DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2017-0667; Product Identifier 2016-SW-053-AD; Amendment
39-19281; AD 2018-10-06]
RIN 2120-AA64

Airworthiness Directives; Bell Helicopter Textron Canada Limited
(Bell) Helicopters

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule.

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SUMMARY: We are adopting a new airworthiness directive (AD) for Bell
Model 407 helicopters. This AD requires repetitive inspections of the
tail rotor (TR) driveshaft segment assemblies and a torque check of the
TR adapter retention nuts. This AD was prompted by a report of an in-
flight failure of the TR drive system. The actions of this AD are
intended to detect and correct an unsafe condition on these products.

DATES: This AD is effective June 25, 2018.
The Director of the Federal Register approved the incorporation by
reference of a certain document listed in this AD as of June 25, 2018.

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 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. It is also available on the internet at http://www.
regulations.gov by searching for and locating Docket No. FAA-2017-
0667.

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-
0667; 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 incorporated-by-reference service
information, the economic evaluation, any comments received, and other
information. The street address for Docket Operations (phone: 800-647-
5527) is U.S. Department of Transportation, Docket Operations, M-30,
West Building Ground Floor, Room W12-140, 1200 New Jersey Avenue SE,
Washington, DC 20590.

FOR FURTHER INFORMATION CONTACT: David Hatfield, Aviation Safety
Engineer, Safety Management Section, Rotorcraft Standards Branch, FAA,
10101 Hillwood Pkwy, Fort Worth, TX 76177; telephone (817) 222-5110;
email david.hatfield@faa.gov.

SUPPLEMENTARY INFORMATION:

Discussion

On July 7, 2017, at 82 FR 31535, the Federal Register published our
notice of proposed rulemaking (NPRM), which proposed to amend 14 CFR
part 39 by adding an AD that would apply to Bell Model 407 helicopters.
The NPRM proposed to require repetitively inspecting each TR driveshaft
segment assembly for rotational and axial play between the adapter and
the TR driveshaft. The NPRM also proposed a one-time verification of
the installation torque of each adapter retention nut. The proposed
requirements were intended to detect a loose TR driveshaft splined
connection, which if not corrected could result in wear in the splines,
failure of the TR drive system, and subsequent loss of directional
control of the helicopter.
The NPRM was prompted by AD No. CF-2016-21, dated July 7, 2016 (AD
CF-2016-21), issued by Transport Canada, which is the aviation
authority for Canada, to correct an unsafe condition for Bell Model 407
helicopters. Transport Canada advises that a Model 407 helicopter
experienced in-flight failure of the TR drive system, which resulted in
loss of directional control. According to Transport Canada, the splines
connecting the adapter part number (P/N) 406-040-328-105 to the shaft
assembly P/N 407-040-330-107 were ``severely worn and no longer capable
of performing their function.'' The investigation revealed other Model
407 helicopters with the same axial and radial play or looseness of
some splined connections. AD CF-2016-21 states that these parts should
be clamped together with threaded fasteners with no detectable
looseness. Transport Canada advises that undetected looseness at the
splined connection could result in wear of the parts and eventual loss
of directional control of the helicopter.
For these reasons, AD CF-2016-21 requires a repetitive inspection
of the TR driveshaft assemblies for play and a one-time torque
verification of the TR adapter retention nuts.
Since the NPRM was issued, the FAA's Aircraft Certification Service
has changed its organization structure. The new structure replaces
product directorates with functional divisions. We have revised some of
the office titles and nomenclature throughout this Final rule to
reflect the new organizational changes. Additional information about
the new structure can be found in the Notice published on July 25, 2017
(82 FR 34564).

Comments

After our NPRM was published, we received comments from two
commenters.

Request

Westwind Helicopters questioned the need for the AD. In support, it
stated that the AD inspections are identical to the periodic and
progressive inspections in the Bell maintenance manual and to the one-
time inspection in Bell Alert Service Bulletin (ASB) 407-16-113, dated
February 12, 2016 (ASB 407-16-113). The commenter noted the AD would
result in multiple documentation requirements for operators for the
same maintenance item. The commenter did not request a change to the
AD.
We partially agree. The commenter is correct that the AD may result
in additional documentation. However, while an operator may incorporate
the procedures described in the Bell maintenance manuals and ASB into
its maintenance program, not all operators are required to do so. In
order for the inspections to become mandatory, and to correct the
unsafe condition identified in the NPRM, the FAA must issue an AD.
Bell requested that a statement be added to the AD that
accomplishing the Bell ASB meets the intent of the AD and that no
further action is required.
We partially agree. Operators may take credit for inspections
previously accomplished in accordance with ASB 407-16-113 under
paragraph (d) of the AD. However, we disagree that no further action is
required because this AD requires repetitive inspections of the TR
driveshaft, whereas ASB 407-16-113 specifies a one-time inspection.

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 issuing this AD because we evaluated all information
provided by Transport Canada, reviewed the relevant information,
considered the comments received, and determined the 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

We reviewed ASB 407-16-113, which specifies procedures for
inspecting the TR driveshaft assemblies for noticeable rotational or
axial play between each adapter and TR driveshaft. ASB 407-16-113 also
specifies procedures for performing a torque check of each TR adapter
retention nut on the four TR driveshaft segments.
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.
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.

Costs of Compliance

We estimate this AD affects 667 helicopters of U.S. Registry. We
estimate that operators will incur the following costs in order to
comply with this AD. At an average labor rate of $85 per work-hour,
inspecting the TR driveshaft segments and adapters for play requires
about 1 work-hour, for a cost per helicopter of $85, and a cost of
$56,695 to the U.S. fleet per inspection cycle. Determining the torque
of the four adapter retention nuts requires about 3 work-hours for a
cost per helicopter of $255 and a cost of $170,085 to the U.S. fleet.
If required, repairing a worn driveshaft adapter would require
about 3 work-hours, and required parts cost about $1,259, for a cost
per helicopter of $1,514.
Replacing an adapter retention nut requires about 1 work-hour, and
required parts cost are negligible, for a cost of $85 per helicopter
and $56,695 for the U.S. fleet per inspection cycle.

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 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) Is not a ``significant rule'' under 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 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):