DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2017-1125; Product Identifier 2017-SW-078-AD]
RIN 2120-AA64

Airworthiness Directives; MD Helicopters Inc. 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 MD
Helicopters Inc. (MDHI) Model 600N helicopters. This proposed AD would
require establishing a life limit for the main rotor (M/R) blade upper
control collective/longitudinal link assembly (link assembly). This
proposed AD is prompted by the discovery that the life limit was
omitted from the maintenance manual. 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 November 9, 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-
1125; or in person at the Docket Operations between 9 a.m. and 5 p.m.,
Monday through Friday, except Federal holidays. The AD docket contains
this proposed AD, the economic evaluation, any comments received, and
other information. The street address for the 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
MD Helicopters, Inc., Attn: Customer Support Division, 4555 E. McDowell
Rd., Mail Stop M615, Mesa, AZ 85215-9734; telephone 1-800-388-3378; fax
480-346-6813; or at http://www.mdhelicopters.com. 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: Galib Abumeri, Aerospace Engineer
(Structures), Airframe Section, Los Angeles ACO Branch, Compliance and
Airworthiness Division, FAA, 3960 Paramount Blvd., Lakewood, California
90712; telephone 562-627-5324; email galib.abumeri@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

We propose to adopt a new AD for MDHI Model 600N helicopters with a
yaw stability augmentation system and with a link assembly part number
(P/N) 600N7617-1 installed. This proposed AD would require establishing
a life limit of 15,000 hours time-in-service (TIS) for the link
assembly.

This proposed AD is prompted by a report from MDHI that during a
review of the Airworthiness Limitations section of the applicable
maintenance manual, MDHI discovered that it did not include a life
limit for link assemblies installed on MDHI Model 600N helicopters with
a yaw stability augmentation system. Link assembly P/N 600N7617-1,
which is made of aluminum, is a life-limited part with a life limit of
15,000 hours TIS. MDHI subsequently revised the Airworthiness
Limitations section of the maintenance manual to include the life
limit. The proposed actions are intended to prevent a link assembly
remaining in service beyond its life limit, which could result in
fatigue failure, loss of M/R blade pitch control, and subsequent loss
of helicopter control.

Related Service Information

We reviewed MDHI CSP-HMI-2 MDHI Maintenance Manual, Chapter 04,
Airworthiness Limitations, Revision 47, dated September 30, 2016. This
service information specifies a 15,000-hour TIS life limit for link
assembly P/N 600N7617-1 for helicopters with a yaw stability
augmentation system.

FAA's Determination

We are proposing this AD because we evaluated all known relevant
information and determined that an unsafe condition exists and is
likely to exist or develop on other products of these same type
designs.

Proposed AD Requirements

This proposed AD would require creating a component history card or
equivalent record for each affected link assembly, if one does not
exist, and recording a life limit of 15,000 hours TIS. This proposed AD
would also require determining the hours TIS of the link assembly and
replacing each link assembly that has reached or exceeded its life
limit.

Costs of Compliance

We estimate that this proposed AD would affect 26 helicopters of
U.S. Registry and that labor costs average $85 a work-hour. Based on
these estimates, we expect it would take 30 minutes to determine the
hours TIS of each link assembly and update the aircraft records for a
cost of $85 per helicopter and $2,210 for the U.S. fleet. Replacing a
link assembly, if needed, would require 2 work-hours, and parts would
cost $984 for a cost of $1,154 per link 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):