AD 98-12383

[Federal Register Volume 63, Number 90 (Monday, May 11, 1998)] [Proposed Rules] [Pages 25787-25789] From the Federal Register Online via the Government Publishing Office [www.gpo.gov] [FR Doc No: 98-12383]

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 97-CE-128-AD] RIN 2120-AA64

Airworthiness Directives; Stemme GmbH & Co. KG Model S10-V Sailplanes

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 certain Stemme GmbH & Co. KG (Stemme) Model S10-V sailplanes. The proposed action would require replacing the propeller blade suspension forks with parts of improved design. 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 propeller suspension fork failure caused by design deficiency, which, if not corrected, could result in loss of a propeller blade and loss of sailplane controllability.

DATES: Comments must be received on or before June 15, 1998.

ADDRESSES: Submit comments in triplicate to the Federal Aviation Administration (FAA), Central Region, Office of the Regional Counsel, Attention: Rules Docket No. 97-CE-128-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 Stemme GmbH & Co. KG, Gustav-Meyer-Allee 25, D-13355 Berlin, Federal Republic of Germany. 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. 97-CE-128-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. 97-CE-128-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 certain Stemme S10-V sailplanes. The LBA reports one incident of a failure of the propeller blade suspension fork during flight, which caused loss of sailplane controllability. Investigation of this incident revealed that the thread end groove area of the propeller blade suspension fork does not have an adequate design. This inadequate design causes fatigue of the propeller blade suspension fork to the point of failure. This condition, if not corrected, could result in loss of the propeller blade

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during flight and possible loss of sailplane controllability.

Relevant Service Information

Stemme has issued Service Bulletin No. A31-10-020, Am-index: 02.a, dated October 7, 1996, which specifies procedures for replacing the propeller blade suspension fork, part number (P/N) 10AP-V08, distance ring, P/N 10AP-V05, and nut, P/N 10AP-V06, with a new propeller blade suspension fork of improved design, P/N A09-10AP-V08, a new distance ring of improved design, P/N A09-10AP-05, and a new nut of improved design, P/N A09-10AP-V06. The LBA classified this service bulletin as mandatory and issued German AD 95-177/2, dated January 30, 1997, in order to assure the continued airworthiness of these sailplanes in Germany.

The FAA's Determination

This sailplane 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 Stemme Model S10-V sailplanes of the same type design registered in the United States, the proposed AD would require replacing the propeller blade suspension fork, distance ring, and nut with parts of improved design. Accomplishment of the proposed installation would be in accordance with Stemme GmbH & Co. KG Service Bulletin No. A31-10-020, Am-index: 02.a, dated October 7, 1996.

Cost Impact

The FAA estimates that 7 sailplanes in the U.S. registry would be affected by the proposed AD, that it would take 6 hours per sailplane to accomplish the proposed action, and that the average labor rate is approximately $60 an hour. Parts cost approximately $930 per sailplane. Based on these figures, the total cost impact of the proposed AD on U.S. operators is estimated to be $9,030.

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:

Stemme GmbH & Co. KG: Docket No. 97-CE-128-AD.

Applicability: Model S10-V sailplanes (serial numbers (S/N) 14- 002 through 14-026, and converted sailplanes S/N 4-003M through 14- 036M), certificated in any category.

Note 1: 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 (c) 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 upon the accumulation of 100 hours total time-in-service (TIS) on the sailplane propeller or within the next 10 hours TIS after the effective date of this AD, whichever occurs later, unless already accomplished. To prevent propeller suspension fork failure caused by design deficiency, which, if not corrected, could result in loss of a propeller blade and loss of sailplane controllability, accomplish the following: (a) Replace the propeller blade suspension fork, part number (P/ N) 10AP-V08 (or an FAA-approved equivalent P/N), with new P/N A09- 10AP-V08 (or an FAA-approved equivalent P/N), distance ring, P/N 10AP-V05 (or an FAA-approved equivalent P/N), with new P/N A09-10AP- V05 (or an FAA-approved equivalent P/N), and nut, P/N 10AP-V06 (or an FAA-approved equivalent P/N), with new P/N A09-10AP-V06 (or an FAA-approved equivalent part number) in accordance with Stemme GmbH & Co. KG Service Bulletin No. A31-10-020, Am-index: 02.a, dated October 7, 1996. (b) 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 sailplane to a location where the requirements of this AD can be accomplished. (c) An alternative method of compliance or adjustment of the compliance times 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.

(d) Questions or technical information related to pages 3 and 4 of Stemme GmbH & Co. KG Service Bulletin, Modification v.p. propeller/failure blade suspension, No. A31-10-020, Am-index: 02.a, dated October 7, 1996, should be directed to Stemme GmbH & Co. KG, Gustav-Meyer-Allee 25, D-13355 Berlin, Federal Republic of Germany. 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.

Note 3: The subject of this AD is addressed in German AD 95-177/ 2, dated January 30, 1997.

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Issued in Kansas City, Missouri, on May 4, 1998. Marvin R. Nuss, Acting Manager, Small Airplane Directorate, Aircraft Certification Service. [FR Doc. 98-12383 Filed 5-8-98; 8:45 am] BILLING CODE 4910-13-U