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]
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(EASA) superseded its mandatory continuing airworthiness information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.
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@example.com.
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
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
Discussion of Final Airworthiness Directive
The FAA received a comment from one commenter. An individual
supported the NPRM without change.
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:
|Remove freewheel clutch from
||4 work-hours x $85 per hour =
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.
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
(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
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.
Sec. 39.13 [Amended]
2. The FAA amends Sec. 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: