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PROPOSED AD SCHEMPP-HIRTH FLUGZEUGBAU GMBH: Docket No. FAA-2021-0878; Project Identifier MCAI-2020-01460-G.
(a) COMMENTS DUE DATE

    The FAA must receive comments on this airworthiness directive (AD)  by
    December 6, 2021.

(b) AFFECTED ADS

    None.

(c) APPLICABILITY

    This AD  applies to the Schempp-Hirth Flugzeugbau GmbH gliders identi-
    fied in paragraphs (c)(1) and (2) of this AD, certificated in any cat-
    egory.

(1) Model Duo Discus gliders, serial number (S/N) 1 through 541 inclusive,
    except S/N 534.

(2) Model Duo Discus T gliders, S/N 1 through 174 inclusive.

(d) SUBJECT

    Joint Aircraft System Component (JASC) Code 2760, Drag Control System.

(e) UNSAFE CONDITION

    This AD was prompted by mandatory continuing airworthiness information
    (MCAI)  originated  by an  aviation  authority of  another  country to
    identify and correct an unsafe  condition on an aviation product.  The
    MCAI describes  the unsafe  condition as  jerky extension  of the  air
    brakes at very  high air speeds,  including cases where  the air brake
    blades interlock. The  FAA is issuing  this AD to  prevent and correct
    damage  of  the  airbrake  end-stops.  The  unsafe  condition,  if not
    addressed, could  result in  blockage of  the air  brakes and  reduced
    control of the glider.

(f) COMPLIANCE

    Comply with this AD within the compliance times specified,  unless al-
    ready done.

(g) REQUIRED ACTIONS

(1) For gliders with air brake end stop plastic bushings (22 mm) installed
    Within 3 months after the effective date of this AD, replace each  air
    brake end  stop plastic  bushing (22 mm)  with  an air  brake end stop
    plastic bushing (32 mm)  in accordance with Schempp-Hirth  Flugzeugbau
    GmbH Working Instructions for Technical Note 890-16 rev1 and Technical
    Note 396-20 rev1 action 1, dated September 18, 2020.

(2) For gliders with single air brake metal end stops installed:  Within 3
    months after the  effective date of  this AD, inspect  each single air
    brake  metal end  stop for  overlap in  accordance with  Schempp-Hirth
    Flugzeugbau GmbH Working Instructions  for Technical Note 396-20  rev1
    action 2, dated September 18, 2020.  If there is insufficient overlap,
    before further flight,  repair using a  method approved by  the FAA or
    the European Union Aviation Safety Agency (EASA).

(h) PARTS INSTALLATION PROHIBITION

    As of the effective date of this AD,  do not install  an air brake end
    stop plastic bushing (22 mm) on any glider.

(i) 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 (j)(1) of this AD or email:  9-AVS-AIR-
    730-AMOC@faa.gov.

(2) Before using any approved AMOC,  notify your appropriate principal in-
    spector, or lacking  a principal inspector,  the manager of  the local
    flight standards district office/certificate holding district office.

(j) RELATED INFORMATION

(1) For more information about this AD,  contact Jim Rutherford,  Aviation
    Safety Engineer,  General Aviation & Rotorcraft Section, International
    Validation Branch, FAA, 901 Locust,  Room 301,  Kansas City, MO 64106;
    phone: (816) 329-4165; fax: (816) 329-4090; email: jim.rutherford@faa.
    gov.

(2) Refer to EASA AD 2020-0233, dated October 27, 2020,  for more informa-
    tion.  You may examine  the EASA AD  in the AD docket  at https://www.
    regulations.gov by searching  for  and  locating it in Docket No. FAA-
    2021-0878.

(3) For service information identified in this AD,  contact  Schempp-Hirth
    Flugzeugbau  GmbH,  Krebenstrasse 25,  73230 Kirchheim/Teck,  Germany;
    phone: +49 7021 7298-0;  fax: +49 7021 7298-199;  email: info@schempp-
    hirth.com;  website: https://www.schempp-hirth.com.  You may view this
    referenced service information at the FAA, Airworthiness Products Sec-
    tion,  Operational Safety Branch,  901 Locust,  Kansas City, MO 64106.
    For information on the availability of this material at the FAA,  call
    (816) 329-4148.

Issued on October 8, 2021. Gaetano A. Sciortino, Deputy Director for Stra-
tegic Initiatives,  Compliance & Airworthiness Division, Aircraft Certifi-
cation Service.

DATES: The FAA must receive comments  on this proposed AD  by  December 6,
2021.
PREAMBLE 

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2021-0878; Project Identifier MCAI-2020-01460-G]
RIN 2120-AA64

Airworthiness Directives; Schempp-Hirth Flugzeugbau GmbH Gliders

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed rulemaking (NPRM).

-----------------------------------------------------------------------

SUMMARY: The FAA proposes to adopt a new airworthiness directive (AD)
for certain Schempp-Hirth Flugzeugbau GmbH Model Duo Discus and Duo
Discus T gliders. This proposed AD was prompted by mandatory continuing
airworthiness information (MCAI) originated by an aviation authority of
another country to identify and correct an unsafe condition on an
aviation product. The MCAI describes the unsafe condition as jerky
extension of the air brakes at very high air speeds, including cases
where the air brake blades interlock. This proposed AD would require
replacing certain air brake end stop bushings, inspecting certain other
air brake end stops, and repairing if necessary. 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 December 6,
2021.

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 https://www.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.
For service information identified in this NPRM, contact Schempp-
Hirth Flugzeugbau GmbH, Krebenstrasse 25, 73230 Kirchheim/Teck,
Germany; phone: +49 7021 7298-0; fax: +49 7021 7298-199; email:
info@schempp-hirth.com; website: https://www.schempp-hirth.com. You may
view this referenced service information 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 (816) 329-4148.

Examining the AD Docket

You may examine the AD docket at https://www.regulations.gov by
searching for and locating Docket No. FAA-2021-0878; 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 MCAI,
any comments received, and other information. The street address for
Docket Operations is listed above.

FOR FURTHER INFORMATION CONTACT: Jim Rutherford, Aviation Safety
Engineer, General Aviation & Rotorcraft Section, International
Validation Branch, FAA, 901 Locust, Room 301, Kansas City, MO 64106;
phone: (816) 329-4165; fax: (816) 329-4090; email:
jim.rutherford@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-2021-0878; Project Identifier
MCAI-2020-01460-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
https://www.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 Jim
Rutherford, Aviation Safety Engineer, FAA, General Aviation &
Rotorcraft Section, International Validation Branch, FAA, 901 Locust,
Room 301, Kansas City, MO 64106. 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 2020-0233, dated October 27, 2020 (referred to after this as
``the MCAI''), to address an unsafe condition on certain serial-
numbered (S/N) Schempp-Hirth Flugzeugbau GmbH Model Duo Discus, Duo
Discus C, and Duo Discus T gliders. The MCAI states:

Occurrences were reported of experiencing jerky extension of the
airbrakes at very high air speeds, in some cases of which the
airbrake blades interlocked. An increasing number of age-related
damage was observed on a specific version (22 mm plastic bushes) of
the airbrake end-stops.
This condition, if not corrected, could lead to blockage of the
airbrakes, possibly resulting in reduced control of the (powered)
sailplane.
To address this potential unsafe condition, Schempp-Hirth issued
the applicable [technical note] TN (original issue) to provide
instructions to replace the affected parts with a new version
bushing, made of better material.
Since [EASA planned AD] PAD 20-119 was issued, it was discovered
that early s/n sailplanes were equipped with a single metal end stop
per airbrake. The applicable TN was revised accordingly. The PAD was
revised to include those metal end stops in the definition of
`affected part' to ensure these are inspected.
For the reasons described above, this [EASA] AD requires
replacement of certain affected parts with serviceable parts. For
other affected parts, this [EASA] AD requires a one-time inspection
for sufficient overlap and, depending on findings, accomplishment of
applicable corrective action(s). This [EASA] AD also prohibits
(re)installation of affected parts.

You may examine the MCAI in the AD docket at https://www.regulations.gov by
searching for and locating Docket No. FAA-2021-0878.

Related Service Information Under 1 CFR Part 51

The FAA reviewed Schempp-Hirth Flugzeugbau GmbH Working
Instructions for Technical Note 890-16 rev1 and Technical Note 396-20
rev1 action 1, dated September 18, 2020. The service information
contains procedures for replacing each air brake end stop plastic
bushing (22 mm) with an air brake end stop plastic bushing (32 mm). The
FAA also reviewed Schempp-Hirth Flugzeugbau GmbH Working Instructions
for Technical Note 396-20 rev1 action 2, dated September 18, 2020. The
service information contains procedures for inspecting each single air
brake metal end stop for overlap. This service information 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

This product has been approved by the aviation authority of another
country and is 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
service information referenced above. The FAA is issuing this NPRM
after determining the unsafe condition described previously is likely
to exist or develop on other products of the same type design.

Proposed AD Requirements

This proposed AD would require accomplishing the actions specified
in the service information already described, except as described under
``Differences Between this Proposed AD and the MCAI.'' This proposed AD
would also require repairing any single air brake metal end stop with
insufficient overlap.

Differences Between This Proposed AD and the MCAI


The MCAI applies to Schempp-Hirth Flugzeugbau GmbH Model Duo Discus
C gliders, and this proposed AD would not because this model does not
have an FAA type certificate.
The MCAI allows credit for modifications done prior to the
effective date of the EASA AD in accordance with the original issue of
Schempp-Hirth TN 396-20/TN 890-16, but this proposed AD would not
provide such credit.
The MCAI prohibits installation of air brake end stop plastic
bushings (22 mm) after a glider has been modified with an air brake end
stop plastic bushing (32 mm). This proposed AD would prohibit
installation of air brake end stop plastic bushings (22 mm) as of the
effective date of this AD.

Costs of Compliance

The FAA estimates that this AD, if adopted as proposed, would
affect 27 gliders of U.S. registry.
The FAA estimates the following costs to comply with this proposed
AD:

Estimated Costs

Action
Labor cost
Parts cost
Cost per product
Cost on U.S. operators
Replace plastic end stop bushings 4 work-hours x $85 per hour = $340
$150
$490
Up to $13,230 (depending on number of gliders with plastic end stop bushings)
Inspect metal end stops 1 work-hour x $85 per hour = $85
0
85
Up to $2,295 (depending on number of gliders with metal end stops)

The FAA estimates the following costs to do any necessary repairs
that would be required based on the results of the proposed inspection.
The FAA has no way of determining the number of gliders that might need
these repairs:

On-Condition Costs

Action
Labor cost
Parts cost
Cost per product
Repair metal end stops 4 work-hours x $85 per hour = $340
$150
$490

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: