04-5264. Airworthiness Directives; LET a.s. Model Blanik L-13 AC Sailplanes

AGENCY:

Federal Aviation Administration (FAA), DOT.

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

The FAA proposes to adopt a new airworthiness directive (AD) for all LET a.s. (formerly LET n.p.) (LET) Model Blanik L-13 AC sailplanes. This proposed AD would 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. This proposed AD is the result of mandatory continuing airworthiness information (MCAI) issued by the airworthiness authority for the Czech Republic. We are issuing this proposed AD to detect and correct cracks in the bedding of the front and rear control levers, which could result in failure of the bridge of controls for the sailplane. This failure could lead to loss of sailplane control.

DATES:

We must receive any comments on this proposed AD by April 16, 2004.

ADDRESSES:

Use one of the following to submit comments on this proposed AD:

• By mail: FAA, Central Region, Office of the Regional Counsel, Attention: Rules Docket No. 2003-CE-57-AD, 901 Locust, Room 506, Kansas City, Missouri 64106.
• By fax: [phone].
• By e-mail: [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.

You may get the service information identified in this proposed AD from LET n.p., Kunovice 686 04, Czech Republic; telephone: [phone]; facsimile: [phone].

You may view the AD docket at FAA, Central Region, Office of the Regional Counsel, Attention: Rules Docket No. 2003-CE-57-AD, 901 Locust, Room 506, Kansas City, Missouri 64106. Office hours are 8 a.m. to 4 p.m., Monday through Friday, except Federal holidays.

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? We invite you to submit any written relevant data, views, or arguments regarding this proposal. Send your comments to an address listed under ADDRESSES. Include “AD Docket No. 2003-CE-57-AD” in the subject line of your comments. If you want us to acknowledge receipt of your mailed comments, send us a self-addressed, stamped postcard with the docket number written on it. We will date-stamp your postcard and mail it back to you.

Are there any specific portions of this proposed AD I should pay attention to? We specifically invite comments on the overall regulatory, economic, environmental, and energy aspects of this proposed AD. If you contact us through a nonwritten communication and that contact relates to a substantive part of this proposed AD, we will summarize the contact and place the summary in the docket. We will consider all comments received by the closing date and may amend this proposed AD in light of those comments and contacts.

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 bridge of controls (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 bridge of controls for the sailplane could lead to loss of sailplane control.

Is there service information that applies to this subject? LET has issued Letecke Zavody Mandatory Bulletin No.: L13/095a, dated October 18, 2001.

What are the provisions of this service information? The service bulletin includes procedures for:

—Inspecting the bedding of the front and rear control levers (Drawing (DWG) No. A741 215N and DWG No. A741 210N) for cracks; and

—if any cracks are found, replacing with parts found free of cracks.

What action did the CAA take? The CAA classified this service bulletin as mandatory and issued Czech AD Number CAA-AD-090/2001, dated October 25, 2001, to ensure the continued airworthiness of these sailplanes in the Czech Republic.

Did the CAA inform the United States under the bilateral airworthiness agreement? These LET Model Blanik L-13 AC sailplanes are manufactured in the Czech Republic 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.

Under this bilateral airworthiness agreement, the CAA has kept us informed of the situation described above.

FAA's Determination and Requirements of This Proposed AD

What has FAA decided? We have examined the CAA's findings, reviewed all available information, and determined that AD action is necessary for products of this type design that are certificated for operation in the United States.

Since the unsafe condition described previously is likely to exist or develop on other LET Model Blanik L-13 AC sailplanes of the same type design that are registered in the United States, we are proposing AD action to detect and correct cracks in the bedding of the front and rear control levers, which could result in failure of the bridge of controls for the sailplane.

What would this proposed AD require? This proposed AD would require you to incorporate the actions in the previously-referenced service bulletin.

How does the revision to 14 CFR part 39 affect this proposed AD? On July 10, 2002, we 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 relates to altered products, special flight permits, and alternative methods of compliance. 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.

Costs of Compliance

How many sailplanes 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 accomplish this proposed inspection:

Labor cost	Parts cost	Total cost per sailplane	Total cost on U.S. operators
1 workhour × $65 per hour = $65	Not Applicable.	$65	$65 × 5 = $325

Since the replacement of parts will vary based on the damage found as a result of the proposed inspection, we are unable to estimate the costs to do any necessary replacements.

Regulatory Findings

Would this proposed AD impact various entities? We have determined that this proposed AD would not have federalism implications under Executive Order 13132. This proposed AD 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.

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

1. Is not a “significant regulatory action” under Executive Order 12866;

2. Is not a “significant rule” under the DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); and

3. 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.

We prepared a summary of the costs to comply with this proposed AD and placed it in the AD Docket. You may get a copy of this summary by sending a request to us at the address listed under ADDRESSES. Include “AD Docket No. 2003-CE-57-AD” in your request.

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 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.: 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 April 16, 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, 988604, 008605, and 008606, that are certificated in any category.

What Is the Unsafe Condition Presented in This AD?

(d) This AD is the result of mandatory continuing airworthiness information (MCAI) issued by the airworthiness authority for the Czech Republic. The actions specified in this AD are intended to detect and correct cracks in the bedding of the front and rear control levers, which could result in failure of the bridge of controls 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) Inspect the bedding of the front and rear control levers (Drawing (DWG) No. A741 215N and DWG No. A741 210N) for cracks	Within the next 25 hours time-in-service (TIS) after the effective date of this AD, unless already done. Repetitively inspect thereafter at every 25 hours TIS	Follow the WORK PROCEDURE paragraph of LET Letecke Zavody Mandatory Bulletin No.: L13/095a, dated October 18, 2001.
(2) If any cracks are found during any inspection required by paragraph (e)(1) of this AD, replace with parts shown free of cracks. Repetitive inspections are still required	Before further flight after any inspection required by paragraph (e)(1) of this AD.	Follow the WORK PROCEDURE paragraph of LET Letecke Zavody Mandatory Bulletin No.: L13/095a, dated October 18, 2001, and the applicable sailplane maintenance manual.

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 March 2, 2004.

Sandra J. Campbell,

Acting Manager, Small Airplane Directorate, Aircraft Certification Service.