SAIB ACE-98-10 —

No. ACE-98-10 November 24, 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 K7 sailplane owners on the following:

• Middle Elevator Bearing Support (Modification No. 3) • Rear Cockpit Control Stick Attachment (Modification No. 10) • Elevator fitting inspection (Technical Note No. 18)

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 corresponding U.S. airworthiness directives on U.S. type certificated Model K7 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.

Middle Elevator Bearing Support (Modification No. 3) Alexander Schleicher has determined through service history that the middle elevator bearing support is susceptible to developed cracks. To eliminate this possibility, Alexander Schleicher has issued Modification No. 3 that requires an inspection and replacement of this support. For your information, Modification No. 3 is enclosed. The FAA highly encourages you to ensure that this modification has been accomplished on your sailplane. If this modification has not been accomplished, the manufacturer has estimated that it will take approximately ten hours to complete. Alexander Schleicher has the parts available to accomplish this modification. The cost is approximately $50.00 U.S. dollars.

Rear Cockpit Control Stick Attachment (Modification No. 10) Alexander Schleicher has determined through service history that the rear cockpit control stick can come out of the socket. To eliminate this possibility, Alexander Schleicher has issued Modification No. 10 that requires inspection and modification of the control stick attachment. For your information, Alexander Schleicher Modification No. 10 is enclosed. The FAA highly encourages you to ensure that this modification has been accomplished on your sailplane. If this modification has not been accomplished, the manufacturer has estimated that it will take approximately two hours to complete. Alexander Schleicher has the parts available to accomplish this modification. The cost is approximately $10.00 U.S. dollars.

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Elevator fitting inspection (Technical Note No. 18) 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. To eliminate this possibility, Alexander Schleicher has issued Technical Note No. 18 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. 18. 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 No. 1 ribs.

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 18, and the LBA issue 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 K7. This information is provided to you for your information only. • AD 61-13-03; To preclude the buckling of the fuselage steel tube members on each side at the rear of the fuselage. • AD 64-07-05; To preclude elevator control failures due to deflection of a long unsupported section of the push-pull control. • AD 75-23-03; To prevent structural failure of the elevator and loss of control of the elevator. It is necessary to read, “Elevator fitting inspection (Technical Note No. 18)” in the text above.

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.

John Murray, 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.