SAIB ACE-98-06 —

No. ACE-98-06 November 12, 1997

Published by: FAA, AFS-610, P.O. Box 26460, Oklahoma City, OK 73125 This is issued for informational purposes only and any recommendation for corrective action is not mandatory.

The purpose of this Special Airworthiness Information Bulletin (SAIB) is to provide safety information to Alexander Schleicher Model ASK-13 sailplane owners on the following:

• Installation of an additional fair lead in the rudder cables (Modification No. 1). • Wing Main Fittings (Service Bulletin No. 13). • Inspecting the bearing brackets and the toggle force of the airbrake control circuit (Technical Note No. 14). • Elevator fitting inspection (Technical Note No. 12).

Background The FAA is currently conducting an assessment of foreign airworthiness directives that have been issued by the German Luftfahrt-Bundesamt (LBA) on German type certificated sailplanes. The LBA has issued German airworthiness directives on the service difficulty issues listed above. The FAA is currently assessing the need to issue a corresponding U.S. airworthiness directive on U.S. type certificated Model ASK-13 sailplanes. In the interim, the FAA is using this Special Airworthiness Information Bulletin to inform U.S. owners of this model sailplane of the service difficulties reported by the manufacturer. If an airworthiness directive is determined to be appropriate, a Notice of Proposed Rulemaking will be issued. The following is a brief description of the main areas of each issue.

Installation of an additional fair lead in the rudder cables. Alexander Schleicher has determined through service history that limited rudder travel may result from inadequate cable fairing guides in the type design. It is possible for the rudder cables to get caught behind the retaining bolt of the rear airbrake actuating lever. To eliminate this possibility, Alexander Schleicher has issued Modification No. 1 that installs an additional lead fearing in the rudder cable circuit. For your information, LBA Airworthiness Directive 1/68 is enclosed as well as Alexander Schleicher Modification No. 1. The FAA highly encourages you to determine if this modification has been accomplished on your sailplane (note the serial number applicability in the technical note). If this modification has not been accomplished, the manufacturer has estimated that it will take approximately three hours to accomplish the modification. Alexander Schleicher has stated that locally procured parts are acceptable and will cost approximately $10.00 U.S. dollars to accomplish the modification.

Wing Main Fittings. Alexander Schleicher has determined that there have been approximately three occurrences where excessive play between the main fitting and spar were noted. If there is an excessive tolerance on the backside of the main fitting holes, this can lead to failure of the main spar prior to design ultimate load. For your information, LBA Airworthiness Directive 91-144 is enclosed as well as

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Alexander Schleicher Service Bulletin No. 13. The FAA highly encourages you to determine if this modification has been accomplished on your sailplane (note the serial number applicability in the technical note). If this modification has not been accomplished, the manufacturer has estimated that it will take approximately five hours to perform the inspection and an additional fifty hours to accomplish the modification. Alexander Schleicher has the parts available to accomplish this modification. The cost is approximately $500.00 U.S. dollars.

Inspecting the bearing brackets and the toggle force of the airbrake control circuit. There have been approximately three occurrences where the bearing brackets of the airbrake control circuit have been broken. A failure of this bracket can result in a failure of the airbrake system. For your information, LBA Airworthiness Directive 91-173 is enclosed as well as Alexander Schleicher Technical Note No. 14. The FAA highly encourages you to determine if this modification has been accomplished on your sailplane (note the serial number applicability in the technical note). If this modification has not been accomplished, the manufacturer has estimated that it will take approximately one hour to perform the inspection and an additional five hours to accomplish the modification. Alexander Schleicher has the parts available to accomplish this modification. The cost is approximately $50.00 U.S. dollars.

Elevator fitting inspection (Technical Note No. 12) Alexander Schleicher has determined that there has been an occurrence on a Model K7 where the loss of elevator control was caused due to a disbond of a glue joint at the number 1 elevator rib. The Models K7 and K13 are similar in design in this area. To eliminate this possibility, Alexander Schleicher has issued Technical Note 12 that requires inspection of the glued joint between rib number 1 and the leading edge plywood and the elevator spar respectively for adequate condition. For your information, LBA Airworthiness Directive 72-7/3 is enclosed as well as Alexander Schleicher Technical Note No. 12. The FAA highly encourages you to accomplish this inspection, and modification if required, on your sailplane. If this inspection/modification has not been accomplished, the manufacturer has estimated that it will take approximately one hour to conduct the inspection and ten hours to accomplish the modification. Alexander Schleicher has the parts available to accomplish this modification. The cost is approximately $50.00 U.S. dollars for a set of pins. NOTE: The FAA issued AD 75-23-03 applicable to this airworthiness issue. Subsequent to the issuance of this AD, there was another occurrence of a disbonding. For this reason, Alexander Schleicher issued Technical Note 12, and the LBA issued the German AD 72-7/3 in December 1989.

Additional Information The FAA has issued the following Airworthiness Directives (AD) on the Alexander Schleicher Model ASK-13. This information is provided to you for your information only. • AD 68-25-05; To prevent the whell brake cable from fouling with the release lever of the cg coupling. • AD 69-05-04; To prevent the landing gear end buffer plate from slipping inside the rubber buffer. • AD 75-23-03; To prevent structural failure of the elevator and loss of control of the elevator control. It is necessary to read, “Elevator fitting inspection (Technical Note No. 12)” in the text above.

For Further Information Contact: Alexander Schleicher GmbH & Co. Segelflugzeugbau, Postfach 60, D-36161 Poppenhausen, Germany; Telephone 49.6658.8920; Facsimile 49.6658.8940 or 49.6658.8923.

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John Murrey, Eastern Sailplanes, United States Alexander Schleicher Dealer, 398 Miami Street, Post Office Box 753, Waynesville, OH 45068; Telephone (513) 897-5667; Facsimile (513) 897-5909.

Mike Kiesov, Aerospace Engineer/Pilot, FAA, Small Airplane Directorate, 1201 Walnut, Kansas City, Missouri, 64106; telephone (816) 426-6934; Facsimile (816) 426-2169.

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FOR ATTACHMENTS, CONTACT: MIKE KIESOV OR BRIAN HANCOCK AT (816) 426-6934.