AD 99-19-33 SUPERSEDED

This amendment adopts a new airworthiness directive (AD) that applies to all LET Aeronautical Works (LET) Model L-13 "Blanik" sailplanes. This AD requires painting (using a contrasting color, i.e., red paint) the left hand elevator drive mechanism in order to not have the elevator drive bellcrank inadvertently installed backwards. 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 prevent the elevator drive bellcrank from being installed backwards, which could result in an incorrect rigging of the elevator flight control with potential reduced or loss of control of the sailplane.

Final rule

99-19-33 LET AERONAUTICAL WORKS: Amendment 39-11320; Docket No. 99-CE-16-AD. Applicability: Model L-13 "Blanik" sailplanes, all serial numbers, 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 (d) 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 as indicated in the body of this AD, unless already accomplished.

To prevent the elevator drive bellcrank from being installed backwards, which could result in an incorrect rigging of the elevator flight control with potential reduced or loss of control of the sailplane, accomplish the following:

(a) Within the next 3 calendar months after the effective date of this AD, paint (using a contrasting color, i.e., red paint) the elevator drive mechanism to prevent the elevator drive bellcrank from being inadvertently installed backwards. Accomplish this action in accordance with the Work Procedure section, including Figure 1, of LET Mandatory Bulletin No. L13/082a, dated December 10, 1998.

(b) As of the effective date of this AD, no person may install, on any affected sailplane, an elevator drive bellcrank where the following has not been accomplished:

(1) The elevator bellcrank inspected to assure that it is not installed backwards; and

(2) The elevator drive bellcrank painted as required by paragraph (a) of this AD.(c) 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.

(d) An alternative method of compliance or adjustment of the compliance time 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.

(e) Questions or technical information related to LET Mandatory Bulletin No. L13/082a, dated December 10, 1998, should be directed to LET Aeronautical Works, Kunovice 686 04, Czech Republic; telephone: +420 632 55 44 96; facsimile: +420 632 611 26. 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.

(f) The modification required by this AD shall be done in accordance with LET Mandatory Bulletin No. L13/082a, dated December 10, 1998. This incorporation by reference was approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies may be obtained from LET Aeronautical Works, Kunovice 686 04, Czech Republic. Copies may be inspected at the FAA, Central Region, Office of the Regional Counsel, Room 1558, 601 E. 12th Street, Kansas City, Missouri, or at the Office of the Federal Register, 800 North Capitol Street, NW, suite 700, Washington, DC.

NOTE 3: The subject of this AD is addressed in Czech Republic AD Number: CAA-AD-4-099/98, dated December 30, 1998.

(g) This amendment becomes effective on November 8, 1999.

Events Leading to the Issuance of This AD
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 was published in the Federal Register as a notice of proposed rulemaking (NPRM) on June 14, 1999 (64 FR 31760). The NPRM proposed to require painting (using a contrasting color, i.e., red paint) the left hand elevator drive mechanism in order to not have the elevator drive bellcrank inadvertently installed backwards. Accomplishment of the proposed action as specified in the NPRM would be required in accordance with LET Mandatory Bulletin No. L13/082a, dated December 10, 1998.

The NPRM was the result of mandatory continuing airworthiness information (MCAI) issued by the airworthiness authority for the Czech Republic.

Interested persons have been afforded an opportunity to participate in the making of this amendment. No comments were received onthe proposed rule or the FAA's determination of the cost to the public.

The FAA's Determination
After careful review of all available information related to the subject presented above, the FAA has determined that air safety and the public interest require the adoption of the rule as proposed except for minor editorial corrections. The FAA has 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.

Compliance Time of This AD
Although flight control problems caused by improper installation of the elevator drive bellcrank are only unsafe while the affected sailplanes are in flight, the condition could occur after any time the elevator drive bellcrank is reinstalled on the sailplane. The chance of this situation occurring is the same for a sailplane with 10 hours time-in- service (TIS) as it is for a sailplane with 500 hours TIS. For this reason, the FAA is utilizing acompliance based on calendar time instead of hours TIS in this AD in order to assure that the unsafe condition is addressed on all sailplanes in a reasonable time period.

Cost Impact
The FAA estimates that 140 sailplanes in the U.S. registry will be affected by this AD, that it will take approximately 1 workhour per sailplane to accomplish this action, and that the average labor rate is approximately $60 an hour. Parts cost approximately $5 per sailplane. Based on these figures, the total cost impact of this AD on U.S. operators is estimated to be $9,100, or $65 per sailplane.

Regulatory Impact
The regulations adopted herein will 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 final rule does 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) 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, pursuant to 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. Section 39.13 is amended by adding a new airworthiness directive (AD) to read as follows:

Service information that applies to this AD may be obtained from LET Aeronautical Works, Kunovice
686 04, Czech Republic; telephone: +420 632 55 44 96; facsimile: +420 632 611 26. This information may also be
examined at the Federal Aviation Administration (FAA), Central Region, Office of the Regional Counsel, Attention:
Rules Docket No. 99-CE-16-AD, Room 1558, 601 E. 12th Street, Kansas City, Missouri 64106; or at the Office of the
Federal Register, 800 North Capitol Street, NW, suite 700, Washington, DC.

Mike Kiesov, Aerospace Engineer, FAA, Small Airplane Directorate,
1201 Walnut, suite 900, Kansas City, Missouri 64106; telephone: (816) 426-6934; facsimile: (816) 426-2169.