DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2020-0618; Product Identifier 2019-SW-064-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 AS-365N2, AS 365 N3, EC 155B, EC155B1, and
SA-365N1 helicopters. This proposed AD would require inspecting the
tail rotor gearbox (TGB) housing recess, and depending on the
inspection results, performing more in-depth inspections and removing
certain parts from service. The proposed AD would also prohibit
installing a TGB unless it has passed certain inspections and has a new
TGB control rod bearing installed. This proposed AD was prompted by the
discovery of a foreign object obstructing the oil duct of a TGB control
bearing. 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 August 7,
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-2020-0618;
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 (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: Rao Edupuganti, Aviation Safety
Engineer, Regulations and Policy Section, Rotorcraft Standards Branch,
FAA, 10101 Hillwood Pkwy., Fort Worth, TX 76177; telephone 817-222-
5110; email rao.edupuganti@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 that the FAA receives,
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. 2019-0165-E, dated July 12,
2019, to correct an unsafe condition for Airbus Helicopters (formerly
Eurocopter, Eurocopter France, Aerospatiale, Sud Aviation) Model AS 365
N2, AS 365 N3, EC 155 B, EC 155 B1, and SA 365 N1 helicopters. EASA
advises of a foreign object that was found obstructing the oil duct of
the TGB control bearing during a routine inspection, causing a lack of
lubrication on the bearing. EASA states this condition, if not detected
and corrected, could affect the correct operation of the TGB and
possibly result in reduced control of the helicopter.

Accordingly, the EASA AD requires a one-time inspection of the TGB
housing recess for oil retention and depending on the outcome of the
inspection, removing any foreign object from the TGB oil duct housing
and re-inspecting the TGB housing recess for oil retention. If there is
still oil retention, the EASA AD requires marking and returning the TGB
to Airbus Helicopters and installing a TGB that has passed the
inspection procedures specified in the related Airbus Helicopter
service information. If there is no oil retention, the EASA AD requires
removing any foreign object from the TGB oil duct cover and inspecting
the TGB oil duct cover for correct oil flow. If the oil does not flow
correctly, the EASA AD requires marking and returning the TGB to Airbus
Helicopters and installing a TGB that has passed the inspection
procedures specified in the related Airbus Helicopters service
information. If the oil flows correctly and a foreign object was
previously removed, the EASA AD requires replacing the TGB control rod
bearing with a new bearing. The EASA AD also prohibits installation of
a TGB unless it has passed the inspections specified in the related Airbus
Helicopters service information.

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
after evaluating all known relevant information and determining 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 one document that co-publishes four Airbus
Helicopters Emergency Alert Service Bulletin (EASB) identification
numbers: No. 65.00.09 for non FAA-type certificated military Model
AS565MA, MB, MBe, SA, SB, and UB helicopters; No. 65.00.19 for Model
AS365N1, N2, and N3 helicopters, and non FAA-type certificated military
Model AS365F, Fi, K, and K2 helicopters; No. 65.06 for non FAA-type
certificated military Model SA366GA helicopters; and No. 65A008 for
Model EC115B and B1 helicopters, all Revision 0 and dated July 10,
2019. EASB Nos. 65.00.19 and 65A008 are proposed for incorporation by
reference in this proposed AD. EASB Nos. 65.00.09 and 65.06 are not
proposed for incorporation by reference in this proposed AD.

This service information specifies procedures, using an endoscope
(borescope), to inspect the TGB housing recess for oil retention and
the two T holes for visibility. If there is oil retention and the two T
holes are not visible, this service information specifies removing the
TGB control rod and inspecting for and removing any foreign objects in
the TGB oil duct, and then repeating the TGB housing recess
inspections. If there is oil retention and the two T holes are not
visible after these additional inspections, the service information
specifies marking the TGB as not fit for helicopter installation and
returning the TGB to Airbus Helicopters. If there is no oil retention
and the two T holes are visible after these additional inspections, the
service information specifies removing any foreign objects in the TGB
oil duct and inspecting for proper oil flow at the end of the BTP oil
duct cover. If the oil does not flow properly, this service information
specifies marking the TGB as not fit for helicopter installation and
returning the TGB to Airbus Helicopters. If the oil flows properly, the
service information specifies replacing the TGB control rod bearing
with a new bearing.

This service information also specifies procedures to close the
filter plug cover with an airworthy O-ring, install the filter plug,
replace a TGB, and perform a ground run-up. Additionally, this service
information specifies procedures to perform the inspections on a non-
installed TGB.

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.

Proposed AD Requirements

This proposed AD would require compliance with portions of the
manufacturer's service information. This proposed AD would require
opening the TGB oil filter plug cover and removing the TGB oil filter
plug. This proposed AD would then require, using a borescope,
inspecting for oil retention and visibility of the two T holes in the
TGB housing recess. If there is any oil retention and the two T holes
are not completely visible, this proposed AD would require removing the
TGB control rod and inspecting for and removing any foreign object in
the TGB oil duct. This proposed AD would then require re-inspecting the
TGB housing recess with all of the oil drained. If, during the re-
inspection, there is any oil retention and the two T holes are not
completely visible, this proposed AD would require replacing the TGB.
If, during the re-inspection, there is no oil retention and the two T
holes are completely visible, this proposed AD would require inspecting
for and removing any foreign object from the TGB oil duct and
inspecting the TGB oil duct for correct oil flow. If the oil does not
flow correctly, this proposed AD would require replacing the TGB. If
the oil flows correctly, this proposed AD would require removing the
TGB control rod bearing from service.

This proposed AD would also prohibit the installation of a TGB
unless it passes the inspections required by this AD. A non-installed
TGB would be inspected in a level position using shims.

Differences Between This Proposed AD and the EASA AD

If required to remove a TGB, the EASA AD requires marking and
returning the TGB to Airbus Helicopters, whereas this proposed AD would
not require marking or returning the TGB to Airbus Helicopters.

Costs of Compliance

The FAA estimates that this proposed AD affects 20 helicopters of
U.S. Registry. The FAA estimates that operators may incur the following
costs in order to comply with this proposed AD. Labor costs are
estimated at $85 per work-hour.

Inspecting the TGB housing recess would take about 2 work-hours for
an estimated cost of $170 per helicopter and $3,400 for the U.S. fleet.

Inspecting for and removing any foreign objects would take a
minimal amount of time and have a nominal cost.

Removing any oil retention and re-inspecting the TGB would take
about 5 work-hours for an estimated cost of $425 per helicopter.

Inspecting for correct oil flow would take about 1 work-hour for an
estimated cost of $85 per helicopter.

Replacing the TGB control rod bearing would take about 8 work-hours
and parts would cost about $2,000 for an estimated replacement cost of
$2,680 per bearing.

Replacing a TGB would take about 40 work-hours and parts would cost
about $48,600 (overhauled) for an estimated replacement cost of $52,000
per TGB.

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):