DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2022-0465; Project Identifier AD-2022-00330-R]
Airworthiness Directives; Leonardo S.p.a. Helicopters
AGENCY: Federal Aviation Administration (FAA), DOT.
ACTION: Notice of proposed rulemaking (NPRM).
SUMMARY: The FAA proposes to supersede Airworthiness Directive
2021-20-10, which applies to certain Leonardo S.p.a. Model AB139 and
AW139 helicopters. AD 2021-20-10 requires removing from service a
certain part-numbered main gearbox (MGB) spherical bearing lock nut
(lock nut) that is installed on certain part-numbered MGBs and
replacing it with a newly designed MGB lock nut. AD 2021-20-10 also
prohibits installing any MGB with the affected MGB lock nut and
prohibits installing any affected MGB lock nut on any helicopter. Since
the FAA issued AD 2021-20-10, it was discovered that a part number (P/
N) was incorrectly listed and that the applicability needed to be
clarified. This proposed AD would retain the requirements of AD 2021-
20-10 and would clarify the applicability. The FAA is proposing this AD
to address the unsafe condition on these products.
DATES: The FAA must receive comments on this proposed AD by June
ADDRESSES: You may send comments, using the procedures found in
11.43 and 11.45, by any of the following methods:
Federal eRulemaking Portal: Go to https://www.regulations.gov. Follow
for submitting comments.
Fax: (202) 493-2251.
Mail: U.S. Department of Transportation, Docket
Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New
Jersey Avenue SE, Washington, DC 20590.
Hand Delivery: Deliver to Mail address above between 9
a.m. and 5 p.m., Monday through Friday, except Federal holidays.
For service information identified in this NPRM, 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 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)
Examining the AD Docket
You may examine the AD docket at https://www.regulations.gov by
searching for and locating Docket No. FAA-2022-0465; 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 NPRM, the European
Union Aviation Safety Agency (EASA) AD, any comments received, and
other information. The street address for Docket Operations is listed
FOR FURTHER INFORMATION CONTACT: Kristi Bradley, Program Manager,
Program Management Section, Operational Safety Branch, Compliance &
Airworthiness Division, FAA, 10101 Hillwood Pkwy., Fort Worth, TX
76177; telephone (817) 222-5110; email firstname.lastname@example.org.
The FAA invites you to send any written relevant data, views, or
arguments about this proposal. Send your comments to an address listed
under ADDRESSES. Include ``Docket No. FAA-2022-0465; Project Identifier
AD-2022-00330-R'' at the beginning of your comments. The most helpful
comments reference a specific portion of the proposal, explain the
reason for any recommended change, and include supporting data. The FAA
will consider all comments received by the closing date and may amend
this proposal because of those comments.
Except for Confidential Business Information (CBI) as described in
the following paragraph, and other information as described in 14 CFR
11.35, the FAA will post all comments received, without change, to
https://www.regulations.gov, including any personal information you
provide. The agency will also post a report summarizing each
substantive verbal contact received about this NPRM.
Confidential Business Information
CBI is commercial or financial information that is both customarily
and actually treated as private by its owner. Under the Freedom of
Information Act (FOIA) (5 U.S.C. 552), CBI is exempt from public
disclosure. If your comments responsive to this NPRM contain commercial
or financial information that is customarily treated as private, that
you actually treat as private, and that is relevant or responsive to
this NPRM, it is important that you clearly designate the submitted
comments as CBI. Please mark each page of your submission containing
CBI as ``PROPIN.'' The FAA will treat such marked submissions as
confidential under the FOIA, and they will not be placed in the public
docket of this NPRM. Submissions containing CBI should be sent to
Kristi Bradley, Program Manager, COS Program Management Section,
Operational Safety Branch, Compliance & Airworthiness Division, FAA,
10101 Hillwood Pkwy., Fort Worth, TX 76177; telephone (817) 222-5110;
email email@example.com. Any commentary that the FAA receives
which is not specifically designated as CBI will be placed in the
public docket for this rulemaking.
The FAA issued AD 2021-20-10, Amendment 39-21748 (86 FR 57574,
October 18, 2021) (AD 2021-20-10), for Leonardo S.p.a. Model AB139 and
AW139 helicopters, without MGB lock nut 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.
AD 2021-20-10 requires, within 100 hours time in service (TIS), or
during the next scheduled MGB overhaul, whichever occurs first after
the effective date of the AD, removing a certain part-numbered MGB lock
nut from service and replacing it with a different part-numbered MGB
lock nut. AD 2021-20-10 also prohibits installing an MGB having an
affected MGB lock nut on any helicopter and also prohibits installing
an affected MGB lock nut on any helicopter as of the effective date of
AD 2021-20-10 was prompted by 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
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 retained the requirements of EASA AD 2020-0011 and corrected
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,
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.
Accordingly, EASA AD 2021-0121 requires replacing each affected MGB
lock nut with a newly designed MGB lock nut, and prohibits installing
an affected MGB on any helicopter.
Actions Since AD 2021-20-10 Was Issued
Since the FAA issued AD 2021-20-10, it was discovered that MGB P/N
3G6320A00133 is incorrectly listed as MGB P/N 3G320A00133 in both the
preamble and applicability paragraph of the AD. Also, the FAA
determined that all MGBs, regardless of S/N, are affected by the unsafe
Therefore, this proposed AD would remove any reference to S/Ns in the
applicability. In addition, this proposed AD includes the total U.S.
fleet costs, which were inadvertently excluded in AD 2021-20-10.
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 is proposing this AD
after evaluating all known relevant information and determining that
the unsafe condition described previously is likely to exist or develop
on other helicopters of the same type designs.
Related Service Information Under 1 CFR Part 51
This proposed AD would require Leonardo Helicopters Alert Service
Bulletin No. 139-609, Revision A, dated April 13, 2021, which the
Director of the Federal Register approved for incorporation by
reference as of November 22, 2021 (86 FR 57574, October 18, 2021).
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 Alert Service Bulletin
No. 139-567, Revision B, dated October 18, 2019, which provides
additional information for replacing the MGB lock nut.
Proposed AD Requirements in This NPRM
This proposed AD would retain all of the requirements of AD 2021-
Differences Between This Proposed AD and EASA AD 2021-0121
EASA AD 2021-0121 requires a compliance time based on number of
landings, whereas this proposed AD would require 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 proposed AD would not. EASA AD 2021-0121 applies to all
serial-numbered Model AB139 and AW139 helicopters, whereas this
proposed AD would apply to all Model AB139 and AW139 helicopters,
regardless of S/N, with a certain part-numbered MGB lock nut and MGB
Costs of Compliance
The FAA estimates that this AD, if adopted as proposed, would
affect 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 proposed AD.
Replacing each affected MGB lock nut with a newly designed MGB lock
nut would take about 190 work-hours (during next MGB overhaul) and
parts would cost about $7,600 for an estimated cost of $23,750 per
helicopter and $3,087,500 for the U.S. fleet.
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.
The FAA determined that this proposed AD would not have federalism
implications under Executive Order 13132. This proposed AD would 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, I certify this proposed regulation:
(1) Is not a ``significant regulatory action'' under Executive
(2) Would not affect intrastate aviation in Alaska, and
(3) Would 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
The Proposed Amendment
Accordingly, under the authority delegated to me by the
Administrator, the FAA proposes to amend 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:
a. Removing Airworthiness Directive 2021-20-10, Amendment 39-21748 (86
FR 57574, October 18, 2021); and
b. Adding the following new airworthiness directive: