Airworthiness Directives; Bombardier Model DHC-8-400, -401 and -402 Airplanes

[Federal Register Volume 73, Number 151 (Tuesday, August 5, 2008)]
[Rules and Regulations]
[Pages 45343-45344]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: E8-17612]



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Federal Register / Vol. 73, No. 151 / Tuesday, August 5, 2008 / Rules 
and Regulations

[[Page 45343]]



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


Airworthiness Directives; Bombardier Model DHC-8-400, -401 and -
402 Airplanes

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

[[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

0
Accordingly, under the authority delegated to me by the Administrator, 
the FAA amends 14 CFR part 39 as follows:

PART 39--AIRWORTHINESS DIRECTIVES

0
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]

0
2. The FAA amends Sec.  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

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