AD 2017-10-11

We are adopting a new airworthiness directive (AD) for Stemme AG Model S10-VT gliders (type certificate previously held by Stemme GmbH & Co. KG). This AD results from mandatory continuing airworthiness information (MCAI) issued by the aviation authority of another country to identify and correct an unsafe condition on an aviation product. The MCAI describes the unsafe condition as certain propeller front transmission gear wheels having insufficient material strength because of improper heat treatment

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during manufacturing. We are issuing this AD to require actions to address the unsafe condition on these products.

Final rule; request for comments.

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 adding the following new AD:

2017-10-11 Stemme AG: Amendment 39-18885; Docket No. FAA-2017-0451; Directorate Identifier 2017-CE-015-AD.

(a) Effective Date

This airworthiness directive (AD) becomes effective June 15, 2017.

(b) Affected ADs

None.

(c) Applicability

This AD applies to Stemme AG Model S10-VT gliders (type certificate previously held by Stemme GmbH & Co. KG), all serial numbers, that are:
(1) Equipped with a front gearbox, part number (P/N) 11AG, with a serial number listed in table 1 to paragraph (c) of this AD; and
(2) are certificated in any category.

Table 1 to Paragraph (c) of This AD--Affected P/N 11AG (Front Gearbox) S/
Ns ------------------------------------------------------------------------

------------------------------------------------------------------------
80058/0814 80065/0616
80059/0915 80066/0716
80060/0915 80067/0916
80061/1115 80068/1016
80062/1215 80069/0117
80063/0116 80070/0217
80064/0416 80071/0217 ------------------------------------------------------------------------

Note 1 to paragraph (c) of this AD: Page 2 of Stemme AG Service Bulletin No. P062-980010, dated April 21, 2017, provides a pictorial of where the serial number of the affected gearboxes are located.

(d) Subject

Air Transport Association of America (ATA) Code 61: Propellers/ Propulsors.

(e) Reason

This AD wasprompted by mandatory continuing airworthiness information (MCAI) issued by the aviation authority of another country to identify and correct an unsafe condition on an aviation product. The MCAI describes the unsafe condition as certain propeller front transmission gear wheels having insufficient material strength because of improper heat treatment during manufacturing. We are issuing this AD to prevent failure of the propeller front transmission gear wheels. This failure could cause loss of power between the engine and the propeller, which could result in reduced control.

(f) Actions and Compliance

Unless already done, do the following actions.
(1) Before further flight after June 15, 2017 (the effective date of this AD), replace the front gearbox following a method approved specifically for this AD by the FAA, Small Airplane Directorate. Contact the FAA using the information in paragraph (g)(1) of this AD to obtain FAA-approved repair instructions approved specificallyfor compliance with this AD and incorporate those instructions.

Note 2 to paragraph (f)(1) of this AD: At the issue date of this AD, no design solution is available to restore the airworthiness of the respective type design to a level corresponding to its approved type design specifications.

(2) As of June 15, 2017 (the effective date of this AD), do not install a front gear box listed in paragraph (c) of this AD.

(g) Other FAA AD Provisions

The following provisions also apply to 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 glider 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.

(h) Related Information

(1) Refer to MCAI European Aviation Safety Agency (EASA) AD No. 2017-0072-E, dated April 26, 2017, and Stemme AG Service Bulletin No. P062-980010, dated April 21, 2017, for related information. You may examine the MCAI on the Internet at http://www.regulations.gov by searching for and locating Docket No. FAA-2017-0451.
(2) For information concerning this action, contact STEMME AG service information identified in this AD, contact STEMME AG, Flugplatzstrasse F2, Nr. 6-7, D-15344 Strausberg, Germany; telephone: +49 (0) 3341-3612-0, fax: +49 (0) 3341-3612-30; Internet: www.stemme.com.

Discussion

The European Aviation Safety Agency (EASA), which is the Technical Agent for the Member States of the European Community, has issued AD No. 2017-0072-E, dated April 26, 2017 (referred to after this as ``the MCAI''), to correct an unsafe condition for the specified products. The MCAI states:

It has been determined that, following improper heat treatment during manufacture, the material strength of an identified batch of propeller front transmission gear wheels is insufficient.
This condition, if not corrected, can lead to failure of a gear wheel, with possible loss of the power transmission between the engine and the propeller and, eventually, reduced control of the sailplane.
Prompted by these determinations, Stemme issued Service Bulletin (SB) P062-980010, providing instructions not to operate sailplanes equipped with affected parts.
For the reasons described above, this [EASA] AD requires replacement of affected gearboxes.

You may examine the MCAI on the Internet at http://www.regulations.gov by searching for and locating Docket No. FAA-2017- 0451.

FAA's Determination and Requirements of the 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 of the unsafe condition described in the MCAI and service information referenced above. We are issuing this AD because we evaluated all information provided by the State of Design Authority and determined the unsafe condition exists and is likely to exist or develop on other products of the same type design.

FAA's Determination of the Effective Date

An unsafe condition exists that requires the immediate adoption of this AD. The FAA has found that the risk to the flying public justifies waiving notice and comment prior to adoption of this rule because improper heat treatment of the propeller front transmission gear wheels could cause the gear wheel to fail. This failure could cause loss of power between the engine and the propeller, which could result in reduced control. Therefore, we determined that notice and opportunity for public comment before issuing this AD are impracticable and that good cause exists for making this amendment effective in fewer than 30 days.

Comments Invited

This AD is a final rule that involves requirements affecting flight safety, and we did not precede it by notice and opportunity for public comment. We invite you to send any written relevant data, views, or arguments about this AD. Send your comments to an address listed under the ADDRESSES section. Include ``Docket No. FAA-2017-0451; Directorate Identifier 2017-CE-015-AD'' at the beginning of your comments. We specifically invite comments on the overall regulatory, economic, environmental, and energy aspects of this AD. We will consider all comments received by the closing date and may amend this AD because of 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 AD.

Costs of Compliance

There are approximately 50 Stemme AG Model S10-VT gliders of U.S. registry but only 14 serial numbers of the part number (P/N) 11AG front gearbox. Therefore, the most gliders of U.S. registry affected would be 14. According to Stemme AG, there are only 2 of the affected gearboxes installed on gliders of U.S. registery.
At the issue date of this AD, no design solution is available to restore the airworthiness of the respective type design to a level corresponding to its approved type design specifications. Therefore, the FAA cannot determine the cost of returning the affected gliders to service.

Authority for This Rulemaking

Title 49 of theUnited 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 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 that this AD:
(1) Is not a ``significant regulatory action'' under Executive Order 12866,

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(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.

List of Subjects in 14 CFR Part 39

Air transportation, Aircraft, Aviation safety, Incorporation by reference, Safety.