Document ID: FAA-2021-1010-0004
Agency: faa
Document Type: Rule
Title: Airworthiness Directives: Stemme AG Gliders
Posted Date: 2022-01-26T05:00Z

[Federal Register Volume 87, Number 17 (Wednesday, January 26, 2022)]
[Rules and Regulations]
[Pages 3926-3928]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2022-01479]

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2021-1010; Project Identifier MCAI-2020-00807-G; 
Amendment 39-21924; AD 2022-03-07]
RIN 2120-AA64

Airworthiness Directives; Stemme AG 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 Stemme AG TSA-M Model S6 and S6-RT gliders. 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 a new version of the propeller gearbox tooth 
belt with a reduced life limit. This AD requires establishing a life 
limit of 5 years for certain propeller gearbox tooth belts. The FAA is 
issuing this AD to address the unsafe condition on these products.

DATES: This AD is effective March 2, 2022.

ADDRESSES: For service information identified in this final rule, 
contact Stemme AG, Flugplatzstrasse F2, Nr. 6-7, D-15344 Strausberg, 
Germany; phone: +49 (0) 3341 3612-0; fax: +49 (0) 3341 3612-30; email: 
[email protected]; website: https://www.stemme.com. 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 https://www.regulations.gov by 
searching for and locating Docket No. FAA-2021-1010.

Examining the AD Docket

    You may examine the AD docket at https://www.regulations.gov by 
searching for and locating Docket No. FAA-2021-1010; 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; 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 certain Stemme AG TSA-M 
Model S6 and S6-RT gliders. The NPRM published in the Federal Register 
on November 22, 2021 (86 FR 66229). 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 2020-0140, dated June 23, 2020 (referred to after 
this as ``the MCAI''), to address an unsafe condition on Stemme AG 
(Stemme) TSA-M Model S6 and S6-RT powered sailplanes (gliders) and ASP 
S15-1 airplanes. The MCAI states:

    The airworthiness limitations for Stemme TSA-M powered 
sailplanes and Stemme ASP aeroplanes, which are approved by EASA, 
are currently defined and published in Chapter 4 of the applicable 
AMM [aircraft maintenance manual]. These instructions have been 
identified as mandatory for continued airworthiness.

[[Page 3927]]

    Failure to accomplish these instructions could result in an 
unsafe condition.
    During a regular incoming part inspection at Stemme, the 
supplier delivered a new version of the tooth belts used in the 
propeller gearbox. The new part (with marking ``Carbon'') deviates 
from the previously used part (with marking ``Extreme'') by its 
layer build up. The new tooth belt has been found airworthy, 
although with a reduced life limit.
    Before Stemme identified the issue, new tooth belts were 
delivered, identified as Part Number (P/N) 830.185, the same as the 
previous part. These parts have to be identified by inspection, 
changed to P/N 832.502, and the reduced life limit implemented.
    Consequently, Stemme issued the applicable ALS [airworthiness 
limitations section] introducing the new life limit for the new 
part. Stemme also issued the SB [service bulletin] providing 
additional instructions on relevant inspections and corrective 
actions.
    For the reasons described above, this [EASA] AD requires a one-
time inspection of the propeller gearbox tooth belts, and, depending 
on findings, re-identification. This [EASA] AD also requires 
implementation of the reduced life limit by accomplishment of the 
actions specified in the applicable ALS.

    After issuance of the MCAI, EASA approved extending the life limit 
of the new ``Synchroforce Carbon'' belt to 5 years, the same as the 
original ``Extreme'' belt, as documented by Stemme in Revision 15 to 
the AMM Chapter 04 ALS.
    You may examine the MCAI in the AD docket at https://www.regulations.gov by searching for and locating Docket No. FAA-2021-
1010.

Discussion of Final Airworthiness Directive

Comments

    The FAA received one comment from an individual commenter. The 
commenter supported the NPRM without change.

Conclusion

    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, considered the comment 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. This AD is 
adopted as proposed in the NPRM.

Related Service Information

    The FAA reviewed Stemme Service Bulletin Doc. No. P062-980049, 
Revision 00, dated May 27, 2020. This service information specifies 
identifying the front propeller gearbox tooth belt, revising the AMM 
and illustrated parts catalogue, and introducing a life limit for the 
propeller gearbox tooth belt marked ``Synchroforce Carbon.''

Differences Between This AD and the MCAI or Service Information

    The MCAI applies to Stemme AG Model ASP S15-1 airplanes, and this 
AD does not because that model does not have an FAA type certificate.
    The MCAI requires an inspection to determine whether the propeller 
gearbox tooth belts are ``Synchroforce Carbon'' or ``Extreme.'' This AD 
does not require this inspection because instead, it applies only to 
gliders with a ``Synchroforce Carbon'' propeller gearbox tooth belt 
installed.
    The MCAI requires revising the existing aircraft maintenance 
program (AMP) to introduce the reduced life limit for the affected 
propeller gearbox tooth belt, as well as other life limits, as 
specified in the Temporary Revision to the aircraft maintenance manual 
airworthiness limitations section (ALS). After the AMP is revised, the 
MCAI does not require recording AD compliance on a continued basis each 
time a task in the revised AMP is performed. Because the AMP is not 
required for U.S. operators and the ALS specified in the MCAI includes 
additional tasks that do not address the unsafe condition, this AD 
establishes a life limit for the affected propeller gearbox tooth belt 
by requiring that it be removed from service after 5 years. Operators 
are required to record AD compliance each time an affected propeller 
gearbox tooth belt reaches its life limit and is replaced.
    Stemme Service Bulletin Doc. No. P062-980049, Revision 00, dated 
May 27, 2020, requires reporting information to Stemme AG, and this AD 
does not.

Costs of Compliance

    The FAA estimates that this AD affects 3 gliders of U.S. registry. 
The FAA estimates that it will take 4 work hours to replace the 
propeller gearbox tooth belt and require a part costing $300. The 
average labor rate is $85 per work hour. Based on these figures, the 
FAA estimates the cost to replace the propeller gearbox tooth belt on 
U.S. operators to be $1,920 or $640 per glider, every 5 years.

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. 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 
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(g), 40113, 44701.

[[Page 3928]]

Sec.  39.13  [Amended]

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

2022-03-07 Stemme AG: Amendment 39-21924; Docket No. FAA-2021-1010; 
Project Identifier MCAI-2020-00807-G.

(a) Effective Date

    This airworthiness directive (AD) is effective March 2, 2022.

(b) Affected ADs

    None.

(c) Applicability

    This AD applies to Stemme AG TSA-M Model S6 and S6-RT gliders, 
all serial numbers, certificated in any category, with a propeller 
gearbox tooth belt marked ``Synchroforce Carbon'' installed.

(d) Subject

    Joint Aircraft System Component (JASC) Code 6100, Propeller 
System.

(e) Unsafe Condition

    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 a new version of 
the propeller gearbox tooth belt with a reduced life limit. The FAA 
is issuing this AD to prevent a propeller gearbox tooth belt 
remaining in service beyond its fatigue life. The unsafe condition, 
if not addressed, could result in failure of the propeller gearbox 
tooth belt and reduced control of the glider.

(f) Compliance

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

(g) Required Actions

    Before the propeller gearbox tooth belt accumulates 5 years 
since installation on a glider or within 30 days after the effective 
date of this AD, whichever occurs later, and thereafter at intervals 
not to exceed 5 years, remove the propeller gearbox tooth belt from 
service and install a propeller gearbox tooth belt with zero hours 
time-in-service.

(h) 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 certification office, send it to the 
attention of the person identified in paragraph (i)(1) of this AD 
and email to: [email protected].
    (2) 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) 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; email: 
[email protected].
    (2) Refer to European Union Aviation Safety Agency (EASA) AD 
2020-0140, dated June 23, 2020, for more information. You may 
examine the EASA AD in the AD docket at https://www.regulations.gov 
by searching for and locating Docket No. FAA-2021-1010.

(j) Material Incorporated by Reference

    None.

    Issued on January 20, 2022.
Lance T. Gant,
Director, Compliance & Airworthiness Division, Aircraft Certification 
Service.
[FR Doc. 2022-01479 Filed 1-25-22; 8:45 am]
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