AD 2013-09-09

We are superseding an existing airworthiness directive (AD) for all Slingsby Sailplanes Ltd. Models Dart T.51, Dart T.51/17, and Dart T.51/17R sailplanes equipped with aluminum alloy spar booms. 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 an incident of glue joint failure on a starboard wing caused by water entering the area of the airbrake box that resulted in delamination and corrosion in the area of the aluminum alloy spar booms and the wing attach fittings. We are issuing this AD to require actions to address the unsafe condition on these products.

Final rule.

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

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 39-10863 (63 FR 58624, November 2, 1998), and adding the following new AD:

2013-09-09 Slingsby Sailplanes Ltd.: Amendment 39-17451; Docket No. FAA-2013-0220; Directorate Identifier 2013-CE-002-AD.

(a) Effective Date

This airworthiness directive (AD) becomes effective June 20, 2013.

(b) Affected ADs

This AD supersedes AD 98-22-15, Amendment 39-10863 (63 FR 58624, November 2, 1998).

(c) Applicability

This AD applies to Slingsby Sailplanes Ltd. Models Dart T.51, Dart T.51/17, and Dart T.51/17R sailplanes, all serial numbers, that are:
(1) Equipped with aluminum alloy spar booms; and
(2) certificated in any category.

(d) Subject

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

(e) Reason

This AD was prompted by an incident of glue joint failure on a starboard wing caused by water entering the area of the airbrake box that resulted in delamination and corrosion in the area of the aluminum alloy spar booms and the wing attach fittings. The manufacturer has also issued revised service information that changes the repetitive inspection interval and method. We are issuing this AD to prevent failure of the spar assembly and adjoining structure, which could result in reduced controllability or complete loss of control.

(f) Actions and Compliance Retained From AD 98-22-15, Amendment 39- 10863 (63 FR 58624, November 2, 1998)

Unless already done, do the following actions specified in paragraphs (f)(1) and (f)(2) of this AD:
(1) Within the next 6 calendar months after December 14, 1998 (the effective dateretained from AD 98-22-15, Amendment 39-10863 (63 FR 58624, November 2, 1998)), inspect the aluminum alloy spar booms and the wing attach fittings for delamination or corrosion damage following the ACTION section of Slingsby Aviation Ltd. Technical Instruction T.I. No. 109/T51, Issue No. 2, dated October 7, 1997, or the ACTION section of Slingsby Aviation Ltd. Technical Instruction T.I. No. 109/T51, Issue 3, dated August 21, 2000.

Note 1 to paragraph (f)(1) of this AD: Slingsby Aviation Ltd. Technical Instruction T.I. No. 109/T51, Issue No. 2, dated October 7, 1997, and T.I. No. 109/T51, Issue 3, dated August 21, 2000, include guidance to determine whether an affected sailplane is equipped with aluminum alloy spar booms.

(2) If any corrosion or delamination damage is found during the inspection required by paragraph (f)(1) of this AD, before further flight, contact the manufacturer at the address specified in paragraph (j)(5) of this AD to obtain an FAA-approved repairscheme and incorporate the repair.

(g) New Actions and Compliance

Unless already done, do the following actions specified in paragraphs (g)(1) and (g)(2) of this AD:
(1) Within 5 years after the last inspection required by AD 98- 22-15, Amendment 39-10863 (63 FR 58624, November 2, 1998) and repetitively thereafter at intervals not to exceed 12 months, using an endoscope, inspect the aluminum alloy spar booms and the wing attach fittings for delamination or corrosion damage following paragraph 11 of the ACTION section of Slingsby Aviation Ltd. Technical Instruction T.I. No. 109/T51, Issue 3, dated August 21, 2000.
(2) If any corrosion or delamination damage is found during any inspection required by paragraph (g)(1) of this AD, before further flight, contact the manufacturer at the address specified in paragraph (j)(5) of this AD to obtain an FAA-approved repair scheme and incorporate the repair.

(h) Other FAA AD Provisions

The following provisions also applyto this AD:
(1) Alternative Methods of Compliance (AMOCs): The Manager, Standards 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: Jim Rutherford, Aerospace Engineer, FAA, Small Airplane Directorate, 901 Locust, Room 301, Kansas City, Missouri 64106; telephone: (816) 329-4165; fax: (816) 329-4090; email: jim.rutherford@faa.gov. Before using any approved AMOC on any sailplane 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 isreturned to service.
(3) Reporting Requirements: For any reporting requirement in this AD, a federal agency may not conduct or sponsor, and a person is not required to respond to, nor shall a person be subject to a penalty for

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failure to comply with a collection of information subject to the requirements of the Paperwork Reduction Act unless that collection of information displays a current valid OMB Control Number. The OMB Control Number for this information collection is 2120-0056. Public reporting for this collection of information is estimated to be approximately 5 minutes per response, including the time for reviewing instructions, completing and reviewing the collection of information. All responses to this collection of information are mandatory. Comments concerning the accuracy of this burden and suggestions for reducing the burden should be directed to the FAA at: 800 Independence Ave. SW., Washington, DC 20591, Attn: Information Collection ClearanceOfficer, AES-200.

(i) Related Information

Refer to Civil Aviation Authority (CAA) AD British AD 005-09-97, dated October 3, 1997, for related information.

(j) Material Incorporated by Reference

(1) The Director of the Federal Register approved the incorporation by reference (IBR) of the service information listed in this paragraph under 5 U.S.C. 552(a) and 1 CFR part 51.
(2) You must use this service information as applicable to do the actions required by this AD, unless the AD specifies otherwise.
(3) The following service information was approved for IBR on June 20, 2013.
(i) Slingsby Aviation Ltd. Technical Instruction T.I. No. 109/ T51, Issue 3, dated August 21, 2000.
(ii) Reserved.
(4) The following service information was approved for IBR on December 14, 1998 (63 FR 58624, November 2, 1998).
(i) Slingsby Aviation Ltd. Technical Instruction T.I. No. 109/ T51, Issue No. 2, dated October 7, 1997.
(ii) Reserved.
(5) For Slingsby Sailplanes Ltd. service information identified in this AD, contact Slingsby Advanced Composites Ltd., Ings Lane, Kirkbymoorside, North Yorkshire, England YO62 6EZ; telephone: +44(0)1751 432474; Internet: none.
(6) You may view this service information at the FAA, Small Airplane Directorate, 901 Locust, Kansas City, Missouri 64106. For information on the availability of this material at the FAA, call (816) 329-4148.
(7) You may view this service information that is incorporated by reference 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

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 March 6, 2013 (78 FR 14467), and proposed to supersede AD 98-22-15, Amendment 39-10863 (63 FR 58624, November 2, 1998).
Since we issued AD 98-22-15, Amendment 39-10863 (63 FR 58624, November 2, 1998), Slingsby Aviation Ltd. has revised the related service information to remove the 5-year repetitive ``cutout'' inspection and to add a repetitive annual inspection using an endoscope. The endoscope inspection method would be done using existing drain holes in the lower wing skin.
Using revised service information is mandatory within the United Kingdom airworthiness system. It is not necessary for the Civil Aviation Authority (CAA), which is the aviation authority for the United Kingdom, to issue an AD to mandate the use of new service information.
ADaction is the only way the FAA can mandate the use of new service information; however, owners/operators may request approval from the FAA to use an alternative method of compliance (AMOC).
Several U.S. operators have complained that the repetitive 5-year ``cutout'' inspection in the wooden wing skin, currently required by AD 98-22-15, Amendment 39-10863 (63 FR 58624, November 2, 1998), was by default growing larger and larger with each inspection.
We have determined that the current 5-year repetitive ``cutout'' inspections will eventually weaken the wing structure and could result in an unsafe condition. We concur with the change to the annual endoscope inspection.

Comments

We gave the public the opportunity to participate in developing this AD. We have considered the comments received. John Wells, Michael Hoke, Chad Croix Wille, and one anonymous commenter support the NPRM (78 FR 14467, March 6, 2013).

Conclusion

We reviewed the relevant data, considered the comments received, and determined that air safety and the public interest require adopting the AD as proposed except for minor editorial changes. We have determined that these minor changes:
Are consistent with the intent that was proposed in the NPRM (78 FR 14467, March 6, 2013) for correcting the unsafe condition; and
Do not add any additional burden upon the public than was already proposed in the NPRM (78 FR 14467, March 6, 2013).

Costs of Compliance

We estimate that this AD will affect 10 products of U.S. registry. We also estimate that it will take about 40 work-hours per product to comply with the initial inspection requirement retained from AD 98-22- 15, Amendment 39-10863 (63 FR 58624, November 2, 1998) in this AD. The average labor rate is $85 per work-hour.
Based on these figures, we estimate the cost of the initial inspection required in this AD on U.S. operators to be $34,000, or $3,400 per product.
We also estimate that it will take about 2 work-hours per product to comply with the new repetitive inspection requirement in this AD. The average labor rate is $85 per work-hour.
Based on these figures, we estimate the cost of the new repetitive inspection required in this AD on U.S. operators to be $1,700, or $170 per product.
We have no way of determining the number of repetitive inspections an owner/operator will incur over the life of the sailplane or the number of sailplanes that will need repairs.

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

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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 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),
(3) Will not affect intrastate aviation in Alaska, and
(4) 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.

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 between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The AD docket contains the NPRM (78 FR 14467, March 6, 2013), 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.