AD 98-06-37

This amendment adopts a new airworthiness directive (AD) that applies to certain Alexander Schleicher Segelflugzeugbau (Alexander Schleicher) Model ASK-21 sailplanes. This AD requires replacing any tow release cable assembly that does not have a swivel-type end with a cable assembly that does have a swivel-type end. This AD is the result of mandatory continuing airworthiness information (MCAI) issued by the airworthiness authority for Germany. The actions specified by this AD are intended to prevent the inability to release the tow rope because of the design of the cable assembly, which could result in loss of control of the sailplane during towing operations.

Final rule

98-06-37 ALEXANDER SCHLEICHER SEGELFLUGZEUGBAU: Amendment 39-10416; Docket No. 97-CE-107-AD.

Applicability: Model ASK-21 sailplanes, serial numbers 21 001 through 21 196, certificated in any category, that are equipped with a tow release cable assembly that does not have a swivel-type end.

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 (c) 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 includespecific proposed actions to address it.

Compliance: Required within the next 3 calendar months after the effective date of this AD, unless already accomplished.

To prevent the inability to release the tow rope because of the design of the cable assembly, which could result in loss of control of the sailplane during towing operations, accomplish the following:

(a) Replace any tow release cable assembly that does not have a swivel-type end with a tow release cable assembly that does have a swivel-type end in accordance with Alexander Schleicher Technical Note No. 10, dated October 10, 1983.

(b) 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.

(c) 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.

(d) Questions or technical information related to Alexander Schleicher Technical Note No. 10, dated October 10, 1983, should be directed to Alexander Schleicher Segelflugzeugbau, 6416 Poppenhausen, Wasserkuppe, Federal Republic of Germany; telephone: 49.6658.890 or 49.6658.8920; facsimile: 49.6658.8923 or 49.6658.8940. 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.

(e) The replacement required by this AD shall be done in accordancewith Alexander Schleicher Technical Note No. 10, dated October 10, 1983. 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 Alexander Schleicher Segelflugzeugbau, 6416 Poppenhausen, Wasserkuppe, Federal Republic of Germany. 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 German AD No. 84-2, dated January 13, 1984.

(f) This amendment (39-10416) becomes effective on April 28, 1998.

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 Alexander Schleicher Model ASK-21 sailplanes was published in the Federal Register as a notice of proposed rulemaking (NPRM) on December 19, 1997 (62 FR 66560). The NPRM proposed to require replacing any tow release cable assembly that does not have a swivel-type end with a tow release cable assembly that does have a swivel-type end. Accomplishment of the proposed action as specified in the NPRM would be in accordance with Alexander Schleicher Technical Note No. 10, dated October 10, 1983.

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

Interested persons have been 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
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 the loops that form in the cable assembly would only occur during flight over time and the bending loads are related to sailplane operation, the FAA has no basis to determine the approximate number of hours time-in-service (TIS) when the unsafe condition is likely to occur. For example, the loops could form in the tow release cable assembly on a sailplane with 10 hours TIS, but not form until 500 hours TIS on another sailplane. For this reason, the FAA has determined that acompliance based on calendar time should be utilized 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 30 sailplanes in the U.S. registry will be affected by this AD, that it will take approximately 2 workhours per sailplane to accomplish this replacement, and that the average labor rate is approximately $60 an hour. Parts cost approximately $20 per sailplane. Based on these figures, the total cost impact of this AD on U.S. operators is estimated to be $4,200, or $140 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: