Example Airworthiness Directive - Enstrom Helicopter Corporation

[Federal Register Volume 80, Number 95 (Monday, May 18, 2015)]
[Rules and Regulations]
[Pages 28172-28175]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2015-11732]
––––––––––––––––––––––––––––––––––
DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2015-1537; Directorate Identifier 2015-SW-014-AD; Amendment 39-18160;
AD 2015-08-51]
RIN 2120-AA64
Airworthiness Directives; The Enstrom Helicopter Corporation
AGENCY: Federal Aviation Administration (FAA), DOT.
ACTION: Final rule; request for comments.
––––––––––––––––––––––––––––––––––
SUMMARY: We are publishing a new airworthiness directive (AD) for Enstrom Helicopter
Corporation (Enstrom) Model F-28A, 280, F-28C, F-28C-2, F-28C-2R, 280C, F-28F, F-28F-R, 280F,
280FX, and 480 helicopters. This AD was sent previously to all known U.S. owners and operators of
these helicopters and supersedes Emergency AD (EAD) 2015-04-51, dated February 12, 2015. This
AD requires inspecting certain main rotor spindles (spindles) for cracks and reporting the inspection
results to the FAA. This AD is prompted by a fatal accident and reports of spindles with cracks. The
actions specified in this AD are intended to detect a crack in a spindle and prevent loss of a main
rotor blade and subsequent loss of control of the helicopter.
DATES: This AD becomes effective June 2, 2015 to all persons except those persons to whom it was
made immediately effective by EAD 2015-08-51, issued on April 10, 2015, which contains the
requirements of this AD.
We must receive comments on this AD by July 17, 2015.
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.

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Examining the AD Docket
You may examine the AD docket on the Internet at http://www.regulations.gov 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, 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 AD, 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, 2601 Meacham Blvd., Room 663, Fort Worth, Texas
76137.
FOR FURTHER INFORMATION CONTACT: Gregory J. Michalik, Senior Aerospace Engineer,
Chicago Aircraft Certification Office, Small Airplane Directorate, FAA, 2300 East Devon Ave., Des
Plaines, IL 60018; (847) 294-7135; email [email protected].
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
On February 12, 2015, we issued EAD 2015-04-51, which was prompted by a fatal accident.
Preliminary results of the investigation indicated that the accident was caused by a crack in the
spindle, which resulted in the main rotor blade separating from the helicopter. The crack was
discovered at the last thread of the spindle retention nut threads. While the investigation could not
determine when the crack initiated, it was able to determine that the crack existed, undetected, for a
significant amount of time before the separation. EAD 2015-04-51 required, before further flight,
conducting a magnetic particle inspection (MPI) in any spindle that had 5,000 or more hours time-inservice (TIS) or where the hours TIS of the spindle is not known. If there was a crack in the spindle,
EAD 2015-04-51 required replacing it before further flight. EAD 2015-04-51 also required reporting
the inspection results to the FAA within 72 hours.
Since we issued EAD 2015-04-51, inspection reports received by the FAA indicate
approximately 20% of the spindles reported with TIS data had evidence of cracks. The FAA also
received inspection reports of spindles without TIS data which did not have evidence of cracks. The
inspection reports include spindles with cracks at less than 5,000 hours TIS. With analysis of
available data, we determined the need to expand the applicability to include spindles with 1,500 or
more hours TIS.
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On April 10, 2015, we issued EAD 2015-08-51, which supersedes EAD 2015-04-51. EAD 201508-51 retains all of the requirements of EAD 2014-04-51 except it reduces the TIS of the spindles to
be inspected from 5,000 hours to 1,500 hours. EAD 2015-08-51 was sent previously to all known
U.S. owners and operators of these helicopters.
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 products of these same
type designs.
Related Service Information
Enstrom has issued Service Directive Bulletin No. 0119, Revision 1, dated April 1, 2015, for all
serial numbered Model F-28A, F-28C, F-28F, 280, 280C, 280F, and 280FX helicopters with a main
rotor spindle, part number (P/N) 28-14282-11 and 28-14282-13. Enstrom has also issued Service
Directive Bulletin No. T-050, Revision 1, dated April 1, 2015, for Model 480 helicopters, serial
numbers 5001 through 5004 and 5006, and with a main rotor spindle, P/N 28-14282-13, except those
aircraft modified with tension-torsion straps. Both service directives specify, for any spindle that has
been in service more than 3,500 hours, within 5 hours TIS, sending the spindle to Enstrom for an
MPI. For any spindle with less than 3,500 hours TIS, the service directives specify sending the
spindle to Enstrom for an MPI at or before it reaches 3,500 hours TIS. The service directives also
specify repeating the MPI every 300 hours for spindles with over 3,500 hours TIS.
AD Requirements
This AD requires conducting an MPI before further flight to determine if a crack exists in any
spindle that has 1,500 or more hours TIS or where the hours TIS of the spindle is not known. If there
is a crack in the spindle, this AD requires replacing it before further flight. The MPI of the spindle
must be conducted by a Level II or Level III inspector qualified in the MPI method in the
Aeronautics Sector according to the EN4179 or NAS410 standard or equivalent. This AD also
requires reporting certain information to the FAA within 72 hours.
Differences Between This AD and the Service Information
This AD requires that the MPI be conducted by a Level II or Level III inspector or equivalent
and that the results of the MPI be reported to the FAA, whereas the service information specifies that
the MPI be accomplished by or reported to Enstrom. This AD requires an MPI on spindles with 1,500
or more hours TIS, whereas the service information specifies performing an initial MPI on spindles
with 3,500 or more hours TIS. This AD does not require a recurring inspection, whereas the service
information specifies to repeat the MPI every 300 hours TIS for spindles with over 3,500 hours TIS.
This AD requires the MPI before further flight, whereas the service information specifies that it be
accomplished within 5 hours TIS.
Interim Action
We consider this AD to be an interim action. The inspection reports that are required by this AD
will enable us to obtain better insight into the root cause and extent of the cracking, and eventually to
develop final action to address the unsafe condition. Once final action has been identified, we might
consider further rulemaking.

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Costs of Compliance
We estimate that this AD affects 323 helicopters of U.S. Registry and that operators may incur
the following costs to comply with this AD. Inspecting the spindles will take about 15 work-hours per
helicopter and reporting the required inspection information will take about 0.5 work-hour. We
estimate an average labor rate of $85 per work-hour, for a total cost of $1,318 per helicopter and
$425,714 for the U.S. fleet. Replacing a spindle will cost $8,164 for parts and no additional workhours.
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
Providing an opportunity for public comments prior to adopting these AD requirements would
delay implementing the safety actions needed to correct this known unsafe condition. Therefore, we
found and continue to find that the risk to the flying public justifies waiving notice and comment
prior to the adoption of this rule because the previously described unsafe condition can adversely
affect the controllability of the helicopter and the initial required action must be accomplished before
further flight.
Since it was found that immediate corrective action was required, notice and opportunity for
prior public comment before issuing this AD were impracticable and contrary to the public interest
and good cause existed to make the AD effective immediately by EAD 2015-08-51, issued on April
10, 2015, to all known U.S. owners and operators of these helicopters. These conditions still exist and
the AD is hereby published in the Federal Register as an amendment to section 39.13 of the Federal
Aviation Regulations (14 CFR 39.13) to make it effective to all persons.
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.

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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.
§ 39.13 [Amended]
2. The FAA amends § 39.13 by adding the following new airworthiness directive (AD):

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AIRWORTHINESS DIRECTIVE
FAA
Aviation Safety

www.faa.gov/aircraft/safety/alerts/
www.gpoaccess.gov/fr/advanced.html

2015-08-51 The Enstrom Helicopter Corporation (Enstrom): Amendment 39-18160; Docket No.
FAA-2015-1537; Directorate Identifier 2015-SW-014-AD.
(a) Applicability
This AD applies to Enstrom Model F-28A, 280, F-28C, F-28C-2, F-28C-2R, 280C, F-28F, F28F-R, 280F, and 280FX helicopters, all serial numbers; and Enstrom Model 480 helicopters, serial
numbers 5001 through 5006; with a main rotor spindle (spindle), part number (P/N) 28-14282-11 or
28-14282-13, installed, certificated in any category. This AD applies to any helicopter that has a
spindle with 1,500 or more hours time-in-service (TIS) or where the hours TIS of the spindle is not
known.
(b) Unsafe Condition
This AD defines the unsafe condition as a crack in the spindle, which, if not detected, could
result in loss of a main rotor blade and subsequent loss of control of the helicopter.
(c) Affected ADs
This AD supersedes Emergency AD 2015-04-51, Directorate Identifier 2015-SW-002-AD, dated
February 12, 2015.
(d) Effective Date
This AD becomes effective June 2, 2015 to all persons except those persons to whom it was
made immediately effective by Emergency AD 2015-08-51, issued on April 10, 2015, which contains
the requirements of this AD.
(e) Compliance
You are responsible for performing each action required by this AD within the specified
compliance time unless it has been accomplished on or after February 11, 2015.
(f) Required Actions
(1) Before further flight, conduct a magnetic particle inspection (MPI) of the spindle to
determine if a crack exists, paying particular attention to the threaded portion of the spindle. The MPI
of the spindle must be conducted by a Level II or Level III inspector qualified in the MPI in the
Aeronautics Sector according to the EN4179 or NAS410 standard or equivalent. If there is a crack in
the spindle, replace it with an airworthy spindle before further flight.
(2) Within 72 hours after accomplishing the MPI, report the information requested in Appendix 1
to this AD by mail to the Manager, Chicago Aircraft Certification Office, Federal Aviation
Administration, ATTN: Gregory J. Michalik, 2300 East Devon Ave., Des Plaines, IL, 60018; by fax
to (847) 294-7834; or email to [email protected].

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(g) Alternative Methods of Compliance (AMOCs)
(1) The Manager, Chicago Aircraft Certification Office, FAA, may approve AMOCs for this
AD. Send your proposal to: Gregory J. Michalik, Senior Aerospace Engineer, Chicago Aircraft
Certification Office, Small Airplane Directorate, FAA, 2300 East Devon Ave., Des Plaines, IL,
60018; (847) 294-7135; email [email protected].
(2) For operations conducted under a 14 CFR part 119 operating certificate or under 14 CFR part
91, subpart K, we suggest that you notify your principal inspector, or lacking a principal inspector,
the manager of the local flight standards district office or certificate holding district office before
operating any aircraft complying with this AD through an AMOC.
(3) Any AMOC approved previously in accordance with EAD 2015-04-51, dated February 12,
2015, is approved as an AMOC for the corresponding requirements in paragraph (f)(1) of this AD.
(h) Additional Information
Enstrom Helicopter Corporation Service Directive Bulletin No. 0119, Revision 1, dated April 1,
2015, and Enstrom Helicopter Corporation Service Directive Bulletin No. T-050, Revision 1, dated
April 1, 2015, which are not incorporated by reference, contain additional information about the
subject of this AD. For service information identified in this AD, 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 this service information at the FAA, Office of the
Regional Counsel, Southwest Region, 2601 Meacham Blvd., Room 663, Fort Worth, Texas 76137.
(i) Subject
Joint Aircraft Service Component (JASC) Code: 6220, Main Rotor Head.
Appendix 1 to AD 2015-08-51
Spindle Inspection (Sample Format)
Provide the following information by mail to the Manager, Chicago Aircraft Certification Office,
Federal Aviation Administration, ATTN: Gregory J. Michalik, 2300 East Devon Ave., Des Plaines,
IL, 60018; by fax to (847) 294-7834; or email to [email protected].
Aircraft Registration No.:
Helicopter Model:
Helicopter Serial Number:
Helicopter Owner or Operator:
Contact Phone No.:
Spindle Part Number and Serial Number:
Total Hours Time-in-Service (TIS) on Spindle:
Total Hours TIS on Helicopter (if hours TIS on spindle were not available):
Who Performed the Inspection:
Date and Location Inspection was Accomplished:
Crack Found? If yes, describe the crack size, location, orientation (provide a sketch or picture):
Provide Any Other Comments:
Issued in Fort Worth, Texas, on May 8, 2015.
Lance T. Gant,
Acting Directorate Manager, Rotorcraft Directorate,
Aircraft Certification Service.
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