The FAA is adopting a new airworthiness directive (AD) for all Stemme GmbH (Stemme) TSA-M Model S6-RT and Stemme S 12 gliders. This AD was prompted by a report of a leaking elec...
[Docket No. FAA-2026-7222; Project Identifier MCAI-2026-00565-G; Amendment 39-23416; AD 2026-15-04]
RIN 2120-AA64
AGENCY:
Federal Aviation Administration (FAA), DOT.
ACTION:
Final rule; request for comments.
SUMMARY:
The FAA is adopting a new airworthiness directive (AD) for all Stemme GmbH (Stemme) TSA-M Model S6-RT and Stemme S 12 gliders. This AD was prompted by a report of a leaking electrical fuel transfer pump. This AD requires inspecting affected electrical fuel transfer pumps for certain non-conforming parts, and if found, replacing them with approved parts. This AD also prohibits installation of certain non-conforming parts on affected gliders. The FAA is issuing this AD to address the unsafe condition on these products.
DATES:
This AD is effective July 24, 2026.
The Director of the Federal Register approved the incorporation by reference of a certain publication listed in this AD as of July 24, 2026.
The FAA must receive comments on this AD by September 8, 2026.
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
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.
AD Docket:
You may examine the AD docket at
regulations.gov
under Docket No. FAA-2026-7222; 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, the mandatory continuing airworthiness information (MCAI), any comments received, and other information. The street address for Docket Operations is listed above.
Material Incorporated by Reference:
For Stemme material identified in this AD, contact Stemme,
( printed page 46710)
Flugplatzstrasse F2 Nr. 6-7, Strausberg, Germany 15344; phone: +49 (0) 3341 3612; email:
airworthiness@stemme.com;
website:
stemme.com.
You may view this material at the FAA, Airworthiness Products Section, Operational Safety Branch, 1100 Main, Kansas City, MO 64105. For information on the availability of this material at the FAA, call (817) 222-5110. It is also available atregulations.gov
under Docket No. FAA-2026-7222.
FOR FURTHER INFORMATION CONTACT:
George Weir, Aviation Safety Engineer, FAA, 1600 Stewart Avenue, Suite 410, Westbury, NY 11590; phone: (817) 222-4045; email:
george.a.weir@faa.gov.
SUPPLEMENTARY INFORMATION:
Comments Invited
The FAA invites you to send any written data, views, or arguments about this final rule. Send your comments using a method listed under the
ADDRESSES
section. Include “Docket No. FAA-2026-7222; Project Identifier MCAI-2026-00565-G” at the beginning of your comments. The most helpful comments reference a specific portion of the final rule, 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 final rule 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
regulations.gov, including any personal information you provide. The agency will also post a report summarizing each substantive verbal contact received about this final rule.
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 AD 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 AD, it is important that you clearly designate the submitted 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 AD. Submissions containing CBI should be sent to George Weir, Aviation Safety Engineer, FAA, 1600 Stewart Avenue, Suite 410, Westbury, NY 11590. 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 Emergency AD 2026-0108-E, dated June 5, 2026 (referred to as the MCAI), to correct an unsafe condition on all Stemme TSA-M Model S6-RT and Stemme S 12 gliders. The MCAI states that a leaking electrical fuel transfer pump installed on a Model Stemme S 12 glider was found. The two glider models share the same electrical fuel transfer pump design. Each of these glider models have two electrical fuel transfer pumps. An investigation revealed that leakage resulted from the installation of non-conforming parts that occurred during manufacturing and that also have been delivered as spare parts. Non-conforming parts are electrical fuel transfer pumps identified with “HEP-02A” (unknown manufacturer) instead of “HEP-02” under part number 830521. To address the unsafe condition, Stemme published service material to provide inspection instructions to identify affected electrical fuel transfer pumps. This condition, if not addressed, could result in an in-flight fire and a potential explosion in the wing or center fuselage.
You may examine the MCAI in the AD docket at
regulations.gov
under Docket No. FAA-2026-7222.
Material Incorporated by Reference Under 1 CFR Part 51
The FAA reviewed Stemme Service Bulletin P062-980092, Revision 00, dated May 29, 2026. This material specifies procedures for a one-time inspection of the two electrical fuel pumps to verify if non-conforming parts, as defined in this AD, are installed. This material 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.
FAA's Determination
These products have been approved by the civil 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, that authority has notified the FAA of the unsafe condition described in the MCAI and material referenced above. The FAA is issuing this AD after determining that the unsafe condition described previously is likely to exist or develop on other products of the same type design.
AD Requirements
This AD requires visual inspection of both electrical fuel transfer pumps for non-conforming parts, and replacement of any electrical fuel transfer pumps if non-conforming parts are identified. This AD also prohibits the installation of certain non-conforming parts.
Interim Action
The FAA considers this AD to be an interim action. If final action is later identified, the FAA might consider further rulemaking.
Justification for Immediate Adoption and Determination of the Effective Date
Section 553(b) of the Administrative Procedure Act (APA) (5 U.S.C. 551et seq.) authorizes agencies to dispense with notice and comment procedures for rules when the agency, for “good cause,” finds that those procedures are “impracticable, unnecessary, or contrary to the public interest.” Under this section, an agency, upon finding good cause, may issue a final rule without providing notice and seeking comment prior to issuance. Further, section 553(d) of the APA authorizes agencies to make rules effective in less than thirty days, upon a finding of good cause.
An unsafe condition exists that requires the immediate adoption of this AD without providing an opportunity for public comments prior to adoption. The FAA has found that the risk to the flying public justifies forgoing notice and comment prior to adoption of this rule because EASA issued an emergency AD indicating that fuel leakage from an electrical fuel transfer pump on TSA-M Model S6-RT and Stemme S 12 gliders could result in an in-flight fire and a possible explosion in the wing or center fuselage, which could injure occupants and persons on the ground. Thus, an inspection of these gliders is necessary before further flight. This compliance time is shorter than the time necessary for the public to comment and for publication of the final rule. Accordingly, notice and opportunity for prior public comment are impracticable and contrary to the public interest pursuant to 5 U.S.C. 553(b).
In addition, the FAA finds that good cause exists pursuant to 5 U.S.C. 553(d) for making this amendment effective in less than 30 days, for the same reasons the FAA found good cause to forgo notice and comment.
( printed page 46711)
Regulatory Flexibility Act
The requirements of the Regulatory Flexibility Act (RFA) do not apply when an agency finds good cause pursuant to 5 U.S.C. 553 to adopt a rule without prior notice and comment. Because the FAA has determined that it has good cause to adopt this rule without prior notice and comment, RFA analysis is not required.
Costs of Compliance
The FAA estimates that this AD affects 33 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
Inspect both electrical fuel transfer pumps
3 work-hours × $85 per hour = $255
$0
$255
$8,415
The FAA estimates the following costs to do any necessary replacements that would be required based on the results of the inspection. The agency has no way of determining the number of gliders that might need these replacements.
On-Condition Costs
Action
Labor
cost
Parts
cost
Cost per
product
Replace both electrical fuel transfer pumps
3 work-hours × $85 per hour = $255 (up to)
$48 (up to)
$303 (up to)
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
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:
This airworthiness directive (AD) is effective July 24, 2026.
(b) Affected ADs
None.
(c) Applicability
This AD applies to all Stemme GmbH TSA-M Model S6-RT and Stemme S 12 gliders, certificated in any category.
(d) Subject
Joint Aircraft System Component (JASC) Code 2800, Aircraft Fuel System.
(e) Unsafe Condition
This AD was prompted by a report of a leaking electrical fuel transfer pump. The FAA is issuing this AD to detect and replace certain non-conforming parts. The unsafe condition, if not addressed, could result in an in-flight fire and possible explosion in the wing or center fuselage.
(f) Compliance
Comply with this AD within the compliance times specified, unless already done.
(g) Definitions
For the purpose of this AD the definitions in paragraphs (g)(1) through (4) of this AD apply.
(1) Non-conforming part: Any electrical fuel pump defined as “non-conforming” as described in Stemme Service Bulletin (SB) P062-980092, Revision 00, dated May 29, 2026 (Stemme SB P062-980092).
(2) Conforming part: Any electrical fuel pump defined as “conforming” as described in Stemme SB P062-980092.
(3) Group 1 gliders: Model Stemme S 12 gliders, serial numbers (S/Ns) 12-057 through 12-062 and TSA-M Model S6-RT gliders, S/Ns 019, 029, and 030.
(4) Group 2 gliders: Gliders that are not Group 1.
(h) Required Actions
(1) For Group 1 gliders: Before further flight after the effective date of this AD, accomplish a one-time inspection of the two electrical fuel pumps to verify if non-conforming parts are installed, in accordance with Stemme SB P062-980092.
(2) For Group 2 gliders: The inspection required by paragraph (h)(1) of this AD is not
( printed page 46712)
required for a Group 2 glider, provided that no electrical fuel pump has been replaced on that glider after January 1, 2023.
(3) If, during the inspection required by paragraph (h)(1) of this AD, any non-conforming part as defined in paragraph (g)(1) of this AD, is found, before further flight, replace any non-conforming electrical fuel pump with a conforming electrical fuel pump by contacting either the Manager, International Validation Branch, FAA; European Union Aviation Safety Agency (EASA); or Stemme's EASA Design Organization Approval (DOA); for approved replacement instructions and, within the compliance time specified therein, accomplish those instructions accordingly, including any follow-on action(s), as applicable. If approved by the DOA, the approval must include the DOA-authorized signature.
(i) Parts Installation Prohibition
As of the effective date of this AD, do not install a non-conforming part, as defined paragraph (g)(1) of this AD, on any glider.
(j) 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 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 International Validation Branch, send it to the attention of the person identified in paragraph (k) of this AD and email to
AMOC@faa.gov.
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.
(k) Additional Information
George Weir, Aviation Safety Engineer, FAA, 1600 Stewart Avenue, Suite 410, Westbury, NY 11590; phone: (817) 222-4045; email:
george.a.weir@faa.gov.
(l) Material Incorporated by Reference
(1) The Director of the Federal Register approved the incorporation by reference of the material listed in this paragraph under 5 U.S.C. 552(a) and 1 CFR part 51.
(2) You must use this material as applicable to do the actions required by this AD, unless the AD specifies otherwise.
(i) Stemme Service Bulletin P062-980092, Revision 00, dated May 29, 2026.
(ii) [Reserved]
(3) For Stemme material identified in this AD, contact Stemme GmbH, Flugplatzstrasse F2 Nr. 6-7, Strausberg, Germany 15344; phone: +49 (0) 3341 3612; email:
airworthiness@stemme.com;
website:
stemme.com.
(4) You may view this material at the FAA, Airworthiness Products Section, Operational Safety Branch, 1100 Main, Kansas City, MO 64105. For information on the availability of this material at the FAA, call (817) 222-5110.