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Airworthiness Directive packet

AD 2023-02-03

Airworthiness Directives; Stemme AG Gliders

1 · Quick read — prepared by AircraftDirectives

Our plain-language summary — not the regulation

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 number
2023-02-03
Federal Register document
2023-01285
Citation
88 FR 4721
Amendment
39-22310
Docket
Docket No. FAA-2022-1421
Action
Final rule.
Published
2023-01-25
Effective
2023-03-01
Effective (as stated in the rule)
This AD is effective March 1, 2023.
Issued by
Transportation Department, Federal Aviation Administration
Regulation
14 CFR 39
Applies to (in our index)
Stemme S10/S12

2 · Official Federal Register document — government source, verbatim

Reproduced unedited from the Federal Register
[Federal Register Volume 88, Number 16 (Wednesday, January 25, 2023)]
[Rules and Regulations]
[Pages 4721-4722]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2023-01285]


========================================================================
Rules and Regulations
                                                Federal Register
________________________________________________________________________

This section of the FEDERAL REGISTER contains regulatory documents 
having general applicability and legal effect, most of which are keyed 
to and codified in the Code of Federal Regulations, which is published 
under 50 titles pursuant to 44 U.S.C. 1510.

The Code of Federal Regulations is sold by the Superintendent of Documents. 

========================================================================


Federal Register / Vol. 88, No. 16 / Wednesday, January 25, 2023 / 
Rules and Regulations

[[Page 4721]]


DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2022-1421; Project Identifier MCAI-2022-01088-G; 
Amendment 39-22310; AD 2023-02-03]
RIN 2120-AA64


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: (816) 329-4165; email: [email protected].

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


[[Page 4722]]

    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

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:
0
a. Removing Airworthiness Directive 2022-01-09, Amendment 39-21897 (87 
FR 1666, January 12, 2022); and
0
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 Sec.  39.19. In accordance with Sec.  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: [email protected]. 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: (816) 329-4165; email: 
[email protected].
    (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: +49 (0) 3341 3612-0; 
fax: +49 (0) 3341 3612-30; email: [email protected]; 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 (817) 222-5110.

(j) Material Incorporated by Reference

    None.

    Issued on January 19, 2023.
Christina Underwood,
Acting Director, Compliance & Airworthiness Division, Aircraft 
Certification Service.
[FR Doc. 2023-01285 Filed 1-24-23; 8:45 am]
BILLING CODE 4910-13-P

Sources. Section 1 is written by AircraftDirectives from the record below and is a reading aid only. Section 2 is the United States Government's own text, reproduced without edit.

Federal Register: https://www.federalregister.gov/documents/2023/01/25/2023-01285/airworthiness-directives-stemme-ag-gliders

Official PDF: https://www.govinfo.gov/content/pkg/FR-2023-01-25/pdf/2023-01285.pdf

FAA DRS record: https://drs.faa.gov/browse/excelExternalWindow/FR-ADFRAWD-2023-01285-0000000000.0001

Packet generated 2026-08-18 08:15 UTC.

This packet is not an airworthiness determination and not legal or maintenance advice. AircraftDirectives reproduces official records and condenses their wording for easier reading. It does not decide, certify or imply whether any aircraft, engine, appliance or part is airworthy, compliant, affected by this directive, or eligible for return to service. No inspection, approval, or determination of any kind is performed or implied by this document.

Section 1 is a reading aid, not the rule. It is our own plain-language condensation, written to help a reader find the relevant directive quickly. It is NOT a substitute for the regulation, it may omit conditions, exceptions, compliance times, alternative methods of compliance (AMOCs) and applicability limits, and it has no legal force whatsoever. Only the official text governs. Where Section 1 and Section 2 differ in any respect, Section 2 - and the official source it was retrieved from - controls absolutely.

Responsibility remains with the owner/operator. Under 14 CFR §91.403 and §91.417 the owner or operator is responsible for maintaining airworthiness and for required records; under §39.7 no person may operate a product to which an airworthiness directive applies except in accordance with that directive. Determining applicability to a specific serial number and configuration, and performing or supervising any required action, is the responsibility of the owner/operator and appropriately certificated personnel.

Accuracy and currency. Section 2 was retrieved at the time stamped above and is reproduced without edit; Federal Register material is a work of the United States Government. Directives are amended, corrected and superseded over time, and this sheet is a snapshot, not a live record - it does not update after printing. Re-check the official sources before acting on it. This packet is provided without warranty of any kind, express or implied, including fitness for a particular purpose. We do not sell parts and have no commercial interest in any action a directive may require.

AircraftDirectives · AD 2023-02-03 · Section 1 is our plain-language reading aid; Section 2 is the official Federal Register text and controls where the two differ. Not an airworthiness determination — 14 CFR §91.403 / §91.417 responsibility remains with the owner/operator. Retrieved 2026-08-18 08:15 UTC.