Proposed Rule2026-20393
Airworthiness Directives; DG Aviation GmbH (Type Certificate Previously Held by DG Flugzeugbau GmbH) Gliders
Primary source
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Published
October 5, 2026
Issuing agencies
Transportation DepartmentFederal Aviation Administration
Abstract
The FAA proposes to supersede Airworthiness Directive (AD) 2025-13-08, which applies to all DG Aviation GmbH Model DG-1000T gliders. AD 2025-13-08 requires revising the glider flight manual and installing "Motor INOP" placards to prohibit operation with the powerplant. Since issuance of AD 2025-13-08, a design improvement to the propeller adapter ring has been developed that is considered terminating action for the operational prohibition of AD 2025-13-08. This proposed AD would retain the requirement to revise the flight manual, would provide an optional terminating action for the retained actions by incorporating a specified modification, would allow removal of the "Motor INOP" placards following accomplishment of that optional terminating action, and would require removal, inspection, and reinstallation of the propeller adapter disk, including installation of safety pins. This proposed AD would also prohibit the installation of affected propeller adapter rings. The FAA is proposing this AD to address the unsafe condition on these products.
Full Text
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<title>Federal Register, Volume 91 Issue 191 (Monday, October 5, 2026)</title>
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[Federal Register Volume 91, Number 191 (Monday, October 5, 2026)]
[Proposed Rules]
[Pages 63175-63177]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 2026-20393]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2026-11798; Project Identifier MCAI-2025-01608-G]
RIN 2120-AA64
Airworthiness Directives; DG Aviation GmbH (Type Certificate
Previously Held by DG Flugzeugbau GmbH) Gliders
AGENCY: Federal Aviation Administration (FAA), DOT.
ACTION: Notice of proposed rulemaking (NPRM).
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SUMMARY: The FAA proposes to supersede Airworthiness Directive (AD)
2025-13-08, which applies to all DG Aviation GmbH Model DG-1000T
gliders. AD 2025-13-08 requires revising the glider flight manual and
installing ``Motor INOP'' placards to prohibit operation with the
powerplant. Since issuance of AD 2025-13-08, a design improvement to
the propeller adapter ring has been developed that is considered
terminating action for the operational prohibition of AD 2025-13-08.
This proposed AD would retain the requirement to revise the flight
manual, would provide an optional terminating action for the retained
actions by incorporating a specified modification, would allow removal
of the ``Motor INOP'' placards following accomplishment of that
optional terminating action, and would require removal, inspection, and
reinstallation of the propeller adapter disk, including installation of
safety pins. This proposed AD would also prohibit the installation of
affected propeller adapter rings. The FAA is proposing this AD to
address the unsafe condition on these products.
DATES: The FAA must receive comments on this proposed AD by November
19, 2026.
ADDRESSES: You may send comments, using the procedures found in 14 CFR
11.43 and 11.45, by any of the following methods:
<bullet> Federal eRulemaking Portal: Go to <a href="http://regulations.gov">regulations.gov</a>. Follow
the instructions for submitting comments.
<bullet> Fax: (202) 493-2251.
<bullet> Mail: U.S. Department of Transportation, Docket
Operations, M-91, West Building Fifth Floor, Room W58-213, 1200 New
Jersey Avenue SE, Washington, DC 20590.
<bullet> 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 <a href="http://regulations.gov">regulations.gov</a> under
Docket No. FAA-2026-11798; 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 NPRM, 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:
<bullet> For DG Aviation GmbH material identified in this proposed
AD, contact DG Aviation GmbH, Rita Rodrigues, Otto Lilienthal Weg 2/Am
Flugplatz, Bruchsal, Germany; phone: +49 (0) 7251 36660-32; email:
<a href="/cdn-cgi/l/email-protection#eb99848f99828c9e8e98ab8f8cc68a9d828a9f828485c58f8e"><span class="__cf_email__" data-cfemail="5e2c313a2c37392b3b2d1e3a39733f28373f2a373130703a3b">[email protected]</span></a>; website: <a href="https://www.dg-aviation.de/en/dg-flugzeugbau/contact">https://www.dg-aviation.de/en/dg-flugzeugbau/contact</a>.
<bullet> You may view this material at the FAA, Operational Safety
Branch, 1100 Main, Kansas City, MO 64105. For information on the
availability of this material at the FAA, call (817) 222-5110.
FOR FURTHER INFORMATION CONTACT: Aaron T. Nguyen, Aviation Safety
Engineer, FAA, 1600 Stewart Avenue, Suite 410, Westbury, NY 11590;
phone: (281) 799-3453; email: <a href="/cdn-cgi/l/email-protection#95f4f4e7fafbbbe1bbfbf2e0ecf0fbd5f3f4f4bbf2fae3"><span class="__cf_email__" data-cfemail="e28383908d8ccc96cc8c85979b878ca2848383cc858d94">[email protected]</span></a>.
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
<a href="http://regulations.gov">regulations.gov</a>, 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
[[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 <a href="http://regulations.gov">regulations.gov</a> 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:
Estimated Costs
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Cost per Cost on U.S.
Action Labor cost Parts cost product operators
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Revise glider flight manual........... 1 work-hour x $85 per $0 $85 $170
hour = $85.
Fabricate and install placard......... 1 work-hour x $85 per 35 120 240
hour = $85.
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The following presents the cost of the optional terminating action
for this proposed AD:
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Cost per
Action Labor cost Parts cost product
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Replace adapter disk, safety pins, and dynamic 1 work-hour x $85 per hour = $85.. $1,126 $1,211
balancing weights.
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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.
[[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.
List of Subjects in 14 CFR Part 39
Air transportation, Aircraft, Aviation safety, Incorporation by
reference, Safety.
The Proposed Amendment
Accordingly, under the authority delegated to me by the
Administrator, the FAA proposes to amend 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 2025-13-08, Amendment 39-23074 (90
FR 30575, July 10, 2025); and
0
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: <a href="/cdn-cgi/l/email-protection#16575b59555670777738717960"><span class="__cf_email__" data-cfemail="53121e1c10133532327d343c25">[email protected]</span></a>.
(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:
<a href="/cdn-cgi/l/email-protection#5a3b3b283534742e74343d2f233f341a3c3b3b743d352c"><span class="__cf_email__" data-cfemail="7819190a1716560c56161f0d011d16381e1919561f170e">[email protected]</span></a>.
(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: <a href="/cdn-cgi/l/email-protection#a0d2cfc4d2c9c7d5c5d3e0c4c78dc1d6c9c1d4c9cfce8ec4c5"><span class="__cf_email__" data-cfemail="96e4f9f2e4fff1e3f3e5d6f2f1bbf7e0fff7e2fff9f8b8f2f3">[email protected]</span></a>; website: <a href="https://www.dg-aviation.de/en/dg-flugzeugbau/contact">https://www.dg-aviation.de/en/dg-flugzeugbau/contact</a>.
(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 <a href="http://www.archives.gov/federal-register/cfr/ibr-locations">www.archives.gov/federal-register/cfr/ibr-locations</a> or email <a href="/cdn-cgi/l/email-protection#0d6b7f2364637e7d686e796462634d636c7f6c236a627b"><span class="__cf_email__" data-cfemail="ee889cc087809d9e8b8d9a878180ae808f9c8fc0898198">[email protected]</span></a>.
Issued on September 30, 2026.
Steven W. Thompson,
Acting Deputy Director, Compliance & Airworthiness Division, Aircraft
Certification Service.
[FR Doc. 2026-20393 Filed 10-2-26; 8:45 am]
BILLING CODE 4910-13-P
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