DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2020-0847; Product Identifier 2018-SW-087-AD; Amendment
39-21434; AD 2021-04-13]
RIN 2120-AA64

Airworthiness Directives; Airbus Helicopters

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule.

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SUMMARY: The FAA is adopting a new airworthiness directive (AD) for all
Airbus Helicopters Model AS350B, AS350BA, AS350B1, AS350B2, AS350B3,
and AS350D helicopters; Model AS355E, AS355F, AS355F1, AS355F2, AS355N,
and AS355NP helicopters; and Model EC130 B4 and EC130 T2 helicopters.
This AD requires a one-time inspection to verify the presence and
correct installation of the main rotor mast (MRM) upper bearing
retaining rings, a repetitive inspection of the sealant bead on the MRM
for damage, and corrective actions if necessary. This AD was prompted
by a report of a missing retaining ring of the inner race of the MRM upper
bearing. The actions of this AD are intended to address an unsafe
condition on these products.

DATES: This AD is effective April 14, 2021.
The Director of the Federal Register approved the incorporation by
reference of certain documents listed in this AD as of April 14, 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. It is also available on the internet at https://www.
regulations.gov by searching for and locating Docket No. FAA-2020-0847.

Examining the AD Docket

You may examine the AD docket on the internet at https://www.regulations.gov
by searching for and locating Docket No. FAA-2020-
0847; 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 AD, the European Aviation Safety Agency (now European Union
Aviation Safety Agency) (EASA) AD, any service information that is
incorporated by reference, 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: Scott Franke, Aviation Safety
Engineer, General Aviation & Rotorcraft Section, International
Validation Branch, FAA, 10101 Hillwood Pkwy., Fort Worth, TX 76177;
telephone 817-222-5110; email scott.franke@faa.gov.

SUPPLEMENTARY INFORMATION:

Discussion

The FAA issued a notice of proposed rulemaking (NPRM) to amend 14
CFR part 39 by adding an AD that would apply to all Airbus Helicopters
Model AS350B, AS350BA, AS350B1, AS350B2, AS350B3, and AS350D
helicopters; Model AS355E, AS355F, AS355F1, AS355F2, AS355N, and
AS355NP helicopters; and Model EC130 B4 and EC130 T2 helicopters. The
NPRM published in the Federal Register on September 21, 2020 (85 FR
59217). The NPRM proposed to require a one-time inspection to verify
the presence and correct installation of the MRM upper bearing
retaining rings, a repetitive inspection of the sealant bead on the MRM
for damage, and corrective actions if necessary. The proposed
requirements were intended to detect, and correct if applicable, a
missing retaining ring of the inner race of the MRM upper bearing. The
FAA is issuing this AD to address this condition, which, if not
detected and corrected, can lead to damage to the MRM and surrounding
elements, possibly resulting in loss of control of the helicopter.
The NPRM was prompted by EASA AD 2018-0206, dated September 20,
2018 (EASA AD 2018-0206), issued by EASA, which is the Technical Agent
for the Member States of the European Union, to correct an unsafe
condition for certain Airbus Helicopters Model AS350B, AS350BA,
AS350BB, AS350B1, AS350B2, AS350B3, and AS350D helicopters; Model
AS355E, AS355F, AS355F1, AS355F2, AS355N, and AS355NP helicopters; and
Model EC130 B4 and EC130 T2 helicopters. Model AS355BB helicopters are
not certificated by the FAA and are not included on the U.S. type
certificate data sheet; this AD therefore does not include those
helicopters in the applicability. EASA advises that during a scheduled
inspection on an Airbus Helicopters Model AS350B3 helicopter, one of
the two retaining rings of the inner race of the MRM upper bearing was
found missing. These two retaining rings ensure that the inner race is
correctly positioned with respect to the rollers, and, if one or both
of these retaining rings are missing, it can lead to an unlimited shift
of the inner race and compromise the function of the MRM upper bearing.
This condition, if not detected and corrected, can lead to damage to
the MRM and surrounding elements, possibly resulting in loss of control
of the helicopter.
Airbus Helicopters developed an inspection to check that the upper
and lower retaining rings of the inner race of the MRM upper bearing
are present and correctly installed. EASA determined that the same
condition may exist or develop on Airbus Helicopters Model AS350
helicopters, Model AS355 helicopters, and Model EC130 helicopters
because they share a similar design and supply chain. Until the check
of the upper and lower bearing retaining rings is accomplished, EASA
specifies that repetitive inspections of the MRM upper bearing sealant
bead (sealant bead) should be accomplished to ensure the MRM remains
serviceable. EASA considers its AD an interim measure pending further
investigation results, and notes that further AD action may follow.

Comments

The FAA gave the public the opportunity to participate in
developing this final rule. The FAA received 4 comments in support of
the NPRM.

FAA's Determination

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 issuing this AD after
evaluating all of the information provided by EASA and determining the
unsafe condition exists and is likely to exist or develop on other
helicopters of the same type design and that air safety and the public
interest require adopting the AD requirements as proposed.

Differences Between This AD and the EASA AD

Although EASA AD 2018-0206 specifies accomplishing the inspection
of the installation of the MRM upper bearing inner race retaining rings
within 660 hours time in service (TIS) or 24 months, whichever occurs
first, the FAA has determined that interval does not address the
identified unsafe condition soon enough to ensure an adequate level of
safety for the affected fleet. In developing an appropriate compliance
time for this AD, the FAA considered the degree of urgency associated
with the subject unsafe condition and the manufacturer's
recommendation. In light of all of these factors, the FAA finds that a
compliance time of within 660 hours TIS or 6 months, whichever occurs
first, represents an appropriate interval of time for affected
helicopters to continue to operate without compromising safety.
Although paragraph (5) of EASA AD 2018-0206 specifies that
operators may contact the manufacturer for instructions if there are
signs of degradation on the MRM inner race, paragraph (i)(3) of this AD
requires operators to repair or replace the MRM if there is any
degradation as indicated by damage to the retaining rings (including
but not limited to cracks, scratches, and gouges), deterioration, or
wear.

Related Service Information Under 1 CFR Part 51

Airbus Helicopters has issued the following service information.
Airbus Helicopters Alert Service Bulletin AS350-62.00.42,
Revision 0, dated September 17, 2018.
Airbus Helicopters Alert Service Bulletin AS355-62.00.37,
Revision 0, dated September 17, 2018.
Airbus Helicopters Alert Service Bulletin EC130-62A017,
Revision 0, dated September 17, 2018.
This service information describes procedures for a one-time
inspection to verify presence and correct installation of the MRM upper
bearing retaining rings, a repetitive inspection of the sealant bead on
the MRM for damage, and corrective actions. Damage of the sealant bead
includes flaws, cracks, folds, separation, or absence of the sealant
bead. Corrective actions include repair and replacement. These
documents are distinct since they apply to different helicopter models.
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.

Costs of Compliance

The FAA estimates that this AD affects 1,212 helicopters of U.S.
registry. The FAA estimates the following costs to comply with this AD:

Estimated Costs for Required Actions

The FAA estimates the following costs to do any necessary on-
condition actions that would be required based on the results of any
required actions. The FAA has no way of determining the number of
aircraft that might need these on-condition actions:

Estimated Costs of On-Condition Actions

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.

Adoption of 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.