[Federal Register Volume 72, Number 219 (Wednesday, November 14, 2007)]
[Proposed Rules]
[Pages 64010-64012]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: E7-22264]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2007-27192; Directorate Identifier 2007-CE-008-AD]
RIN 2120-AA64


Airworthiness Directives; Viking Air Limited Model DHC-6 Series 
Airplanes

AGENCY: Federal Aviation Administration (FAA), Department of 
Transportation (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 that would supersede an existing AD. 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:

    Certain structural components must be replaced by new components 
at a certain stage of the aircraft's life to avoid any possibility 
of fatigue failure.

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 December 14, 
2007.

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 W12-140, 1200 New 
Jersey Avenue, SE., Washington, DC 20590, 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 Management Facility, 
U.S. Department of Transportation, Docket Operations, M-30, West 
Building Ground Floor, Room W12-140, 1200 New Jersey Avenue, SE., 
Washington, DC 20590.
    Docket Management Facility 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 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: George Duckett, Aerospace Engineer, 
FAA, New York Certification Office, 1600 Stewart Avenue, suite 410, 
Westbury, New York 11590; telephone: (516) 228-7325; 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-2007-
27192; Directorate Identifier 2007-CE-008-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 because of those comments.
    We will post all comments we receive, without change, to http://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

    On February 4, 1983, we issued AD 83-02-02, Amendment 39-4553. That 
AD required actions intended to address an unsafe condition on the 
products listed above.
    Since we issued AD 83-02-02, structural evaluations of the DHC-6 
series airplanes have shown that the service life limits and inspection 
schedules need to be revised.
    Transport Canada, which is the aviation authority for Canada, has 
issued AD No. CF-2000-14, dated May 25, 2000, (referred to after this 
as ``the MCAI''), to correct an unsafe condition for the specified 
products. The MCAI refers to the Product Support Manual (PSM) 1-6-11, 
Revision 5, dated January 11, 2000, which describes the unsafe 
condition as:

    Certain structural components must be replaced by new components 
at a certain stage of the aircraft's life to avoid any possibility 
of fatigue failure.

    The MCAI requires you to inspect, modify, and/or retire affected 
structural components to maintain the structural integrity of DHC-6 
airplanes.
    You may obtain further information by examining the MCAI in the AD 
docket.

Relevant Service Information

    Viking Air Limited has issued PSM 1-6-11, Revision 6, dated March 
28, 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 the 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 this State of Design Authority, they 
have notified us

[[Page 64011]]

of the unsafe condition described in the MCAI and service information 
referenced above. We are proposing this AD because we evaluated all 
information and determined the unsafe condition exists and is likely to 
exist or develop on other products of the same type design.

Differences Between This Proposed 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 166 products of U.S. registry. We also estimate that 
it would take about 30 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 $988 per product.
    Based on these figures, we estimate the cost of the proposed AD on 
U.S. operators to be $562,408, or $3,388 per product.
    We have no way of determining the number of airplanes that may need 
any modifications, repairs, or replacements based on the results of the 
repetitive inspections.
    In addition, since the proposed AD is reducing the life limit of 
certain structural components of the affected airplanes, there would be 
replacement costs incurred earlier than expected. The FAA has no way of 
determining the operational usage of each airplane. Therefore, we 
cannot determine what these costs would be.

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 removing AD 83-02-02, Amendment 
39-4553; and adding the following new AD:

Viking Air Limited (formerly Bombardier Inc.): Docket No. FAA-2007-
27192; Directorate Identifier 2007-CE-008-AD.

Comments Due Date

    (a) We must receive comments by December 14, 2007.

Affected ADs

    (b) This AD supersedes AD 83-02-02, Amendment 39-4553.

Applicability

    (c) This AD applies to Models DHC-6-1, DHC-6-100, DHC-6-200, and 
DHC-6-300 airplanes, all serial numbers, certificated in any 
category.

Subject

    (d) Air Transport Association of America (ATA) Code 51: 
Structures.

Reason

    (e) The mandatory continuing airworthiness information (MCAI) 
refers to the Product Support Manual (PSM) 1-6-11, Revision 5, dated 
January 11, 2000, which states:
    Certain structural components must be replaced by new components 
at a certain stage of the aircraft's life to avoid any possibility 
of fatigue failure.
    The MCAI requires you to inspect, modify, and/or retire affected 
structural components to maintain the structural integrity of DHC-6 
airplanes.

Actions and Compliance

    (f) Unless already done, within 30 days after the effective date 
of this AD, for all aircraft, incorporate the inspections, 
modifications, and/or retirement of components specified in 
Bombardier Inc. (formerly de Havilland) DHC-6 ``Twin Otter'' PSM 1-
6-11, Revision 6, dated March 28, 2007, into the aircraft 
maintenance program. The compliance times are specified in the 
manual. For aircraft that are approaching or have exceeded the 
threshold of the new or revised inspections introduced by this AD, 
compliance with the threshold inspection may be modified as detailed 
below:
    (1) Pre Mod 6/1117 Wing Assemblies:
    (i) If the last inspection done of the main wing spar attachment 
lug fastener holes, before the effective date of this AD, was an 
eddy current inspection following Bombardier Inc. (formerly de 
Havilland) DHC-6 ``Twin Otter'' PSM 1-6-11, Revision 5, dated 
January 11, 2000; or PSM 1-6-11, Revision 6, dated March 28, 2007; 
do the repeat high frequency eddy current inspection in accordance 
with the schedule in PSM 1-6-11, Revision 6, dated March 28, 2007.
    (ii) If the last inspection done of the main wing spar 
attachment lug fastener holes, before the effective date of this AD, 
was an ultrasonic inspection following Bombardier Service Bulletin 
6/525, dated September 6, 1996, do the first high frequency eddy 
current inspection within 1,000 hours time-in-service (TIS) or 2,000 
flights, whichever occurs first, after the last ultrasonic 
inspection. Repetitively inspect thereafter in accordance with the 
schedule in PSM 1-6-11, dated March 28, 2007.
    (2) Post Mod 6/1117 and Post Mod 6/1630 Wing Assemblies: If the 
inspection threshold for the lower wing skin, stringers, and aft

[[Page 64012]]

spar lower flange WS122 to WS263 (ribs 8 to 20) has been exceeded or 
will be exceeded within 6 months after the effective date of this 
AD, do the initial inspection within the next 500 hours TIS, 1,000 
flights, or 6 months after the effective date of this AD, whichever 
occurs first, following PSM 1-6-11, Revision 6, dated March 28, 
2007.
    (g) You may take ``unless already done'' credit if the above 
actions were done following the procedures described in Bombardier 
Inc. (formerly de Havilland) DHC-6 ``Twin Otter'' PSM 1-6-11, 
Revision 5, dated January 11, 2000.

FAA AD Differences

    Note: This AD differs from the MCAI and/or service information 
as follows: The MCAI references PSM 1-6-11, Revision 5, dated 
January 11, 2000. PSM 1-6-11, Revision 6, dated March 28, 2007, has 
since been issued and is referenced for compliance in this AD.

Other FAA AD Provisions

    (h) The following provisions also apply to this AD:
    (1) Alternative Methods of Compliance (AMOCs): The Manager, New 
York Aircraft Certification Office, 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: George Duckett, Aerospace 
Engineer, Airframe and Propulsion Branch, FAA, New York 
Certification Office, 1600 Stewart Avenue, suite 410, Westbury, New 
York 11590; telephone: (516) 228-7325; 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 (44 
U.S.C. 3501 et seq.), the Office of Management and Budget (OMB) has 
approved the information collection requirements and has assigned 
OMB Control Number 2120-0056.

Related Information

    (i) Refer to MCAI Transport Canada AD No. CF-2000-14, dated May 
25, 2000; and Viking Air Limited Structural Components Service Life 
Limits Manual PSM 1-6-11, Revision 6, dated March 28, 2007, for 
related information.

    Issued in Kansas City, Missouri, on November 6, 2007.
David R. Showers,
Acting Manager, Small Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. E7-22264 Filed 11-13-07; 8:45 am]
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