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###### Department of Transportation

###### Federal Aviation Administration

          - 14 CFR Part 39
          - [Docket No. FAA-2009-0953; Directorate Identifier 2009-SW-45-AD]
          - RIN 2120-AA64

# AGENCY:

Federal Aviation Administration, DOT.

# ACTION:

Notice of proposed rulemaking (NPRM).

# SUMMARY:

This document proposes superseding an existing airworthiness directive (AD) for MD Helicopters, Inc. (MDHI) Model MD-900 helicopters. That AD 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 proposal would require the same actions, except it would reduce the life limit of the swashplate spherical slider bearing (slider bearing). It would further correct what was described as a “bellcrank arm” life limit in the current AD and correctly describe it as another “bellcrank assembly” life limit. This proposal 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 the proposed 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.

# DATES:

Comments must be received on or before December 21, 2009.

# ADDRESSES:

Use one of the following addresses to submit comments on this proposed AD:
      -  Federal eRulemaking Portal:                          Go to                          http://www.regulations.gov . Follow the instructions for submitting comments.                    
      -  Fax:                          202-493-2251.                    
      -  Mail:                          U.S. Department of Transportation, Docket Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New Jersey Avenue, SE., Washington, DC 20590.                    
      -  Hand Delivery:                          U.S. Department of Transportation, Docket Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New Jersey Avenue, SE., Washington, DC 20590, between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays.                    

                        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                         *www.mdhelicopters.com*.                    

                        You may examine the comments to this proposed AD in the AD docket on the Internet at                         *http://www.regulations.gov*.                    

# FOR FURTHER INFORMATION CONTACT:

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

# SUPPLEMENTARY INFORMATION:

## Comments Invited

                    We invite you to submit any written data, views, or arguments regarding this proposed AD. Send your comments to the address listed under the caption                     **ADDRESSES**                    . Include the docket number “FAA-2009-0953, Directorate Identifier 2009-SW-45-AD” at the beginning of your comments. We specifically invite comments on the overall regulatory, economic, environmental, and energy aspects of the proposed AD. We will consider all comments received by the closing date and may amend the proposed AD in light of those comments.                

                    We will post all comments we receive, without change, to                     *http://www.regulations.gov,*                     including any personal information you provide. We will also post a report summarizing each substantive verbal contact with FAA personnel concerning this proposed rulemaking. Using the search function of our docket web site, you can find and read the comments to any of our dockets, including the name of the individual who sent or signed the comment. You may review the DOT's complete Privacy Act Statement in the                     **Federal Register**                     published on April 11, 2000 (65 FR 19477-78).                

## Examining the Docket

                    You may examine the docket that contains the proposed AD, any comments, and other information in person at the Docket Operations office between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The Docket Operations office (telephone (800) 647-5527) is located in Room W12-140 on the ground floor of the West Building at the street address stated in the                     **ADDRESSES**                     section. Comments will be available in the AD docket shortly after receipt.                

## Discussion

On June 17, 1997, we issued AD 97-13-09, Amendment 39-10056 (62 FR 34163, June 25, 1997), to require applying a specified serial number (S/N) to the following parts: for helicopters with S/N 0002 through 0012, to the mid-forward truss assembly, P/N 900F2401200-102, and to the forward and aft deck fitting assemblies, P/N 900F2401500-103 and 900F2401600-103, respectively; for helicopters with S/N 0002 through 0048, to the VSCS bellcrank assemblies, P/N 900F2341712-101 and P/N 900FP341712-103, and to the mid-aft truss strut assembly, P/N 900F2401300-103. That AD also reduced the life limits for the nonrotating swashplate assembly, P/N 900C2010192-105, -107, -109, and -111, from 8,300 hours TIS to 554 hours TIS; the collective drive link assembly, P/N 900C2010207-101, from 3,900 hours TIS to 1,480 hours TIS; and the slider bearing, P/N 900C3010042-103, from 2,100 hours TIS to 480 hours TIS. Finally, that AD established life limits for the bellcrank assembly, P/N 900FP341712-103, and the bellcrank arm, P/N 900F2341713-101 (used in the bellcrank assembly, P/N 900F2341712-101), of 2,700 hours TIS. That AD was prompted by an analysis that indicated a need to reduce the life limits on several parts and by the addition of non-serialized parts to the life-limited parts list. The requirements of that AD were intended to establish new life limits for various parts and reduce the existing life limits on other parts.

                    On July 28, 1999, we issued superseding AD 99-16-13, Amendment 39-11248 (64 FR 42824, August 6, 1999), to correct the P/N for the bellcrank arm from P/N 900F2341713-101 to P/N 900F2341712-101, and to increase the life limits for the nonrotating swashplate, P/N 900C2010192-105, -107, -109, or -111, from 554 hours TIS to 1,800 hours TIS; the collective drive link assembly, P/N 900C2010207-101, from 1,480 hours TIS to 3,307 hours TIS; and the slider bearing, P/N 900C3010042-103, from 480 hours TIS to 2,030 hours TIS, and maintaining the 2,700 hours TIS for the bellcrank assembly and bellcrank arm. AD 99-16-13 was prompted by both the need to correct a P/N as well as additional analyses (modified fatigue spectrums, fatigue tests, and flight strain data) supporting an increase in the life limits for certain parts. The requirements of that AD are intended to                           ( print page 54496)                        increase the life limits of various parts, correct the bellcrank arm P/N, and specify applying serial numbers to various parts.                

Since issuing AD 99-16-13, we have received two reports from the manufacturer of cracks in the attachment ear of the slider bearing, P/N 900C3010042-103. A review of the service history and a further review of the design data for the slider bearing now indicate that a reduced life limit is required to maintain continued operational safety. The manufacturer has made available an alternate replacement slider bearing, P/N 900C3010042-105, that has improved durability characteristics and an increased life limit of 12,807 hours TIS. Further, we have determined that even though we corrected P/N “900F2341713-101” to read “900F2341712-101” in AD 99-16-13, we incorrectly described the part as a “bellcrank arm” in both AD 99-16-13 and AD 97-13-09. The correct nomenclature for P/N 900F2341712-101 is “bellcrank assembly.” We propose to correct that error in this action.

We have reviewed MD Helicopters Service Bulletin SB900-096, dated February 28, 2005, which contains a reduction of the life limit of the slider bearing from 2,030 hours TIS to 700 hours TIS.

This previously described unsafe condition is likely to exist or develop on other helicopters of the same type design. Therefore, the proposed AD would supersede AD 99-16-13 to decrease the life limit of the slider bearing from 2,030 hours TIS to 700 hours TIS. Additionally, this AD changes the nomenclature for P/N 900F2341712-101 from bellcrank arm to bellcrank assembly. The proposed AD would also retain the requirements of the existing AD to apply serial numbers to various parts, and retain the life limits of various other parts.

We estimate that this proposed AD would affect 27 helicopters of U.S. registry and that it would take approximately 2.5 work hours per helicopter to accomplish the serialization of the affected parts at an average rate of $80 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 rate of $80 per work hour. Required parts would cost $11,080 per helicopter for the slider bearing. Based on these figures, we estimate the total cost impact of the proposed AD on U.S. operators to be $98,520.

## Regulatory Findings

We have determined that this proposed AD would not have federalism implications under Executive Order 13132. Additionally, this proposed AD 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.

For the reasons discussed above, I certify that the 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. 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 a draft economic evaluation of the estimated costs to comply with this proposed AD. See the AD docket to examine the draft 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.

# 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.

§ 39.13 

2. Section 39.13 is amended by removing Amendment 39-11248 (64 FR 42824, August 6, 1999), and by adding a new airworthiness directive (AD), to read as follows:

**MD Helicopters, Inc. Model MD-900 Helicopters:**                                 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.

# Note:

                                     The Airworthiness Limitations Section of the MD-900 Rotorcraft Maintenance Manual, Reissue 1, Revision 25,                                           ( print page 54497)                                        dated April 16, 2006, and MD Helicopters Service Bulletin SB900-096, dated February 28, 2005, pertain to the subject of this AD. 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.                                
      ( print page 54498)    

Issued in Fort Worth, Texas, on October 8, 2009.

Larry M. Kelly,

Acting Manager, Rotorcraft Directorate, Aircraft Certification Service.

BILLING CODE 4910-13-P

[FR Doc. E9-25439 Filed 10-21-09; 8:45 am]

BILLING CODE 4910-13-C