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###### Department of Transportation

###### Federal Aviation Administration

          - 14 CFR Part 39
          - [Docket No. FAA-2017-0952; Product Identifier 2017-CE-028-AD]
          - RIN 2120-AA64

# AGENCY:

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

# ACTION:

Notice of proposed rulemaking (NPRM).

# SUMMARY:

We propose to supersede Airworthiness Directive (AD) 2017-10-11 for Stemme AG Model Stemme S10-VT gliders (type certificate previously held by Stemme GmbH & Co. KG). 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 propeller front transmission gear wheels having insufficient material strength because of improper heat treatment during manufacturing. We are issuing this proposed AD to require actions to address the unsafe condition on these products and to add Stemme AG Model Stemme S 12 to the applicability.

# DATES:

We must receive comments on this proposed AD by November 24, 2017.

# 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.                    

                        For service information identified in this proposed 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.*                         You may review copies of the referenced service information at the FAA, Policy and Innovation Division, 901 Locust,                               ( print page 46939)                            Kansas City, Missouri 64106. For information on the availability of this material at the FAA, call (816) 329-4148.                    

## 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 the 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:

                        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.*

# 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-2017-0952; Product Identifier 2017-CE-028-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

We issued AD 2017-10-11, Amendment 39-18885 (82 FR 24239, May 26, 2017) (“AD 2017-10-11”) to address an unsafe condition on all Stemme AG Model Stemme S10-VT gliders (type certificate previously held by Stemme GmbH & Co. KG) equipped with a certain front gearbox, part number 11AG, and was based on mandatory continuing airworthiness information (MCAI) originated by an aviation authority of another country.

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.

## 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 NPRM.                

## 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 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 Service Information

The service information for this proposed 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 proposed 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 proposed 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 could 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 19 work-hours per product to comply with the basic requirements of this proposed AD. The average labor rate is $85 per work-hour. Required parts would 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 the proposed AD on U.S. operators to be $50,610, or $3,615 per product.

## 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, and domestic business jet transport airplanes to the Director of the Policy and Innovation Division.

## 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:                          ( print page 46940)    

(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.

# List of Subjects in 14 CFR Part 39

      - Air transportation
      - Aircraft
      - Aviation safety
      - Incorporation by reference
      - 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.

§ 39.13 

2. The FAA amends § 39.13 by removing Amendment 39-18885 ( 82 FR 24239, May 26, 2017), and adding the following new AD:

**Stemme AG**                        : Docket No. FAA-2017-0952; Product Identifier 2017-CE-028-AD.                    

## (a) Comments Due Date

We must receive comments by November 24, 2017.

## (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.

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 was prompted 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 proposed AD to add Stemme AG Model Stemme S 12 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 and Compliance

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, dated June 14, 2017, as specified in STEMME Service Bulletin Dok. Nr.: P062-980010, Issue: 01, dated June 14, 2017.                    

                        (2)                         *For Model Stemme S 12 gliders:*                         Before further flight after the effective date of this AD, replace the front gearbox following STEMME Procedural Specification Dok. Nr.: P320-900060, dated June 14, 2017, as specified in STEMME Service Bulletin Dok. Nr.: P062-980010, Issue: 01, dated June 14, 2017.                    

(3) As of 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

                        (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-2017-0952. For service information related to 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.*                         You may review copies of the referenced service information at the 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.                    

Issued in Kansas City, Missouri, on September 26, 2017.

Pat Mullen,

Acting Deputy Director, Policy & Innovation Division, Aircraft Certification Service.

[FR Doc. 2017-21226 Filed 10-6-17; 8:45 am]

 BILLING CODE 4910-13-P