DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2017-1191; Product Identifier 2017-SW-046-AD; Amendment
39-19134; AD 2017-26-03]
RIN 2120-AA64

Airworthiness Directives; The Enstrom Helicopter Corporation Helicopters

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule; request for comments.

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SUMMARY: We are adopting a new airworthiness directive (AD) for the
Enstrom Helicopter Corporation (Enstrom) Model F-28, F-28A, F-28C, F-
28C-2, F-28C-2R, F-28F, F-28F-R, TH-28, 280, 280C, 280F, 280FX, 480,
and 480B helicopters. This AD requires inspecting certain rod end
bearing assemblies. This AD is prompted by an accident. The actions of
this AD are intended to prevent an unsafe condition on these
helicopters.

DATES: This AD becomes effective January 4, 2018.
The Director of the Federal Register approved the incorporation by
reference of certain documents listed in this AD as of January 4, 2018.
We must receive comments on this AD by February 20, 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-2017-1191;
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 AD, any incorporated-by-reference service information,
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 final rule, contact
Enstrom Helicopter Corporation, 2209 22nd Street, Menominee, MI;
telephone (906) 863-1200; fax (906) 863-6821; or at
www.enstromhelicopter.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-2017-1191.

FOR FURTHER INFORMATION CONTACT: Manzoor Javed, Senior Aerospace
Engineer, Chicago ACO Branch, Compliance and Airworthiness Division,
Aircraft Certification Service, FAA, 2300 East Devon Ave., Des Plaines,
IL 60018; telephone (847) 294-8112; email manzoor.javed@faa.gov.

SUPPLEMENTARY INFORMATION:

Comments Invited

This AD is a final rule that involves requirements affecting flight
safety, and we did not provide you with notice and an opportunity to
provide your comments prior to it becoming effective. However, 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 resulted
from adopting this AD. The most helpful comments reference a specific
portion of the AD, 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 them 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 rulemaking during the
comment period. We will consider all the comments we receive and may
conduct additional rulemaking based on those comments.

Discussion

We are adopting a new AD for Enstrom Model F-28, F-28A, F-28C, F-
28C-2, F-28C-2R, F-28F, F-28F-R, TH-28, 280, 280C, 280F, 280FX, 480,
and 480B helicopters with a rod end bearing assembly (bearing assembly)
part number (P/N) 01-824-08E-011, 09455-01-824-08E-011, ECD091-1,
ASMK8T, M81935/1-08K, MS21242S8K, or MTK8 installed. We received a
report of an accident involving an Enstrom Model 480B helicopter in
which one of the main rotor (M/R) blades departed in-flight. The
preliminary investigation indicated that failure of a rod end bearing
assembly of one of the M/R hydraulic damper assemblies may have caused
the M/R blade to depart from the helicopter. Based on a partially
visible marking, the FAA believes the failed part is assembly P/N
ECD091-1, vendor P/N 09455-01-824-08E-011. Analysis of the failed
assembly revealed corrosion in the root of the threaded portion of the
rod end. Enstrom identified a potential failure mode whereby failure of
the rod end bearing assembly may result in the loss of the M/R blade.
Because there is no indication of a specific manufacturing or design
issue that would limit the potential for this corrosion to have
occurred on other similarly-designed rod ends, the FAA determined it
necessary to require an inspection of all approved rod end P/Ns.
Accordingly, this AD requires, within 5 hours time-in-service
(TIS), a one-time inspection of the bearing assemblies for corrosion on
the threaded portion of the rod end. If there is any corrosion, this AD
requires replacing the bearing assembly before further flight. This AD
also requires reporting information about the inspection to the FAA
within 10 days.
The actions specified by this AD are intended to detect corrosion
in the bearing assembly to prevent failure of the rod end, loss of an
M/R blade, and subsequent loss of control of the helicopter. Additional
inspections at longer intervals may also be necessary.

We plan to publish a notice of proposed rulemaking to give the public
an opportunity to comment on those long-term requirements.

FAA's Determination

We are issuing this AD because we evaluated all the relevant
information and determined the unsafe condition described previously is
likely to exist or develop in other helicopters of these same type
designs.

Related Service Information Under 1 CFR Part 51

Enstrom has issued Service Directive Bulletin (SDB) No. 0127,
Revision 1, dated October 6, 2017, for Model F-28, F-28A, F-28C, F-28C-
2, F-28C-2R, F-28F, F-28F-R, 280, 280C, 280F, and 280FX helicopters and
SDB No. T-058, dated August 2, 2017, for Model TH-28, 480, and 480B
helicopters. This service information provides procedures for
inspecting certain vendor specific bearing assemblies P/N ECD091-1 for
corrosion on the threaded portion of the rod end.
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.

AD Requirements

This AD requires, within 5 hours TIS, inspecting each M/R hydraulic
damper bearing assembly P/N ECD091-1, and for model F-28, F-28A, F-28C,
F-28C-2, F-28C-2R, F-28F, F-28F-R, 280, 280C, 280F, and 280FX
helicopters each belt tension shaft bearing assembly P/N 01-824-08E-
011, 09455-01-824-08E-011, ASMK8T, ECD091-1, MTK8, M81935/1-08K, and
MS21242S8K, for corrosion at the root of the thread on the rod end with
a 5X or higher power magnifying glass. If there is any corrosion, this
AD requires replacing the bearing assembly before further flight.
This AD also requires, within 10 days after completing each
inspection, reporting the findings of the inspection to the FAA's
Chicago ACO Branch, including: The owner's contact information,
helicopter registration number and model, date of the inspection, total
hours of the bearing assembly and helicopter, bearing assembly serial
number, the location of any corrosion, and a description of any
corrosion.

Differences Between This AD and the Service Information

The service information specifies repeating the visual inspection
for corrosion at every 100 hour or annual inspection, while this AD
does not, as this time interval would allow for sufficient time for
notice and comment.
Also, the service information only applies to bearing assembly P/N
ECD091-1 and only specifies performing an inspection if marked with
vendor P/N 09455-01-824-08E-011 or if the marking is missing or
illegible. This AD applies to all P/N ECD091-1, 09455-01-824-08E-011,
MTK8, ASMK8T, 01-824-08E-011, M81935/1-08K, and MS21242S8K bearing
assemblies. Because the FAA does not have any data that positively
confirms the root cause as a manufacturing batch, the AD requires
inspections on all P/Ns of the same type design. The data received
about the initial inspections will be used to determine the effectivity
of any follow-on actions.
Finally, the service information specifies reporting the inspection
findings to Enstrom, while this AD requires reporting the findings to
the FAA.

Interim Action

We consider this AD interim action. The inspection reports that are
required by this AD will enable us to obtain better insight into the
nature of the corrosion and to develop final action to address the
unsafe condition. Once final action has been identified, we might
consider further rulemaking.

Costs of Compliance

We estimate that this AD affects 513 helicopters of U.S. Registry.
At an average labor rate of $85 per work-hour, we estimate that
operators may incur the following costs in order to comply with this
AD.
Inspecting the bearing assemblies will require 5 work-hours, for a
cost per helicopter of $425 and a total cost of $218,025 to the U.S.
fleet.
Reporting the inspection results required by this AD will require
about 0.5 work-hour, for a cost per helicopter of $43, and a total cost
of $22,059 to the U.S. fleet.
If required, replacing one bearing assembly will not incur any
additional work-hours, and required parts will cost $410, for a cost
per helicopter of $410.

Paperwork Reduction Act

A federal agency may not conduct or sponsor, and a person is not
required to respond to, nor shall a person be subject to penalty for
failure to comply with a collection of information subject to the
requirements of the Paperwork Reduction Act unless that collection of
information displays a current valid OMB control number. The control
number for the collection of information required by this AD is 2120-
0056. The paperwork cost associated with this AD has been detailed in
the Costs of Compliance section of this document and includes time for
reviewing instructions, as well as completing and reviewing the
collection of information. Therefore, all reporting required by this AD
is mandatory. Comments concerning the accuracy of this burden and
suggestions for reducing the burden should be directed to the FAA at
800 Independence Ave. SW, Washington, DC 20591. ATTN: Information
Collection Clearance Officer, AES-200.

FAA's Justification and Determination of the Effective Date

An unsafe condition exists that requires the immediate adoption of
this AD without providing an opportunity for public comments prior to
adoption. The FAA has found that the risk to the flying public
justifies waiving notice and comment prior to adoption of this rule
because the bearing assembly inspection required by this AD must be
accomplished within 5 hours TIS. Therefore, we find good cause that
notice and opportunity for prior public comment are impracticable. In
addition, for the reason(s) stated above, we find that good cause
exists for making this amendment effective in less than 30 days.

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 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, 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):