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###### Department of Transportation

###### Federal Aviation Administration

          - 14 CFR Part 39
          - [Docket No. FAA-2021-0716; Project Identifier 2019-CE-023-AD]
          - RIN 2120-AA64

# AGENCY:

Federal Aviation Administration (FAA), DOT.

# ACTION:

Notice of proposed rulemaking (NPRM).

# SUMMARY:

The FAA proposes to adopt a new airworthiness directive (AD) for all Stemme AG Model Stemme S 12 gliders. This proposed 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 an airspeed indicator (ASI) with speed markings inconsistent with the approved and published values. This proposed AD would require inspecting the ASI markings and, depending on findings, either replacing the ASI or amending the existing aircraft flight manual (AFM) until the ASI is replaced. The FAA is proposing this AD to address the unsafe condition on these products.

# DATES:

The FAA must receive comments on this proposed AD by October 12, 2021.

# ADDRESSES:

You may send comments, using the procedures found in 14 CFR 11.43 and 11.45, by any of the following methods:
      -  Federal eRulemaking Portal:                          Go to                          https://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:                          Deliver to Mail address above between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays.                    

                        For service information identified in this NPRM, contact STEMME AG, Flugplatzstrasse F2, Nr. 6-7, D-15344 Strausberg, Germany; phone: +49 (0) 3341 3612-0, fax: +49 (0) 3341 3612-30; email:                         *airworthiness@stemme.de;*                         website:                         *https://www.stemme.com.*                         You may view this service information at the FAA, Airworthiness Products Section, Operational Safety Branch, 901 Locust, Kansas City, MO 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 at                     *https://www.regulations.gov*                     by searching for and locating Docket No. FAA-2021-0716; or in person at Docket Operations between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The AD docket contains this NPRM, the MCAI, any comments received, and other information. The street address for Docket Operations is listed above.                

# FOR FURTHER INFORMATION CONTACT:

                        Jim Rutherford, Aviation Safety Engineer, General Aviation & Rotorcraft Section, International Validation Branch, FAA, 901 Locust, Room 301, Kansas City, MO 64106; phone: (816) 329-4165; fax: (816) 329-4090; email:                         *jim.rutherford@faa.gov.*

# SUPPLEMENTARY INFORMATION:

## Comments Invited

                    The FAA invites you to send any written relevant data, views, or arguments about this proposal. Send your comments to an address listed under                     **ADDRESSES**                    . Include “Docket No. FAA-2021-0716; Project Identifier 2019-CE-023-AD” at the beginning of your comments. The most helpful comments reference a specific portion of the proposal, explain the reason for any recommended change, and include supporting data. The FAA will consider all comments received by the closing date and may amend this proposal because of those comments.                

                    Except for Confidential Business Information (CBI) as described in the following paragraph, and other information as described in 14 CFR 11.35, the FAA will post all comments received, without change, to                     *https://www.regulations.gov,*                     including any personal information you provide. The agency will also post a report summarizing each substantive verbal contact received about this NPRM.                

## Confidential Business Information

                    CBI is commercial or financial information that is both customarily and actually treated as private by its owner. Under the Freedom of Information Act (FOIA) (5 U.S.C. 552), CBI is exempt from public disclosure. If your comments responsive to this NPRM contain commercial or financial information that is customarily treated as private, that you actually treat as private, and that is relevant or responsive to this NPRM, it is important that you clearly designate the submitted                           ( print page 48066)                        comments as CBI. Please mark each page of your submission containing CBI as “PROPIN.” The FAA will treat such marked submissions as confidential under the FOIA, and they will not be placed in the public docket of this NPRM. Submissions containing CBI should be sent to Jim Rutherford, Aviation Safety Engineer, General Aviation & Rotorcraft Section, International Validation Branch, FAA, 901 Locust, Room 301, Kansas City, MO 64106. Any commentary that the FAA receives which is not specifically designated as CBI will be placed in the public docket for this rulemaking.                

## Background

The European Union Aviation Safety Agency (EASA), which is the Technical Agent for the Member States of the European Union, has issued EASA AD 2019-0082, dated April 12, 2019 (referred to after this as “the MCAI”), to address an unsafe condition on Stemme AG Model Stemme S 12 gliders. The MCAI states:

During a production inspection of a new powered sailplane, an ASI was found with speed markings inconsistent with the approved and published values (begin[ning] of the white and green arc). Subsequent investigation of the production records for delivered Stemme S 12 powered sailplanes does not exclude that a similar, non-conforming ASI was installed during production.

This condition, if not corrected, could lead to erroneous information being provided to the pilot, particularly at the lower speed operation limits, possibly resulting in reduced control of the powered sailplane.

To address this unsafe condition, Stemme AG issued the SB [service bulletin] to provide inspections instructions.

For the reason described above, this [EASA] AD requires a one-time inspection of the markings of the affected part and, depending on findings, amending the Aircraft Flight Manual (AFM) and replacing the affected part. This [EASA] AD also prohibits installation of affected parts.

                    You may examine the MCAI in the AD docket at                     *https://www.regulations.gov*                     by searching for and locating Docket No. FAA-2021-0716.                

## Related Service Information Under 1 CFR Part 51

                    The FAA reviewed Stemme Service Bulletin No. P062-980027, Revision 00, dated December 17, 2018. The service information specifies checking the ASI markings and provides illustrations of correct markings. The service information specifies the procedure to replace an affected ASI with an ASI with correct markings. The service information also includes a temporary page to insert into the AFM until the ASI is replaced. 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                     **ADDRESSES**                    .                

## FAA's Determination

This product has been approved by the aviation authority of another country and is approved for operation in the United States. Pursuant to the FAA's bilateral agreement with this State of Design Authority, it has notified the FAA of the unsafe condition described in the MCAI and service information referenced above. The FAA is issuing this NPRM after determining the unsafe condition described previously is likely to exist or develop on other products of the same type design.

## Proposed AD Requirements in This NPRM

This proposed AD would require a one-time inspection of the ASI markings and, depending on findings, either replacing the ASI before further flight or amending the existing AFM until the ASI is replaced within 3 months.

## Costs of Compliance

The FAA estimates that this AD, if adopted as proposed, would affect 20 gliders of U.S. registry. The FAA estimates that it would take about 0.5 work-hour per glider to comply with the inspection requirements of this AD. The average labor rate is $85 per work-hour.

Based on these figures, the FAA estimates the cost of this AD on U.S. operators to be $850 or $42.50 per glider.

The FAA estimates that amending the AFM to insert and then remove the temporary page as a result of the inspection would take about 1 work-hour per glider for a total cost of $85 per glider. The FAA estimates that replacing the ASI would take about 3.5 work-hours and require parts costing $603, for a total cost of $900.50 per glider. The FAA has no way of determining the number of gliders that may need these actions.

The FAA has included all known costs in its cost estimate. According to the manufacturer, however, some of the costs of this AD may be covered under warranty, thereby reducing the cost impact on affected operators.

## 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.

The FAA is 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

The FAA 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:

(1) Is not a “significant regulatory action” under Executive Order 12866,

(2) Would not affect intrastate aviation in Alaska, and

(3) Would 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 adding the following new airworthiness directive: 

**Stemme AG:**                         Docket No. FAA-2021-0716; Project Identifier 2019-CE-023-AD.                    

## (a) Comments Due Date

                        The FAA must receive comments on this airworthiness directive (AD) by October 12, 2021.                              ( print page 48067)    

## (b) Affected ADs

None.

## (c) Applicability

This AD applies to Stemme AG Model Stemme S 12 gliders, all serial numbers, certificated in any category.

## (d) Subject

Joint Aircraft System Component (JASC) Code 3414, Airspeed/Mach Indicator.

## (e) Unsafe Condition

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 an airspeed indicator (ASI) with speed markings inconsistent with the approved and published values (beginning of the white and green arc). The FAA is issuing this AD to prevent erroneous information being provided to the pilot, particularly at the lower speed operation limits. The unsafe condition, if not addressed, could result in reduced control of the glider.

## (f) Compliance

Comply with this AD within the compliance times specified, unless already done.

## (g) Required Actions

(1) Within 30 days after the effective date of this AD, inspect ASI part number (P/N) IF-W230 or IF-W190 for incorrect markings in accordance with the table in the Appendix, “2.3. Airspeed Indicator Markings,” of Stemme Service Bulletin No. P062-980027, Revision 00, dated December 17, 2018 (the SB). If an ASI marking is incorrect, before further flight, perform one of the following:

(i) Replace the ASI by following the Actions, Action 2, of the SB; or

(ii) Amend the existing aircraft flight manual (AFM) for your glider by inserting the Appendix, temporary page 2-3 SB, “2.3. Airspeed Indicator Markings,” of the SB. Within 3 months after amending the AFM, replace the ASI by following the Actions, Action 2, of the SB and remove temporary page 2-3 SB, “2.3. Airspeed Indicator Markings,” from the AFM.

(2) As of the effective date of this AD, do not install ASI P/N IF-W230 or IF-W190 on any glider unless it has passed the inspection required by this AD.

## (h) Alternative Methods of Compliance (AMOCs)

                        (1) The Manager, International Validation Branch, FAA, has the authority to approve AMOCs for this AD, if requested using the procedures found in 14 CFR 39.19. In accordance with 14 CFR 39.19, send your request to your principal inspector or local Flight Standards District Office, as appropriate. If sending information directly to the manager of the certification office, send it to the attention of the person identified in Related Information or email:                         *9-AVS-AIR-730-AMOC@faa.gov.*

(2) Before using any approved AMOC, notify your appropriate principal inspector, or lacking a principal inspector, the manager of the local flight standards district office/certificate holding district office.

## (i) Related Information

                        (1) For more information about this AD, contact Jim Rutherford, Aviation Safety Engineer, General Aviation & Rotorcraft Section, International Validation Branch, FAA, 901 Locust, Room 301, Kansas City, MO 64106; phone: (816) 329-4165; fax: (816) 329-4090; email:                         *jim.rutherford@faa.gov.*

                        (2) Refer to European Union Aviation Safety Agency (EASA) AD 2019-0082, dated April 12, 2019, for more information. You may examine the EASA AD in the AD docket at                         *https://www.regulations.gov*                         by searching for and locating it in Docket No. FAA-2021-0716.                    

                        (3) For service information identified in this AD, contact STEMME AG, Flugplatzstrasse F2, Nr. 6-7, D-15344 Strausberg, Germany; phone: +49 (0) 3341 3612-0, fax: +49 (0) 3341 3612-30; email:                         *airworthiness@stemme.de;*                         website:                         *https://www.stemme.com.*                         You may view this referenced service information at the FAA, Airworthiness Products Section, Operational Safety Branch, 901 Locust, Kansas City, MO 64106. For information on the availability of this material at the FAA, call (816) 329-4148.                    

Issued on August 20, 2021.

Lance T. Gant, 

Director, Compliance & Airworthiness Division, Aircraft Certification Service.

[FR Doc. 2021-18387 Filed 8-26-21; 8:45 am]

BILLING CODE 4910-13-P