AD 98-7250

[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-

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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.

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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