Airworthiness Directives; Schempp-Hirth Flugzeugbau GmbH Gliders

[Federal Register Volume 90, Number 41 (Tuesday, March 4, 2025)]
[Rules and Regulations]
[Pages 11129-11131]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2025-03442]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2024-2135; Project Identifier MCAI-2024-00157-G; 
Amendment 39-22972; AD 2025-04-14]
RIN 2120-AA64


Airworthiness Directives; Schempp-Hirth Flugzeugbau GmbH Gliders

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule.

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

DATES: This AD is effective April 8, 2025.
    The Director of the Federal Register approved the incorporation by 
reference of certain publications listed in this AD as of April 8, 
2025.

ADDRESSES: 
    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 final rule, the mandatory continuing airworthiness 
information (MCAI), any comments received, 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.
    Material Incorporated by Reference:
    <bullet> For Schempp-Hirth Flugzeugbau GmbH material identified in 
this 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.
    <bullet> 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. It is also available at regulations.gov under 
Docket No. FAA-2024-2135.

FOR FURTHER INFORMATION CONTACT: Fred Guerin, Aviation Safety Engineer, 
FAA, 1600 Stewart Avenue, Suite 410, Westbury, NY 11590; phone: (206) 
231-2346; email: [email protected].

SUPPLEMENTARY INFORMATION: 

Background

    The FAA issued a notice of proposed rulemaking (NPRM) to amend 14 
CFR part 39 by adding an AD that would apply to all Schempp-Hirth 
Flugzeugbau GmbH Model Duo Discus and Duo Discus T gliders. The NPRM 
published in the Federal Register on August 30, 2024 (89 FR 70580). The 
NPRM was prompted by AD 2024-0059, dated March 5, 2024, issued by the 
European Union Aviation Safety Agency (EASA), which is the Technical 
Agent for the Member States of the European Union (EASA AD 2024-0059) 
(also referred to as the MCAI). 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

[[Page 11130]]

temporarily deformed due to forces related to acceleration, which 
allowed the locking mechanism to move into the open position. These 
conditions, if not addressed, could lead to the canopy opening in 
flight, resulting in loss of control of the glider.
    In the NPRM, the FAA proposed to require modifying the canopy 
locking mechanism. The FAA is issuing this AD to address the unsafe 
condition on these products.
    You may examine the MCAI in the AD docket at regulations.gov under 
Docket No. FAA-2024-2135.

Discussion of Final Airworthiness Directive

Comments

    The FAA received a comment from an individual who supported the 
NPRM without change.
    The FAA received additional comments from two individual 
commenters. The following presents the comments received on the NPRM 
and the FAA's response to each comment.

Requests To Withdraw the NPRM

    An individual commenter noted that the service information was 
presented by the factory on July 2, 2004, and it was not clear why in 
October 2024 there is now an issue with these gliders. The commenter 
further stated that the canopy locking mechanism works as designed when 
used properly and that although an inexperienced pilot could close the 
canopy, slide the levers forward, and not have the canopy properly 
latched, learning how to correctly latch the canopy is a matter of 
education rather than an indication that an AD is needed. The FAA 
infers that the commenter requested that the NPRM be withdrawn.
    Another commenter stated that an AD is not warranted because, 
regardless of additional mechanisms, pilots must properly confirm 
canopy closure and latching and brief passengers on remaining clear of 
the canopy latch. The commenter mentioned that most instances of 
canopies opening are the result of pilot error and personally witnessed 
inexperienced pilots in the front seat rest their hand on the canopy 
latch to catch airflow along the canopy and that this is an 
unacceptable practice and should be corrected by the pilot in charge, 
as well as covered during the pre-flight briefing with any new pilot or 
passenger.
    The FAA disagrees with the commenters' requests. The FAA issues an 
AD once an unsafe condition has been identified and the unsafe 
condition is likely to exist or develop in other products of the same 
type design. Schempp-Hirth Flugzeugbau GmbH issued technical notes in 
2004 and 2005 based upon data gathered from numerous glider operators. 
However, a subsequent fatal accident in 2023 highlights the risk 
associated with the inadequate design. While the FAA agrees with the 
comment that a proper preflight inspection includes confirming a canopy 
closure, the fatal accident in 2023 indicates that the risks associated 
with the inadequate design still exist. The FAA agrees with EASA's risk 
assessment that an unsafe condition exists on the affected gliders and 
an AD action is necessary.
    The FAA has not changed this AD regarding these comments.

Request To Revise Applicability

    An individual commenter stated that the applicability in the 
proposed AD is Schempp-Hirth Flugzeugbau GmbH Model Duo Discus and Duo 
Discus T gliders, all serial numbers, certificated in any category, but 
Schempp-Hirth Flugzeugbau Technical Note No. 380-1, No. 396-6, dated 
July 27, 2004, with Appendix to Technical Note No. 380-1/396-6, only 
specifies Duo Discus sailplanes with serial numbers 1 to 422. The FAA 
infers that the commenter is requesting that the applicability be 
revised to specify gliders with specific serial numbers.
    The FAA agrees. The FAA revised paragraph (c) of this AD, 
Applicability, to specify Schempp-Hirth Flugzeugbau GmbH Model Duo 
Discus gliders serial numbers (S/Ns) 1 through 422 (inclusive) and Duo 
Discus T gliders S/Ns 1 through 96 (inclusive), certificated in any 
category.

Conclusion

    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 comments received, and determined that air safety 
requires adopting this AD as proposed. Accordingly, the FAA is issuing 
this AD to address the unsafe condition on these products. Except for 
any other changes discussed previously, this AD is adopted as proposed 
in the NPRM. None of the changes will increase the economic burden on 
any operator.

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 the ADDRESSES section.

Differences Between This AD and the MCAI

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

Costs of Compliance

    The FAA estimates that this AD affects 34 gliders of U.S. registry.
    The FAA estimates the following costs to comply with this AD:

                                                 Estimated Costs
----------------------------------------------------------------------------------------------------------------
                                                                                    Cost per       Cost on U.S.
               Action                        Labor cost           Parts cost        product         operators
----------------------------------------------------------------------------------------------------------------
Modify canopy locking mechanism.....  2 work-hours x $85 per             $100             $270           $9,180
                                       hour = $170.
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[[Page 11131]]

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:
    (1) Is not a ``significant regulatory action'' under Executive 
Order 12866,
    (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 
reference, Safety.

The Amendment

    Accordingly, under the authority delegated to me by the 
Administrator, the FAA amends 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(f), 40113, 44701.


Sec.  39.13  [Amended]

0
2. The FAA amends Sec.  39.13 by adding the following new airworthiness 
directive:

2025-04-14 Schempp-Hirth Flugzeugbau GmbH: Amendment 39-22972; 
Docket No. FAA-2024-2135; Project Identifier MCAI-2024-00157-G.

(a) Effective Date

    This airworthiness directive (AD) is effective April 8, 2025.

(b) Affected ADs

    None.

(c) Applicability

    This AD applies to Schempp-Hirth Flugzeugbau GmbH Model Duo 
Discus gliders serial numbers (S/Ns) 1 through 422 (inclusive) and 
Duo Discus T gliders S/Ns 1 through 96 (inclusive), certificated in 
any category.

(d) Subject

    Joint Aircraft System Component (JASC) Code 5200, Doors; 5210, 
Passenger/Crew Doors.

(e) Unsafe Condition

    This AD was prompted by reports of gliders' canopies opening 
during air tow. The FAA is issuing this AD to address the canopy 
locking mechanism opening during flight. The unsafe condition, if 
not addressed, could lead to the canopy opening in flight, resulting 
in loss of control of the glider.

(f) Compliance

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

(g) Required Actions

    Within 12 months after the effective date of this AD, modify the 
canopy locking mechanism by installing a compression spring in the 
canopy locking mechanism, installing spring washers at the canopy 
actuating levers, 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, in accordance with the applicable technical note specified 
in paragraph (g)(1) or (2) of this AD.
    (1) For Model Duo Discus gliders: Appendix to Technical Note No. 
380-1/396-6 attached to Schempp-Hirth Flugzeugbau GmbH Technical 
Note No. 380-1, No. 396-6 dated July 27, 2004 (issued as one 
document).
    (2) For Model Duo Discus T gliders: Appendix to Technical Note 
No. 868-4/890-5 attached to Schempp-Hirth Flugzeugbau GmbH Technical 
Note No. 868-4, No. 890-5 dated February 23, 2005 (issued as one 
document).

(h) 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 (i) of 
this AD or email to: [email protected]. If mailing information, also 
submit information by email. 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.

(i) Additional Information

    For more information about this AD, contact Fred Guerin, 
Aviation Safety Engineer, FAA, 1600 Stewart Avenue, Suite 410, 
Westbury, NY 11590; phone: (206) 231-2346; email: 
[email protected].

(j) 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 the AD specifies otherwise.
    (i) 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).
    (ii) 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).
    (3) For Schempp-Hirth Flugzeugbau GmbH material identified in 
this 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.
    (4) 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.
    (5) 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 [email protected].

    Issued on February 21, 2025.
Steven W. Thompson,
Acting Deputy Director, Compliance & Airworthiness Division, Aircraft 
Certification Service.
[FR Doc. 2025-03442 Filed 3-3-25; 8:45 am]
BILLING CODE 4910-13-P

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