
[Federal Register: May 23, 2008 (Volume 73, Number 101)]
[Proposed Rules]               
[Page 30005-30007]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr23my08-13]                         

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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]
RIN 2120-AA64

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

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: We propose to adopt a new airworthiness directive (AD) for the 
products listed above. This proposed 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.

    The proposed AD would require actions that are intended to address 
the unsafe condition described in the MCAI.

DATES: We must receive comments on this proposed AD by June 23, 2008.

ADDRESSES: You may send comments by any of the following methods:
     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 W12-40, 1200 New 
Jersey Avenue, SE., Washington, DC, between 9 a.m. and 5 p.m., Monday 
through Friday, except Federal holidays.

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 this proposed AD, 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.

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: 

Comments Invited

    We invite you to send any written relevant data, views, or 
arguments about this proposed AD. Send your comments to an address 
listed under the ADDRESSES section. Include ``Docket No. FAA-2008-0586; 
Directorate Identifier 2008-NM-043-AD'' at the beginning of your 
comments. We specifically invite comments on the overall regulatory, 
economic, environmental, and energy aspects of this proposed AD. We 
will consider all comments received by the closing date and may amend 
this proposed AD based on 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 we 
receive about this proposed AD.

Discussion

    Transport Canada Civil Aviation (TCCA), which is the aviation 
authority for Canada, has issued Canadian Airworthiness Directive CF-
2008-05R1, dated February 27, 2008. (referred to after this as ``the 
MCAI''), 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

[[Page 30006]]

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.

Relevant Service Information

    Bombardier has issued Service Bulletin 84-27-31, dated April 27, 
2007. The actions described in this service information are intended to 
correct the unsafe condition identified in the MCAI.

FAA's Determination and Requirements of This Proposed AD

    This product has been approved by the aviation authority of another 
country, and is approved for operation in the United States. Pursuant 
to our bilateral agreement with the State of Design Authority, we have 
been notified of the unsafe condition described in the MCAI and service 
information referenced above. We are proposing this AD because we 
evaluated all pertinent information and determined an unsafe condition 
exists and is likely to exist or develop on other products of the same 
type design.

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 proposed different actions in this AD from those 
in the MCAI in order to follow FAA policies. Any such differences are 
highlighted in a NOTE within the proposed AD.

Costs of Compliance

    Based on the service information, we estimate that this proposed AD 
would affect about 42 products of U.S. registry. We also estimate that 
it would take about 7 work-hours per product to comply with the basic 
requirements of this proposed AD. The average labor rate is $80 per 
work-hour. Required parts would 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 
costs. 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 the proposed AD on 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 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 proposed AD would not have federalism 
implications under Executive Order 13132. 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 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. 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 proposed AD and placed it in the AD docket.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Safety.

The Proposed Amendment

    Accordingly, under the authority delegated to me by the 
Administrator, the FAA proposes to amend 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.


Sec.  39.13  [Amended]

    2. The FAA amends Sec.  39.13 by adding the following new AD:

Bombardier, Inc. (Formerly de Havilland, Inc.): Docket No. FAA-2008-
0586; Directorate Identifier 2008-NM-043-AD.

Comments Due Date

    (a) We must receive comments by June 23, 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) 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, unless already done: Replace all

[[Page 30007]]

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.

    Issued in Renton, Washington, on May 8, 2008.
Michael J. Kaszycki,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
 [FR Doc. E8-11566 Filed 5-22-08; 8:45 am]

BILLING CODE 4910-13-P
