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Proposed Rule

Airworthiness Directives; MD Helicopters, Inc. Model 369A, 369D, 369E, 369F, 369FF, 369H, 369HE, 369HS, 369HM, 500N, and OH-6A Helicopters

Document Details

Information about this document as published in the Federal Register.

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AGENCY:

Federal Aviation Administration, DOT.

ACTION:

Notice of proposed rulemaking (NPRM).

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: 9-asw-adcomments@faa.gov. 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.

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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.

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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 Start Printed Page 47041the 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.

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List of Subjects in 14 CFR Part 39

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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:

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PART 39—AIRWORTHINESS DIRECTIVES

1. The authority citation for part 39 continues to read as follows:

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Authority: 49 U.S.C. 106(g), 40113, 44701.

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[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 nameComponent part number (P/N)
Mid Aft Fairing Assembly369H6200-61, -62, standard gear.
Aft Support Assembly369H6200-23, -24 (-23 to be reinstalled on the right-hand side and -24 to be reinstalled on the left-hand side, all configurations).
Aft Fairing Assembly369H92113-91, -92, extended gear.
Aft Filler Assembly369H92113-131, -132, extended gear.
Aft Fillet Assembly369A6200-45, -46, standard gear.
Aft Fillet Assembly369H92113-111, -112, extended gear.
Mid Fwd Fairing Assembly369H6200-41, -42, standard gear.
Fwd Fairing Assembly369H92113-81, -82, extended gear.
Fwd Support Assembly369H6200-23, -24 (-23 becomes right-hand side and -24 becomes left-hand side).
Fwd Filler Assembly369H92113-121, -122, extended gear.
Fwd Fillet Assembly369A6200-57, -58, standard gear.
Fwd Fillet Assembly369H92113-101, -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.

Start Signature

Issued in Fort Worth, Texas, on July 28, 2004.

David A. Downey,

Manager, Rotorcraft Directorate, Aircraft Certification Service.

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[FR Doc. 04-17794 Filed 8-3-04; 8:45 am]

BILLING CODE 4910-13-P