04-22581. Airworthiness Directives; LET a.s. Model Blanik L-13 AC Sailplanes

AGENCY:

Federal Aviation Administration, DOT.

ACTION:

Supplemental notice of proposed rulemaking (NPRM); Reopening of the comment period.

SUMMARY:

This document proposes to revise an earlier proposed airworthiness directive (AD) that would apply to all LET a.s. (formerly LET n.p.) (LET) Model Blanik L-13 AC sailplanes. The earlier NPRM would have required you to repetitively inspect the bedding of the front and rear control levers for cracks, and, if any cracks are found, replace with parts found free of cracks. The earlier NPRM resulted from mandatory continuing airworthiness information (MCAI) issued by the airworthiness authority for the Czech Republic. The MCAI is a report of one occurrence of cracks in the attachment of control levers on the control bridge. Since FAA issued the NPRM, FAA has received and evaluated new service information that eliminates the repetitive inspection, requires replacement of parts, and changes the serial number effectivity. Since these actions impose an additional burden over that proposed in the NPRM, we are reopening the comment period to allow the public the chance to comment on these additional actions.

DATES:

The Federal Aviation Administration (FAA) must receive any comments on this proposed rule on or before November 8, 2004.

ADDRESSES:

Submit comments to FAA, Central Region, Office of the Regional Counsel, Attention: Rules Docket No. 2003-CE-57-AD, 901 Locust, Room 506, Kansas City, Missouri 64106. You may view any comments at this location between 8 a.m. and 4 p.m., Monday through Friday, except Federal holidays. You may also send comments electronically to the following address: [e-mail]. Comments sent electronically must contain “Docket No. 2003-CE-57-AD” in the subject line. If you send comments electronically as attached electronic files, the files must be formatted in Microsoft Word 97 for Windows or ASCII text.

You may get service information that applies to this proposed AD from LET a.s., Kunovice 686 04, Czech Republic; telephone: [phone]; facsimile: [phone]. You may also view this information at the Rules Docket at the address above.

FOR FURTHER INFORMATION CONTACT:

Greg Davison, Aerospace Engineer, FAA, Small Airplane Directorate, 901 Locust, Room 301, Kansas City, Missouri 64106; telephone: [phone]; facsimile: [phone].

SUPPLEMENTARY INFORMATION:

Comments Invited

How do I comment on this proposed AD? The FAA invites comments on this proposed rule. You may submit whatever written data, views, or arguments you choose. You need to include the proposed rule's docket number and submit your comments to the address specified under the caption ADDRESSES. We will consider all comments received on or before the closing date. We may amend this proposed rule in light of comments received. Factual information that supports your ideas and suggestions is extremely helpful in evaluating the effectiveness of this proposed AD action and determining whether we need to take additional rulemaking action.

Are there any specific portions of this proposed AD I should pay attention to? The FAA specifically invites comments on the overall regulatory, economic, environmental, and energy aspects of this proposed rule that might suggest a need to modify the rule. You may view 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 contact we have with the public that concerns the substantive parts of this proposed AD.

How can I be sure FAA receives my comment? If you want FAA to acknowledge the receipt of your mailed comments, you must include a self-addressed, stamped postcard. On the postcard, write “Comments to Docket No. 2003-CE-57-AD.” We will date stamp and mail the postcard back to you.

Discussion

What events have caused this proposed AD? The Civil Aviation Authority (CAA), which is the airworthiness authority for the Czech Republic, recently notified FAA that an unsafe condition may exist on certain LET Model Blanik L-13 AC sailplanes. The CAA reports one occurrence of cracks in the attachment of control levers on the control bridge (Drawing No. A71 210N) on a Model Blanik L-13 AC sailplane after 130 hours time-in-service (TIS) of aerobatics. The cracks are due to material fatigue.

What are the consequences if the condition is not corrected? Failure of the control bridge for the sailplane could lead to loss of sailplane control.

Has FAA taken any action to this point? We issued a proposal to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) to include an AD that would apply to all LET a.s. (formerly LET n.p.) (LET) Model Blanik L-13 AC sailplanes. This proposal was published in the Federal Register as a notice of proposed rulemaking (NPRM) on March 9, 2004 (69 FR 10939). The NPRM proposed to require you to repetitively inspect the bedding of the front and rear control levers for cracks, and, if any cracks are found, replace with parts found free of cracks.

You would have to do the proposed actions following Letecke Zavody Mandatory Bulletin No.: L13/095a, dated October 18, 2001.

Was the public invited to comment? The FAA encouraged interested persons to participate in the making of this amendment. We did not receive any comments on the NPRM or our estimate of the cost impact upon the public.

Since issuance of the NPRM, LET has issued the new Letecke Zavody Mandatory Bulletin No.: L13AC/014a, dated July 17, 2003. This service bulletin eliminates the repetitive inspection, requires the replacement of parts, and changes the serial number effectivity.

The CAA has not amended the Czech AD to reflect this service information. However, FAA has evaluated the new service information and determined that the NPRM should be changed to reflect the requirements in the new LET service bulletin.

The Supplemental NPRM

How will the changes to the NPRM impact the public? Proposing to eliminate the repetitive inspection, require the replacement of parts, and changing the serial number effectivity goes beyond the scope of what was already proposed and imposes an additional burden on the public. Therefore, we are issuing a supplemental NPRM and reopening the comment period to allow the public additional time to comment.

How does the revision to 14 CFR part 39 affect this proposed AD? On July 10, 2002, FAA published a new version of 14 CFR part 39 (67 FR 47997, July 22, 2002), which governs FAA's AD system. This regulation now includes material that relate to special flight permits, alternative methods of compliance, and altered products. This material previously was included in each individual AD. Since this material is included in 14 CFR part 39, we will not include it in future AD actions.

Cost Impact

How many airplanes would this proposed AD impact? We estimate that this proposed AD affects 5 sailplanes in the U.S. registry.

What would be the cost impact of this proposed AD on owners/operators of the affected sailplanes? We estimate the following costs to do the proposed replacement:

Labor cost	Parts cost	Total cost per airplane	Total cost on U.S. operators
7 workhours × $65 per hour = $455	$2,000	$2,455	$12,275

Regulatory Impact

Would this proposed AD impact various entities? The regulations proposed herein would 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, it is determined that this proposed rule would not have federalism implications under Executive Order 13132.

Would this proposed AD involve a significant rule or regulatory action? For the reasons discussed above, I certify that this proposed 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, under 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.

§ 39.13

[Amended]

2. The FAA amends § 39.13 by adding the following new airworthiness directive (AD):

LET a.s. (Formerly LET n.p.): Docket No. 2003-CE-57-AD.

When Is the Last Date I Can Submit Comments on This Proposed AD?

(a) We must receive comments on this proposed airworthiness directive (AD) by November 8, 2004.

What Other ADs Are Affected by This Action?

(b) None.

What Sailplanes Are Affected by This AD?

(c) This AD affects Model Blanik L-13 AC sailplanes, serial numbers 988601, 988603, 008605, 008606, and 028902, that are certificated in any category:

What Is the Unsafe Condition Presented in This AD?

(d) This AD is the result of a report of one occurrence of cracks in the attachment of control levers on the control bridge. The actions specified in this AD are intended to correct cracks in the bedding of the front and rear control levers, which could result in failure of the control bridge for the sailplane. This failure could lead to loss of sailplane control.

What Must I Do To Address This Problem?

(e) To address this problem, you must do the following:

Actions	Compliance	Procedures
(1) Replace the original control bridge (Drawing No. A741 210N) with the new strengthened control column mounting bridge (Drawing No. A740 370N)	Within the next 25 hours time-in-service (TIS) after the effective date of this AD, unless already done	Follow the WORK PROCEDURE paragraph of LET Letecke Zavody Mandatory Bulletin No.: L13AC/014a, dated July 17, 2003.
(2) Do not install any original control bridge (Drawing No. A741 210N)	As of the effective date of this AD	Not Applicable.

May I Request an Alternative Method of Compliance?

(f) You may request a different method of compliance or a different compliance time for this AD by following the procedures in 14 CFR 39.19. Unless FAA authorizes otherwise, send your request to your principal inspector. The principal inspector may add comments and will send your request to the Manager, Standards Office, Small Airplane Directorate, FAA. For information on any already approved alternative methods of compliance, contact Greg Davison, Aerospace Engineer, FAA, Small Airplane Directorate, 901 Locust, Room 301, Kansas City, Missouri 64106; telephone: [phone]; facsimile: [phone].

May I Get Copies of the Documents Referenced in This AD?

(g) You may get copies of the documents referenced in this AD from LET a.s., Kunovice 686 04, Czech Republic; telephone: [phone]; facsimile: [phone]. You may view these documents at FAA, Central Region, Office of the Regional Counsel, 901 Locust, Room 506, Kansas City, Missouri 64106.

Is There Other Information That Relates to This Subject?

(h) Czech Airworthiness Directive CAA-AD-090/2001, dated October 25, 2001, also addresses the subject of this AD.

Issued in Kansas City, Missouri, on October 1, 2004.

Dorenda D. Baker,

Manager, Small Airplane Directorate, Aircraft Certification Service.