DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2017-1105; Product Identifier 2017-SW-023-AD; Amendment
39-19803; AD 2019-23-09]
RIN 2120-AA64

Airworthiness Directives; Bell Helicopter Textron Canada Limited
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
Bell Helicopter Textron Canada Limited (BHTC) Model 427 helicopters.
This AD requires inspecting the inboard skin of the vertical fin around
the four tailboom attachment points. This AD was prompted by reports of
cracked vertical fin skins that resulted from metal fatigue. The
actions of this AD are intended to prevent an unsafe condition on these
products.

DATES: This AD is effective January 10, 2020.
The Director of the Federal Register approved the incorporation by
reference of a certain document listed in this AD as of January 10,
2020.

ADDRESSES: For service information identified in this final 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 https://www.bellcustomer.com. You may review the
referenced service information at the FAA, Office of the Regional Counsel, South-
west 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-2017-1105.

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-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 AD, the Transport Canada AD, any service information that is
incorporated by reference, the economic evaluation, 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: 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:

Discussion

On June 1, 2018, at 83 FR 25408, the Federal Register published the
FAA's notice of proposed rulemaking (NPRM), which proposed to amend 14
CFR part 39 by adding an AD that would apply to BHTC Model 427
helicopters with a vertical fin part number (P/N) 427-035-840-105 or P/
N 427-035-840-109 installed. The NPRM proposed to require inspecting
the inboard skin of the vertical fin around the four tailboom
attachment points. The proposed requirements were intended to detect a
crack on the vertical fin skin. This condition could lead to structural
failure of the fin, separation of the skin from the helicopter, damage
to the main or tail rotor blades and loss of helicopter control.
The NPRM was prompted by Canadian AD No. CF-2017-03, dated January
31, 2017 (Transport Canada AD CF-2017-03), issued by Transport Canada,
which is the aviation authority for Canada, to correct an unsafe
condition for BHTC Model 427 helicopters with vertical fin 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.

Comments

After the NPRM was published, the FAA received comments from one
commenter. However, the comment addressed neither the proposed actions
nor the determination of the cost to the public. Therefore, the FAA has
made no changes to this AD.

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
the FAA's bilateral agreement with Canada, Transport Canada, its
technical representative, has notified the FAA about the unsafe
condition described in the Transport Canada AD. The FAA is issuing this
AD after evaluating all known relevant information and determined that
an unsafe condition exists and is likely to exist or develop on other
helicopters of these same type designs and that air safety and the
public interest require adopting the AD requirements as proposed.

Related Service Information Under 1 CFR Part 51

The FAA reviewed Bell Helicopter Alert Service Bulletin 427-15-38,
Revision A, dated November 14, 2016, which specifies repetitive
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 serial numbers are to 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.

Costs of Compliance

The FAA estimates that this AD affects 27 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.
Performing the visual inspection requires about 2.25 work-
hours for an estimated cost of $191 per helicopter and $5,157 for the
U.S. fleet.
Replacing the fin requires about 4 work-hours, and parts
cost about $10,000, for an estimated cost of $10,340 per helicopter.
Assigning a serial number to the fin takes about 0.5 work-
hours for an estimated 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.
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.
The FAA prepared an economic evaluation of the estimated costs to
comply with this 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.

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 (AD):