DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2020-0847; Product Identifier 2018-SW-087-AD]
RIN 2120-AA64

Airworthiness Directives; Airbus Helicopters

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: The FAA proposes to adopt 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 proposed AD was prompted by a report of a missing
retaining ring of the inner race of the main rotor mast (MRM) upper
bearing. This proposed AD would 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 FAA is proposing
this AD to address the unsafe condition on these products.

DATES: The FAA must receive comments on this proposed AD by November 5,
2020.

ADDRESSES: You may send comments, using the procedures found in 14 CFR
11.43 and 11.45, by any of the following methods:

Federal eRulemaking Portal: Go to https://www.regulations.gov. Follow
the instructions 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 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 this service information at the FAA, Office of the Regional
Counsel, Southwest Region, 10101 Hillwood Pkwy., Room 6N-321, Fort
Worth, TX 76177.

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 NPRM, the Mandatory Continuing Airworthiness Information (MCAI),
any comments received, and other information. The street address for
Docket Operations is listed above. Comments will be available in the AD
docket shortly after receipt.

FOR FURTHER INFORMATION CONTACT: Scott Franke, Aviation Safety
Engineer, International Validation Branch, General Aviation &
Rotorcraft Unit, FAA, 10101 Hillwood Pkwy., Fort Worth, TX 76177;
telephone 817-222-5110; email scott.franke@faa.gov.

SUPPLEMENTARY INFORMATION:

Comments Invited

The FAA invites you to send any written relevant data, views, or
arguments about this proposal. Send your comments to an address listed
under the ADDRESSES section. Include "Docket No. FAA-2020-0847;
Product Identifier 2018-SW-087-AD" 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 NPRM 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 FAA 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 Scott Franke, Aviation Safety
Engineer, International Validation Branch, General Aviation &
Rotorcraft Unit, FAA, 10101 Hillwood Pkwy., Fort Worth, TX 76177;
telephone 817 222-5110; email scott.franke@faa.gov. Any commentary that
the FAA receives which is not specifically designated as CBI will be
placed in the public docket for this rulemaking.

Discussion

The European Aviation Safety Agency (now European Union Aviation
Safety Agency) (EASA), which is the Technical Agent for the Member
States of the European Union, has issued EASA AD 2018-0206, dated
September 20, 2018 (referred to after this as the Mandatory Continuing
Airworthiness Information, or "the MCAI"), 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 proposed 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 the actions specified in the MCAI an
interim measure pending further investigation results, and notes that
further AD action may follow.

You may examine the MCAI in the AD docket on the internet at
https://www.regulations.gov by searching for and locating Docket No.
FAA-2020-0847.

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.

FAA's Determination

This product has been approved by the aviation authority of another
country, and is approved for operation in the United States. Pursuant
to the FAA's bilateral agreement with the State of Design Authority,
the FAA has been notified of the unsafe condition described in the MCAI
and service information referenced above. The FAA is proposing this AD
after evaluating all the relevant information and determining the
unsafe condition described previously is likely to exist or develop on
other products of the same type design.

Proposed Requirements of This NPRM

This proposed AD would require accomplishing the actions specified
in the service information described previously, except as discussed
under "Differences Between this Proposed AD and the MCAI."

Differences Between This Proposed AD and the MCAI

Although the MCAI 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 would 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 the MCAI 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 proposed AD
would require 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.

Costs of Compliance

The FAA estimates that this proposed AD affects 1,212 helicopters
of U.S. registry. The FAA estimates the following costs to comply with
this proposed 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 products identified in this rulemaking action.

Regulatory Findings

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 above, I certify this proposed regulation:

(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 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 adding the following new airworthiness
directive (AD):