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2021-12-06 AIRBUS HELICOPTERS: Amendment 39-21593; Docket No. FAA-2017-1036; Product Identifier 2018-SW-015-AD.
(a) APPLICABILITY

    This airworthiness directive (AD)  applies to Airbus Helicopters Model
    AS-365N2, AS 365 N3, SA-365N and SA-365N1 helicopters, certificated in
    any category.

(b) UNSAFE CONDITION

    This AD defines the unsafe condition as  failure  of  a  main  gearbox
    (MGB) planet gear assembly.  This condition could result in failure of
    the MGB and subsequent loss of helicopter control.

(c) AFFECTED ADS

    None.

(d) EFFECTIVE DATE

    This AD is effective July 20, 2021.

(e) COMPLIANCE

    You are responsible for performing  each  action  required  by this AD
    within the specified compliance time unless it has already been accom-
    plished prior to that time.

(f) REQUIRED ACTIONS

(1) For  helicopters  with at least one Type X planet gear assembly with a
    serial  number (S/N)  listed in  Appendix 4.A.  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 main gearbox (MGB), be-
    fore further flight, replace the MGB or as an alternative to replacing
    an affected MGB, replace the epicyclic reduction gear module Post Mod-
    ification (MOD) 0763C52 in the affected MGB  in accordance  with para-
    graph 3.B.2  of the Accomplishment Instructions  of Airbus Helicopters
    Service Bulletin SB No. AS365-63.00.21 Revision 3, dated July 26, 2018
    (SB AS365-63.00.21),  except you  are not  required to  contact Airbus
    Helicopters.

(2) For helicopters  without any Type X planet gear assembly installed but
    with at least one  Type Y planet gear  assembly with an S/N  listed in
    Appendix 4.B. of ASB AS365-05.00.78  installed on the MGB, within  300
    hours  time-in-service (TIS),  or  before  any gear  accumulates 1,300
    hours TIS since new, whichever occurs first, replace the MGB or as  an
    alternative to replacing the MGB, replace the epicyclic reduction gear
    module MOD 0763C52 in the  affected MGB in accordance with  paragraphs
    3.B.2. of the Accomplishment Instructions of SB AS365-63.00.21, except
    you are not required to contact Airbus Helicopters.

(3) As of the effective date of this AD, do not install an MGB with a Type
    X or Type Y gear assembly  with an S/N listed in Appendix 4.A. or 4.B.
    of ASB AS365-05.00.78 installed on the MGB, on any helicopter.

(4) For all helicopters, 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, inspect the lower MGB magnetic plugs for part-
    icles.

(i) If there are particles that consist of any scale, flake,  or splinter,
    or particles  other than  cotter pin  fragments, pieces  of lock wire,
    swarf, abrasion,  or miscellaneous  non-metallic waste  and the planet
    gear assembly has logged less than 50 hours TIS since new, inspect the
    MGB plugs  for particles  before further  flight and  inspect the  oil
    filter for particles within 5 hours TIS. Thereafter, for 25 hours TIS,
    continue to inspect  the MGB plugs  for particles before  each flight,
    inspect the  oil filter  for particles  at intervals  not to  exceed 5
    hours  TIS, and perform the actions required  by paragraphs (f)(4)(ii)
    (A) through (B) of this AD.

(ii) If there are particles that consist of any scale, flake, or splinter,
     or particles other  than cotter pin  fragments, pieces of  lock wire,
     swarf, abrasion, or miscellaneous  non-metallic waste and the  planet
     gear assembly has  logged more than  50 hours TIS  since new, inspect
     the cumulative surface area of the particles collected from both  the
     magnetic plug and  the oil filter,  since last MGB  overhaul or since
     new if no overhaul has been performed.

(A) If the total surface area of the particles is less than 3 mm², examine
    the particles with largest  surface area (S), longest  particle length
    (L) and thickest particles (e).

(1) If largest surface area (S) of a particle is less than 1 mm², the L is
    less than 1.5 mm, and the e is less than 0.2 mm, inspect the MGB plugs
    for particles  before further  flight and  inspect the  oil filter for
    particles within 5 hours TIS.  Thereafter, for 25 hours TIS,  continue
    to inspect the MGB plugs for particles before each flight, inspect the
    oil filter for particles at intervals  not to exceed 5 hours TIS,  and
    perform the actions required  by  paragraphs (f)(4)(ii)(A) through (B)
    of this AD.

(2) If largest particle size (S)  is greater than 1 mm²,  the L is greater
    than 1.5 mm, or the e is greater than 0.2 mm,  perform a metallurgical
    analysis for any 16NCD13 particles  using a method  in accordance with
    FAA-approved procedures.

(3) If there are any 16NCD13 particles,  replace the MGB with an airworthy
    MGB.

(4) If there are no 16NCD13 particles, inspect the MGB plugs for particles
    before further flight and inspect the oil filter for particles  within
    5 hours TIS. Thereafter, for 25 hours TIS, continue to inspect the MGB
    plugs for  particles before  each flight,  inspect the  oil filter for
    particles at  intervals not  to exceed  5 hours  TIS, and  perform the
    actions required by paragraphs (f)(4)(ii)(A) through (B) of this AD.

(B) If the total surface area of collected particles  is  greater  than or
    equal to 3 mm², before further flight,  perform a metallurgical analy-
    sis for any 6NCD13 particles using a method  in  accordance  with FAA-
    approved procedures.

(1) If there are any 16NCD13 particles, before further flight, replace the
    MGB with an airworthy MGB.

(2) If there are no 16NCD13 particles, inspect the MGB plugs for particles
    before further flight and inspect the oil filter for particles  within
    5 hours TIS. Thereafter, for 25 hours TIS, continue to inspect the MGB
    plugs for  particles before  each flight,  inspect the  oil filter for
    particles at  intervals not  to exceed  5 hours  TIS, and  perform the
    actions required by paragraphs (f)(4)(ii)(A) through (B) of this AD.

(g) SPECIAL FLIGHT PERMITS

    Special flight  permits may  be permitted  provided that  there are no
    passengers on board.

(h) 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 (i)(1)  of this AD. Information may  be
    emailed to: 9-AVS-AIR-730-AMOC@faa.gov.

(2) Before using any approved AMOC,  notify your appropriate principal in-
    spector, or lacking  a principal inspector,  the manager of  the local
    flight standards district office/certificate holding district office.

(i) ADDITIONAL INFORMATION

(1) For more information about this AD,  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.

(2) The subject of this AD is addressed in European Aviation Safety Agency
    (now European  Union  Aviation  Safety  Agency) (EASA) AD 2017-0116R2,
    dated  March  2,  2018.  You may  view  the  EASA  AD at  https://www.
    regulations.gov in Docket No. FAA-2017-1036.

(j) SUBJECT

    Joint Aircraft Service Component (JASC) Code:  6300,  Main Rotor Drive
    System.

(k) MATERIAL INCORPORATED BY REFERENCE

(1) The Director of the Federal Register  approved  the  incorporation  by
    reference of the service information listed  in this paragraph under 5
    U.S.C. 552(a) and 1 CFR part 51.

(2) You must use  this service information as applicable to do the actions
    required by this AD, unless the AD specifies otherwise.

(i) Airbus  Helicopters  Alert  Service  Bulletin  ASB No. AS365-05.00.78,
    Revision 3, dated March 2, 2018.

(ii) Airbus Helicopters Service Bulletin SB No. AS365-63.00.21, Revision 3
     dated July 26, 2018.

(3) For Airbus Helicopters service information identified in this AD, con-
    tact 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.

(4) You may view  this  service  information  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.

(5) You may view this service information  that is incorporated  by refer-
    ence at the National  Archives and Records Administration  (NARA). For
    information  on  the availability  of  this material  at  NARA, email:
    fedreg.legal@nara.gov,  or  go  to:  https://www.archives.gov/federal-
    register/cfr/ibr-locations.html.

Issued  on  May 27, 2021.  Ross Landes,  Deputy  Director  for  Regulatory
Operations,  Compliance & Airworthiness Division,  Aircraft  Certification
Service.

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.
PREAMBLE 

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: