DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2017-0270; Product Identifier 2016-SW-032-AD; Amendment
39-18993; AD 2017-17-03]
RIN 2120-AA64

Airworthiness Directives; MD Helicopters, Inc., Helicopters

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule.

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SUMMARY: We are superseding Airworthiness Directive (AD) 2014-16-01 for
MD Helicopters, Inc. (MDHI), Model MD900 helicopters. AD 2014-16-01
required an eddy current inspection of the main rotor upper hub
assembly (upper hub) for a crack. This AD requires additional
inspections and replacing the fillet seal. This AD was prompted by
three additional reports of upper hub cracks. The actions of this AD
are intended to prevent an unsafe condition on these products.

DATES: This AD is effective September 25, 2017.
The Director of the Federal Register approved the incorporation by
reference of a certain publication listed in this AD as of September
25, 2017.

ADDRESSES: For service information identified in this final 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. It is also available on the Internet at http://www.
regulations.gov by searching for and locating Docket No. FAA-2017-0270.

Examining the AD Docket

You may examine the AD docket on the Internet at http://www.regulations.
gov in Docket No. FAA-2017-0270; or in person at the
Docket Management Facility between 9 a.m. and 5 p.m., Monday through
Friday, except Federal holidays. The AD docket contains this AD, any
incorporated-by-reference information, the economic evaluation, any
comments received, and other information. The address for the Docket
Office (phone: 800-647-5527) is Document Management Facility, 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: Eric Schrieber, Aviation Safety
Engineer, Los Angeles ACO Branch, Compliance and Airworthiness
Division, FAA, 3960 Paramount Blvd., Lakewood, California 90712;
telephone (562) 627-5348; email eric.schrieber@faa.gov.

SUPPLEMENTARY INFORMATION:

Discussion

We issued a notice of proposed rulemaking (NPRM) to amend 14 CFR
part 39 to remove AD 2014-16-01, Amendment 39-17925 (79 FR 45322,
August 5, 2014) and add a new AD. AD 2014-16-01 applied to MDHI Model
MD900 helicopters, serial numbers 900-00008 through 900-00140, with an
upper hub part number (P/N) 900R2101006-105, -107, -109, or -111
installed. AD 2014-16-01 required eddy current inspecting the upper hub
and replacing it if there is a crack. The NPRM published in the Federal
Register on April 3, 2017 (82 FR 16138).
The NPRM was prompted by reports of three additional cracks found
in the MD900 fleet. These cracks were not discovered by the one-time
eddy current inspection required by AD 2014-16-01, but were found
during regular maintenance of the upper hub. The NPRM proposed to
require for MDHI MD900 helicopters with an upper hub, regardless of heli-
copter serial number, repetitive visual inspections of the fillet seal and the
areas around the flexbeam boltholes for a crack and repetitive visual
inspections of the lead leg shims and bushings for corrosion around the
flexbeam boltholes. The NPRM also proposed repetitive ultrasonic eddy-
current inspections of the areas adjacent to the flexbeam boltholes for
a crack. If during any inspection there is corrosion or a crack, the
NPRM proposed replacing the upper hub before further flight. Finally,
after each inspection, the NPRM proposed installing a fillet seal to
the bushing and upper hub interface.

Comments

We gave the public the opportunity to participate in developing
this AD, but we did not receive any comments on the NPRM.

FAA's Determination

We have reviewed the relevant information and determined that an
unsafe condition exists and is likely to exist or develop on other
helicopters of the same type design and that air safety and the public
interest require adopting the AD requirements as proposed.

Related Service Information Under 1 CFR Part 51

MDHI has issued Service Bulletin SB900-125, dated February 19,
2016, which describes procedures for repetitive visual and eddy current
inspections of the upper hub upper and lower flexbeam bolthole areas
and for applying a fillet seal on the interface of the bushing and the
flex beam retention bolt hole.
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.

Differences Between This AD and the Service Information

The service information applies to upper hubs with 1,000 or more
hours TIS. This AD applies to all upper hubs regardless of hours TIS.
The service information applies to upper hub P/N 900R2101006-107 and -
109; this AD also applies to upper hub P/N 900R2101006-105 and -111.

Costs of Compliance

We estimate that this AD affects 23 helicopters of U.S. Registry.
At an average labor rate of $85 per hour, we estimate that operators
may incur the following costs in order to comply with this AD.
Inspecting the fillet seal around the flexbeam boltholes (100 hour
TIS inspection) requires about 1 work-hour, for a cost per helicopter
of $85 and a cost of $1,955 for the fleet, per inspection cycle.
Inspecting the flexbeam area and lead leg shims and bushings (annual
inspection) requires about 2 work-hours, for a cost per helicopter of
$170 and a cost of $3,910 for the fleet, per inspection cycle. Eddy
current inspecting (1,000 hour TIS inspection) the upper hub requires
about 2 work-hours, for a cost per helicopter of $170 and a cost of
$3,910 for the fleet.
If required, replacing the upper hub requires about 11 work-hours,
and required parts would cost about $15,998, for a cost per helicopter
of $16,933. If required, replacing a missing or damaged fillet seal
requires about .5 work-hour, and required parts cost would be minimal,
for a cost per helicopter of $43.

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 have determined that 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 a regulatory distinction is required, 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.

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 removing Airworthiness Directive (AD)
2014-16-01, Amendment 39-17925 (79 FR 45322, August 5, 2014), and
adding the following new AD: