SUPPLEMENTARY INFORMATION:

Comments Invited

The FAA invites you to send any written relevant data, views, or arguments about this proposal. Send your comments using a method listed under ADDRESSES . Include Docket No. FAA-2026-11798; Project Identifier MCAI-2025-01608-G” 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 the 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 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 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 Aaron T. Nguyen, Aviation Safety Engineer, FAA, 1600 Stewart Avenue, Suite 410, Westbury, NY 11590. Any commentary that the FAA receives which is not specifically ( printed page 63176) designated as CBI will be placed in the public docket for this rulemaking.

Background

The FAA issued AD 2025-13-08, Amendment 39-23074 (90 FR 30575, July 10, 2025) (AD 2025-13-08), for all DG Aviation GmbH Model DG-1000T gliders. AD 2025-13-08 was prompted by an MCAI originated by the European Union Aviation Safety Agency (EASA), which is the Technical Agent for the Member States of the European Union. EASA issued EASA Emergency AD 2025-0112-E, dated May 14, 2025 (EASA Emergency AD 2025-0112-E), to correct an unsafe condition identified as propeller separation.

AD 2025-13-08 requires revising the glider flight manual and installing “Motor INOP” placards to prohibit operation with the powerplant. The FAA issued AD 2025-13-08 to detect and address failure of a propeller.

Actions Since AD 2025-13-08 Was Issued

Since the FAA issued AD 2025-13-08, EASA superseded EASA Emergency AD 2025-0112-E, and issued EASA AD 2025-0220, dated October 10, 2025 (EASA AD 2025-0220) (also referred to as the MCAI), to correct an unsafe condition on all DG Aviation GmbH Model DG-1000T gliders. The MCAI states that propeller separation occurred due to complete failure of the damper element. The design approval holder subsequently developed a modification that introduces a safety mechanism for the propeller adapter ring. The FAA is issuing this AD to detect and address failure of a propeller. The unsafe condition, if not addressed, could lead to separation of the propeller, which could result in reduced or loss of control of the glider or the propeller impacting the glider, passengers in the glider, or people on the ground.

You may examine the MCAI in the AD docket at regulations.gov under Docket No. FAA-2026-11798.

Material Incorporated by Reference Under 1 CFR Part 51

The FAA reviewed DG Aviation GmbH Technical Note No. 1000/52, Issue 01.b, dated October 8, 2025. This material specifies procedures for revising the DG Aviation GmbH Model DG-1000T glider flight manual, and removal, inspection, and reinstallation of the propeller adapter disk, including installation of safety pins.

This proposed AD would also require DG aviation GmbH Service Information No. 116-25, Issue 01.b, dated May 12, 2025, which the Director of the Federal Register approved for incorporation by reference as of July 25, 2025 (90 FR 30575, July 10, 2025).

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 NPRM after determining that 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 retain all requirements of AD 2025-13-08, would provide an optional terminating action for the retained actions by incorporating a specified modification, and would allow for the removal of the “Motor INOP” placards following accomplishment of that optional terminating action.

Costs of Compliance

The FAA estimates that this AD, if adopted as proposed, would affect two gliders of U.S. registry.

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

The following presents the cost of the optional terminating action for this proposed AD:

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. ( printed page 63177)

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.

The Proposed Amendment

Accordingly, under the authority delegated to me by the Administrator, the FAA proposes to amend 14 CFR part 39 as follows:

1. The authority citation for part 39 continues to read as follows:

Authority: 49 U.S.C. 106(g), 40113, 44701.

2. The FAA amends § 39.13 by:

a. Removing Airworthiness Directive 2025-13-08, Amendment 39-23074 ( 90 FR 30575, July 10, 2025); and

b. Adding the following new airworthiness directive:

DG Aviation GmbH (Type Certificate Previously Held by DG Flugzeugbau GmbH): Docket No. FAA-2026-11798; Project Identifier MCAI-2025-01608-G.

(a) Comments Due Date

The FAA must receive comments on this airworthiness directive (AD) by November 19, 2026.

(b) Affected ADs

This AD replaces AD 2025-13-08, Amendment 39-23074 (90 FR 30575, July 10, 2025) (AD 2025-13-08).

(c) Applicability

This AD applies to all DG Aviation GmbH (Type Certificate previously held by DG Flugzeugbau GmbH) Model DG-1000T gliders, certificated in any category.

(d) Subject

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

(e) Unsafe Condition

This AD was prompted by reports of propeller separation due to failure of the adapter ring damper element. The FAA is issuing this AD to detect and address failure of a propeller. The unsafe condition, if not addressed, could result in separation of the propeller, which could result in reduced or loss of control of the glider or the propeller impacting the glider, passengers in the glider, or people on the ground.

(f) Compliance

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

(g) Retained Actions from AD 2025-13-08

Within 3 days after July 25, 2025 (the effective date of AD 2025-13-08), comply with either paragraph (g)(1) or (2) of this AD.

(1) Revise the flight manual for your glider and install “Motor INOP” placards in accordance with paragraphs 1 and 3 of the Instructions in DG aviation GmbH Service Information No. 116-25, Issue 01.b, dated May 12, 2025. The owner/operator (pilot) holding at least a private pilot certificate may revise the existing flight manual and must enter compliance with the applicable paragraph of this AD into the glider maintenance records in accordance with 14 CFR 43.9(a) and 91.417(a)(2)(v). The record must be maintained as required by 14 CFR 91.417, 121.380, or 135.439.

(2) Remove the powerplant from the glider.

(h) New Optional Terminating Action for This AD

Modification of a glider in accordance with the Instructions in DG Aviation GmbH Technical Note No. 1000/52, Issue 01.b, dated October 8, 2025, constitutes terminating action for the actions required by paragraphs (g)(1) and (2) of this AD for that glider. Following modification of the glider in accordance with the Instructions in DG Aviation GmbH Technical Note No. 1000/52, Issue 01.b, dated October 8, 2025, the flight manual amendment and placard required by paragraph (g)(1) of this AD may be removed.

(i) Parts Installation Prohibition

From the effective date of this AD, do not install any propeller adapter ring having part number (P/N) 10 M 067, version a, or any earlier approved part number on any glider.

(j) Credit for Previous Actions

This paragraph provides credit for the actions required by paragraph (g)(1) of this AD, if those actions were performed before the effective date of this AD using DG aviation GmbH Service Information No. 116-25, Issue 01.a, dated May 5, 2025.

(k) Special Flight Permits

Special flight permits, as described in 14 CFR 21.197 and 21.199, are not allowed.

(l) 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 International Validation Branch, send it to the attention of the person identified in paragraph (m)(1) of this AD and email to: AMOC@faa.gov.

(2) Before using any approved AMOC, notify your appropriate principal inspector, or lacking a principal inspector, the manager of the responsible Flight Standards Office/certificate holding district office.

(m) Additional Information

(1) For more information about this AD, contact Aaron T. Nguyen, Aviation Safety Engineer, FAA, 1600 Stewart Avenue, Suite 410, Westbury, NY 11590; phone: (281) 799-3453; email: aaron.t.nguyen@faa.gov.

(2) Material identified in this AD that is not incorporated by reference is available at the address specified in paragraph (n)(5) of this AD.

(n) Material Incorporated by Reference

(1) The Director of the Federal Register approved the incorporation by reference (IBR) 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 this AD specifies otherwise.

(3) The following material was approved for IBR on [DATE 35 DAYS AFTER PUBLICATION OF THE FINAL RULE].

(i) DG Aviation GmbH Technical Note No. 1000/52, Issue 01.b, dated October 8, 2025.

(ii) [Reserved]

(4) The following material was approved for IBR on July 25, 2025 (90 FR 30575, July 10, 2025).

(i) DG aviation GmbH Service Information No. 116-25, Issue 01.b, dated May 12, 2025.

(ii) [Reserved]

(5) For DG aviation GmbH and DG Aviation GmbH material identified in this AD, contact DG Aviation GmbH, Rita Rodrigues, Otto Lilienthal Weg 2/Am Flugplatz, Bruchsal, Germany; phone: +49 (0) 7251 36660-32; email: rodrigues@dg-aviation.de; website: www.dg-aviation.de/​en/​dg-flugzeugbau/​contact.

(6) 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.

(7) You may view this material at the National Archives and Records Administration (NARA). For information on the availability of this material at NARA, visit www.archives.gov/​federal-register/​cfr/​ibr-locations or email fr.inspection@nara.gov.

91 FR 63175