2023-01285. Airworthiness Directives; Stemme AG Gliders

AGENCY:

Federal Aviation Administration (FAA), DOT.

ACTION:

Final rule.

SUMMARY:

The FAA is superseding Airworthiness Directive (AD) 2022-01-09 for certain Stemme AG Model Stemme S 10-VT and Model Stemme S 12 gliders. AD 2022-01-09 required removing the affected freewheel clutch from service and prohibited the installation of affected parts. Since the FAA issued AD 2022-01-09, the European Union Aviation Safety Agency (EASA) superseded its mandatory continuing airworthiness information (MCAI) to amend the definition of an affected part. This AD retains the requirements of AD 2022-01-09 for removing the affected freewheel clutch from service and continues to prohibit the installation of an affected part, and amends the definition of an affected part and clarifies the part installation prohibition. The FAA is issuing this AD to address the unsafe condition on these products.

DATES:

This AD is effective March 1, 2023.

ADDRESSES:

AD Docket: You may examine the AD docket at regulations.gov under Docket No. FAA-2022-1421; 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 final rule, any comments received, the MCAI, and other information. The address for Docket Operations is U.S. Department of Transportation, Docket Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New Jersey Avenue SE, Washington, DC 20590.

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: [phone]; email: [e-mail].

SUPPLEMENTARY INFORMATION:

Background

The FAA issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 to supersede AD 2022-01-09, Amendment 39-21897 (87 FR 1666, January 12, 2022) (AD 2022-01-09). AD 2022-01-09 applied to all Stemme AG Model Stemme S 10-VT and Model Stemme S 12 gliders with a freewheel clutch part number (P/N) 12AK with a serial number starting with “12-” installed. AD 2022-01-09 required removing the affected freewheel clutch from service and prohibited installing an affected part on any glider. The FAA issued AD 2022-01-09 to address unintended slipping of the freewheel clutch with overheating (burnishing) of the friction pads inside of the clutch, which if not addressed, could result in a loss of thrust and consequent loss of glider control.

The NPRM published in the Federal Register on November 18, 2022 (87 FR 69220). The NPRM was prompted by EASA AD 2021-0278R1, dated August 11, 2022 (referred to after this as “the MCAI”), issued by EASA, which is the Technical Agent for the Member States of the European Union. The MCAI states that the definition of affected part is amended to exclude certain modified and re-identified freewheel clutches. You may examine the MCAI in the AD docket at regulations.gov under Docket No. FAA-2022-1421.

In the NPRM, the FAA proposed to retain the requirements of AD 2022-01-09 for removing the affected freewheel clutch from service and continue to prohibit the installation of an affected part, and amend the definition of an affected part and clarify the part installation prohibition.

Discussion of Final Airworthiness Directive

Comments

The FAA received a comment from one commenter. An individual supported the NPRM without change.

Conclusion

These products have been approved by the aviation authority of another country and are 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 referenced above. The FAA reviewed the relevant data, considered the comment received, and determined that air safety requires adopting the AD as proposed. Accordingly, the FAA is issuing this AD to address the unsafe condition on these products. Except for minor editorial changes, including correcting a typographical error in the Required Action and Compliance paragraph, this AD is adopted as proposed in the NPRM.

Costs of Compliance

The FAA estimates that this AD affects 63 gliders of U.S. registry.

The FAA estimates the following costs to comply with this AD:

Estimated Costs

Action	Labor cost	Parts cost	Cost per product	Cost on U.S. operators
Remove freewheel clutch from service	4 work-hours × $85 per hour = $340	$500	$840	$52,920

The new requirements of this AD add no additional economic burden over that already required by AD 2022-01-09.

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 has 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,

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

(3) 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 Amendment

Accordingly, under the authority delegated to me by the Administrator, the FAA amends 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

[Amended]

2. The FAA amends § 39.13 by:

a. Removing Airworthiness Directive 2022-01-09, Amendment 39-21897 ( 87 FR 1666, January 12, 2022); and

b. Adding the following new airworthiness directive:

2023-02-03 Stemme AG: Amendment 39-22310; Docket No. FAA-2022-1421; Project Identifier MCAI-2022-01088-G.

(a) Effective Date

This airworthiness directive (AD) is effective March 1, 2023.

(b) Affected ADs

This AD replaces AD 2022-01-09, Amendment 39-21897 (87 FR 1666, January 12, 2022).

(c) Applicability

This AD applies to Stemme AG Model Stemme S 10-VT and Model Stemme S 12 gliders, all serial numbers, certificated in any category, with a freewheel clutch having part number 12AK with a serial number starting with “12-” installed, except those which have been modified by following the instructions of Stemme Service Bulletin Doc. No. P062-980058, Revision 02, dated April 19, 2022, and have been re-identified with “/M” at the end of the serial number.

(d) Subject

Joint Aircraft System Component (JASC) Code 7100, Powerplant System.

(e) Unsafe Condition

This AD was prompted by 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 identifies the unsafe condition as unintended slipping of the freewheel clutch with overheating (burnishing) of the friction pads inside of the clutch. The FAA is issuing this AD to ensure removal of the affected freewheel clutch from service. The unsafe condition, if not addressed, could result in a loss of thrust and consequent loss of glider control.

(f) Compliance

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

(g) Required Action and Compliance

(1) Before further flight after the effective date of this AD, remove the freewheel clutch from service.

(2) As of the effective date of this AD, do not install a freewheel clutch part number 12AK with a serial number starting with “12-” on any glider, unless it has been modified by following the instructions of Stemme Service Bulletin Doc. No. P062-980058, Revision 02, dated April 19, 2022, and has been re-identified with “/M” at the end of the serial number.

(h) Alternative Methods of Compliance (AMOCs)

The Manager, International Validation Branch, FAA, has the authority to approve AMOCs for this AD, if requested using the procedures found in § 39.19. In accordance with § 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 International Validation Branch, mail it to the address identified in paragraph (i)(2) of this AD or email to: [e-mail]. If mailing information, also submit information by email. 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. AMOCs approved for AD 2022-01-09 are approved as AMOCs for the corresponding provisions of this AD.

(i) Additional Information

(1) Refer to European Union Aviation Safety Agency (EASA) AD 2021-0278R1, dated August 11, 2022, for related information. This EASA AD may be found in the AD docket at regulations.gov under Docket No. FAA-2022-1421.

(2) 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: [phone]; email: [e-mail].

(3) For service information identified in this AD that is not incorporated by reference, contact Stemme AG, Flugplatzstrasse F2, Nr. 6-7, D-15344 Strausberg, Germany; phone: [phone]; fax: [phone]; email: [e-mail]; website: 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 [phone].

(j) Material Incorporated by Reference

None.

Issued on January 19, 2023.

Christina Underwood,

Acting Director, Compliance & Airworthiness Division, Aircraft Certification Service.