[Federal Register Volume 69, Number 145 (Thursday, July 29, 2004)]
[Proposed Rules]
[Pages 45291-45293]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 04-17223]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2003-SW-51-AD]
RIN 2120-AA64


Airworthiness Directives; MD Helicopters, Inc. Model 600N 
Helicopters

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: This document proposes adopting a new airworthiness directive 
(AD) for the MD Helicopters, Inc. Model 600N helicopters. The AD would 
require replacing the fuselage Station 75 control support bracket 
assembly (control support bracket), reducing the life limit, and 
revising the Limitations section of the applicable maintenance manual 
to state the reduced life limits on certain serial-numbered 
helicopters. This proposal is prompted by information received from the 
manufacturer indicating that the fatigue life of the control support 
bracket is shorter than the original analysis indicated. The actions 
specified by the proposed AD are intended to prevent failure of the 
control support bracket

[[Page 45292]]

and subsequent loss of control of the helicopter.

DATES: Comments must be received on or before September 27, 2004.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Office of the Regional Counsel, Southwest Region, 
Attention: Rules Docket No. 2003-SW-51-AD, 2601 Meacham Blvd., Room 
663, Fort Worth, Texas 76137. You may also send comments electronically 
to the Rules Docket at the following address: [email protected]. 
Comments may be inspected at the Office of the Regional Counsel between 
9 a.m. and 3 p.m., Monday through Friday, except Federal holidays.

FOR FURTHER INFORMATION CONTACT: Fred Guerin, Aviation Safety Engineer, 
FAA, Los Angeles Aircraft Certification Office, Airframe Branch, 3960 
Paramount Blvd., Lakewood, California 90712, telephone (562) 627-5232, 
fax (562) 627-5210.

SUPPLEMENTARY INFORMATION:

Comments Invited

    Interested persons are invited to participate in the making of the 
proposed rule by submitting such written data, views, or arguments as 
they may desire. Communications should identify the Rules Docket number 
and be submitted in triplicate to the address specified above. All 
communications received on or before the closing date for comments will 
be considered before taking action on the proposed rule. The proposals 
contained in this document may be changed in light of the comments 
received.
    Comments are specifically invited on the overall regulatory, 
economic, environmental, and energy aspects of the proposed rule. All 
comments submitted will be available, both before and after the closing 
date for comments, in the Rules Docket for examination by interested 
persons. A report summarizing each FAA-public contact concerned with 
the substance of this proposal will be filed in the Rules Docket.
    Commenters wishing the FAA to acknowledge receipt of their mailed 
comments submitted in response to this proposal must submit a self-
addressed, stamped postcard on which the following statement is made: 
``Comments to Docket No. 2003-SW-51-AD.'' The postcard will be date 
stamped and returned to the commenter.

Discussion

    This document proposes adopting a new AD for MD Helicopters, Inc. 
Model 600N helicopters. The AD would require replacing the control 
support bracket assembly, part number (P/N) 369N2608-11, on helicopters 
that have a yaw stability augmentation system (YSAS) installed, with an 
airworthy assembly, P/N 600N2608-1. The revised time limits are 
dependent upon the time the YSAS was initially installed. Revising the 
applicable maintenance manual to state the reduced life limits would 
also be required. This proposal is prompted by information received 
from the manufacturer indicating that the fatigue life of the control 
support bracket is shorter than the original analysis indicated for 
those models in which a YSAS is installed. The actions specified by the 
proposed AD are intended to prevent failure of the control support 
bracket and subsequent loss of control of the helicopter.
    The FAA has reviewed MD Helicopters, Inc. Service Bulletin No. 
SB600N-040, dated September 18, 2003, which describes the revised 
finite life for the control support bracket on certain serial-numbered 
helicopters, and requiring replacing them upon reaching the revised 
life limit, or no later than November 30, 2005, whichever occurs first.
    This unsafe condition is likely to exist or develop on other 
helicopters of the same type design. Therefore, the proposed AD would 
require replacing the control support bracket before it reaches a 
certain number of hours time-in-service, or no later than November 30, 
2005, whichever occurs first.
    The FAA estimates that this proposed AD would affect 13 helicopters 
of U.S. registry, and replacing the control support bracket would take 
approximately 40 work hours per helicopter to accomplish at an average 
labor rate of $65 per work hour. Required parts would cost 
approximately $5,617 per helicopter. Based on these figures, the total 
cost impact of the proposed AD on U.S. operators would be $106,821 to 
replace the control support bracket on each helicopter in the fleet.
    The regulations proposed herein 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. Therefore, it 
is determined that this proposal would not have federalism implications 
under Executive Order 13132.
    For the reasons discussed above, I certify that 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); 
and (3) if promulgated, 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. A copy of the economic 
evaluation prepared for this action is contained in the Rules Docket. A 
copy of it may be obtained by contacting the Rules Docket at the 
location provided under the caption ADDRESSES.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Safety.

The Proposed Amendment

    Accordingly, pursuant to the authority delegated to me by the 
Administrator, the Federal Aviation Administration proposes to amend 
part 39 of the Federal Aviation Regulations (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. Section 39.13 is amended by adding a new airworthiness directive 
to read as follows:

MD Helicopters, Inc.: Docket No. 2003-SW-51-AD.

    Applicability: Model 600N helicopters, serial numbers with a 
prefix of ``RN'' and numbers 025, 029, 032, 034 through 038, 040, 
041, 045, 048, or 067; or, any Model 600N helicopter with a yaw 
stability augmentation system (YSAS) installed, and with a control 
support bracket assembly, part number (P/N) 369N2608-11, installed, 
certificated in any category.
    Compliance: Required as indicated, unless accomplished 
previously.
    To prevent failure of the fuselage Station 75 control support 
bracket assembly (control support bracket) and subsequent loss of 
control of the helicopter, accomplish the following:
    (a) Replace the control support bracket, part number 369N2608-
11, with an airworthy control support bracket assembly, P/N 
600N2608-1, no later than November 30, 2005, or by the time the 
helicopter reaches the hours time-in-service (TIS) listed in the 
chart below, whichever occurs first:

------------------------------------------------------------------------
                                                          Revised finite
                Helicopter serial number                    life (TIS)
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RN025...................................................            2556
RN029...................................................            2377
RN032...................................................            2498
RN034...................................................            2456
RN035...................................................            2243
RN036...................................................            2652
RN037...................................................            2544

[[Page 45293]]

 
RN038...................................................            2531
RN040...................................................            2562
RN041...................................................            2763
RN045...................................................            2015
RN048...................................................            2125
RN067...................................................            1600
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    Note: MD Helicopters, Inc. Service Bulletin No. SB600N-040, 
dated September 18, 2003, pertains to the subject of this AD.

    (b) For helicopters with a YSAS installed that are not listed in 
the previous table, replace the control support bracket, P/N 
369N2608-11, with an airworthy control support bracket, P/N 
600N2608-1, no later than November 30, 2005, or by the time the 
helicopter reaches 1,600 hours TIS since the installation of the 
YSAS.
    (c) For helicopters with no YSAS installed, but with a control 
support bracket, P/N 369N26080-11, installed, replace the control 
support bracket, with an airworthy control support bracket, P/N 
600N2608-1, prior to the installation of a YSAS.
    (d) This AD revises the Limitations section of the applicable 
maintenance manual by reducing the life limit of the control support 
bracket assembly, part number 369N2608-11, to the life limits stated 
in paragraph (a) of this AD or to 1,600 hours TIS, whichever occurs 
first.
    (e) To request a different method of compliance or a different 
compliance time for this AD, follow the procedures in 14 CFR 39.19. 
Contact the Los Angeles Aircraft Certification Office, Transport 
Airplane Directorate, FAA, for information about previously approved 
alternative methods of compliance.

    Issued in Fort Worth, Texas, on July 14, 2004.
David A. Downey,
Manager, Rotorcraft Directorate, Aircraft Certification Service.
[FR Doc. 04-17223 Filed 7-28-04; 8:45 am]
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