DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2022-1406; Project Identifier MCAI-2022-00590-G]
RIN 2120-AA64

Airworthiness Directives; DG Flugzeugbau GmbH and 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 supersede Airworthiness Directive (AD)
2015-09-04 R1, which applies to DG Flugzeugbau GmbH Model DG-1000T
gliders equipped with a Solo Kleinmotoren GmbH (currently Solo
Vertriebs-und Entwicklungs-GmbH) (Solo) Model 2350 C engine. AD 2015-
09-04 R1 prohibits operation of the engine and requires performing a
magnetic particle or dye penetrant inspection of the propeller shaft
and reporting the results of the inspection to Solo. This proposed AD
is 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 identifies
the unsafe condition as occurrences of rupture of the eccentric axle on
Solo Model 2350 C engines (installed on DG Flugzeugbau GmbH Model DG-
1000T gliders in the United States) and an occurrence on a Solo Model
2350 D engine (installed on Schempp-Hirth Flugzeugbau GmbH (Schempp-
Hirth) Model Duo Discus T gliders in the United States). This proposed
AD would require repetitive replacement of the eccentric axle, would
add the Schempp-Hirth Model Duo Discus T gliders to the applicability,
and would retain from AD 2015-09-04 R1 the option of operating the
glider with the engine non-operative instead of replacing the eccentric
axle. The FAA is proposing this AD to address the unsafe condition on
these products.

DATES: The FAA must receive comments on this NPRM by January 27, 2023.

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-2022-1406; 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.
Material Incorporated by Reference:
For service information identified in this NPRM, contact
Solo Kleinmotoren GmbH, Postfach 600152, D71050 Sindelfingen, Germany;
phone: +49 703 1301-0; fax: +49 703 1301-136; email: aircraft@solo-germany.com;
website: aircraft.solo.global/gb/.
You may view this 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 (817) 222-5110.

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; 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-2022-1406; Project Identifier
MCAI-2022-00590-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 Jim
Rutherford, Aviation Safety Engineer, 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 FAA issued AD 2015-09-04 R1, Amendment 39-18492 (81 FR 26124,
May 2, 2016) (AD 2015-09-04 R1), for DG Flugzeugbau GmbH Model DG-1000T
gliders equipped with a Solo Model 2350 C engine. AD 2015-09-04 R1 was
prompted by MCAI originated by the European Aviation Safety Agency (now
European Union Aviation Safety Agency) (EASA), which is the Technical
Agent for the Member States of the European Union. EASA issued AD 2015-
0052R1, dated November 19, 2015 (EASA AD 2015-0052R1), to correct an
unsafe condition identified as engine shaft failure.
AD 2015-09-04 R1 prohibits operation of the engine and requires
performing a magnetic particle or dye penetrant inspection of the
propeller shaft and reporting the results of the inspection to Solo.
The FAA issued AD 2015-09-04 R1 to prevent failure of the engine shaft
with consequent propeller detachment that could result in damage to the
glider or injury of persons on the ground.

Actions Since AD 2015-09-04 R1 Was Issued

Since the FAA issued AD 2015-09-04 R1, EASA superseded AD 2015-
0052R1 and issued EASA AD 2022-0044R1, dated April 29, 2022 (referred
to hereafter as ``the MCAI''). The MCAI states an occurrence of rupture
of the eccentric axle on a Solo Model 2350 D engine (installed on
Schempp-Hirth Model Duo Discus T gliders in the United States). The
MCAI specifies replacing the eccentric axle with a new part and
establishing a life limit for this part. You may examine the MCAI in
the AD docket at regulations.gov under Docket No. FAA-2022-1406.

Related Service Information Under 1 CFR Part 51

The FAA reviewed Solo Kleinmotoren GmbH Technische Mitteilung
(English translation: Service Bulletin), Nr. 4603-19, Ausgabe (English
translation: dated) January 31, 2022, which specifies procedures for
replacing the eccentric axle with eccentric axle part number (P/N)
2031211V2 for Solo Model 2350 D engines, which are installed on
Schempp-Hirth Model Duo Discus T gliders in the United States.
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 described 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 these same type designs.

Proposed AD Requirements in This NPRM

This proposed AD would retain a certain action from AD 2015-09-04
R1. The operating limitation for the DG Flugzeugbau GmbH Model DG-1000T
gliders equipped with a Solo Model 2350 C would continue to be allowed
by the proposed AD instead of replacing the eccentric axle. This
proposed AD would also add the Schempp-Hirth Model Duo Discus T gliders
equipped with a Solo Model 2350 D engine to the applicability, and
require repetitive replacement of the eccentric axle. This proposed AD
would also require incorporation of the final rule into the Limitations
section of the existing aircraft flight manual for your glider if the
operator chooses to operate the glider with the engine inoperative. The
proposed incorporation of the operating limitation into the flight
manual of the glider and removal of the operating limitation may be
performed by the owner/operator (pilot) holding at least a private
pilot certificate and must be entered into the aircraft records showing
compliance in accordance with 14 CFR 43.9(a) and 14 CFR
91.417(a)(2)(v). The record must be maintained as required by 14 CFR
91.417, 121.380, or 135.439. The proposed incorporation of the
operating limitation into the flight manual of the glider and removal
of the operating limitation are not considered maintenance actions and
may be done equally by a pilot or a mechanic and are exceptions to the
FAA's standard practice.

Differences Between This Proposed AD and the MCAI

The MCAI, for the DG Flugzeugbau GmbH Model DG-1000T gliders
equipped with a Solo Model 2350 C engine, has a compliance time for the
initial eccentric axle replacement based on the effective date of
superseded EASA AD 2015-0052-E, dated March 27, 2015. This proposed AD
would have a compliance time for these gliders based on the effective
date of the final rule because there was not a requirement in AD 2015-
09-04 R1 to replace the eccentric axle.

Costs of Compliance

The FAA estimates that this AD, if adopted as proposed, would
affect 8 gliders of U.S. registry. The FAA estimates the following
costs to comply with this proposed AD:

Estimated Costs

If any operator chooses to not replace the eccentric axle and
instead operates the glider with the engine inoperative, the proposed
operating limitation incorporation would take .5 work-hour at $85 per
hour for a total of $42.50 per airplane. If at any time after, the
operator chooses to remove the operating limitation, this proposed
action would also take .5 work-hour at $85 per hour for a total of
$42.50 per airplane.

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 that the 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:
a. Removing Airworthiness Directive 2015-09-04 R1, Amendment 39-
18492 (81 FR 26124, May 2, 2016); and
b. Adding the following new airworthiness directive: