[Federal Register Volume 69, Number 149 (Wednesday, August 4, 2004)]
[Proposed Rules]
[Pages 47040-47041]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 04-17794]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2003-SW-37-AD]
RIN 2120-AA64


Airworthiness Directives; MD Helicopters, Inc. Model 369A, 369D, 
369E, 369F, 369FF, 369H, 369HE, 369HS, 369HM, 500N, and OH-6A 
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 specified MD Helicopters, Inc. (MDHI) model helicopters. 
The AD would require replacing or reworking certain forward (fwd) and 
aft landing gear assemblies. This proposal is prompted by five reports 
of landing gear strut (strut) failures. The actions specified by the 
proposed AD are intended to prevent cracking of the fwd and aft struts, 
failure of a strut, and subsequent loss of control of the helicopter 
during landing.

DATES: Comments must be received on or before October 4, 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-37-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: John Cecil, Aviation Safety Engineer, 
FAA, Los Angeles Aircraft Certification Office, Airframe Branch, 3960 
Paramount Blvd., Lakewood, California 90712-4137, telephone (562) 627-
5228, 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-37-AD.'' The postcard will be date 
stamped and returned to the commenter.

Discussion

    This document proposes adopting a new AD for MDHI Model 369A, 369D, 
369E, 369F, 369FF, 369H, 369HE, 369HS, 369HM, 500N, and OH-6A 
helicopters. The AD would require removing all landing gear fairings; 
determining the number and location of rivets that attach the landing 
gear fairing support assembly to the landing gear strut; and if three 
rivets (fwd, aft and inboard) are present, replacing or reworking the 
landing gear assembly. If only the fwd and aft rivets are present, no 
rework would be required by the proposed AD. This proposal is prompted 
by five reports of strut failures. Operators of the helicopters with 
failed struts do not fall into any clear category of service. For 
example, one was a tour operator in Niagara Falls, New York and another 
was a police department operator in Calgary, Canada. In its original 
design, the fairing support was attached to the strut with three 
rivets. In 1994 the manufacturer released a design change to attach the 
fairing support assembly with only forward and aft rivets because of 
the possibility of reduced service life of the strut with the 
additional inboard rivet hole present. Some landing gear struts entered 
service with an additional rivet hole drilled on the inboard side of 
the strut. This additional rivet hole is resulting in decreased 
strength of the strut and subsequent cracking. The actions specified by 
the proposed AD are intended to prevent cracking of the fwd and aft 
struts, failure of a strut, and subsequent loss of control of the 
helicopter during landing.
    The FAA has reviewed MD Helicopters Service Bulletin SB369H-244, 
SB369E-094, SB500N-022, SB369D-200, and SB369F-078, dated April 7, 2000 
(SB), which describes procedures for determining the number and 
location of rivets attaching the landing gear fairing support assembly 
to the landing gear strut. Where three rivets are present, instructions 
are provided to rework the landing gear assembly and replace any 
cracked strut assembly.
    This unsafe condition is likely to exist or develop on other 
helicopters of the same type design. Therefore, the proposed AD would 
require removing all landing gear fairings; determining the number and 
location of rivets that attach the landing gear fairing support 
assembly to the landing gear strut; and if three rivets (fwd, aft and 
inboard) are present, replacing or reworking the landing gear assembly. 
If only two rivets are present, no rework is required by this AD. 
Although this action does not propose to require that access holes be 
drilled through the fairings to facilitate future inspections as 
described in the manufacturer's SB, that action may be part of a future 
AD if additional repetitive inspections become necessary. The actions 
would be required to be accomplished in accordance with the service 
bulletin described previously.
    The FAA estimates that this proposed AD would affect 651 
helicopters of U.S. registry, and determining the number of rivets 
would take approximately 7 work hours, reworking an affected ``3-hole'' 
strut would take approximately 1 work hour, and installing a new strut 
would take approximately 1.5 work hours. The average labor rate is $65 
per work hour. Required parts (new struts) would cost approximately 
$9,937 each. Assuming all 651 helicopters will require inspection, 325 
helicopters will need two struts reworked, and 5 aircraft will need two 
new struts installed, the total cost of the proposed AD on U.S. 
operators would be $438,800.
    The regulations proposed herein would not have a substantial direct 
effect on the States, on the relationship between the national 
Government and

[[Page 47041]]

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 draft 
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-37-AD.

    Applicability: Model 369A, 369D, 369E, 369F, 369FF, 369H, 369HE, 
369HS, 369HM, 500N, and OH-6A helicopters, with any of the following 
components installed, certificated in any category:

------------------------------------------------------------------------
             Component name                Component part number (P/N)
------------------------------------------------------------------------
Mid Aft Fairing Assembly...............  369H6200-61, -62, standard
                                          gear.
Aft Support Assembly...................  369H6200-23, -24 (-23 to be
                                          reinstalled on the right-hand
                                          side and -24 to be reinstalled
                                          on the left-hand side, all
                                          configurations).
Aft Fairing Assembly...................  369H92113-91, -92, extended
                                          gear.
Aft Filler Assembly....................  369H92113-131, -132, extended
                                          gear.
Aft Fillet Assembly....................  369A6200-45, -46, standard
                                          gear.
Aft Fillet Assembly....................  369H92113-111, -112, extended
                                          gear.
Mid Fwd Fairing Assembly...............  369H6200-41, -42, standard
                                          gear.
Fwd Fairing Assembly...................  369H92113-81, -82, extended
                                          gear.
Fwd Support Assembly...................  369H6200-23, -24 (-23 becomes
                                          right-hand side and -24
                                          becomes left-hand side).
Fwd Filler Assembly....................  369H92113-121, -122, extended
                                          gear.
Fwd Fillet Assembly....................  369A6200-57, -58, standard
                                          gear.
Fwd Fillet Assembly....................  369H92113-101, -102, extended
                                          gear.
------------------------------------------------------------------------

    Compliance: Within the next 4 months, unless accomplished 
previously.
    To prevent cracking of the fwd and aft struts, failure of a 
strut, and subsequent loss of control of the helicopter during 
landing, accomplish the following:
    (a) Remove all landing gear fairings (fairings) and inspect each 
landing gear fairing support assembly (support assembly) to 
determine the number and location of the rivets attaching the 
support assembly to the landing gear strut assembly (strut 
assembly).
    (1) If three rivets (forward, aft and inboard) are used to 
attach the support assembly to the strut assembly,
    (i) for each FORWARD landing gear assembly, remove the landing 
gear fillet assembly (fillet assembly), the three rivets, and the 
support assembly, and clean and dye-penetrant inspect the 0.125 
(3.18mm) diameter hole in the inboard surface of the strut assembly.
    (A) If the strut assembly is cracked, replace the cracked strut 
assembly with an airworthy strut assembly and install the other 
landing gear components in accordance with steps (8) through (11) of 
paragraph C of the Accomplishment Instructions of MD Helicopters 
Service Bulletin SB369H-244, SB369E-094, SB500N-022, SB369D-200, and 
SB369F-078, dated April 7, 2000 (SB).
    (B) If the strut assembly is not cracked, rework the landing 
gear assembly and install the other landing gear components in 
accordance with steps (5) and (8) through (11) of paragraph C of the 
Accomplishment Instructions of the SB.
    (ii) for each AFT landing gear assembly, remove the fillet 
assembly, the three rivets, and the support assembly, and clean and 
dye-penetrant inspect the 0.125 (3.18mm) diameter hole in the 
inboard surface of the strut assembly.
    (A) If the strut assembly is cracked, replace the cracked strut 
assembly with an airworthy strut assembly and install the other 
landing gear components in accordance with steps (8) through (13) of 
paragraph B of the Accomplishment Instructions of the SB.
    (B) If the strut assembly is not cracked, rework the landing 
gear assembly and install the other landing gear components in 
accordance with steps (5) and (8) through (13) of Paragraph B of the 
Accomplishment Instructions of the SB.
    (2) If only two rivets (forward and aft) are used to attach the 
support assembly to the strut assembly, neither the inspection of 
the strut assembly nor the rework of those landing gear assemblies 
is required by this AD.

    Note: Creating an access hole to facilitate inspections is 
described in steps (6) and (7) of Paragraphs B and C of the SB, but 
is not required by this AD.

    (b) 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 28, 2004.
David A. Downey,
Manager, Rotorcraft Directorate, Aircraft Certification Service.
[FR Doc. 04-17794 Filed 8-3-04; 8:45 am]
BILLING CODE 4910-13-P