preamble attached >>>
ADs updated daily at www.Tdata.com
2021-20-10 LEONARDO S.P.A.: Amendment 39-21748; Docket No. FAA-2021-0579; Project Identifier MCAI-2020-00267.
(a) EFFECTIVE DATE

    This airworthiness directive (AD) is effective November 22, 2021.

(b) AFFECTED ADS

    None.

(c) APPLICABILITY

    This AD applies to Leonardo S.p.a. Model AB139 and AW139  helicopters,
    certificated in  any category,  without main  gearbox (MGB)  spherical
    bearing lock nut (lock  nut) part number (P/N)  3G6320A09152 installed
    and with:

(1) MGB  P/N  3G6320A00131,  3G6320A00132,   3G6320A00133,   3G6320A00134,
    3G6320A00135,    3G6320A00136,    3G6320A22031,    4G6320A00132,    or
    4G6320A00133 installed, or

(2) MGB  P/N  3G320A00133  with   serial  number  (S/N)  M23,  or  MGB P/N
    3G6320A00134, with  S/N M6,  N76, N92,  P124, P129,  P131, P162, P184,
    Q230, Q243, Q249, R272, V21,  V39, V96, V163, V211, V241,  V272, V281,
    V384, V386, or V622 installed, or

(3) MGB P/N 3G6320A00136 with S/N AW1, AW2, AW3, AW5, or AW10 installed.

(d) SUBJECT

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

(e) UNSAFE CONDITION

    This AD was  prompted by a  cracked MGB lock  nut. The FAA  is issuing
    this AD to replace an affected MGB  lock nut with a new MGB lock  nut.
    The unsafe condition, if not addressed, could result in failure of the
    MGB planetary gears, resulting in loss of control of the helicopter.

(f) COMPLIANCE

    Comply  with this  AD within  the compliance  times specified,  unless
    already done.

(g) REQUIRED ACTIONS

(1) Within  100 hours  time-in-service, or  during the  next scheduled MGB
    overhaul, whichever occurs first after the effective date of this  AD,
    remove each  MGB lock  nut P/N  3G6320A09151 from  service and replace
    with MGB lock nut P/N 3G6320A09152 in accordance with Annex A, steps 1
    through 17,  of Leonardo  Helicopters Alert  Service Bulletin  No. 139
    -609, Revision A, dated April 13, 2021, except you are not required to
    send parts to Leonardo Helicopters.

NOTE TO PARAGRAPH (g)(1): Leonardo Helicopters service information  refers
to an MGB lock nut as a ring nut.

(2) As of the effective date of this AD, do not install any MGB having MGB
    lock nut P/N 3G630A09151 on any helicopter, and do not install any MGB
    lock nut P/N 3G630A09151 on any helicopter.

(h) SPECIAL FLIGHT PERMITS

    Special flight permits are prohibited.

(i) 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 (j)(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
    inspector, or lacking a principal inspector, the manager of the  local
    flight standards district office/certificate holding  district office.

(j) RELATED INFORMATION

(1) For more information about this AD, contact Rao Edupuganti,  Aerospace
    Engineer, Dynamic Systems Section, Technical Innovation Policy Branch,
    Policy & Innovation Division,  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 Union Aviation  Safety
    Agency (EASA) AD 2021-0121, dated May  4, 2021. You may view the  EASA
    AD at https://www.regulations.gov in Docket No. FAA-2021-0579.

(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) Leonardo Helicopters Alert  Service Bulletin No. 139-609,  Revision A,
    dated April 13, 2021.

(ii) [Reserved]

(3) For service information identified in this AD, contact Leonardo S.p.A.
    Helicopters, Emanuele Bufano, Head  of Airworthiness, Viale G.  Agusta
    520, 21017 C. Costa di Samarate (Va) Italy; telephone +39-0331-225074;
    fax +39-0331-229046; or at https://customerportal.leonardocompany.com/
    en-US/.

(4) You may view this  service information at the FAA, Office  of the Reg-
    ional 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:
    fr.inspection@nara.gov,  or  go  to:  https://www.archives.gov/federal
    -register/cfr/ibr-locations.html.

Issued  on  September 16, 2021. Lance T. Gant, Director, Compliance & Air-
worthiness Division, Aircraft Certification Service.

FOR  FURTHER  INFORMATION  CONTACT:  Rao  Edupuganti,  Aerospace Engineer,
Dynamic  Systems Section,  Technical Innovation  Policy Branch,  Policy  &
Innovation  Division, 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-2021-0579; Project Identifier MCAI-2020-00267-R;
Amendment 39-21748; AD 2021-20-10]
RIN 2120-AA64

Airworthiness Directives; Leonardo S.p.a. Helicopters

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule.

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

SUMMARY: The FAA is adopting a new airworthiness directive (AD) for
certain Leonardo S.p.a. Model AB139 and AW139 helicopters. This AD was
prompted by a report of several occurrences of a cracked main gearbox
(MGB) spherical bearing lock nut (lock nut). This AD requires removing
from service a certain part-numbered MGB lock nut that is installed on
certain part-numbered MGBs and replacing it with newly designed MGB
lock nut. This AD also prohibits installing any MGB with the affected
MGB lock nut and prohibits installing any affected MGB lock nut on any
helicopter. The FAA is issuing this AD to address the unsafe condition
on these products.

DATES: This AD is effective November 22, 2021.

The Director of the Federal Register approved the incorporation by
reference of a certain document listed in this AD as of November 22, 2021.

ADDRESSES: For service information identified in this final rule,
contact Leonardo S.p.A. Helicopters, Emanuele Bufano, Head of
Airworthiness, Viale G.Agusta 520, 21017 C.Costa di Samarate (Va)
Italy; telephone +39-0331-225074; fax +39-0331-229046; or at
https://customerportal.leonardocompany.com/en-US/.

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. For information on the availability of
this material at the FAA, call (817) 222-5110. Service information that
is incorporated by reference is also available at https://www.regulations.gov
by searching for and locating Docket No. FAA-2021-0579.

Examining the AD Docket


You may examine the AD docket at https://www.regulations.gov by
searching for and locating Docket No. FAA-2021-0579; 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 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, Aerospace Engineer,
Dynamic Systems Section, Technical Innovation Policy Branch, Policy &
Innovation Division, FAA, 10101 Hillwood Pkwy., Fort Worth, TX 76177;
telephone (817) 222-5110; email rao.edupuganti@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 Leonardo S.p.a. Model
AB139 and AW139 helicopters, without MGB lock nut part number (P/N)
3G6320A09152 installed and with MGB P/N 3G6320A00131, 3G6320A00132,
3G6320A00133, 3G6320A00134, 3G6320A00135, 3G6320A00136, 3G6320A22031,
4G6320A00132, or 4G6320A00133 installed; or MGB P/N 3G320A00133 with
serial number (S/N) M23, or MGB P/N 3G6320A00134, with S/N M6, N76,
N92, P124, P129, P131, P162, P184, Q230, Q243, Q249, R272, V21, V39,
V96, V163, V211, V241, V272, V281, V384, V386, or V622 installed; or
MGB P/N 3G6320A00136 with S/N AW1, AW2, AW3, AW5, or AW10 installed.
The NPRM published in the Federal Register on July 26, 2021 (86 FR
39984). In the NPRM, the FAA proposed to require within 100 hours time
in service (TIS) or during the next scheduled MGB overhaul, whichever
occurs first after the effective date of this AD, removing a certain
part-numbered MGB lock nut from service and replacing it with a
different part-numbered MGB lock nut. The NPRM also proposed to
prohibit installing an MGB having an affected MGB lock nut and also
prohibit installing an affected MGB lock nut on any helicopter as of
the effective date of the NPRM.

The NPRM was prompted a series of EASA ADs beginning with EASA AD
2019-0036, dated February 15, 2019 (EASA AD 2019-0036), issued by EASA,
which is the Technical Agent for the Member States of the European
Union, to correct an unsafe condition for all serial-numbered Leonardo
S.p.a. Helicopters (formerly Finmeccanica S.p.A, AgustaWestland S.p.A.,
Agusta S.p.A.; and AgustaWestland Philadelphia Corporation, formerly
Agusta Aerospace Corporation) Model AB139 and AW139 helicopters. EASA
advised that an occurrence was reported of a cracked MGB lock nut P/N
3G6310A09151, which is used to keep the planetary gears in position.
EASA AD 2019-0036 required replacing each MGB lock nut with an
airworthy MGB lock nut. EASA advised this condition, if not detected
and corrected, could lead to failure of the MGB planetary gears,
resulting in loss of control of the helicopter.

After EASA issued EASA AD 2019-0036, an additional occurrence was
reported of a cracked MGB lock nut P/N 3G6320A09151. Accordingly, EASA
superseded EASA AD 2019-0036 with EASA AD 2019-0174, dated July 18,
2019 (EASA AD 2019-0174), which retained the requirements of EASA AD
2019-0036 but reduced the compliance times. After EASA issued EASA AD
2019-0174, Leonardo Helicopters issued Alert Service Bulletin No. 139-
609, dated December 18, 2019 to provide instructions for replacing the
affected MGB lock nut with MGB lock nut P/N 3G6320A09152, which has a
redesigned flange reducing the stress at the bearing nut locations
where cracks were detected.

Accordingly, EASA then issued EASA AD 2020-0011, dated January 29,
2020, and corrected January 30, 2020 (EASA AD 2020-0011), which
superseded EASA AD 2019-0174, and partially retained the requirements
of EASA AD 2019-0174. EASA AD 2020-0011 revised the compliance times in
EASA AD 2019-0174, required replacing each affected MGB lock nut with a
newly designed MGB lock nut, and prohibited installing an affected MGB
on any helicopter. After EASA issued EASA AD 2020-0011, EASA identified
certain MGB part numbers that were inadvertently categorized
incorrectly and therefore listed in the wrong group of helicopters.
Accordingly, EASA issued EASA AD 2020-0011R1, dated November 20, 2020
(EASA AD 2020-011R1), thereby revising EASA AD 2020-0011. EASA AD 2020-
0011R1 retains the requirements of EASA AD 2020-0011 and corrects
Appendix 1 of EASA AD 2020-0011.

After EASA issued EASA AD 2020-0011R1, Leonardo Helicopters issued
Alert Service Bulletin No. 139-609, Revision A, dated April 13, 2021
(ASB 139-609 Rev A), which identifies an additional part-numbered MGB,
which is also affected by the unsafe condition. Accordingly, EASA
superseded EASA AD 2020-0011R1 with EASA AD 2021-0121, dated May 4,
2021 (EASA AD 2021-0121). EASA AD 2021-0121 adds an additional part-
numbered MGB with a certain S/N to the list of affected parts. EASA AD
2021-0121 retains the requirements of EASA AD 2020-0011R1, and corrects
Table 1 and Appendix 1 of EASA AD 2020-0011R1.

Discussion of Final Airworthiness Directive

Comments


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

Conclusion


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 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.

Related Service Information Under 1 CFR Part 51


The FAA reviewed ASB 139-609 Rev A, which specifies procedures for
replacing an affected MGB lock nut with
the new MGB lock nut, within certain compliance times for certain part-
numbered MGBs with certain serial numbers.
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.

Other Related Service Information


The FAA also reviewed Leonardo Helicopters ASB No. 139-567,
Revision B, dated October 18, 2019, which provides additional
information for replacing the MGB lock nut.

Differences Between This AD and EASA AD 2021-0121


EASA AD 2021-0121 requires a compliance time based on number of
landings, whereas this AD requires a compliance time based on hours
TIS. The service information referenced in EASA AD 2021-0121 requires
submitting certain information and parts to Leonardo, whereas this AD
does not. EASA AD 2021-0121 applies to all serial-numbered Model AB139
and AW139 helicopters, whereas this AD only applies to Model AB139 and
AW139 helicopters without certain part-numbered MGB lock nuts installed
and with certain part-numbered MGBs installed.

Costs of Compliance


The FAA estimates that this AD affects 130 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 each affected MGB lock nut with a newly designed MGB lock
nut takes about 190 work-hours (during next MGB overhaul) and parts
cost about $7,600 for an estimated cost of $23,750 per replacement.

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: