[Federal Register Volume 86, Number 198 (Monday, October 18, 2021)]
[Rules and Regulations]
[Pages 57574-57577]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2021-22468]


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

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.

[[Page 57575]]


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 [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 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

[[Page 57576]]

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

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:

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: [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.

[[Page 57577]]

(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 
[email protected].
    (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 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 reference at the National Archives and Records Administration 
(NARA). For information on the availability of this material at 
NARA, email: [email protected], or go to: https://www.archives.gov/federal-register/cfr/ibr-locations.html.

    Issued on September 16, 2021.
Lance T. Gant,
Director, Compliance & Airworthiness Division, Aircraft Certification 
Service.
[FR Doc. 2021-22468 Filed 10-15-21; 8:45 am]
BILLING CODE 4910-13-P


