DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2017-1105; Product Identifier 2017-SW-023-AD]
RIN 2120-AA64

Airworthiness Directives; Bell Helicopter Textron Canada
Helicopters

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: We propose to adopt a new airworthiness directive (AD) for
Bell Helicopter Textron Canada (BHTC) Model 427 helicopters. This
proposed AD would require inspecting the inboard skin of the vertical
fin around the four tailboom attachment points. This proposed AD is
prompted by reports of cracked vertical fin skins that resulted from
metal fatigue. The actions of this proposed AD are intended to prevent
an unsafe condition on these products.

DATES: We must receive comments on this proposed AD by July 31, 2018.

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

Federal eRulemaking Docket: Go to http://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 http://www.regulations.
gov by searching for and locating Docket No. FAA-2017-1105;
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 Transport Canada AD, the economic evaluation, any
comments received, and other information. The street address for Docket
Operations (telephone 800-647-5527) is in the ADDRESSES section.
Comments will be available in the AD docket shortly after receipt.

For service information identified in this proposed rule, contact
Bell Helicopter Textron Canada Limited, 12,800 Rue de l'Avenir,
Mirabel, Quebec J7J1R4; telephone (450) 437-2862 or (800) 363-8023; fax
(450) 433-0272; or at http://www.bellcustomer.com/files/. You may
review 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: Matt Fuller, Senior Aviation Safety
Engineer, Safety Management Section, Rotorcraft Standards Branch, FAA,
10101 Hillwood Pkwy., Fort Worth, TX 76177; telephone (817) 222-5110;
email matthew.fuller@faa.gov.

SUPPLEMENTARY INFORMATION:

Comments Invited

We invite you to participate in this rulemaking by submitting
written comments, data, or views. We also invite 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.

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

Discussion

Transport Canada, which is the aviation authority for Canada, has
issued Canadian AD No. CF-2017-03, dated January 31, 2017, to correct
an unsafe condition for BHTC Model 427 helicopters with vertical fin
part number (P/N) 427-035-840-105 or P/N 427-035-840-109 installed.
Transport Canada advises of three reports of cracked vertical fin skins
that resulted from metal fatigue. If not detected, the crack may grow
to a critical length, causing the fin to fail, separate from the
helicopter and damage the main or tail rotor blades, leading to their
in-flight failure. Loss of the fin may also adversely affect the
helicopter's directional stability, leading to loss of directional
control, Transport Canada advises.

Transport Canada consequently requires repetitively inspecting the
vertical fins for a crack, and if a crack is detected, replacing the
fin before further flight.

FAA's Determination

These helicopters have been approved by the aviation authority of
Canada and are approved for operation in the United States. Pursuant to
our bilateral agreement with Canada, Transport Canada, its technical
representative, has notified us of the unsafe condition described in
its AD. We are proposing this AD because we evaluated all known
relevant information and determined that an unsafe condition is likely
to exist or develop on other products of the same type design.

Related Service Information Under 1 CFR Part 51

We reviewed Bell Helicopter Alert Service Bulletin 427-15-38,
Revision A, dated November 14, 2016, which specifies recurring
inspections of the vertical fins every 100 hours time-in-service (TIS)
once the vertical fin has accumulated 1,500 hours TIS. This inspection
also was incorporated in Chapter 4 of the maintenance manual. This
service information also specifies that serial numbers be assigned to
vertical fins that do not have a serial number.

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 within 25 hours TIS or before the
helicopter has accumulated 1,500 hours TIS, whichever occurs later and
thereafter at intervals not to exceed 100 hours TIS:

Removing and cleaning the vertical fin attachment area.

Using a 10X magnifying glass, visually inspecting the
inboard skin of the vertical fin around the four tailboom attachment
points for a crack and replacing the fin before further flight if there
is a crack.

Assigning a serial number if the vertical fin does not
have a serial number.

Costs of Compliance

We estimate that this proposed AD would affect 27 helicopters of
U.S. Registry and that labor costs average $85 a work hour. Based on
these estimates, we expect the following costs:

Performing the visual inspection would require 2.25 work-
hours and no parts for a cost of about $191 per helicopter and $5,157
for the U.S. fleet per inspection cycle.

Replacing the fin would require 4 work-hours, and parts
would cost $10,000, for a cost of $10,340 per helicopter.

Assigning a serial number to the fin would require 0.5
work-hour for a cost of $43 per helicopter.

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.

We are 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

We 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. Is not a "significant rule" under the DOT Regulatory Policies
and Procedures (44 FR 11034, February 26, 1979);

3. Will not affect intrastate aviation in Alaska to the extent that
it justifies making a regulatory distinction; and

4. 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.

We prepared an economic evaluation of the estimated costs to comply
with this proposed AD and placed it in the AD docket.

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):