SAIB ACE-98-09

SPECIAL

AIRWORTHINESS

INFORMATION

BULLETIN

AIRCRAFT CERTIFICATION SERVICE 800 INDEPENDENCE AVENUE, S.W.

WASHINGTON, DC 20591

U.S. Department of Transportation Federal Aviation Administration

No. ACE-98-09 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 Models Ka 6, Ka 6 B, Ka 6 BR, Ka 6 C, Ka 6 CR, Ka 6 CR-Pe, and Ka 6 E sailplanes owners on the following:

• Ka 6 and Ka 6 B Interchange of Rear Stabilizer Connection (Modification No. 2)

• Ka 6 and Ka 6 B Spar Root Plywood Inserts (Modification No. 2)

• All Ka 6 Series Strengthening of the Plywood Web on the Outer Spar at Aileron Bellcrank (Modification No. 3)

• Ka 6 E Elevator Spar Extension (Technical Note No. 18)

• All Ka 6 Series Elevator fitting inspection (Technical Note No. 21)

Background The FAA is currently conducting an assessment of fo reign 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 Ka 6 Series 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 ai rworthiness 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.

Ka 6 and Ka 6 B Interchange of Rear Stabilizer Connection (Modification No. 2) Alexander Schleicher has noted several occurrences of excessive wear in the rear spar stabilizer connection area. To eliminate this possibility, Alexander Schleicher has issued Modification No. 2 that requires replacing the bolts at the rear stabilizer connection. For your information, Modification No. 2 has been enclosed. The FAA highly encourages you to accomplish this modification on your sailplane. If this modifi cation has not been accomplished, the manufacturer has estimated that it will take approximately twen ty hours to complete. Alexander Schleicher has parts available to accomplish this modification at the cost of approximately $120.00 U.S. dollars.

Ka 6 and Ka 6 B Spar Root Plywood Inserts (Modification No. 2) Alexander Schleicher has determined that there ha ve been several occurrences of cracks that were noted in the plywood root spar c onnection. To eliminate this possibility, Alexander Schleicher has issued Modification No. 2 that requires modificati on of the spar connection. For your information, Modification No. 2 has been enclosed. The FAA highly encourages you to accomplish this modification on your sailplane. If this modifi cation has not been accomplished, the manufacturer

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has estimated that it will take approximately fort y hours to complete. Alexander Schleicher has parts available to accomplish this modification at the cost of approximately $240.00 U.S. dollars.

Strengthening of the Plywood Web on the Outer Spar at Aileron Bellcrank (Modification # 3) Alexander Schleicher has determined that there ha ve been several occurrences of spar web damage when the aileron bellcrank was disconnected. To eliminate this possibility, Alexander Schleicher has issued Modification No. 1 that requires stre ngthening the plywood web on the outer spar at the aileron bellcrank. For your information, Modifi cation #3 has been enclosed. The FAA highly encourages you to accomplish this modification on your sailplane. If this modification has not been accomplished, the manufacturer has estimated that it will take approximately one hour to conduct the inspection and six hours to accomplish the modification. Alexander Schleicher has specified that locally procured parts are acceptable and should cost approximately $20.00 U.S. dollars.

Ka 6 E Elevator Spar Extension (Technical Note No. 18) Alexander Schleicher has determined that there is a possibility of the elevator halves not being properly secured during assembly by inserting th e securing pin outside of the tube end. To eliminate this possibility, Alexander Schleicher has issued Technical Note No. 18 that requires a tube extention to be riveted to the tube spar. For your information, Technical Note No. 18 has been enclosed. The FAA highly encourages you to accomp lish this modification on your sailplane. If this modification has not been accomplished, the manufacturer has estimated that it will take approximately two hours to complete. Alexander Sc hleicher has the required parts available at the cost of approximately $10.00 U.S. dollars.

Elevator fitting inspection (Technical Note No. 21) 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 Ka 6 series and K7 are similar in design in this area. 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 Airworthine ss Directive 72-7/3 is enclosed as well as Alexander Schleicher Technical Note No. 21. The FAA highly encourages you to accomplish this inspection, and modification if required, on your sailp lane. 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 th e modification. Alexander Schleicher has the parts available to accomplish this modification. Th e 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 th is airworthiness issue. Subsequent to the issuance of this AD, there was another occurre nce of a disbonding. For this reason, Alexander Schleicher issued Technical Note No. 21, 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 Models Ka 6 Series. This information is provided to you for your information only.

• AD 64-07-05 [Model Ka 6] ; To preclude elevator control fa ilures due to deflection of a long unsupported section of the push-pull control.

• AD 64-14-06 [Model Ka 6]; Cracks in the forward horizontal stabilizer fitting.

• AD 69-05-06 [Model Ka 6 E]; To prevent the failure of the thermos-bottle mounting brackets.

• AD 64-09-06 [All Ka 6 Series]; Cracks and faulty welds in the airbrake push-pull rod.

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• AD 75-23-03[All Ka 6 Series] ; 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. Segelf lugzeugbau, Postfach 60, D-36161 Poppenhausen, Germany; Telephone 49.6658.8920; Facsimile 49.6658.8940 or 49.6658.8923.

John Murray, Eastern Sailplanes, United States Al exander Schleicher Dealer, 398 Miami Street, Post Office Box 753, Waynesville, OH 45068; Te lephone (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.