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###### Department of Transportation

###### Federal Aviation Administration 

          - 14 CFR Part 39 
          - [Docket No. FAA-2008-0586; Directorate Identifier 2008-NM-043-AD; Amendment 39-15625; AD 2008-16-07] 
          - RIN 2120-AA64 

# AGENCY:

Federal Aviation Administration (FAA), Department of Transportation (DOT). 

# ACTION:

Final rule. 

# SUMMARY:

We are adopting a new airworthiness directive (AD) for the products listed above. This AD results from mandatory continuing airworthiness information (MCAI) originated by an aviation authority of another country to identify and correct an unsafe condition on an aviation product. The MCAI describes the unsafe condition as: 

There was one reported failure of the elevator centering torsion spring. Investigation revealed that the tangs on the torsion spring had been bent due to difficulty encountered during installation of the elevator centering torsion spring on the horizontal stabilizer torque tube. The bending of the tangs on the torsion spring would degrade its durability and could lead to premature failure of the elevator centering torsion spring. A control rod disconnect between the elevator aft quadrant and the elevator Power Control Unit input torque tube, in combination with the loss or reduction in elevator centering capability, could result in a significant reduction in aircraft pitch control.

We are issuing this AD to require actions to correct the unsafe condition on these products. 

# DATES:

This AD becomes effective September 9, 2008. 

The Director of the Federal Register approved the incorporation by reference of a certain publication listed in this AD as of September 9, 2008. 

# ADDRESSES:

                        You may examine the AD docket on the Internet at                         *http://www.regulations.gov*                         or in person at the U.S. Department of Transportation, Docket Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New Jersey Avenue, SE., Washington, DC.                     

# FOR FURTHER INFORMATION CONTACT:

Fabio Buttitta, Aerospace Engineer, Systems and Flight Test Branch, ANE-172, FAA, New York Aircraft Certification Office, 1600 Stewart Avenue, Suite 410, Westbury, New York 11590; telephone (516) 228-7303; fax (516) 794-5531. 

# SUPPLEMENTARY INFORMATION:

## Discussion 

                    We issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 to include an AD that would apply to the specified products. That NPRM was published in the                     **Federal Register**                     on May 23, 2008 (73 FR 30005). That NPRM proposed to correct an unsafe condition for the specified products. The MCAI states:                 

There was one reported failure of the elevator centering torsion spring. Investigation revealed that the tangs on the torsion spring had been bent due to difficulty encountered during installation of the elevator centering torsion spring on the horizontal stabilizer torque tube. The bending of the tangs on the torsion spring would degrade its durability and could lead to premature failure of the elevator centering torsion spring. A control rod disconnect between the elevator aft quadrant and the elevator Power Control Unit input torque tube, in combination with the loss or reduction in elevator centering capability, could result in a significant reduction in aircraft pitch control.

Corrective actions include replacing all elevator centering torsion springs with new elevator centering torsion springs. You may obtain further information by examining the MCAI in the AD docket. 

## Comments 

We gave the public the opportunity to participate in developing this AD. We received no comments on the NPRM or on the determination of the cost to the public. 

## Conclusion 

We reviewed the available data and determined that air safety and the public interest require adopting the AD as proposed. 

## Differences Between This AD and the MCAI or Service Information 

We have reviewed the MCAI and related service information and, in general, agree with their substance. But we might have found it necessary to use different words from those in the MCAI to ensure the AD is clear for U.S. operators and is enforceable. In making these changes, we do not intend to differ substantively from the information provided in the MCAI and related service information. 

We might also have required different actions in this AD from those in the MCAI in order to follow our FAA policies. Any such differences are highlighted in a NOTE within the AD. 

## Costs of Compliance 

We estimate that this AD will affect about 42 products of U.S. registry. We also estimate that it will take about 7 work-hours per product to comply with the basic requirements of this AD. The average labor rate is $80 per work-hour. Required parts will cost about $1,746 per product. Where the service information lists required parts costs that are covered under warranty, we have assumed that there will be no charge for these parts. As we do not control warranty coverage for affected parties, some parties may incur costs higher than estimated here. Based on these figures, we estimate the cost of this AD to the U.S. operators to be $96,852, or $2,306 per product. 

## 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                           ( print page 45344)                        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.                 

## Regulatory Findings 

We 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 this AD:*

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 regulatory evaluation of the estimated costs to comply with this AD and placed it in the AD docket. 

## Examining the AD Docket 

                    You may examine the AD docket on the Internet at                     *http://www.regulations.gov*; or in person at the Docket Operations office between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The AD docket contains the NPRM, the regulatory evaluation, any comments received, and other information. The street address for the Docket Operations office (telephone (800) 647-5527) is in the                     **ADDRESSES**                     section. Comments will be available in the AD docket shortly after receipt.                 

# List of Subjects in 14 CFR Part 39

      - Air transportation
      - Aircraft
      - Aviation safety
      - Incorporation by reference
      - Safety

## Adoption of the Amendment 

Accordingly, under the authority delegated to me by the Administrator, the FAA amends 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. The FAA amends § 39.13 by adding the following new AD: 

**2008-16-07 Bombardier, Inc. (Formerly de Havilland, Inc.):**                             Amendment 39-15625. Docket No. FAA-2008-0586; Directorate Identifier 2008-NM-043-AD.                         

## Effective Date 

(a) This airworthiness directive (AD) becomes effective September 9, 2008. 

## Affected ADs 

(b) None. 

## Applicability 

(c) This AD applies to Bombardier Model DHC-8-400, -401 and -402 airplanes, certificated in any category, having serial numbers 4001, 4003, 4004, and 4006 through 4081. 

## Subject 

(d) Air Transport Association (ATA) of America Code 27: Flight Controls. 

## Reason 

(e) The mandatory continuing airworthiness information (MCAI) states: 

There was one reported failure of the elevator centering torsion spring. Investigation revealed that the tangs on the torsion spring had been bent due to difficulty encountered during installation of the elevator centering torsion spring on the horizontal stabilizer torque tube. The bending of the tangs on the torsion spring would degrade its durability and could lead to premature failure of the elevator centering torsion spring. A control rod disconnect between the elevator aft quadrant and the elevator Power Control Unit input torque tube, in combination with the loss or reduction in elevator centering capability, could result in a significant reduction in aircraft pitch control.

Corrective actions include replacing all elevator centering torsion springs with new elevator centering torsion springs. 

## Actions and Compliance 

(f) Unless already done: Prior to the accumulation of 22,000 total flight hours, or within 5,000 flight hours after the effective date of this AD, whichever comes later, replace all elevator centering torsion springs with new elevator centering torsion springs by incorporating Modsum 4-113482, in accordance with Bombardier Service Bulletin 84-27-31, dated April 27, 2007. 

## FAA AD Differences 

**Note:**                             This AD differs from the MCAI and/or service information as follows: No differences.                         

## Other FAA AD Provisions 

(g) The following provisions also apply to this AD: 

                            (1)                             *Alternative Methods of Compliance (AMOCs):*                             The Manager, New York Aircraft Certification Office (ACO), FAA, has the authority to approve AMOCs for this AD, if requested using the procedures found in 14 CFR 39.19. Send information to ATTN: Fabio Buttitta, Aerospace Engineer, Systems and Flight Test Branch, ANE-172, FAA, New York ACO, 1600 Stewart Avenue, Suite 410, Westbury, New York 11590; telephone (516) 228-7303; fax (516) 794-5531. Before using any approved AMOC on any airplane to which the AMOC applies, notify your appropriate principal inspector (PI) in the FAA Flight Standards District Office (FSDO), or lacking a PI, your local FSDO.                         

                            (2)                             *Airworthy Product:*                             For any requirement in this AD to obtain corrective actions from a manufacturer or other source, use these actions if they are FAA-approved. Corrective actions are considered FAA-approved if they are approved by the State of Design Authority (or their delegated agent). You are required to assure the product is airworthy before it is returned to service.                         

                            (3)                             *Reporting Requirements:*                             For any reporting requirement in this AD, under the provisions of the Paperwork Reduction Act, the Office of Management and Budget (OMB) has approved the information collection requirements and has assigned OMB Control Number 2120-0056.                         

## Related Information 

(h) Refer to MCAI Canadian Airworthiness Directive CF-2008-05R1, dated February 27, 2008, and Bombardier Service Bulletin 84-27-31, dated April 27, 2007, for related information. 

## Material Incorporated by Reference 

(i) You must use Bombardier Service Bulletin 84-27-31, dated April 27, 2007, to do the actions required by this AD, unless the AD specifies otherwise. 

(1) The Director of the Federal Register approved the incorporation by reference of this service information under 5 U.S.C. 552(a) and 1 CFR part 51. 

(2) For service information identified in this AD, contact Bombardier, Inc., Bombardier Regional Aircraft Division, 123 Garratt Boulevard, Downsview, Ontario M3K 1Y5, Canada. 

                            (3) You may review copies at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington; or at the National Archives and Records Administration (NARA). For information on the availability of this material at NARA, call (202) 741-6030, or go to:                             *http://www.archives.gov/​federal-register/​cfr/​ibr-locations.html*.                         

Issued in Renton, Washington, on July 23, 2008. 

Ali Bahrami, 

Manager, Transport Airplane Directorate, Aircraft Certification Service.

[FR Doc. E8-17612 Filed 8-4-08; 8:45 am] 

BILLING CODE 4910-13-P