AD 2018-03-16

We are superseding Airworthiness Directive (AD) 2017-10-11 for Stemme AG Model Stemme S10-VT gliders (type certificate previously held by Stemme GmbH & Co. KG). This AD results from mandatory continuing airworthiness information (MCAI) issued by an aviation authority of another country to identify and address 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 require actions to address the unsafe condition on these products and to add Stemme AG Model Stemme S 12 gliders to the Applicability section.

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 39-18885 (82 FR 24239, May 26, 2017), and adding the following new AD:

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2018-03-16 Stemme AG: Amendment 39-19189; Docket No. FAA-2017-0952; Product Identifier 2017-CE-028-AD.

(a) Effective Date

This airworthiness directive (AD) becomes effective March 20, 2018.

(b) Affected ADs

This AD replaces AD 2017-10-11, Amendment 39-18885 (82 FR 24239, May 26, 2017) (``AD 2017-10-11'').

(c) Applicability

This AD applies to Stemme AG Model Stemme S10-VT gliders (type certificate previously held by Stemme GmbH & Co. KG), all serial numbers, and Stemme AG Model Stemme S 12 gliders, 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 80059/0915 80060/0915 80061/1115 80062/1215
80063/0116 80064/0416 80065/0616 80066/0716 80067/0916
80068/1016 80069/0117 80070/0217 80071/0217 .................... ----------------------------------------------------------------------------------------------------------------

Note1 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 was prompted by mandatory continuing airworthiness information (MCAI) issued by the aviation authority of another country to identify and address 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 add a model glider to the Applicability, paragraph (c) of this AD, and 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 andCompliance

Unless already done, do the following actions:
(1) For Model Stemme S10-VT gliders: Before further flight after June 15, 2017 (the effective date of AD 2017-10-11), replace the front gearbox following STEMME Procedural Specification Dok. Nr.: P320-900060, as specified in STEMME Service Bulletin Dok. Nr.: P062- 980010, Issue: 01, both dated June 14, 2017.
(2) For Model Stemme S 12 gliders: Before further flight after March 20, 2018 (the effective date of this AD), replace the front gearbox following STEMME Procedural Specification Dok. Nr.: P320- 900060, as specified in STEMME Service Bulletin Dok. Nr.: P062- 980010, Issue: 01, both dated June 14, 2017.
(3) As of March 20, 2018 (the effective date of this AD), do not install a front gear box listed in table 1 of paragraph (c) of this AD.
(4) The service information for this AD allows the owner/ operator to do certain maintenance tasks. Also, the service information specifies certain maintenance tasks be done by Stemme AG. However, for this AD, we do not allow the owner/operator to do any maintenance tasks; all maintenance tasks must be done by an appropriately certified mechanic or maintenance shop. In addition, we do not require any maintenance tasks be done specifically by Stemme AG; any appropriately certified mechanic or maintenance shop may do the tasks required by this AD.

(g) Other FAA AD Provisions

The following provisions also apply to this AD:
(1) Alternative Methods of Compliance (AMOCs): The Manager, Small Airplane Standards Branch, 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 Standards Branch, 901 Locust, Room 301, Kansas City, Missouri 64106; telephone: (816) 329-4165; fax: (816) 329- 4090; email: jim.rutherford@faa.gov.
(i) 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.
(ii) AMOCs approved for AD 2017-10-11, Amendment 39-18885 (82 FR 24239, May 26, 2017) are approved as AMOCs for the corresponding provisions of this AD.
(2) Contacting the Manufacturer: For any requirement in this AD to obtain corrective actions from a manufacturer, the action must be accomplished using a method approved by the Manager, Small Airplane Standards Branch, FAA; or the European Aviation Safety Agency (EASA).

(h) Related Information

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. https://www.regulations.gov/document?D=FAA-2017-0952-0002.

(i) 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 this AD specifies otherwise.
(i) STEMME Service Bulletin Dok. Nr.: P062-980010, Issue: 01, dated June 14, 2017.
(ii) STEMME Procedural Specification Dok. Nr.: P320-900060, dated June 14, 2017.
(3) For 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: https://www.stemme.com.
(4) You may view this service information at FAA, Policy and Innovation Division, 901 Locust, Kansas City, Missouri 64106. For information on the availability of this material at the FAA, call 816-329-4148. In addition, you can access this service information on the internet at http://www.regulations.gov by searching for and locating Docket No. FAA-2017-0639.
(5) 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 by adding an AD that would apply to all Stemme AG Model Stemme S10-VT gliders (type certificate previously held by Stemme GmbH & Co. KG) and all Stemme AG Model Stemme S 12 gliders equipped with a certain front gearbox, part number 11AG. That NPRM was published in the Federal Register on October 10, 2017 (82 FR 46938), and proposed to supersede AD 2017-10-11, Amendment 39-18885 (82 FR 24239, May 26, 2017) (``AD 2017-10-11'').
Since we issued AD 2017-10-11, we have type certificated Stemme AG Model Stemme S 12 gliders in the United States and have determined those model gliders should also be included in the applicability of AD 2017-10-11. In addition, Stemme AG has issued new service information with procedures for addressing the unsafe condition.

Comments

We gave the public the opportunity to participate in developing this AD. The following presents the comment received on the proposal and the FAA's response to the comment.

Request for Manufacturer To Be Responsible for All Associated Cost

Taylor Ray stated that the manufacturer should be responsible for replacing the front gearbox on the affected gliders at no cost to the owners/operators. We infer that the commenter is referring to the cost for both parts and labor.
Taylor Ray stated that since the unsafe condition resulted from the manufacturing process, the manufacturer should be responsible for fixing the unsafe condition.
We neither agree nor disagree since the FAA does not get involved in who pays for the cost of mitigating an unsafe condition. The primary concern the FAA has when issuing an AD is addressing unsafe conditions on various aircraft flying in the United States. While we provide information related to the estimated labor and parts cost associated with each AD, we do not control warranty coverage for owner/operators of the affected aircraft nor can

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we mandate the manufacturer to cover all associated costs. We have contacted Stemme AG about this issue. The following is the response we received: ``All costs will be paid by Stemme AG (parts + work) for customers who are affected within the one-year warranty. Customers who are out of the one-year warranty will receive parts for free, but unfortunately, they have to pay for the necessary work (approx. 10 working hours).'' Based on this response from Stemme AG, we revised the Cost of Compliance section in this AD. We changed the number of estimated work-hours per product to replace the front gearbox from 19 to 10, updated the total cost on U.S. operators and cost per product based on this change, and added standard warranty information.

Conclusion

We reviewed the relevant data, considered the comment received, and determined that air safety and the public interest require adopting this AD as proposed except for changes stated above. We have determinedthat these changes:
Are consistent with the intent that was proposed in the NPRM for addressing the unsafe condition; and
Do not add any additional burden upon the public than was already proposed in the NPRM.

Related Service Information Under 1 CFR Part 51

Stemme AG has issued STEMME Service Bulletin Dok. Nr.: P062-980010, Issue: 01, dated June 14, 2017, and STEMME Procedural Specification Dok. Nr.: P320-900060, dated June 14, 2017. In combination, the service information describes procedures for replacing the front gearbox. This service information is reasonably available because the interested parties have access to it through their normal course of business or by the means identified in the ADDRESSES section of this AD.

Differences Between This AD and the Service Information

The service information for this AD allows the owner/operator to do certain maintenance tasks. Also, the service information specifies certain maintenance tasks be done by Stemme AG. However, for this AD, we do not allow the owner/operator to do any maintenance tasks; all maintenance tasks must be done by an appropriately certified mechanic or maintenance shop. In addition, we do not require any maintenance tasks be done specifically by Stemme AG; any appropriately certified mechanic or maintenance shop may do the tasks required by this AD.

Costs of Compliance

According to the U.S. registry, we have a total of 51 of both glider types registered, but there are still only 14 serial numbers of the part number 11AG front gearbox. Therefore, the most gliders that will be affected remains 14. According to Stemme AG, there are a total of 4 of the affected front gearboxes on both glider types of U.S. registry (2 for each model).
It will take an estimated 10 work-hours per product to comply with the basic requirements of this AD. The average labor rate is $85 per work-hour. Required parts will cost about $2,000 per product.
Based on these figures, if we consider the costs for all 14 affected gearboxes, then we estimate the cost of this AD on U.S. operators to be $39,990, or $2,850 per product.
According to the manufacturer, some of the costs of this AD may be covered under warranty, thereby reducing the cost impact on affected individuals. We do not control warranty coverage for affected individuals. As a result, we have included all costs in our cost estimate.

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.
This AD is issued in accordance with authority delegated by the Executive Director, Aircraft Certification Service, as authorized by FAA Order 8000.51C. In accordance with that order, issuance of ADs is normally a function of the Compliance and Airworthiness Division, but during this transition period, the Executive Director has delegated the authority to issue ADs applicable to small airplanes, gliders, balloons, airships, domestic business jet transport airplanes, and associated appliances to the Director of the Policy and Innovation Division.

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 by searching for and locating Docket No. FAA-2017- 0952; or in person at Docket Operations 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 Docket Operations (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.