Airworthiness Directives; Enstrom Helicopter Corporation Helicopters

[Federal Register Volume 77, Number 4 (Friday, January 6, 2012)]
[Rules and Regulations]
[Pages 729-731]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2011-32895]



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Federal Register / Vol. 77, No. 4 / Friday, January 6, 2012 / Rules 
and Regulations

[[Page 729]]



DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2011-1382; Directorate Identifier 2011-SW-053-AD; 
Amendment 39-16900; AD 2011-26-10]
RIN 2120-AA64


Airworthiness Directives; Enstrom Helicopter Corporation 
Helicopters

AGENCY: Federal Aviation Administration (FAA), Department of 
Transportation (DOT).

ACTION: Final rule; request for comments.

-----------------------------------------------------------------------

SUMMARY: We are adopting a new airworthiness directive (AD) for Enstrom 
Helicopter Corporation (Enstrom) Model F-28C, F-28C-2, F-28F, 280C, 
280F, 280FX TH-28, 480, and 480B helicopters with certain trim relays 
to require modifying and testing the lateral and longitudinal cyclic 
trim actuator assemblies. This AD was prompted by four failures in the 
cyclic trim system on certain Enstrom model helicopters that resulted 
in reduced controllability of the helicopter. These actions are 
intended to prevent failure of the cyclic trim system and subsequent 
loss of control of the helicopter.

DATES: This AD becomes effective January 23, 2012.
    The Director of the Federal Register approved the incorporation by 
reference of certain documents listed in this AD as of January 23, 
2012.
    We must receive comments on this AD by March 6, 2012.

ADDRESSES: You may send comments by any of the following methods:
    <bullet> Federal eRulemaking Docket: Go to http://www.regulations.gov. Follow the online instructions for sending your 
comments electronically.
    <bullet> Fax: (202) 493-2251.
    <bullet> 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.
    <bullet> 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 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 St., Menominee, Michigan, 49858-0490; 
telephone: (906) 863-1200; email: 
[email protected]; Web site: http://www.enstromhelicopter.com/enstrom_new/enstrom_support_tec.html. You 
may review copies of 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, Enstrom Program 
Manager, FAA, Chicago Aircraft Certification Office, 2300 East Devon 
Avenue, Room 107, Des Plaines, Illinois 60018; telephone (847) 294-
7135; fax (847) 294-7834; 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

    We are adopting a new AD for the Enstrom Model F-28C, F-28C-2, F-
28F, 280C, 280F, 280FX, TH-28, 480, and 480B helicopters with a trim 
relay, part-number (P/N) KUP14D55-472, M83536/10-015M, or M83536/10-
024M. This AD does not apply to the specified helicopters with a 
reversible trim motor, P/N 28-16621 (Ford Motor Company C1AZ-14553A) or 
P/N AD1R-10 (Signal Electric). This AD requires modifying the lateral 
and longitudinal trim actuator assemblies by replacing the actuator and 
limit switch bracket to provide a positive stop for the trim actuator. 
In the event of a trim actuator runaway, the new bracket will stop the 
actuator, causing the circuit breaker to trip before any significant 
loss of control occurs. After the trim actuator assemblies are 
modified, this AD requires performing operational (ground) and flight 
tests to determine that the trim relay is working correctly. This AD 
was prompted by reports of 4 failures in the cyclic trim system in the 
field, 2 that occurred on the Enstrom Model 480B helicopter and 2 that 
occurred on the Enstrom Model F28 helicopter. These failures resulted 
in reduced controllability of the helicopter. We are issuing this AD to 
prevent failure of the cyclic trim system and subsequent loss of 
control of the helicopter.

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 the same type design.

[[Page 730]]

Related Service Information

    We reviewed Enstrom Service Directive Bulletin (SDB) No. 0110, 
Revision 3, dated July 6, 2011 (SDB 0110), for Model F-28C, F-28C-2, F-
28F, 280C, 280F, and 280FX helicopters; and Enstrom SDB No. T-039, 
Revision 3, dated July 6, 2011 (SDB T-039), for Model TH-28, 480, and 
480B helicopters. SDB 0110 specifies, for helicopters with a trim 
relay, P/N KUP14D55-472, M83536/10-015M, or M83536/10-024M, procedures 
for modifying the lateral and longitudinal trim actuator assembly using 
the cyclic trim assembly kit (modification kit), P/N 28-01063-1, and 
specifies performing an operational check and flight test to determine 
the trim is operating correctly after the modification. SDB T-039 
specifies, for helicopters with a trim relay, P/N M83536/10-024M, 
procedures for modifying the lateral and longitudinal trim actuator 
assembly using the modification kit, P/N 4230045-1, and specifies 
performing an operational check and flight test to determine the trim 
is operating correctly after the modification. The SDBs state that the 
modification kits contain the upgraded bracket.

AD Requirements

    This AD requires, within 5 hours time-in-service (TIS) or at the 
next annual or 100 hour time-in-service inspection, whichever occurs 
first, the following actions:
    <bullet> For the Enstrom Model F-28C, F-28C-2, F-28F, 280C, 280F, 
and 280FX helicopters with a trim relay, P/N KUP14D55-472, M83536/10-
015M, or M83536/10-024M, modify the lateral and longitudinal trim 
actuator assembly using the modification kit, P/N 28-01063-1.
    <bullet> For the Enstrom Model TH-28, 480, and 480B helicopter with 
a trim relay, P/N M83536/10-024M, modify the lateral and longitudinal 
trim actuator assembly using the modification kit, P/N 4230045-1.
    <bullet> For all affected helicopters, after accomplishing the 
modification of the lateral and longitudinal trim actuator assemblies 
and before further flight, perform an operational test and flight test 
to determine the trim is operating correctly.
    The actions required by this AD are to be accomplished by following 
specified portions of the SDBs described previously.

Differences Between This AD and the Service Information

    The SDBs specify, before further flight, to insert a special 
addendum into the Emergency Procedures section of the Flight Manual, 
and this AD does not require this action.

Costs of Compliance

    We estimate that this AD will affect 207 helicopters of U.S. 
Registry. We estimate that operators may incur the following costs in 
order to comply with this AD. For Model 480, 480B, and TH-28, modifying 
the actuator assembly will require 4 work hours at a cost of $85 per 
hour and parts will cost $327; the cost per helicopter will be $667. 
For Model 280C, 280F, 280FX, F-28C, F-28C-2, and F-28F, modifying the 
actuator assembly will require 4 work hours at a cost of $85 per hour; 
parts will cost $383; and the cost per helicopter will be $723.

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 find that 
the risk to the flying public justifies waiving notice and comment 
prior to the adoption of this rule because the required corrective 
actions must be accomplished within 5 hours time-in-service, a very 
short time period based on the average flight-hour utilization rate of 
these helicopters.
    Since an unsafe condition exists that requires the immediate 
adoption of this AD, we determined that notice and opportunity for 
public comment before issuing this AD are impracticable and contrary to 
the public interest and 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

0
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]

0
2. The FAA amends Sec.  39.13 by adding the following new AD:

2011-26-10 Enstrom Helicopter Corporation: Amendment 39-16900; 
Docket No. FAA-2011-1382; Directorate Identifier 2011-SW-053-AD.

(a) Applicability

    This AD applies to the Enstrom Model F-28C, F-28C-2, F-28F, 
280C, 280F, 280FX, TH-28, 480, and 480B helicopters with a trim 
relay, part-number (P/N) KUP14D55-472, M83536/10-015M, or M83536/10-
024M, certificated in any category.

    Note 1:  This AD does not apply to the specified helicopters 
with a reversible trim motor, P/N 28-16621 (Ford Motor Company C1AZ-
14553A) or P/N AD1R-10 (Signal Electric).


[[Page 731]]



(b) Unsafe Condition

    This AD defines the unsafe condition as a failure in the cyclic 
trim system. This condition could result in reduced controllability 
of the helicopter and subsequent loss of control of the helicopter.

(c) Effective Date

    This airworthiness directive (AD) becomes effective January 23, 
2012.

(d) Compliance

    You are responsible for performing each action required by this 
AD within the specified compliance time unless it has already been 
accomplished prior to that time.

(e) Required Actions

    Within 5 hours time-in-service (TIS) or at the next annual or 
100 TIS inspection, whichever comes first:
    (1) For the Enstrom Model F-28C, F-28C-2, F-28F, 280C, 280F, and 
280FX helicopters, modify the lateral and longitudinal trim actuator 
assemblies using the cyclic trim assembly kit (modification kit), P/
N 28-01063-1, in accordance with the instructions in paragraph 6.1 
of the Enstrom Service Directive Bulletin (SDB) No. 0110, Revision 
3, dated July 6, 2011 (SDB No. 0110 R3), except when the 
instructions specify using ``Aeroshell 22 grease'' or ``VC-3 Vibra-
tite thread locker,'' you may use an equivalent product.
    (2) For the Enstrom Model TH-28, 480, and 480B helicopters, 
modify the lateral and longitudinal trim actuator assemblies using 
the modification kit, P/N 4230045-1, in accordance with the 
instructions in paragraph 6.1 of the Enstrom SDB No. T-039, Revision 
3, dated July 6, 2011 (SDB No. T-039 R3), except when the 
instructions specify using ``Aeroshell 22 grease'' or ``VC-3 Vibra-
tite thread locker,'' you may use an equivalent product, and you are 
not required to contact Enstrom Customer Service.
    (3) After modifying the lateral and longitudinal trim actuator 
assemblies in accordance with paragraphs (e)(1) or (e)(2) of this 
AD, before further flight, operationally test the trim limits in 
accordance with paragraph 6.2. of the SDB for your model helicopter, 
and determine during a flight test whether there is appropriate trim 
authority in accordance with paragraph 6.3. of the SDB for your 
model helicopter.

(f) Special Flight Permits

    A one-time special-flight permit may be issued in accordance 
with 14 CFR 21.197 and 21.199 provided the helicopter is operated 
with the trim system circuit breaker pulled.

(g) Alternative Methods of Compliance (AMOCs)

    (1) The Manager, Safety Management Group, FAA, may approve AMOCs 
for this AD. Send your proposal to: Gregory J. Michalik, Enstrom 
Program Manager, FAA, Chicago Aircraft Certification Office, 2300 
East Devon Avenue, Room 107, Des Plaines, Illinois 60018; telephone 
(847) 294-7135; fax (847) 294-7834; email: [email protected].
    (2) For operations conducted under a Part 119 operating 
certificate or under 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.

 (h) Subject

    Joint Aircraft Service Component (JASC) Code: 6710: Main Rotor 
Control.

 (i) Material Incorporated by Reference

    You must use the specified portions of the following service 
information to do the specified actions required by this AD. The 
Director of the Federal Register approved the incorporation by 
reference of this service information under 5 U.S.C. 552(a) and 1 
CFR part 51.
    (2) Enstrom Service Directive Bulletin No. 0110, Revision 3, 
dated July 6, 2011, for the Model F-28C, F-28C-2, F-28F, 280C, 280F; 
and
    (3) 280FX or Enstrom Service Directive Bulletin No. T-039, 
Revision 3, dated July 6, 2011, for the Model TH-28, 480, and 480B.
    (4) For service information identified in this AD, contact 
Enstrom Helicopter Corporation, 2209 22nd St., Menominee, Michigan 
49858-0490; telephone: (906) 863-1200; email: 
[email protected]; Web site: http://www.enstromhelicopter.com/enstrom_new/enstrom_support_tec.html.
    (5) You may review copies of the referenced service information 
at the FAA, Office of the Regional Counsel, Southwest Region, 2601 
Meacham Blvd., Room 663, Fort Worth, Texas 76137 or at the National 
Archives and Records Administration (NARA). For information on the 
availability of this material at NARA, call (202) 741-6030, or go 
to: http://www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html.

    Issued in Fort Worth, Texas, on December 14, 2011.
M. Monica Merritt,
Acting Manager, Rotorcraft Directorate, Aircraft Certification Service.
[FR Doc. 2011-32895 Filed 1-5-12; 8:45 am]
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