DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2022-1406; Project Identifier MCAI-2022-00590-G;
Amendment 39-22347; AD 2023-03-22]
RIN 2120-AA64

Airworthiness Directives; DG Flugzeugbau GmbH and Schempp-Hirth
Flugzeugbau GmbH Gliders

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule.

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SUMMARY: The FAA is superseding Airworthiness Directive (AD) 2015-09-04
R1, which applied 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
prohibited operation of the engine and required performing a magnetic
particle or dye penetrant inspection of the propeller shaft and
reporting the results of the inspection to Solo. This 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 AD requires repetitive
replacement of the eccentric axle, adds the Schempp-Hirth Model Duo
Discus T gliders to the applicability, and retains 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 issuing this AD to
address the unsafe condition on these products.

DATES: This AD is effective April 5, 2023.
The Director of the Federal Register approved the incorporation by
reference of a certain publication listed in this AD as of April 5,
2023.

ADDRESSES:
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 final rule, the 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:
For service information identified in this final rule,
contact Solo Kleinmotoren GmbH, Postfach 600152, D71050 Sindelfingen,
Germany; phone: +49 703 1301-0; fax: +49 703 1301-136; email:
germany.com">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. It is also available at
regulations.gov under Docket No. FAA-2022-1406.

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:

Background

The FAA issued a notice of proposed rulemaking (NPRM) to amend 14
CFR part 39 to supersede AD 2015-09-04 R1, Amendment 39-18492 (81 FR
26124, May 2, 2016) (AD 2015-09-04 R1). AD 2015-09-04 R1 applied to DG
Flugzeugbau GmbH Model DG-1000T gliders equipped with a Solo Model 2350
C engine. AD 2015-09-04 R1 prohibited operation of the engine and
required 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 address failure of the engine
shaft with consequent propeller detachment. The unsafe condition, if
not addressed, could result in damage to the glider or injury of
persons on the ground.
The NPRM published in the Federal Register on December 13, 2022 (87
FR 76166). The NPRM was prompted by AD 2022-0044R1, dated April 29,
2022 (referred to after this as ``the MCAI''), issued by the European
Union Aviation Safety Agency (EASA), which is the Technical Agent for
the Member States of the European Union. 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 requires 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.
In the NPRM, the FAA proposed to retain a certain action from AD
2015-09-04 R1 in that the NPRM proposed to continue to allow the
operating limitation for the DG Flugzeugbau GmbH Model DG-1000T gliders
equipped with a Solo Model 2350 C instead of replacing the eccentric
axle. The NPRM also proposed to 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. The NPRM also proposed to 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 owner/operator (pilot) holding at least a
private pilot certificate may perform the proposed incorporation of the
operating limitation into the flight manual of the glider and removal
of the operating limitation, and the actions must be entered into the
aircraft records showing compliance with this AD 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 existing flight
manual of your glider and removal of the operating limitation are not
considered maintenance actions and may be done equally by a pilot or a
mechanic. This is an exception to the FAA's standard maintenance
regulations.
The FAA is issuing this AD to address the unsafe condition on these
products.

Discussion of Final Airworthiness Directive

Comments

The FAA received no comments on the NPRM or on the determination of
the costs.

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 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 minor editorial changes, this AD is adopted as proposed in the NPRM.

Related Service Information Under 1 CFR Part 51

The FAA reviewed Solo Kleinmotoren GmbH Technische Mitteilung
(English translation: Service Bulletin), Nr. 4603-19, datum (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.

Differences Between This 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 AD has 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 affects 8 gliders of U.S. registry.
The FAA estimates the following costs to comply with this AD:

Estimated Costs

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

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 has determined that 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

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: