Airworthiness Directives; LET Aeronautical Works Model L-13 “Blanik” Sailplanes

AGENCY:

Federal Aviation Administration, DOT.

ACTION:

Final rule.

SUMMARY:

This amendment adopts a new airworthiness directive (AD) that applies to all LET Aeronautical Works (LET) Model L-13 “Blanik” sailplanes. This AD requires you to inspect the tail-fuselage hinge for strength requirements and damage, and also requires you to replace any hinge with damage or that does not meet strength requirements. This AD is the result of mandatory continuing airworthiness information (MCAI) issued by the airworthiness authority for the Czech Republic. The actions specified by this AD are intended to detect and correct any tail-fuselage hinge that is damaged or has inadequate material characteristics. Any tail-fuselage hinge with damage or inadequate material characteristics could fail and result in loss of controlled flight.

DATES:

This AD becomes effective on November 27, 2000.

The Director of the Federal Register approved the incorporation by reference of certain publications listed in the regulations as of November 27, 2000.

ADDRESSES:

You may get the service information referenced in this AD from LET Aeronautical Works, Kunovice 686 04, Czech Republic; telephone: +420 632 55 44 96; facsimile: +420 632 56 41 13. You may examine this information at the Federal Aviation Administration (FAA), Central Region, Office of the Regional Counsel, Attention: Rules Docket No. 99-CE-91-AD, 901 Locust, Room 506, Kansas City, Missouri 64106; or at the Office of the Federal Register, 800 North Capitol Street, NW, suite 700, Washington, DC 20001.

FOR FURTHER INFORMATION CONTACT:

Mike Kiesov, Aerospace Engineer, FAA, Small Airplane Directorate, 901 Locust, Room 301, Kansas City, Missouri 64106; telephone: (816) 329-4144; facsimile: (816) 329-4090.

SUPPLEMENTARY INFORMATION:

Discussion

What events have caused this AD? The Civil Aviation Authority (CAA), which is the airworthiness authority for the Czech Republic, recently notified the FAA that an unsafe condition may exist on all LET Model L-13 “Blanik” sailplanes. The CAA reports an incident involving one of the affected sailplanes where the tail-fuselage attachment fitting was damaged. Further analysis reveals that the material characteristics of the tail-fuselage attachment fitting were inadequate.

What are the consequences if the condition is not corrected? The tail-fuselage attachment fitting is a primary structural element within the empennage. Failure of this part, if not detected and corrected, could result in loss of controlled flight.

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 Model L-13 “Blanik” sailplanes. This proposal was published in the Federal Register as a notice of proposed rulemaking (NPRM) on August 9, 2000 (65 FR 48648). The NPRM proposed to require you to inspect the tail-fuselage hinge for strength requirements and damage, and would require you to replace any hinge with damage or that does not meet strength requirements.

Was the public invited to comment? Interested persons were afforded an opportunity to participate in the making of this amendment. No comments were received on the proposed rule or the FAA's determination of the cost to the public.

The FAA's Determination

What is FAA's Final Determination on this Issue? After careful review of all available information related to the subject presented above, we have determined that air safety and the public interest require the adoption of the rule as proposed except for minor editorial corrections. We determined that these minor corrections:

• Will not change the meaning of the AD; and
• Will not add any additional burden upon the public than was already proposed.

Cost Impact

How many sailplanes does this AD impact? We estimate that this AD affects 140 sailplanes in the U.S. registry.

What is the cost impact of the inspection for the affected sailplanes on the U.S. Register? We estimate that it will take approximately 4 workhours per sailplane to accomplish the inspection, at an average labor rate of $60 an hour. Based on the cost factors presented above, we estimate the total cost impact of the inspection on U.S. operators to be $33,600, or $240 per sailplane.

What is the cost impact of the replacement for the affected sailplanes on the U.S. Register? We estimate that it will take approximately 16 workhours per sailplane to accomplish the replacement (as necessary), at an average labor rate of $60 an hour. The manufacturer will provide the replacement attachment fittings at no cost. Based on the cost factors presented above, we estimate the total labor cost impact of the replacement on U.S. operators to be $960 per sailplane.

Regulatory Impact

Does this AD impact various entities? The regulations adopted herein 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, it is determined that this final rule does not have federalism implications under Executive Order 13132.

Does this AD involve a significant rule or regulatory action? 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) 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 final evaluation prepared for this action is contained 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
• 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.

2. FAA amends Section 39.13 by adding a new AD to read as follows:

2000-20-11 LET Aeronautical Works: Amendment 39-11922; Docket No. 99-CE-91-AD.

(a) What sailplanes are affected by this AD? This AD applies to Model L-13 “Blanik” sailplanes, all serial numbers, certificated in any category.

(b) Who must comply with this AD? Anyone who wishes to operate any of the above sailplanes on the U.S. Register must comply with this AD.

(c) What problem does this AD address? The actions specified by this AD are intended to prevent the tail-fuselage hinge failing and consequent loss of controlled flight.

(d) What actions must I accomplish to address this problem? To address this problem, you must accomplish the following:

(e) Can I comply with this AD in any other way? You may use an alternative method of compliance or adjust the compliance time if:

(1) Your alternative method of compliance provides an equivalent level of safety; and

(2) The Manager, Small Airplane Directorate, approves your alternative. Submit your request through an FAA Principal Maintenance Inspector, who may add comments and then send it to the Manager, Small Airplane Directorate, 901 Locust, Room 301, Kansas City, Missouri 64106.

Note 1:

This AD applies to each sailplane identified in paragraph (a) of this AD, 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 (e) 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 you have not eliminated the unsafe condition, specific actions you propose to address it.

(f) Where can I get information about any already-approved alternative methods of compliance? Contact Mike Kiesov, Aerospace Engineer, FAA, Small Airplane Directorate, 901 Locust, Room 301, Kansas City, Missouri 64106; telephone: (816) 329-4144; facsimile: (816) 329-4090.

(g) What if I need to fly the sailplane to another location to comply with this AD? The FAA can issue a special flight permit under sections 21.197 and 21.199 of the Federal Aviation Regulations (14 CFR 21.197 and 21.199) to operate your sailplane to a location where you can accomplish the requirements of this AD.

(h) Are any service bulletins incorporated into this AD by reference? Actions required by this AD must be done in accourdance with LET Mandatory Bulletin No. L13/085a, dated November 17, 1999. The Director of the Federal Register approved this incorporation by reference under 5 U.S.C. 552(a) and 1 CFR part 51. You can get copies from LET Aeronautical Works, Kunovice 686 04, Czech Republic; telephone: +420 632 55 44 96; facsimile: +420 632 611 26. You can look at copies at the FAA, Central Region, Office of the Regional Counsel, 901 Locust, Room 506, Kansas City, Missouri, or at the Office of the Federal Register, 800 North Capitol Street, NW, suite 700, Washington, DC 20001.

(i) When does this amendment become effective ? This amendment becomes effective on November 27, 2000.

Note 2:

The subject of this AD is addressed in Czech Republic AD Number CAA-AD-T-112/1999, dated November 18, 1999.