other information. The
street 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.
FOR FURTHER INFORMATION CONTACT: Rao Edupuganti, Aviation Safety
Engineer, Dynamic Systems Section, Technical Innovation Policy Branch,
FAA, 10101 Hillwood Pkwy., Fort Worth, TX 76177; telephone 817-222-
5110; email rao.edupuganti@faa.gov.
SUPPLEMENTARY INFORMATION: The FAA issued a notice of proposed
rulemaking (NPRM) to amend 14 CFR part 39 by adding an AD that would
apply to Airbus Helicopters Model AS-365N2, AS 365 N3, SA-365N, and SA-
365N1 helicopters, with at least one Type X or Y planet gear assembly
with a serial number (S/N) listed in Appendices 4.A. through 4.B of
Airbus Helicopters Alert Service Bulletin ASB No. AS365-05.00.78,
Revision 3, dated March 2, 2018 (ASB AS365-05.00.78), installed on the
MGB. The NPRM published in the Federal Register on August 7, 2020 (85
FR 47925). In the NPRM, the FAA proposed to require replacing the MGB
before further flight for helicopters with a Type X planet gear
assembly with a certain S/N installed. The NPRM also proposed to
require, for helicopters with no Type X planet gear assembly installed
but at least one Type Y planet gear assembly with a certain S/N
installed, replacing the MGB within 300 hours time-in-service (TIS) or
before any planet gear assembly accumulates 1,300 hours TIS since new,
whichever occurs first. As an alternative to replacing the MGB, the
NPRM proposed to allow replacing the epicyclic reduction gear module in
the affected MGB.
The NPRM also proposed to prohibit installing an MGB with Type Y or
Type X planet gear assembly installed on any helicopter. Finally, the
NPRM proposed to require, within 10 hours TIS and thereafter before the
first flight of the day or at intervals not to exceed 10 hours TIS,
whichever occurs first, inspecting the lower MGB magnetic plugs for
particles. If there are particles, the NPRM proposed to require
replacing the MGB depending on the type and the size of particles. The
NPRM was prompted by EASA AD 2017-0116, Revision 2, dated March 2,
2018, (EASA AD 2017-01162R2), issued by EASA, which is the Technical
Agent for the Member States of the European Union, to correct an unsafe
condition for Airbus Helicopters Model AS 365 N2, AS 365 N3, SA 365 N,
and SA 365 N1 helicopters. EASA advises that after an accident on a
Model EC225 helicopter, an investigation revealed the failure of a
second stage planet gear of the MGB. EASA states that one of the two
types of planet gear assemblies used in the MGB epicyclic module is
subject to higher outer race contact pressures and therefore is more
susceptible to spalling and cracking. Airbus Helicopters reviewed its
range of helicopters with regard to this issue and provided
instructions to improve the reliability of the installed MGB.
Accordingly, EASA AD 2017-01162R2 requires repetitive inspections
of the MGB magnetic plugs and corrective action if any particles are
detected. EASA AD 2017-01162R2 also requires, if certain MGB planet
gear assemblies are installed, replacing the planet gear assemblies.
Finally, EASA AD 2017-01162R2 prohibits installing an MGB with a Type
X
or Type Y planet gear assembly on any helicopter.
After the NPRM was issued, the FAA discovered that the proposed
applicability was limited to helicopters with at least one affected
assembly installed on the MGB, whereas all Airbus Helicopters Model AS-
365N2, AS 365 N3, SA-365N, and SA-365N1 helicopters, regardless of the
assembly, are subject to the unsafe condition and require repetitive
inspections of the MGB magnetic plugs for particles. The FAA also
determined that any special flight permits would be limited to flights
with no passengers on board.
Therefore, the FAA issued a supplemental notice of proposed
rulemaking (SNPRM) to amend 14 CFR part 39 by adding an AD that would
apply to all Airbus Helicopters Model AS-365N2, AS 365 N3, SA-365N, and
SA-365N1 helicopters. The SNPRM published in the Federal Register on
March 22, 2021 (86 FR 15143). The SNPRM maintained the proposed
corrective actions from the NPRM as follows, but no longer limited the
applicability to only certain helicopters:
Before further flight, for helicopters with a Type X
planet gear assembly with a certain S/N installed, replacing the MGB.
For helicopters with no Type X planet gear assembly
installed but at least one Type Y planet gear assembly with a certain
S/N installed, replacing the MGB within 300 hours TIS or before any
planet gear assembly accumulates 1,300 hours TIS since new, whichever
occurs first.
As an alternative to replacing the MGB, the SNPRM proposed
to allow replacing the epicyclic reduction gear module in the affected
MGB.
The SNPRM also proposed to:
Prohibit installing an MGB with Type Y or Type X planet
gear assembly installed on any helicopter.
Require, within 10 hours TIS and thereafter before the
first flight of the day or at intervals not to exceed 10 hours TIS,
whichever occurs first, inspecting the lower MGB magnetic plugs for
particles and, if there are particles, replacing the MGB, depending on
the type and the size of those particles.
Discussion of Final Airworthiness Directive
Comments
The FAA received no comments on the SNPRM or on the determination
of the costs.
Conclusion
The helicopters 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 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 helicopters.
Related Service Information Under 1 CFR Part 51
Airbus Helicopters has issued ASB AS365-05.00.78 for Model SA-365N,
SA-365N1, AS-365N2, and AS 365 N3 helicopters. This service information
specifies performing periodic inspections of the MGB magnetic plugs for
particles. This service information also specifies identifying the type
of gear assembly installed in the MGB and replacing any Type X assembly
within 50 hours TIS. For Type Y gear assemblies, the service
information requires replacing the assembly within 50 hours TIS or
within 300 hours TIS, depending on the time since new. The service
information specifies Type Z gear assemblies should be left as is.
Airbus Helicopters has also issued Service Bulletin SB No. AS365-
63.00.21, Revision 3, dated July 26, 2018, for Model AS365 helicopters.
This service information contains procedures for replacing the MGB
epicyclic reduction gear as an option to replacing the MGB.
This service information 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 EASA AD
The EASA AD requires a 50-hour or 300-hour TIS compliance time or
by June 30, 2019, whichever occurs first, to determine the type of
planet gear installed in the MGB, and depending on the outcome, to
replace the MGB; the compliance time for this AD is based only on hours
TIS or before further flight. The EASA AD allows a pilot to inspect the
MGB magnetic plugs for particles; this AD does not.
Costs of Compliance
The FAA estimates that this AD affects 34 helicopters of U.S.
Registry and that operators may incur the following costs in order to
comply with this AD. Labor costs are estimated at $85 per work-hour.
Inspecting the magnetic plugs and oil filter for particle deposits
will take about 1 work-hour for an estimated cost of $85 per helicopter
per inspection cycle.
Replacing an MGB will take about 42 work-hours for cost of $3,570
and parts will cost about $295,000 (overhauled) for a total cost of
$298,570 per helicopter.
Replacing the epicyclic reduction gear will take about 56 work-
hours for an estimated cost of $4,760 and parts will cost about $11,404
for a total cost of $16,164 per helicopter.
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 helicopters 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:
|