Applicability: Schleicher ASW 20, all serial numbers, ASW 24 Prototype, serial number 24000

Effective date: July 3, 1998

Compliance : Required as indicated in LBA AD 1998-255

Luftfahrt-Bundesamt, Airworthiness Directive Section, Lilienthalplatz 6, 38108 Braunschweig, Federal Republic of Germany

Manufacturer: Schleicher, Poppenhausen, Germany

Type: ASW 20 and ASW 24 Prototype

Models affected: all

Serial numbers affected: all, (No.24000 for ASW 24 Prototype)

German Type Certificate No.: 314, 363 and 851

Subject: Amendment of the Maintenance Manual / Inspection Program to Increase the Service Life

Reason: Fatigue tests on Glas fibre reinforced plastic (GRP) wings and GRP wing spars have shown that a service life expectancy of 12000 hours can be reached for these components without problems. However, as this fatigue test program did not examine the entire aircraft made of GRP, this service life of 12000 hours can be granted only if the long-term airworthiness of each individual aircraft is demonstrated in a special multi-stage inspection program (over and above the mandatory annual C of A inspections) for the purpose versions of increasing the service life. For the ASW 20 TOP production versions the service life increase applies to the airframe only, the removable engine unit is not to be affected by this AD. The ASW 24 prototype corresponds to an ASW 20 B with fixed flaps and therefore falls within the scope of this AD.

Action: Exchange of pages into the Service Manual.

Compliance: Exchange of pages into the Manual: prior to the next annual inspection, but not later than December 31,1998. The Inspection Program must be performed before reaching a service life of 3000 or 6000 flight hours.

Technical publication of the manufacturer: Schleicher Technical Note No. 39/2 dated April 17,1998 which becomes herewith part of this AD and may be obtained from Messrs.: Alexander Schleicher, GmbH & Co., Segelflugzeugbau, D - 36163 Poppenhausen, Federal Republic of Germany

Accomplishment and log book entry: Action to be accomplished by an approved service station and to be checked and entered in the log book by a licensed inspector.

Holders of affected aircraft registered in Germany have to observe the following: As a result of the a.m. deficiencies, the airworthiness of the aircraft is affected to such an extent that after the expiry of the a.m. dates the aircraft may be operated only after proper accomplishment of the prescribed actions. In the interest of aviation safety outweighing the interest of the receiver in a postponement of the prescribed actions, the immediate compliance with this AD is to be directed.

Instructions about Available Legal Remedies: An appeal to this notice may be raised within a period of one month following notification. Appeals must be submitted in writing or registered at the Luftfahrt-Bundesamt, Lilienthalplatz 6, 38108 Braunschweig.

Enquiries regarding this Airworthiness Directive should be referred to Mr. Olaf Schneider, Airworthiness Directive Section at the above address, fax-no. 0049 531/2355-254. Please note, that in case of any difficulty, reference should be made to the German issue!