DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2021-0792; Project Identifier AD-2020-00593-G;
Amendment 39-21840; AD 2021-24-19]
Airworthiness Directives; DG Flugzeugbau GmbH Gliders
AGENCY: Federal Aviation Administration (FAA), DOT.
ACTION: Final rule.
SUMMARY: The FAA is adopting a new airworthiness directive (AD) for all
DG Flugzeugbau GmbH Model DG-500MB and DG-1000M gliders with a Solo
Kleinmotoren GmbH Solo Model 2625 02i engine installed. This AD was
prompted by mandatory continuing airworthiness information (MCAI)
issued by the aviation authority of another country to identify and
correct an unsafe condition on an aviation product. The MCAI describes
the unsafe condition as an error in the engine control unit (ECU)
software. This AD requires updating the ECU software. The FAA is
issuing this AD to address the unsafe condition on these products.
DATES: This AD is effective January 27, 2022.
The Director of the Federal Register approved the incorporation by
reference of a certain publication listed in this AD as of January 27, 2022.
ADDRESSES: 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">email@example.com; website: https://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 (816) 329-4148. It is also available at https://www.regulations.gov
by searching for and locating Docket No. FAA-2021-0792.
Examining the AD Docket
You may examine the AD docket at https://www.regulations.gov by
searching for and locating Docket No. FAA-2021-0792; 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.
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:
The FAA issued a notice of proposed rulemaking (NPRM) to amend 14
CFR part 39 by adding an AD that would apply to all DG Flugzeugbau GmbH
Model DG-500MB and DG-1000M gliders with a Solo Kleinmotoren GmbH Solo
Model 2625 02i engine installed. The NPRM published in the Federal
Register on September 17, 2021 (86 FR 51838). The NPRM was prompted by
MCAI originated by the European Union Aviation Safety Agency (EASA),
which is the Technical Agent for the Member States of the European
Union. EASA issued EASA AD 2020-0056, dated March 13, 2020 (referred to
after this as "the MCAI"), to address an unsafe condition on Solo
Kleinmotoren GmbH Solo Model 2625 02 engines, variation 02i with
electronic fuel injection, installed on but not limited to Binder
Motorenbau, DG-Flugzeugbau, and Schempp-Hirth powered sailplanes
(gliders). The MCAI states:
An error was found in the ECU affected SW [software] that can
cause brief injection of fuel into one cylinder when the ECU is
This condition, if not corrected, could increase the time needed
to (re)start the engine in flight, possibly resulting in reduced
control of the powered sailplane.
To address this potential unsafe condition, SOLO Kleinmotoren
GmbH, together with the ECU manufactuerer [sic], developed an ECU SW
update and issued the SB [service bulletin] accordingly, providing
For the reason described above, this [EASA] AD requires an
update of the ECU software.
You may examine the MCAI in the AD docket at https://www.regulations.gov
by searching for and locating Docket No. FAA-2021-0792.
The Model 2625 02i engine does not have an FAA type certificate.
For Model DG-1000M gliders, this engine is part of the glider type
certification. For Model DG-500MB gliders, this engine may be installed
as a Model 2525 02 engine modified with a fuel injection system and re-
identified as a Model 2625 02i engine.
Discussion of Final Airworthiness Directive
The FAA received no comments on the NPRM or on the determination of
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 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. This AD is adopted as proposed in the
Related Service Information Under 1 CFR Part 51
The FAA reviewed Solo Kleinmotoren GmbH Service Bulletin No. 4600-
11, Ausgabe 1 (English translation: Issue 1), dated August 19, 2019.
This service information specifies procedures for updating the ECU
software to a version that fixes a software error found in previous ECU
software versions. 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 ADDRESSES.
Costs of Compliance
The FAA estimates that this AD affects 4 gliders of U.S. registry.
The FAA estimates that it would take about 2 work-hours per glider to
comply with the requirements of this AD. The average labor rate is $85
per work-hour. Based on these figures, the FAA estimates the cost of
this AD on U.S. operators to be $680 or $170 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.
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. For the reasons discussed above, I certify 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
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 adding the following new airworthiness