DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2020-0378; Product Identifier 2018-SW-060-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 Airbus Helicopters Model AS350B, AS350B1, AS350B2, AS350B3,
AS350BA, AS350C, AS350D, AS350D1, AS355E, AS355F, AS355F1, AS355F2,
AS355N, AS355NP, EC130B4, and EC130T2 helicopters. This proposed AD
would require visually inspecting each main rotor gearbox (MGB)
suspension bar attachment bracket bolt for missing bolt heads.
Depending on the outcome of the visual inspection, measuring the
tightening torque, removing certain parts, sending photos and reporting
information to Airbus Helicopters, and completing an FAA-approved
repair would be required. This proposed AD is prompted by a report of a
missing MGB suspension bar attachment bolt head. The actions of this
proposed AD are intended to address an unsafe condition on these
products.

DATES: The FAA must receive comments on this proposed AD by June 12,
2020.

ADDRESSES: You may send comments by any of the following methods:

Federal eRulemaking Docket: Go to https://www.regulations.gov. Follow the
online instructions for sending your comments electronically.

Fax: 202-493-2251.

Mail: Send comments to the U.S. Department of
Transportation, Docket Operations, M-30, West Building Ground Floor,
Room W12-140, 1200 New Jersey Avenue SE, Washington, DC 20590-0001.

Hand Delivery: Deliver to the "Mail" address between 9
a.m. and 5 p.m., Monday through Friday, except Federal holidays.

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-
0378; 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 proposed AD, the European Union Aviation Safety Agency (previously
European Aviation Safety Agency) (EASA) AD, 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 service information identified in this proposed 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.

FOR FURTHER INFORMATION CONTACT: Kristi Bradley, Aerospace Engineer,
Safety Management Section, Rotorcraft Standards Branch, FAA, 10101
Hillwood Pkwy., Fort Worth, TX 76177; telephone 817-222-5110; email
kristin.bradley@faa.gov.

SUPPLEMENTARY INFORMATION:

Comments Invited

The FAA invites you to participate in this rulemaking by submitting
written comments, data, or views. The FAA also invites comments
relating to the economic, environmental, energy, or federalism impacts
that might result from adopting the proposals in this document. The
most helpful comments reference a specific portion of the proposal,
explain the reason for any recommended change, and include supporting
data. To ensure the docket does not contain duplicate comments,
commenters should send only one copy of written comments, or if
comments are filed electronically, commenters should submit only one
time.

The FAA will file in the docket all comments received, as well as a
report summarizing each substantive public contact with FAA personnel
concerning this proposed rulemaking. Before acting on this proposal,
the FAA will consider all comments received on or before the closing
date for comments. The FAA will consider comments filed after the
comment period has closed if it is possible to do so without incurring
expense or delay. The FAA may change this proposal in light of the
comments received.

Discussion

EASA, which is the Technical Agent for the Member States of the
European Union, has issued EASA AD No. 2018-0152, dated July 18, 2018
(EASA AD 2018-0152), to correct an unsafe condition for Airbus
Helicopters (formerly Eurocopter, Eurocopter France) Model AS 350 B, AS
350 D, AS 350 B1, AS 350 B2, AS 350 BA, AS 350 BB, AS 350 B3, EC 130
B4, EC 130 T2, AS 355 E, AS355 F, AS355 F1, AS 355 F2, AS 355 N, and
AS355 NP helicopters.

EASA advises of a reported occurrence of a missing MGB suspension
bar attachment bolt head. EASA advises that investigations are ongoing
to determine the root cause of this event. According to Airbus
Helicopters, the missing MGB suspension bar attachment bolt head was
discovered during scheduled maintenance of a Model EC 130 T2
helicopter. EASA states this condition could lead to fatigue failure of
other affected bolts of the same MGB bracket, possibly resulting in
loss of the MGB suspension bar and consequently loss of helicopter
control. As an interim measure to address this potential unsafe
condition, the EASA AD also includes Model AS 350 B, AS 350 D, AS 350
B1, AS 350 B2, AS 350 BA, AS 350 BB, AS 350 B3, EC 130 B4, AS 355 E,
AS355 F, AS355 F1, AS355 F2, AS355 N, and AS355 NP helicopters in its
applicability.

Accordingly, EASA AD 2018-0152 requires a one-time visual
inspection to check that all MGB suspension bar attachment bracket bolt
heads are present and depending on the outcome, measuring the
tightening torque values of the bolts, removing and sending bolts,
washers, and nuts to Airbus Helicopters, installing new bolts, washers,
and nuts, sending photos and reporting certain information to Airbus
Helicopters, and contacting Airbus Helicopters for approved repair
instructions. EASA states EASA AD 2018-0152 is considered an interim
action and further AD action may follow.

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 of the
unsafe condition described in its AD. The FAA is proposing this AD
because the FAA evaluated all known relevant information and determined
that an unsafe condition is likely to exist or develop on other
products of the same type designs.

Related Service Information Under 1 CFR Part 51

The FAA reviewed Airbus Helicopter Alert Service Bulletin (ASB) No.
AS350-05.00.92 for Model AS350B, B1, B2, B3, BA, and D helicopters,
non-FAA type-certificated Model AS350BB helicopters, and military Model
AS350L1 helicopters; Airbus Helicopters ASB No. AS355-05.00.79 for
Model AS355E, F, F1, F2, N, and NP helicopters; and Airbus Helicopters
ASB No. EC130-05A028 for Model EC130B4 and T2 helicopters, all Revision
0 and dated July 16, 2018. This service information specifies a one-
time visual inspection using a light source and a mirror, and using an
endoscope for any attachment bolts that are difficult to access, for
the presence of the 16 attachment bracket bolt heads of the 4 MGB
suspension bars. The service information also specifies different
actions depending on the results of the visual inspection.

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 Airbus Standard Practices Manual (MTC) 20-02-
05-404, Assembly by screws and nuts Joining, dated May 23, 2017. This
service information specifies instructions for installing screws and
nuts, tightening procedures when installing multiple bolts, tightening
torque check and readjustment procedures, tooling information,
measuring locking torque procedures, standard tightening torque
procedures and values, torque tightening of screws in sandwich panels
information, use of consumable materials and their correction
coefficient values pertaining to screws, nuts, and washers, marking
torque stripes, and re-installation criteria and inspection of
attachment components.

Proposed AD Requirements

This proposed AD would require visually inspecting each MGB
suspension bar attachment bracket for missing bolt heads.

If one bolt head is missing, this proposed AD would require
performing actions specified in the service information including
measuring the tightening torque of the remaining bolts of that bracket,
removing the attachment bracket bolts, washers, and nuts of that
bracket, and sending photos and reporting certain information to Airbus
Helicopters.

If two or more bolt heads are missing, this proposed AD would
require repairs in accordance with an FAA-approved method as described
in paragraph (e) of this AD.

Differences Between This Proposed AD and the EASA AD

The EASA AD applies to Model AS350BB helicopters, whereas this
proposed AD does not because that model is not FAA type-certificated.
The EASA AD directs the operators to contact Airbus Helicopters for
repairs if more than one screw head is missing, whereas this proposed
AD does not.

Interim Action

The FAA considers this proposed AD to be an interim action. If
final action is later identified, the FAA might consider further
rulemaking.

Costs of Compliance

The FAA estimates that this proposed AD would affect 1,277
helicopters of U.S. Registry. The FAA estimates that operators may
incur the following costs in order to comply with this AD. Labor costs
are estimated at $85 per work-hour.

Inspecting for any missing MGB suspension bar attachment bracket
bolt heads would take about 2 work-hours for an estimated cost of $170
per helicopter and $217,090 for the U.S. fleet.

Measuring the tightening torque of three MGB suspension bar
attachment bracket bolts and replacing the set of four MGB suspension
bar attachment bracket bolts, washers, and nuts would take about 1
work-hour and parts would cost about $50 for an estimated replacement
cost of $135 per helicopter. Sending photos and reporting required
information would take about 1 work-hour for an estimated cost of $85
per helicopter.

The FAA does not have the data to estimate the costs to do any FAA-
approved repairs if two or more MGB suspension bar attachment bracket
bolt heads are missing.

Paperwork Reduction Act

A federal agency may not conduct or sponsor, and a person is not
required to respond to, nor shall a person be subject to a penalty for
failure to comply with a collection of information subject to the
requirements of the Paperwork Reduction Act unless that collection of
information displays a currently valid OMB Control Number. The OMB
Control Number for this information collection is 2120-0056. Public
reporting for this collection of information is estimated to be
approximately 1 hour per response, including the time for reviewing
instructions, searching existing data sources, gathering and
maintaining the data needed, and completing and reviewing the
collection of information. All responses to this collection of
information are mandatory. Send comments regarding this burden estimate
or any other aspect of this collection of information, including
suggestions for reducing this burden to: Information Collection
Clearance Officer, Federal Aviation Administration, 10101 Hillwood
Parkway, Fort Worth, TX 76177-1524.

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, 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):