DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2024-2135; Project Identifier MCAI-2024-00157-G]
RIN 2120-AA64

Airworthiness Directives; Schempp-Hirth Flugzeugbau GmbH Gliders

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: The FAA proposes to adopt a new airworthiness directive (AD)
for all Schempp-Hirth Flugzeugbau GmbH Model Duo Discus and Duo Discus
T gliders. This proposed AD was prompted by reports of gliders'
canopies opening during air tow. This proposed AD would require
modifying the canopy locking mechanism. The FAA is proposing this AD to
address the unsafe condition on these products.

DATES: The FAA must receive comments on this NPRM by October 15, 2024.

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-2024-2135; 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:

For Schempp-Hirth Flugzeugbau GmbH material identified in
this proposed AD, contact Schempp-Hirth Flugzeugbau GmbH, Krebenstrasse
25, Kirchheim unter Teck, Germany; phone: +49 7021 7298-0; email:
hirth.com">info@schempp-hirth.com; website: schempp-hirth.com.

You may view this material 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.

FOR FURTHER INFORMATION CONTACT: Fred Guerin, Aviation Safety Engineer,
FAA, 1600 Stewart Avenue, Suite 410, Westbury, NY 11590; phone: (206)
231-2346; email: fred.guerin@faa.gov.

SUPPLEMENTARY INFORMATION:

Comments Invited

The FAA invites you to send any written relevant data, views, or
arguments about this proposal. Send your comments to an address listed
under ADDRESSES. Include "Docket No. FAA-2024-2135; Project Identifier
MCAI-2024-00157-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
this 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 Fred
Guerin, 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 AD 2024-0059, dated March 5, 2024 (also referred to as the MCAI),
to correct an unsafe condition on all Schempp-Hirth Flugzeugbau GmbH
Model Duo Discus, Duo Discus T, Nimbus-4D, and Nimbus-4DT/DM sailplanes
(gliders). The MCAI states that occurrences have been reported of the
canopy opening during air tow on the Model Duo Discus and Nimbus
gliders. The investigation concluded that the fuselage could be
temporarily deformed due to forces related to acceleration, which
allowed the locking mechanism to move into the open position. The MCAI
requires modifying the canopy locking mechanism. These conditions, if
not addressed, could lead to the canopy opening in flight, resulting in
loss of control of the glider.

You may examine the MCAI in the AD docket at regulations.gov under
Docket No. FAA-2024-2135.

Material Incorporated by Reference Under 1 CFR Part 51

The FAA reviewed Schempp-Hirth Flugzeugbau GmbH Technical Note No.
380-1, No. 396-6 dated July 27, 2004, with Appendix to Technical Note
No. 380-1/396-6 attached (issued as one document); and Schempp-Hirth
Flugzeugbau GmbH Technical Note No. 868-4, No. 890-5 dated February 23,
2005, with Appendix to Technical Note No. 868-4/890-5 attached (issued
as one document), which specify procedures for installing a compression
spring in the canopy locking mechanism, installing spring washers at
the canopy actuating levers, and modifying the front actuating lever to
include a magnet and applying a red mark to the front and aft inside
the left canopy frame or installing a front actuating lever that has a
magnet. 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 ADDRESSES.

FAA's Determination

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 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 require accomplishing the actions specified
in the material already described, except as discussed under
"Differences Between this Proposed AD and the MCAI."

Differences Between This Proposed AD and the MCAI

While the MCAI applies to Schempp-Hirth Flugzeugbau GmbH Model
Nimbus-4D and Nimbus-4DT/DM gliders, this proposed AD does not because
these models do not have an FAA type certificate.

Costs of Compliance

The FAA estimates that this AD, if adopted as proposed, would
affect 34 gliders of U.S. registry.

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

Estimated Costs

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.

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

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 adding the following new airworthiness
directive: