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Airworthiness Directives; MD Helicopters, Inc. Model MD-900 Helicopters

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Information about this document as published in the Federal Register.

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This document has been published in the Federal Register. Use the PDF linked in the document sidebar for the official electronic format.

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Federal Aviation Administration, DOT.


Final rule.


This amendment supersedes an existing airworthiness directive (AD) for MD Helicopters, Inc. (MDHI) model MD-900 helicopters that currently requires applying serial numbers to certain parts, increasing the life limit for various parts, maintaining a previously established life limit for a certain vertical stabilizer control system (VSCS) bellcrank assembly and bellcrank arm, and correcting the part number for the VSCS bellcrank arm. This amendment requires the same actions as the existing AD, except it reduces the life limit of the swashplate spherical slider bearing (slider bearing). It further corrects what was described as a “bellcrank arm” life limit in the current AD and correctly describes it as another “bellcrank assembly” life limit. This amendment is prompted by two reports of cracks in the slider bearing that occurred well before the previously increased retirement life of 2,030 hours time-in-service (TIS) was reached. The actions specified by this AD are intended to establish appropriate life limits for various parts, and to prevent fatigue failure of those parts and subsequent loss of control of the helicopter.


Effective April 20, 2010.


You may get the service information identified in this AD from MD Helicopters Inc., Attn: Customer Support Division, 4555 E. McDowell Rd., Mail Stop M615, Mesa, Arizona 85215-9734, telephone 1-800-388-3378, fax 480-346-6813, or on the Web at

Examining the Docket: You may examine the docket that contains this AD, any comments, and other information on the Internet at, or at the Docket Operations office, West Building Ground Floor, Room W12-140, 1200 New Jersey Avenue, SE., Washington, DC.

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Roger Durbin, Aviation Safety Engineer, Start Printed Page 12442FAA, Los Angeles Aircraft Certification Office, Airframe Branch, 3960 Paramount Blvd., Lakewood, California 90712, telephone (562) 627-5233, fax (562) 627-5210.

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A proposal to amend 14 CFR part 39 by superseding AD 99-16-13, Amendment 39-11248 (64 FR 42824, August 6, 1999), Docket No. 98-SW-42-AD, for the MDHI Model MD-900 helicopters was published in the Federal Register on October 22, 2009 (74 FR 54495). The action proposed to decrease the life limit of the slider bearing from 2,030 hours TIS to 700 hours time-in-service (TIS). Additionally, changing the nomenclature for part number 900F2341712-101 from bellcrank arm to bellcrank assembly was proposed. The action also proposed to retain the requirements of the existing AD to apply serial numbers to various parts, and to retain the life limits of various other parts.

Interested persons have been afforded an opportunity to participate in the making of this amendment. No comments were received on the proposal or the FAA's determination of the cost to the public. The FAA has determined that air safety and the public interest require the adoption of the rule as proposed.

The FAA estimates that this AD will affect 27 helicopters of U.S. registry, and that it will take approximately 2.5 work hours per helicopter to accomplish the serialization of the affected parts at an average labor rate of $85 per work hour. Additionally, it is estimated that 8 of those aircraft will require replacement of the slider bearing, which will require approximately 7 work hours to accomplish at an average labor rate of $85 per work hour. Required parts will cost approximately $11,080 per helicopter for the slider bearing. Based on these figures, we estimate the total cost impact of the AD on U.S. operators to be $99,137.

Regulatory Findings

We have 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 above, I certify that the 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. 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. See the AD docket to examine the economic evaluation.

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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List of Subjects in 14 CFR Part 39

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Adoption of the Amendment

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Accordingly, pursuant to the authority delegated to me by the Administrator, the Federal Aviation Administration amends part 39 of the Federal Aviation Regulations (

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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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2. Section 39.13 is amended by removing Amendment 39-11248 (

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2010-06-06 MD Helicopters, Inc.: Amendment 39-16230. Docket No. FAA-2009-0953; Directorate Identifier 2009-SW-45-AD. Supersedes AD 99-16-13, Amendment 39-11248, Docket No. 98-SW-42-AD.

Applicability: MD-900 helicopters, certificated in any category.

Compliance: Required as indicated, unless accomplished previously.

To establish appropriate life limits for various parts, and to prevent fatigue failure of those parts and subsequent loss of control of the helicopter, accomplish the following:

(a) Remove from service as follows:

(1) The nonrotating swashplate assembly, part number (P/N) 900C2010192-105, -107, -109, or -111, on or before 1,800 hours time-in-service (TIS).

(2) The collective drive link assembly, P/N 900C2010207-101, on or before 3,307 hours TIS.

(3) The swashplate spherical slider bearing, P/N 900C3010042-103, on or before 700 hours TIS.

(4) The vertical stabilizer control system (VSCS) bellcrank assembly, P/N 900FP341712-103, and bellcrank assembly, P/N 900F2341712-101, on or before 2,700 hours TIS.

(b) Within 100 hours TIS:

(1) For Model MD-900 helicopters with serial numbers (S/N) 900-00002 through 900-00012, apply the appropriate S/N to the mid-forward truss assembly, P/N 900F2401200-102, and the forward and aft deck-fitting assemblies, P/N 900F2401500-103 and P/N 900F2401600-103.

(2) For Model MD-900 helicopters with S/N 900-00002 through 900-00048, apply S/N to the left and right VSCS bellcrank assemblies, P/N 900F2341712-101 and P/N 900FP341712-103, and the mid-aft truss strut assembly, P/N 900F2401300-103.

(3) Apply the S/N, as specified in paragraphs (b)(1) and (b)(2) of this AD, adjacent to the existing P/N, as listed in Appendix A of this AD, using permanent ink or paint. When dry, apply a clear coat over the S/N.

(c) This AD revises the Airworthiness Limitations Section of the MD-900 Maintenance Manual by increasing the life limits for certain parts and reducing the life limit of the slider bearing.


The Airworthiness Limitations Section of the MD-900 Rotorcraft Maintenance Manual, Reissue 1, Revision 25, dated April 16, 2006, and MD Helicopters Service Bulletin SB900-096, dated February 28, 2005, pertain to the subject of this AD.

(d) 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 Manager, Los Angeles Aircraft Certification Office, FAA, for information about previously approved alternative methods of compliance.

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(e) This amendment becomes effective on April 20, 2010.

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Issued in Fort Worth, Texas, on February 18, 2010.

Mark R. Schilling,

Acting Manager, Rotorcraft Directorate, Aircraft Certification Service.

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[FR Doc. 2010-5325 Filed 3-15-10; 8:45 am]