[Federal Register Volume 63, Number 54 (Friday, March 20, 1998)]
[Proposed Rules]
[Pages 13581-13583]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 98-7250]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 98-CE-09-AD]
RIN 2120-AA64


Airworthiness Directives; Glaser-Dirks Flugzeugbau GmbH Model DG-
500M Gliders

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: This document proposes to adopt a new airworthiness directive 
(AD) that would apply to Glaser-Dirks Flugzeugbau GmbH (Glaser-Dirks) 
Model DG-500M gliders. The proposed AD would require installing a 
rudder gap seal and modifying the cooling liquid reservoir mount. The 
proposed AD is the result of mandatory continuing airworthiness 
information (MCAI) issued by the airworthiness authority for Germany. 
The actions specified by the proposed AD are intended to prevent rudder 
vibrations caused by flow separation at the rudder gap, which could 
result in flutter with consequent loss of rudder control.

DATES: Comments must be received on or before April 17, 1998.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Central Region, Office of the Regional Counsel, 
Attention: Rules Docket No. 98-CE-09-AD, Room 1558, 601 E. 12th Street, 
Kansas City, Missouri 64106. Comments may be inspected at this location 
between 8 a.m. and 4 p.m., Monday through Friday, holidays excepted.
    Service information that applies to the proposed AD may be obtained 
from DG Flugzeugbau GmbH, Postfach 4120, D-76625 Bruchsal 4, Germany; 
telephone: +49 7257-89-0; facsimile: +49 7257-8922. This information 
also may be examined at the Rules Docket at the address above.

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

SUPPLEMENTARY INFORMATION:

Comments Invited

    Interested persons are invited to participate in the making of the 
proposed rule by submitting such written data, views, or arguments as 
they may desire. Communications should identify the Rules Docket number 
and be submitted in triplicate to the address specified above. All 
communications received on or before the closing date for comments, 
specified above, will be considered before taking action on the 
proposed rule. The proposals contained in this notice may be changed in 
light of the comments received.
    Comments are specifically invited on the overall regulatory, 
economic, environmental, and energy aspects of the proposed rule. All 
comments submitted will be available, both before and after the closing 
date for comments, in the Rules Docket for examination by interested 
persons. A report that summarizes each FAA-public contact concerned 
with the substance of this proposal will be filed in the Rules Docket.
    Commenters wishing the FAA to acknowledge receipt of their comments 
submitted in response to this notice must submit a self-addressed, 
stamped postcard on which the following statement is made: ``Comments 
to Docket No. 98-CE-09-AD.'' The postcard will be date stamped and 
returned to the commenter.

Availability of NPRMs

    Any person may obtain a copy of this NPRM by submitting a request 
to the FAA, Central Region, Office of the Regional Counsel, Attention: 
Rules Docket No. 98-CE-09-AD, Room 1558, 601 E. 12th Street, Kansas 
City, Missouri 64106.

Discussion

    The Luftfahrt-Bundesamt (LBA), which is the airworthiness authority 
for Germany, recently notified the FAA that an unsafe condition may 
exist on all Glaser-Dirks Model DG-500M gliders. The LBA reports that 
rudder vibrations could occur at high speeds. These vibrations are 
caused by flow separation at the rudder gap. This condition was 
detected during high speed flight tests.
    These conditions, if not corrected, could result in flutter with 
consequent loss of rudder control.

Relevant Service Information

    Glaser-Dirks has issued Technical Note (TN) No. 843/5, dated 
November 30, 1992, which specifies installing a rudder gap seal and 
modifying the cooling liquid reservoir mount. Procedures for installing 
the rudder gap seal are included in the applicable maintenance manual, 
and procedures for modifying the cooling liquid reservoir mount are 
included in Glaser-

[[Page 13582]]

Dirks Working Instruction No. 1 for TN 843/5, dated November 5, 1992.
    The LBA classified this service bulletin as mandatory and issued 
German AD 93-010 Glaser-Dirks, dated January 5, 1993, in order to 
assure the continued airworthiness of these airplanes in Germany.

The FAA's Determination

    This airplane model is manufactured in Germany and is type 
certificated for operation in the United States under the provisions of 
Sec. 21.29 of the Federal Aviation Regulations (14 CFR 21.29) and the 
applicable bilateral airworthiness agreement. Pursuant to this 
bilateral airworthiness agreement, the LBA has kept the FAA informed of 
the situation described above.
    The FAA has examined the findings of the LBA; reviewed all 
available information, including the service information referenced 
above; and determined that AD action is necessary for products of this 
type design that are certificated for operation in the United States.

Explanation of the Provisions of the Proposed AD

    Since an unsafe condition has been identified that is likely to 
exist or develop in other Glaser-Dirks Model DG-500M gliders of the 
same type design registered in the United States, the FAA is proposing 
AD action. The proposed AD would require installing a rudder gap seal 
and modifying the cooling liquid reservoir mount. Accomplishment of the 
proposed installation would be required in accordance with the 
maintenance manual. Accomplishment of the proposed modification would 
be required in accordance with Glaser-Dirks Working Instruction No. 1 
for TN 843/5, dated November 5, 1992, as referenced in Glaser-Dirks TN 
No. 843/5, dated November 30, 1992.

Compliance Time of the Proposed AD

    Although the rudder vibrations identified in this proposed AD occur 
during flight, this unsafe condition is not a result of the number of 
times the glider is operated. The chance of this situation occurring is 
the same for a glider with 10 hours time-in-service (TIS) as it is for 
a glider with 500 hours TIS. For this reason, the FAA has determined 
that a compliance based on calendar time should be utilized in the 
proposed AD in order to assure that the unsafe condition is addressed 
on all gliders in a reasonable time period.

Cost Impact

    The FAA estimates that 5 gliders in the U.S. registry would be 
affected by the proposed AD, that it would take approximately 4 
workhours per airplane to accomplish the proposed action, and that the 
average labor rate is approximately $60 an hour. Parts cost 
approximately $40 per glider. Based on these figures, the total cost 
impact of the proposed AD on U.S. operators is estimated to be $1,400, 
or $280 per glider.

Regulatory Impact

    The regulations proposed herein would not have substantial direct 
effects 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. Therefore, in 
accordance with Executive Order 12612, it is determined that this 
proposal would not have sufficient federalism implications to warrant 
the preparation of a Federalism Assessment.
    For the reasons discussed above, I certify that this action (1) is 
not a ``significant regulatory action'' under Executive Order 12866; 
(2) is not a ``significant rule'' under DOT Regulatory Policies and 
Procedures (44 FR 11034, February 26, 1979); and (3) if promulgated, 
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. A copy of the draft regulatory evaluation 
prepared for this action has been placed in the Rules Docket. A copy of 
it may be obtained by contacting the Rules Docket at the location 
provided under the caption ADDRESSES.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Safety.

The Proposed Amendment

    Accordingly, pursuant to the authority delegated to me by the 
Administrator, the Federal Aviation Administration proposes to amend 
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. Section 39.13 is amended by adding a new airworthiness directive 
(AD) to read as follows:

Glaser-Dirks Flugzeugbau GMBH:  Docket No. 98-CE-09-AD.

    Applicability: Model DG-500M gliders, all serial numbers, 
certificated in any category.

    Note 1: This AD applies to each glider 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 gliders 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 (d) 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 the unsafe condition has not been 
eliminated, the request should include specific proposed actions to 
address it.

    Compliance: Required within the next 3 calendar months after the 
effective date of this AD, unless already accomplished.
    To prevent rudder vibrations caused by flow separation at the 
rudder gap, which could result in flutter with consequent loss of 
rudder control, accomplish the following:
    (a) Install a rudder gap seal in accordance with the 
instructions in the maintenance manual, as referenced in Glaser-
Dirks Technical Note (TN) No. 843/5, dated November 30, 1992.
    (b) Modify the cooling liquid reservoir mount in accordance with 
Glaser-Dirks Working Instruction No. 1 for TN 843/5, dated November 
5, 1992, as referenced in Glaser-Dirks TN No. 843/5, dated November 
30, 1992.
    (c) Special flight permits may be issued in accordance with 
sections 21.197 and 21.199 of the Federal Aviation Regulations (14 
CFR 21.197 and 21.199) to operate the glider to a location where the 
requirements of this AD can be accomplished.
    (d) An alternative method of compliance or adjustment of the 
compliance time that provides an equivalent level of safety may be 
approved by the Manager, Small Airplane Directorate, FAA, 1201 
Walnut, suite 900, Kansas City, Missouri 64106. The request shall be 
forwarded through an appropriate FAA Maintenance Inspector, who may 
add comments and then send it to the Manager, Small Airplane 
Directorate.

    Note 2: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the Small Airplane Directorate.

    (e) Questions or technical information related to Glaser-Dirks 
Technical Note No. 843/5, dated November 30, 1992, should be 
directed to DG Flugzeugbau GmbH, Postfach 4120, D-76625 Bruchsal 4, 
Germany; telephone: +49 7257-89-0; facsimile: +49 7257-8922. This 
service information may be examined at the FAA, Central Region, 
Office of the Regional Counsel, Room 1558, 601 E. 12th Street, 
Kansas City, Missouri 64106.


[[Page 13583]]


    Note 3: The subject of this AD is addressed in German AD 93-010, 
dated January 5, 1993.

    Issued in Kansas City, Missouri, on March 11, 1998.
Michael Gallagher,
Manager, Small Airplane Directorate, Aircraft Certification Service.
[FR Doc. 98-7250 Filed 3-19-98; 8:45 am]
BILLING CODE 4910-13-U