Discussion
What events have caused this AD? The Luftfahrt-Bundesamt (LBA), which is the airworthiness authority for Germany, recently notified FAA that an unsafe condition may exist on certain Stemme Model S10 and S10-V sailplanes. The LBA reports that the current design airbrake eyebolts could cause aerodynamic flutter of the upper airbrake straps at high airspeeds. This can cause damage to the airbrake system.
One reported occurrence resulted in flutter of the upper covering straps on the airbrake cover, which resulted in an uncommanded yawing condition and separation of the landing gear door from the sailplane. This caused damage to the horizontal stabilizer.
What are the consequences if the condition is not corrected? This condition, if not corrected, could result in aerodynamic flutter of the upper covering straps on the airbrake cover and damage to the airbrake system and landing gear doors. Continued operation with such damaged components could result in loss of control of the sailplane.
Is there service information that applies to this subject? Stemme has issued Service Bulletin No. A31-10-055 (pages 5 through 8 English translation), dated October 9, 2000. This service bulletin includes procedures for:
- replacing the eyebolts on the airbrake;
- inspecting the airbrake sheets for proper clearance and adjusting, as necessary; and
- inspecting for damage to the landing gear doors and replacing any damaged parts.
What action did LBA take? The LBA classified this service bulletin as mandatory and issued German AD 2000-369, effective November 30, 2000, in order to assure the continued airworthiness of these sailplanes in Germany. Was this in accordance with the bilateral airworthiness agreement? These sailplane models are manufactured in Germany and are type certificated for operation in the United States under the provisions of section 21.29 of the Federal Aviation Regulations (14 CFR 21.29)and the applicable bilateral airworthiness agreement.
Pursuant to this bilateral airworthiness agreement, LBA has kept FAA informed of the situation described above.
The FAA's Determination and an Explanation of the Provisions of this AD
What has FAA decided? The FAA has examined the findings of LBA; reviewed all available information, including the service information referenced above; and determined that:
- the unsafe condition referenced in this document exists or could develop on other Stemme Models S10 and S10-V sailplanes of the same type design;
- the actions specified in the previously-referenced service information (as specified in this AD) should be accomplished on the affected sailplanes; and
- AD action should be taken in order to correct this unsafe condition.
What does this AD require? This AD requires you to accomplish the actions previously specified in accordance with Stemme Service Bulletin No. A31-10-055 (pages 5 through 8 English translation), dated October 9, 2000.
Will I have the opportunity to comment prior to the issuance of the rule? Because the unsafe condition described in this document could result in airbrake system failure with possible loss of control of the sailplane, 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.
Comments Invited
How do I comment on this AD? Although this action is in the form of a final rule and was not preceded by notice and opportunity for public comment, we invite your comments on the 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." We will consider all comments received on or before the closing date specified above. We may amend this rule in light of comments received. Factual information that supports your ideas and suggestions is extremely helpful in evaluating the effectiveness of the AD action and determining whether we need to take additional rulemaking action.
Are there any specific portions of the AD I should pay attention to? 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.
We are 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 whether the style of this document is clear, and anyother 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.plainlanguage.gov.
How can I be sure 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. 2000-CE-81-AD." We will date stamp and mail the postcard back to you.
Regulatory Impact
Does this AD impact various entities? 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. Therefore, FAA has determined that this final rule does not have federalism implications under Executive Order 13132.
Does this AD involve a significant rule or regulatory action? 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. It has been determined further that this action involves an emergency regulation under DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979). If it is determined that this emergency regulation otherwise would be significant under DOT Regulatory Policies and Procedures, a final regulatory evaluation will be prepared and placed in the Rules Docket (otherwise, an evaluation is not required). A copy of it, if filed, may be obtained 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.
39.13 [Amended]
2. FAA amends 39.13 by adding a new airworthiness directive (AD) to read as follows: