[Federal Register Volume 65, Number 144 (Wednesday, July 26, 2000)]
[Rules and Regulations]
[Pages 45835-45837]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 00-18597]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 99-CE-25-AD; Amendment 39-11832; AD 2000-15-03]
RIN 2120-AA64


Airworthiness Directives; Stemme GmbH & Co. KG Models S10-V and 
S10-VT Sailplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule; request for comments.

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SUMMARY: This amendment adopts a new airworthiness directive (AD) that 
applies to Stemme GmbH & Co. KG (Stemme) Models S10-V and S10-VT 
sailplanes. This AD supersedes AD 98-15-24, which currently requires 
replacing the propeller blade suspension forks with parts of improved 
design on Stemme S10-V sailplanes. This AD requires you to remove the 
propeller blade suspension forks, exchange them with the manufacturer 
for improved design forks, and install the improved design propeller 
blade suspension forks. This AD is the result of analysis that shows 
that the existing propeller blade suspension forks are currently 
cracking more rapidly than originally projected. The actions specified 
by this AD are intended to prevent certain propeller blade suspension 
forks from cracking, which could result in the loss of a propeller 
blade during flight with possible lateral imbalance and loss of thrust.

DATES: This AD becomes effective on August 4, 2000.
    The Director of the Federal Register approved the incorporation by 
reference of certain publications listed in the regulation as of August 
4, 2000.
    The Federal Aviation Administration (FAA) must receive any comments 
on this rule on or before August 25, 2000.

ADDRESSES: Submit comments in triplicate to the FAA, Central Region, 
Office of the Regional Counsel, Attention: Rules Docket No. 99-CE-25-
AD, 901 Locust, Room 506, Kansas City, Missouri 64106.
    You may get the service information referenced in this AD from 
Stemme GmbH & Co. KG, Gustav-Meyer-Allee 25, D-13355 Berlin, Germany; 
telephone: 49.33.41.31.11.70; facsimile: 49.33.41.31.11.73.
    You may examine this information at FAA, Central Region, Office of 
the Regional Counsel, Attention: Rules Docket No. 99-CE-25-AD, 901 
Locust, Room 506, Kansas City, Missouri 64106; or at the Office of the 
Federal Register, 800 North Capitol Street, NW., suite 700, Washington, 
DC.

FOR FURTHER INFORMATION CONTACT: Mr. Mike Kiesov, Aerospace Engineer, 
FAA, Small Airplane Directorate, 1201 Walnut, suite 900, Kansas City, 
Missouri 64106; telephone: (816) 426-6934; facsimile: (816) 426-2169.

SUPPLEMENTARY INFORMATION:

Events Leading to the Issuance of This AD

    Has FAA taken any action to this point? An incident where the 
propeller blade suspension fork failed during flight on a Stemme Model 
S10-V sailplane caused FAA to issue AD 98-15-24, Amendment 39-10674. 
This AD was published in the Federal Register on July 23, 1998 (63 FR 
39484), and required replacing the propeller blade suspension fork, 
distance ring, and nut with parts of improved design on Stemme Model 
S10-V sailplanes.
    After issuing AD 98-15-24, the Luftfahrt-Bundesamt (LBA), which is 
the airworthiness authority for Germany, notified FAA that the improved 
design propeller blade suspension fork (part number (P/N) A09-10AP-V08) 
on one of the affected sailplanes failed during flight. Analysis of 
this propeller blade revealed a fracture located at the end of the 
threaded fastening pin. This caused FAA to issue a proposal to amend 
part 39 of the Federal Aviation Regulations (14 CFR part 39) to include 
an AD that would apply to all Stemme Models S10-V and S10-VT sailplanes 
that incorporate a certain propeller blade suspension fork. This 
proposal was published in the Federal Register as a notice of proposed 
rulemaking (NPRM) on July 21, 1999 (64 FR 39100).
    The NPRM proposed to supersede AD 98-15-24 with a new AD that would 
require you to repetitively exchange (through the manufacturer) the P/N 
A09-10AP-V08 (or FAA-approved equivalent part number) propeller blade 
suspension fork for a fork that has passed X-ray crack testing 
requirements.
    Was the public invited to comment on the NPRM? The FAA invited 
interested persons to participate in the making of the amendment. We 
received no comments on the proposed rule or the cost impact upon the 
public. However, the LBA has informed us that the existing propeller 
blade suspension forks are currently cracking more rapidly than 
originally projected.
    Is there a propeller blade suspension fork design that is better 
than the current design? Stemme has worked

[[Page 45836]]

with the LBA in designing an improved propeller blade suspension fork 
(P/N 10AP-V88) along with a modification to the propeller gearbox 
suspension.
    Has the manufacturer issued service information? Stemme issued 
Service Bulletin No. A31-10-051, Amendment-Index 05.a, dated December 
6, 1999. This service bulletin specifies procedures for accomplishing 
the propeller blade suspension fork replacement and propeller gearbox 
suspension modification, which were described previously.

The FAA's Determination and Followup Action

    What have we decided? After careful review of all available 
information related to the subject presented above, including the 
above-referenced comments, FAA has determined that:

--the propeller blade suspension fork replacement and propeller gearbox 
suspension modification should be accomplished on all Stemme Models 
S10-V and S10-VT sailplanes; and
--AD action should be taken to prevent certain propeller blade 
suspension forks from cracking, which could result in the loss of a 
propeller blade during flight with possible lateral imbalance and loss 
of thrust.

    What is our next action? Since the improved design propeller blade 
suspension fork replacement and propeller gearbox suspension 
modification requirements increase the burden on the owners/operators 
of the affected sailplanes over what was proposed in the NPRM, we are 
required to allow the public additional time to comment on the AD.
    Because of the low hours TIS on the sailplanes where the cracked 
propeller blade suspension forks were found, FAA finds that notice and 
opportunity for public prior comment are impracticable. Therefore, good 
cause exists for making this amendment effective in less than 30 days.
    What does this AD require? This AD requires you to:

--remove the propeller blade suspension forks;
--exchange them with the manufacturer for improved design forks; and
--install the improved design propeller blade suspension forks.

    Accomplishment procedures are specified in Stemme Service Bulletin 
No. A31-10-051, Amendment-Index 05.a, dated December 6, 1999.

Comments Invited

    Can I comment on this AD? This action is in the form of a final 
rule and the FAA did not precede it with notice and opportunity for 
public comment. FAA is issuing this final rule without prior notice 
because an urgent situation concerning safety of flight exists. 
However, FAA is still inviting comments on this rule. You may submit 
whatever written data, views, or arguments you choose. You need to 
include the rule's docket number and submit your comments in triplicate 
to the address specified under the caption ADDRESSES. The FAA will 
consider all comments received on or before the closing date. We may 
amend this rule in light of comments received.
    How can we communicate more clearly with you? The FAA is reviewing 
the writing style we currently use in regulatory documents, in response 
to the Presidential memorandum of June 1, 1998. That memorandum 
requires federal agencies to communicate more clearly with the public. 
We are interested in your comments on the ease of understanding this 
document, and any other suggestions you might have to improve the 
clarity of FAA communications that affect you. You can get more 
information about the Presidential memorandum and the plain language 
initiative at http://www.faa.gov/language/.
    The FAA specifically invites comments on the overall regulatory, 
economic, environmental, and energy aspects of the rule that might 
suggest a need to modify the rule. You may examine all comments we 
receive before and after the closing date of the rule in the Rules 
Docket. We will file a report in the Rules Docket that summarizes each 
FAA contact with the public that concerns the substantive parts of this 
AD.
    How can I be sure the FAA receives my comment? If you want us to 
acknowledge the receipt of your comments, you must include a self-
addressed, stamped postcard. On the postcard, write ``Comments to 
Docket No. 99-CE-25-AD.'' We will date stamp and mail the postcard back 
to you.

Regulatory Impact

    How does this AD impact relations between Federal and State 
governments? These regulations 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. The FAA has 
determined that this final rule does not have federalism implications 
under Executive Order 13132.
    How does this action involve an emergency situation? The FAA has 
determined that this regulation is an emergency regulation that must be 
issued immediately to correct an unsafe condition in aircraft, and is 
not a significant regulatory action under Executive Order 12866. We 
have determined that this action involves an emergency regulation under 
DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 
1979). If FAA determines that this emergency regulation otherwise would 
be significant under DOT Regulatory Policies and Procedures, we will 
prepare a final regulatory evaluation. You may obtain a copy of the 
evaluation (if required) from the Rules Docket.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Incorporation by 
reference, Safety.

Adoption of the Amendment

    Accordingly, under the authority delegated to me by the 
Administrator, the Federal Aviation Administration amends part 39 of 
the Federal Aviation Regulations (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. FAA amends section 39.13 by removing Airworthiness Directive 
(AD) 98-15-24, Amendment 39-10674 (39484, July 23, 1998), and by adding 
a new AD to read as follows:

    2000-15-03 Stemme GmbH & Co. KG: Amendment 39-11832; Docket No. 
99-CE-25-AD.

    (a) What sailplanes are affected by this AD? This AD applies to 
Models S10-V and S10-VT sailplanes, all serial numbers, certificated 
in any category.
    (b) Who must comply with this AD? Anyone who wishes to operate 
any of the above sailplanes on the U.S. Register must comply with 
this AD.
    (c) What problem does this AD address? The actions of this AD 
are intended to prevent certain propeller blade suspension forks 
from cracking, which could result in the loss of a propeller blade 
during flight with possible lateral imbalance and loss of thrust.
    (d) What actions must I accomplish to address this problem? To 
address this problem, you must accomplish the following:

[[Page 45837]]



------------------------------------------------------------------------
           Action                     When               Procedures
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(1) Removal, exchange, and    All actions within    (1) Accomplish, each
 reinstallation:               10 hours time-in-     action accordingly,
                               service as (TIS)      as follows:
                               after August 4,
                               2000 (the effective
                               date of this AD).
    (i) Remove from the                                (i) Removal: In
     sailplane any propeller                            accordance with
     blade suspension fork                              the instructions
     that is not part number                            in the
     (P/N) 10AP-V88.                                    maintenance
                                                        manual.
    (ii) Exchange (through                             (ii) Exchange: In
     the manufacturer) this                             accordance with
     propeller blade                                    the instructions
     suspension fork for a                              in Stemme
     propeller blade                                    Service Bulletin
     suspension fork that is                            No. A31-10-051,
     P/N 10AP-V88..                                     Amendment-Index:
                                                        05.a, dated
                                                        December 6,
                                                        1999.
    (iii) Install the                                  (iii)
     improved design                                    Installation: In
     propeller blade                                    accordance with
     suspension fork (P/N                               the instructions
     10AP-V88) on the                                   in the
     sailplane..                                        maintenance
                                                        manual.
(2) Modify the propeller      Within 10 hours TIS   In accordance with
 gearbox suspension..          after August 4,       the instructions in
                               2000 (the effective   Stemme Service
                               date of this AD)..    Bulletin No. A31-10-
                                                     051, Amendment-
                                                     Index: 05.a, dated
                                                     December 6, 1999.
(3) Dynamically balance the   Prior to further      In accordance with
 propeller..                   flight after the      the instructions in
                               installation and      Stemme Procedural
                               modification          Instruction A17-
                               required in           10AP-V/2-E
                               paragraphs            ``Dynamic balancing
                               (d)(1)(i),            of the Stemme S10
                               (d)(1)(ii),           powered glider
                               (d)(1)(iii), and      propeller in the
                               (d)(2) of this AD..   S10-V and S10-VT
                                                     models.''
(4) Do not install a          As of August 4, 2000  Not Applicable.
 propeller blade suspension    (the effective date
 fork that is not P/N 10AP-    of this AD).
 V88 on any affected
 sailplane.
------------------------------------------------------------------------

    (e) Can I comply with this AD in any other way?
    (1) You may use an alternative method of compliance or adjust 
the compliance time if:
    (i) Your alternative method of compliance provides an equivalent 
level of safety; and
    (ii) The Manager, Small Airplane Directorate, approves your 
alternative. Submit your request through an FAA Principal 
Maintenance Inspector, who may add comments and then send it to the 
Manager, Small Airplane Directorate.
    (2) Alternative methods of compliance that were approved in 
accordance with AD 98-15-24 are not considered approved in 
accordance with this AD.

    Note: This AD applies to each sailplane identified in the 
preceding applicability provision, regardless of whether it has been 
modified, altered, or repaired in the area subject to the 
requirements of this AD. For sailplanes that have been modified, 
altered, or repaired so that the performance of the requirements of 
this AD is affected, the owner/operator must request approval for an 
alternative method of compliance in accordance with paragraph (e) of 
this AD. The request should include an assessment of the effect of 
the modification, alteration, or repair on the unsafe condition 
addressed by this AD; and, if you have not eliminated the unsafe 
condition, specific actions you propose to address it.

    (f) Where can I get information about any already-approved 
alternative methods of compliance? Contact Mike Kiesov, Aerospace 
Engineer, FAA, Small Airplane Directorate, 1201 Walnut, suite 900, 
Kansas City, Missouri 64106; telephone: (816) 426-6934; facsimile: 
(816) 426-2169.
    (g) What if I need to fly the sailplane to another location to 
comply with this AD? The FAA can issue a special flight permit under 
sections 21.197 and 21.199 of the Federal Aviation Regulations (14 
CFR 21.197 and 21.199) to operate your sailplane to a location where 
you can accomplish the requirements of this AD.
    (h) Are any service bulletins incorporated into this AD by 
reference?
    (1) Actions required by this AD must be done as follows:
    (i) Modification: In accordance with Stemme Service Bulletin No. 
A31-10-051, Amendment-Index: 05.a, dated December 6, 1999; and
    (ii) Balancing: In accordance with Stemme Procedural Instruction 
A17-10AP-V/2-E ``Dynamic balancing of the Stemme S10 powered glider 
propeller in the S10-V and S10-VT models'', August 24, 1999.
    (2) The Director of the Federal Register approved this 
incorporation by reference under 5 U.S.C. 552(a) and 1 CFR part 51.
    (3) You can get copies from Stemme GmbH & Co. KG, Gustav-Meyer-
Allee 25, D-13355 Berlin, Germany; telephone: 49.33.41.31.11.70; 
facsimile: 49.33.41.31.11.73.
    (4) You can look at copies at FAA, Central Region, Office of the 
Regional Counsel, 901 Locust, Room 506, Kansas City, Missouri; or at 
the Office of the Federal Register, 800 North Capitol Street, NW, 
suite 700, Washington, DC.
    (i) When does this amendment become effective? This amendment 
becomes effective on August 4, 2000.

    Issued in Kansas City, Missouri, on July 17, 2000.
Marvin R. Nuss,
Acting Manager, Small Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 00-18597 Filed 7-25-00; 8:45 am]
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