Airworthiness Directives; Viking Air Limited Model DHC-6-1, DHC-6-100, DHC-6-200, and DHC-6-300 Airplanes, 7641-7643 [E9-3115]

Download as PDF 7641 Rules and Regulations Federal Register Vol. 74, No. 32 Thursday, February 19, 2009 [Docket No. FAA–2008–1267; Directorate Identifier 2008–CE–069–AD; Amendment 39–15815; AD 2009–04–09] A, dated November 15, 2007, listed in this AD. ADDRESSES: You may examine the AD docket on the Internet at https:// 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. FOR FURTHER INFORMATION CONTACT: Pong Lee, Aerospace Engineer, FAA, New York Aircraft Certification Office, ANE–171, 1600 Stewart Avenue, Suite 410, Westbury, New York 11590; telephone: (516) 228–7324; fax: (516) 794–5531. SUPPLEMENTARY INFORMATION: RIN 2120–AA64 Discussion This section of the FEDERAL REGISTER contains regulatory documents having general applicability and legal effect, most of which are keyed to and codified in the Code of Federal Regulations, which is published under 50 titles pursuant to 44 U.S.C. 1510. The Code of Federal Regulations is sold by the Superintendent of Documents. Prices of new books are listed in the first FEDERAL REGISTER issue of each week. DEPARTMENT OF TRANSPORTATION Federal Aviation Administration 14 CFR Part 39 Airworthiness Directives; Viking Air Limited Model DHC–6–1, DHC–6–100, DHC–6–200, and DHC–6–300 Airplanes AGENCY: Federal Aviation Administration (FAA), Department of Transportation (DOT). ACTION: Final rule. SUMMARY: We are superseding an existing airworthiness directive (AD) for the products listed above. This AD results from mandatory continuing airworthiness information (MCAI) issued 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: yshivers on PROD1PC62 with RULES There have been reports of inter-rivet cracking on several wing front spar adapter assemblies (P/N C6WM1027–1) on the horizontal and vertical flanges. It was determined that the cracking was caused by stress corrosion in the short transverse grain initiated by local riveting induced stresses. We are issuing this AD to require actions to correct the unsafe condition on these products. DATES: This AD becomes effective March 26, 2009. As of August 5, 2008 (73 FR 37353, July 1, 2008), the Director of the Federal Register approved the incorporation by reference of Viking DHC–6 Twin Otter Service Bulletins No. V6/540, dated October 1, 2007; No. V6/541, dated October 1, 2007; and No. V6/542, dated October 1, 2007; and R.W. Martin, Inc. Service Bulletin No. 00160/2, Revision VerDate Nov<24>2008 14:28 Feb 18, 2009 Jkt 217001 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 December 3, 2008 (73 FR 73618), and proposed to supersede AD 2008–11–10, Amendment 39–15532 (73 FR 37353, July 1, 2008). That NPRM proposed to correct an unsafe condition for the specified products. The MCAI states that: There have been reports of inter-rivet cracking on several wing front spar adapter assemblies (P/N C6WM1027–1) on the horizontal and vertical flanges. It was determined that the cracking was caused by stress corrosion in the short transverse grain initiated by local riveting induced stresses. This directive mandates modification and inspection of the wing front spar adapter fitting and replacement of cracked fittings. Since we issued AD 2008–11–10, Amendment 39–15532 (73 FR 37353, July 1, 2008), we have added to the Applicability section additional wing box part numbers that may incorporate a P/N C6WM1027–1 front spar adapter assembly with 10 or more years of service. 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 PO 00000 Frm 00001 Fmt 4700 Sfmt 4700 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 FAA policies. Any such differences are highlighted in a NOTE within the AD. Costs of Compliance We estimate that this AD will affect 157 products of U.S. registry. We also estimate that it will take about 18 workhours per product to comply with the basic requirements of this AD. The average labor rate is $80 per work-hour. Based on these figures, we estimate the cost of this AD to the U.S. operators to be $226,080 or $1,440 per product. In addition, we estimate that any necessary follow-on actions would take about 200 work-hours and require parts costing $3,696, for a cost of $19,696 per product. We have no way of determining the number of products that may need these actions. 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 E:\FR\FM\19FER1.SGM 19FER1 7642 Federal Register / Vol. 74, No. 32 / Thursday, February 19, 2009 / Rules and Regulations 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 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 https:// www.regulations.gov; or in person at the Docket Management Facility 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 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: ■ yshivers on PROD1PC62 with RULES Authority: 49 U.S.C. 106(g), 40113, 44701. § 39.13 [Amended] 2. The FAA amends § 39.13 by removing Amendment 39–15532 (73 FR 37353, July 1, 2008) and adding the following new AD: ■ VerDate Nov<24>2008 14:28 Feb 18, 2009 Jkt 217001 2009–04–09 Viking Air Limited: Amendment 39–15815; Docket No. FAA–2008–1267; Directorate Identifier 2008–CE–069–AD. Effective Date (a) This airworthiness directive (AD) becomes effective March 26, 2009. Affected ADs (b) This AD supersedes AD 2008–11–10, Amendment 39–15532 (73 FR 37353, July 1, 2008). Applicability (c) This AD applies to the following Models DHC–6–1, DHC–6–100, DHC–6–200, and DHC–6–300 airplanes, all serial numbers, that are certificated in any category: (1) Group 1: Equipped with wing boxes, part numbers (P/Ns) C6W1002–1, C6W1002– 3, WR6–1002–59 or WR6–1002–61 that incorporate a P/N C6WM1027–1 front spar adapter assembly with 10 or more years of service; and (2) Group 2: Equipped with wing boxes, P/ Ns C6W1002–5, C6W1002–7, C6W1002–9, C6W1002–11, C6W1002–13, C6W1002–15, C6W1002–17, C6W1002–19, C6W1002–21, C6W1002–23, C6W1002–51, C6W1002–53, C6W1002–55, C6W1002–57 or C6W1002–61 that incorporate a P/N C6WM1027–1 front spar adapter assembly with 10 or more years of service. Subject (d) Air Transport Association of America (ATA) Code 57: Wings. Reason (e) The mandatory continuing airworthiness information (MCAI) states: ‘‘There have been reports of inter-rivet cracking on several wing front spar adapter assemblies (P/N C6WM1027–1) on the horizontal and vertical flanges. It was determined that the cracking was caused by stress corrosion in the short transverse grain initiated by local riveting induced stresses. This directive mandates modification and inspection of the wing front spar adapter fitting and replacement of cracked fittings.’’ Since we issued AD 2008–11–10, Amendment 39–15532 (73 FR 37353, July 1, 2008), we have added to the Applicability section additional wing box part numbers that may incorporate a P/N C6WM1027–1 front spar adapter assembly with 10 or more years of service. Actions and Compliance (f) Unless already done, do the following actions: (1) For Group 1 airplanes, within the next 180 days after August 5, 2008 (the effective date of AD 2008–11–10), install inspection holes in the left-hand (LH) and right-hand (RH) lower wing skins following Viking DHC–6 Twin Otter Service Bulletin Number V6/541, dated October 1, 2007. (2) For Group 2 airplanes, within the next 180 days after the effective date of this AD, install inspection holes in the LH and RH lower wing skins following Viking DHC–6 Twin Otter Service Bulletin Number V6/541, dated October 1, 2007. PO 00000 Frm 00002 Fmt 4700 Sfmt 4700 (3) For Group 1 and Group 2 airplanes, before further flight after installing the inspection holes required in paragraph (f)(1) or (f)(2) of this AD, initially inspect the LH and RH front spar adapter assemblies for cracks, and repetitively thereafter inspect all affected wing box P/Ns at intervals not to exceed 1,200 hours time-in-service or 12 months, whichever occurs first, until the replacement required in paragraph (f)(4) of this AD is done. (i) For wing box P/Ns C6W1002–1, C6W1002–3, C6W1002–5, C6W1002–7, C6W1002–9, C6W1002–11, C6W1002–13, C6W1002–15, C6W1002–17, C6W1002–19, C6W1002–21, C6W1002–23, C6W1002–51, C6W1002–53, C6W1002–55, C6W1002–57, C6W1002–59, and C6W1002–61, inspect following Viking DHC–6 Twin Otter Service Bulletin Number V6/540, dated October 1, 2007. (ii) For wing box P/Ns WR6–1002–59 or WR6–1002–61, inspect following R.W. Martin, Inc. Service Bulletin No. 00160/2, Revision A, dated November 15, 2007. (4) For Group 1 and 2 airplanes, before further flight after doing any inspection required in paragraph (f)(3) of this AD where cracks are found, replace the cracked front spar adapter assembly with a front spar adapter assembly, P/N C6WM1027–3. Do the replacement following Viking DHC–6 Twin Otter Service Bulletin Number V6/542, dated October 1, 2007. This replacement terminates the repetitive inspections required in paragraph (f)(3) of this AD for the replaced front spar adapter assembly. (5) As a terminating action for the repetitive inspections required in paragraph (f)(3) of this AD, at any time after the initial inspection required in paragraph (f)(3) of this AD, you may replace P/N C6WM1027–1 with P/N C6WM1027–3, except it must be replaced prior to further flight as required by paragraph (f)(4) of this AD. FAA AD Differences Note: This AD differs from the MCAI and/ or service information as follows: (1) MCAI Transport Canada AD No. CF– 2007–31, dated December 17, 2007, is applicable to airplane models with front spar adapter assembly P/N C6WM1027–3 that incorporate task C57–10–18 of the DHC–6 Corrosion Prevention and Control Manual (CPCM), PSM 1–6–5. (2) The applicability of this AD does not include airplane models with front spar adapter assembly P/N C6WM1027–3 that incorporate task C57–10–18 of the DHC–6 CPCM, PSM 1–6–5, which is required in the Transport Canada AD No. CF–94–12R1, dated April 13, 1999, and AD No. CF–99–11, dated May 28, 1999. We have addressed the Corrosion Prevention and Control Program in AD 2008–13–11 (73 FR 37355, July 1, 2008), which identifies specific areas that must be inspected to ensure the structural integrity of the DHC–6 fleet. 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, FAA, has the authority to E:\FR\FM\19FER1.SGM 19FER1 Federal Register / Vol. 74, No. 32 / Thursday, February 19, 2009 / Rules and Regulations approve AMOCs for this AD, if requested using the procedures found in 14 CFR 39.19. Send information to ATTN: Pong Lee, Aerospace Engineer, FAA, New York Aircraft Certification Office, ANE–171, 1600 Stewart Avenue, Suite 410, Westbury, New York 11590; telephone: (516) 228–7324; 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 FAAapproved 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. yshivers on PROD1PC62 with RULES Related Information (h) Refer to MCAI Transport Canada AD No. CF–2007–31, dated December 17, 2007; Viking DHC–6 Twin Otter Service Bulletins No. V6/540, dated October 1, 2007; No. V6/ 541, dated October 1, 2007; and No. V6/542, dated October 1, 2007; and R.W. Martin, Inc. Service Bulletin No. 00160/2, Revision A, dated November 15, 2007, for related information. Material Incorporated by Reference (i) You must use Viking DHC–6 Twin Otter Service Bulletins No. V6/540, dated October 1, 2007; No. V6/541, dated October 1, 2007; and No. V6/542, dated October 1, 2007; and R.W. Martin, Inc. Service Bulletin No. 00160/ 2, Revision A, dated November 15, 2007, to do the actions required by this AD, unless the AD specifies otherwise. (1) On August 5, 2008 (73 FR 37353, July 1, 2008), the Director of the Federal Register previously approved the incorporation by reference of Viking DHC–6 Twin Otter Service Bulletins No. V6/540, dated October 1, 2007; No. V6/541, dated October 1, 2007; and No. V6/542, dated October 1, 2007; and R.W. Martin, Inc. Service Bulletin No. 00160/ 2, Revision A, dated November 15, 2007. (2) For service information identified in this AD, contact Viking Air Limited, 9574 Hampden Road, Sidney, B.C., Canada V8L 5V5; telephone: (250) 656–7227; fax: (250) 656–0673; Internet: https:// www.vikingair.com; or R.W. Martin, Inc., 37552 Winchester Road, Hangar 20, Murrieta, California 92563; telephone: (951) 600–0009; fax: (951) 600–1005; Internet: https:// www.rwmi.net. (3) You may review copies of the service information incorporated by reference for this AD at the FAA, Central Region, Office of the Regional Counsel, 901 Locust, Kansas City, Missouri 64106. For information on the availability of this material at the Central Region, call (816) 329–3768. VerDate Nov<24>2008 14:28 Feb 18, 2009 Jkt 217001 (4) You may also review copies of the service information incorporated by reference for this AD 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: https://www.archives.gov/federal_register/ code_of_federal_regulations/ ibr_locations.html. Issued in Kansas City, Missouri, on February 6, 2009. Kim Smith, Manager, Small Airplane Directorate, Aircraft Certification Service. [FR Doc. E9–3115 Filed 2–18–09; 8:45 am] BILLING CODE 4910–13–P DEPARTMENT OF TRANSPORTATION Federal Aviation Administration 14 CFR Part 39 [Docket No. FAA–2007–0169; Directorate Identifier 2007–NE–45–AD; Amendment 39– 15819; AD 2009–04–13] RIN 2120–AA64 Airworthiness Directives; Rolls-Royce Deutschland Ltd & Co KG, BR700– 715A1–30, BR700–715B1–30, and BR700–715C1–30 Turbofan Engines AGENCY: Federal Aviation Administration (FAA), 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) issued 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: The application of most recent 3D FEM modeling has resulted in the need to reconsider the disc lives as currently shown in the Time Limits Manual. The current Post Certification Life Statement for the low pressure (LP) compressor (fan) disc assembly revises the Declared Safe Cyclic Life (DSCL) from 33,000 flight cycles to 25,000 flight cycles for both the BR715 LP (fan) disc assembly Part No. (P/N) BRH10048 and BR715 LP compressor (fan) disc assembly P/N BRH19253, when installed in the BR700–715A1–30 engine model and operated against the Hawaiian Flight Mission. We are issuing this AD to prevent uncontained failure of the LP compressor (fan) disc assembly and damage to the airplane. DATES: This AD becomes effective March 26, 2009. ADDRESSES: The Docket Operations office is located at Docket Management PO 00000 Frm 00003 Fmt 4700 Sfmt 4700 7643 Facility, U.S. Department of Transportation, 1200 New Jersey Avenue, SE., West Building Ground Floor, Room W12–140, Washington, DC 20590–0001. FOR FURTHER INFORMATION CONTACT: Jason Yang, Aerospace Engineer, Engine Certification Office, FAA, Engine and Propeller Directorate, 12 New England Executive Park, Burlington, MA 01803; e-mail: Jason.yang@faa.gov; telephone (781) 238–7747; fax (781) 238–7199. 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 February 5, 2008 (73 FR 6638). That NPRM proposed to correct an unsafe condition for the specified products. The MCAI states that: The application of most recent 3D FEM modeling has resulted in the need to reconsider the disc lives as currently shown in the Time Limits Manual. The current Post Certification Life Statement for the low pressure (LP) compressor (fan) disc assembly revises the Declared Safe Cyclic Life (DSCL) from 33,000 flight cycles to 25,000 flight cycles for both the BR715 LP (fan) disc assembly P/N BRH10048 and BR715 LP compressor (fan) disc assembly P/N BRH19253, when installed in the BR700– 715A1–30 engine model and operated against the Hawaiian Flight Mission. This AD requires, within 25 flight cycles after the effective date of the AD: • Amending the Airworthiness Limitations Section (ALS) of the Time Limits Manual SUBTASK 05–10–01– 860–016, by revising the ‘‘GIVEN LIFE A1–30 RATING (FLIGHT CYCLES)’’ for both the LP compressor (fan) disc assembly P/N BRH10048 and LP compressor (fan) disc assembly P/N BRH19253 from 33,000 flight cycles to 25,000 flight cycles; and • Checking the lifing of both the LP compressor (fan) disc assembly P/N BRH10048 and LP compressor (fan) disc assembly P/N BRH19253 if the relevant compressor (fan) disc assembly is currently installed or was previously installed, in the BR700–715A1–30 engine model and operated under the Hawaiian Flight Mission; and • Removing the relevant compressor (fan) disc assembly from service before further flight, if the consumed life has exceeded the maximum approved life specified in the ALS. Comments We gave the public the opportunity to participate in developing this AD. We considered the comments received. E:\FR\FM\19FER1.SGM 19FER1

Agencies

[Federal Register Volume 74, Number 32 (Thursday, February 19, 2009)]
[Rules and Regulations]
[Pages 7641-7643]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: E9-3115]



========================================================================
Rules and Regulations
                                                Federal Register
________________________________________________________________________

This section of the FEDERAL REGISTER contains regulatory documents 
having general applicability and legal effect, most of which are keyed 
to and codified in the Code of Federal Regulations, which is published 
under 50 titles pursuant to 44 U.S.C. 1510.

The Code of Federal Regulations is sold by the Superintendent of Documents. 
Prices of new books are listed in the first FEDERAL REGISTER issue of each 
week.

========================================================================


Federal Register / Vol. 74, No. 32 / Thursday, February 19, 2009 / 
Rules and Regulations

[[Page 7641]]



DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2008-1267; Directorate Identifier 2008-CE-069-AD; 
Amendment 39-15815; AD 2009-04-09]
RIN 2120-AA64


Airworthiness Directives; Viking Air Limited Model DHC-6-1, DHC-
6-100, DHC-6-200, and DHC-6-300 Airplanes

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

ACTION: Final rule.

-----------------------------------------------------------------------

SUMMARY: We are superseding an existing airworthiness directive (AD) 
for the products listed above. This AD results from mandatory 
continuing airworthiness information (MCAI) issued 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 have been reports of inter-rivet cracking on several wing 
front spar adapter assemblies (P/N C6WM1027-1) on the horizontal and 
vertical flanges. It was determined that the cracking was caused by 
stress corrosion in the short transverse grain initiated by local 
riveting induced stresses.

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

DATES: This AD becomes effective March 26, 2009.
    As of August 5, 2008 (73 FR 37353, July 1, 2008), the Director of 
the Federal Register approved the incorporation by reference of Viking 
DHC-6 Twin Otter Service Bulletins No. V6/540, dated October 1, 2007; 
No. V6/541, dated October 1, 2007; and No. V6/542, dated October 1, 
2007; and R.W. Martin, Inc. Service Bulletin No. 00160/2, Revision A, 
dated November 15, 2007, listed in this AD.

ADDRESSES: You may examine the AD docket on the Internet at https://
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.

FOR FURTHER INFORMATION CONTACT: Pong Lee, Aerospace Engineer, FAA, New 
York Aircraft Certification Office, ANE-171, 1600 Stewart Avenue, Suite 
410, Westbury, New York 11590; telephone: (516) 228-7324; 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 December 3, 2008 (73 
FR 73618), and proposed to supersede AD 2008-11-10, Amendment 39-15532 
(73 FR 37353, July 1, 2008). That NPRM proposed to correct an unsafe 
condition for the specified products. The MCAI states that:

    There have been reports of inter-rivet cracking on several wing 
front spar adapter assemblies (P/N C6WM1027-1) on the horizontal and 
vertical flanges. It was determined that the cracking was caused by 
stress corrosion in the short transverse grain initiated by local 
riveting induced stresses. This directive mandates modification and 
inspection of the wing front spar adapter fitting and replacement of 
cracked fittings.

Since we issued AD 2008-11-10, Amendment 39-15532 (73 FR 37353, July 1, 
2008), we have added to the Applicability section additional wing box 
part numbers that may incorporate a P/N C6WM1027-1 front spar adapter 
assembly with 10 or more years of service.

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 FAA policies. Any such differences are 
highlighted in a NOTE within the AD.

Costs of Compliance

    We estimate that this AD will affect 157 products of U.S. registry. 
We also estimate that it will take about 18 work-hours per product to 
comply with the basic requirements of this AD. The average labor rate 
is $80 per work-hour. Based on these figures, we estimate the cost of 
this AD to the U.S. operators to be $226,080 or $1,440 per product.
    In addition, we estimate that any necessary follow-on actions would 
take about 200 work-hours and require parts costing $3,696, for a cost 
of $19,696 per product. We have no way of determining the number of 
products that may need these actions.

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

[[Page 7642]]

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 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 https://
www.regulations.gov; or in person at the Docket Management Facility 
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 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 removing Amendment 39-15532 (73 FR 
37353, July 1, 2008) and adding the following new AD:

2009-04-09 Viking Air Limited: Amendment 39-15815; Docket No. FAA-
2008-1267; Directorate Identifier 2008-CE-069-AD.

Effective Date

    (a) This airworthiness directive (AD) becomes effective March 
26, 2009.

Affected ADs

    (b) This AD supersedes AD 2008-11-10, Amendment 39-15532 (73 FR 
37353, July 1, 2008).

Applicability

    (c) This AD applies to the following Models DHC-6-1, DHC-6-100, 
DHC-6-200, and DHC-6-300 airplanes, all serial numbers, that are 
certificated in any category:
    (1) Group 1: Equipped with wing boxes, part numbers (P/Ns) 
C6W1002-1, C6W1002-3, WR6-1002-59 or WR6-1002-61 that incorporate a 
P/N C6WM1027-1 front spar adapter assembly with 10 or more years of 
service; and
    (2) Group 2: Equipped with wing boxes, P/Ns C6W1002-5, C6W1002-
7, C6W1002-9, C6W1002-11, C6W1002-13, C6W1002-15, C6W1002-17, 
C6W1002-19, C6W1002-21, C6W1002-23, C6W1002-51, C6W1002-53, C6W1002-
55, C6W1002-57 or C6W1002-61 that incorporate a P/N C6WM1027-1 front 
spar adapter assembly with 10 or more years of service.

Subject

    (d) Air Transport Association of America (ATA) Code 57: Wings.

Reason

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

    ``There have been reports of inter-rivet cracking on several 
wing front spar adapter assemblies (P/N C6WM1027-1) on the 
horizontal and vertical flanges. It was determined that the cracking 
was caused by stress corrosion in the short transverse grain 
initiated by local riveting induced stresses. This directive 
mandates modification and inspection of the wing front spar adapter 
fitting and replacement of cracked fittings.''

Since we issued AD 2008-11-10, Amendment 39-15532 (73 FR 37353, July 
1, 2008), we have added to the Applicability section additional wing 
box part numbers that may incorporate a P/N C6WM1027-1 front spar 
adapter assembly with 10 or more years of service.

Actions and Compliance

    (f) Unless already done, do the following actions:
    (1) For Group 1 airplanes, within the next 180 days after August 
5, 2008 (the effective date of AD 2008-11-10), install inspection 
holes in the left-hand (LH) and right-hand (RH) lower wing skins 
following Viking DHC-6 Twin Otter Service Bulletin Number V6/541, 
dated October 1, 2007.
    (2) For Group 2 airplanes, within the next 180 days after the 
effective date of this AD, install inspection holes in the LH and RH 
lower wing skins following Viking DHC-6 Twin Otter Service Bulletin 
Number V6/541, dated October 1, 2007.
    (3) For Group 1 and Group 2 airplanes, before further flight 
after installing the inspection holes required in paragraph (f)(1) 
or (f)(2) of this AD, initially inspect the LH and RH front spar 
adapter assemblies for cracks, and repetitively thereafter inspect 
all affected wing box P/Ns at intervals not to exceed 1,200 hours 
time-in-service or 12 months, whichever occurs first, until the 
replacement required in paragraph (f)(4) of this AD is done.
    (i) For wing box P/Ns C6W1002-1, C6W1002-3, C6W1002-5, C6W1002-
7, C6W1002-9, C6W1002-11, C6W1002-13, C6W1002-15, C6W1002-17, 
C6W1002-19, C6W1002-21, C6W1002-23, C6W1002-51, C6W1002-53, C6W1002-
55, C6W1002-57, C6W1002-59, and C6W1002-61, inspect following Viking 
DHC-6 Twin Otter Service Bulletin Number V6/540, dated October 1, 
2007.
    (ii) For wing box P/Ns WR6-1002-59 or WR6-1002-61, inspect 
following R.W. Martin, Inc. Service Bulletin No. 00160/2, Revision 
A, dated November 15, 2007.
    (4) For Group 1 and 2 airplanes, before further flight after 
doing any inspection required in paragraph (f)(3) of this AD where 
cracks are found, replace the cracked front spar adapter assembly 
with a front spar adapter assembly, P/N C6WM1027-3. Do the 
replacement following Viking DHC-6 Twin Otter Service Bulletin 
Number V6/542, dated October 1, 2007. This replacement terminates 
the repetitive inspections required in paragraph (f)(3) of this AD 
for the replaced front spar adapter assembly.
    (5) As a terminating action for the repetitive inspections 
required in paragraph (f)(3) of this AD, at any time after the 
initial inspection required in paragraph (f)(3) of this AD, you may 
replace P/N C6WM1027-1 with P/N C6WM1027-3, except it must be 
replaced prior to further flight as required by paragraph (f)(4) of 
this AD.

FAA AD Differences

    Note: This AD differs from the MCAI and/or service information 
as follows:
    (1) MCAI Transport Canada AD No. CF-2007-31, dated December 17, 
2007, is applicable to airplane models with front spar adapter 
assembly P/N C6WM1027-3 that incorporate task C57-10-18 of the DHC-6 
Corrosion Prevention and Control Manual (CPCM), PSM 1-6-5.
    (2) The applicability of this AD does not include airplane 
models with front spar adapter assembly P/N C6WM1027-3 that 
incorporate task C57-10-18 of the DHC-6 CPCM, PSM 1-6-5, which is 
required in the Transport Canada AD No. CF-94-12R1, dated April 13, 
1999, and AD No. CF-99-11, dated May 28, 1999. We have addressed the 
Corrosion Prevention and Control Program in AD 2008-13-11 (73 FR 
37355, July 1, 2008), which identifies specific areas that must be 
inspected to ensure the structural integrity of the DHC-6 fleet.

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, FAA, has the authority to

[[Page 7643]]

approve AMOCs for this AD, if requested using the procedures found 
in 14 CFR 39.19. Send information to ATTN: Pong Lee, Aerospace 
Engineer, FAA, New York Aircraft Certification Office, ANE-171, 1600 
Stewart Avenue, Suite 410, Westbury, New York 11590; telephone: 
(516) 228-7324; 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

    (h) Refer to MCAI Transport Canada AD No. CF-2007-31, dated 
December 17, 2007; Viking DHC-6 Twin Otter Service Bulletins No. V6/
540, dated October 1, 2007; No. V6/541, dated October 1, 2007; and 
No. V6/542, dated October 1, 2007; and R.W. Martin, Inc. Service 
Bulletin No. 00160/2, Revision A, dated November 15, 2007, for 
related information.

Material Incorporated by Reference

    (i) You must use Viking DHC-6 Twin Otter Service Bulletins No. 
V6/540, dated October 1, 2007; No. V6/541, dated October 1, 2007; 
and No. V6/542, dated October 1, 2007; and R.W. Martin, Inc. Service 
Bulletin No. 00160/2, Revision A, dated November 15, 2007, to do the 
actions required by this AD, unless the AD specifies otherwise.
    (1) On August 5, 2008 (73 FR 37353, July 1, 2008), the Director 
of the Federal Register previously approved the incorporation by 
reference of Viking DHC-6 Twin Otter Service Bulletins No. V6/540, 
dated October 1, 2007; No. V6/541, dated October 1, 2007; and No. 
V6/542, dated October 1, 2007; and R.W. Martin, Inc. Service 
Bulletin No. 00160/2, Revision A, dated November 15, 2007.
    (2) For service information identified in this AD, contact 
Viking Air Limited, 9574 Hampden Road, Sidney, B.C., Canada V8L 5V5; 
telephone: (250) 656-7227; fax: (250) 656-0673; Internet: https://
www.vikingair.com; or R.W. Martin, Inc., 37552 Winchester Road, 
Hangar 20, Murrieta, California 92563; telephone: (951) 600-0009; 
fax: (951) 600-1005; Internet: https://www.rwmi.net.
    (3) You may review copies of the service information 
incorporated by reference for this AD at the FAA, Central Region, 
Office of the Regional Counsel, 901 Locust, Kansas City, Missouri 
64106. For information on the availability of this material at the 
Central Region, call (816) 329-3768.
    (4) You may also review copies of the service information 
incorporated by reference for this AD 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: https://
www.archives.gov/federal_register/code_of_federal_regulations/
ibr_locations.html.

    Issued in Kansas City, Missouri, on February 6, 2009.
Kim Smith,
Manager, Small Airplane Directorate, Aircraft Certification Service.
[FR Doc. E9-3115 Filed 2-18-09; 8:45 am]
BILLING CODE 4910-13-P

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