DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2017-0667; Directorate Identifier 2016-SW-053-AD]
RIN 2120-AA64

Airworthiness Directives; Bell Helicopter Textron Canada Limited
(Bell) 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 Model 407 helicopters. This proposed AD would require repetitive
inspections of the tail rotor (TR) driveshaft segment assemblies and a
torque check of the TR adapter retention nuts. This proposed AD is
prompted by a report of an in-flight failure of the TR drive system.
The proposed actions are intended to detect and correct an unsafe
condition on these products.

DATES: We must receive comments on this proposed AD by September 5, 2017.

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-2017-0667;
or in person at the Docket Operations Office 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 the Docket Operations Office (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: David Hatfield, Aviation Safety
Engineer, Safety Management Group, Rotorcraft Directorate, FAA, 10101
Hillwood Pkwy., Fort Worth, TX 76177; telephone (817) 222-5110; email
david.hatfield@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-2016-21, dated July 7, 2016 (AD CF-2016-21),
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. The helicopter landed safely with substantial
damage to the TR segmented shaft and adapter splines, coupling, and
hanger bearings. 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 further 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.

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 Alert Service Bulletin (ASB) 407-16-113, dated
February 12, 2016 (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.

Proposed AD Requirements

This proposed AD would require inspecting each TR driveshaft
segment assembly for rotational and axial play between the adapter and
the TR driveshaft and determining the installation torque of each
adapter retention nut. For helicopters with 4,000 or more hours time-
in-service (TIS), the driveshaft assembly inspection would be required
within 50 hours TIS. For helicopters with less than 4,000 hours TIS,
the driveshaft assembly inspection would be required within 100 hours
TIS. Thereafter, these inspections would be required at intervals not
to exceed 330 hours TIS. The torque verification of the adapter
retention nuts would be a one-time inspection.

If there is play or looseness in the TR driveshaft, the
proposed AD would require correcting the discrepant splined fitting
before further flight.

The proposed AD would also require replacing the adapter
retention nut anytime the adapter is re-assembled.

Costs of Compliance

We estimate that this proposed AD would affect 667 helicopters of
U.S. Registry. We estimate that operators may incur the following costs
in order to comply with this proposed AD. At an average labor rate of
$85 per hour, inspecting the TR driveshaft segments and adapters for
play would require about 1 work-hour, for a cost per helicopter of $85,
and a total cost of $56,695 to the U.S. fleet per inspection cycle.
Determining the torque of the four adapter retention nuts would require
about 3 work-hours for a cost per helicopter of $255 and a total 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 would cost about $1,259, for a
cost per helicopter of $1,514.

Replacing an adapter retention nut would require 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 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):