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Airworthiness Criteria: Glider Design Criteria for Alexander Schleicher GmbH & Co. Segelflugzeugbau Model ASK 21 B Glider

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Federal Aviation Administration (FAA), DOT.


Issuance of final airworthiness design criteria.


These airworthiness design criteria are issued to Alexander Schleicher GmbH & Co. Segelflugzeugbau for the Model ASK 21 B glider. The administrator finds the design criteria, which make up the certification basis for the Model ASK 21 B glider, acceptable.


These airworthiness design criteria are effective July 15, 2019.

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Mr. Jim Rutherford, AIR-692, Federal Aviation Administration, Policy & Innovation Division, Small Airplane Standards Branch, 901 Locust, Room 301, Kansas City, MO 64106, telephone (816) 329-4165, FAX (816) 329-4090.

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On August 16, 2018, Alexander Schleicher GmbH & Co. Segelflugzeugbau (Alexander Start Printed Page 27708Schleicher) applied for validation of a type certificate change to add the Model ASK 21 B glider in accordance with the “Technical Implementation Procedures for Airworthiness and Environmental Certification Between the FAA and the European Aviation Safety Agency (EASA),” Revision 6, dated September 22, 2017. This model is a modified version of the Model ASK 21 glider and will be documented on existing Type Certificate Number (No.) G47EU. The Model ASK 21 B is a two-seat, mid-wing glider constructed from glass-fiber reinforced plastic and features a 55.8 foot (17 meters) wingspan with airbrakes on the upper wing surface. The glider has a non-retractable landing gear with a nose wheel and shock-absorbed, braked main wheel and a T-type tailplane. The glider has a maximum weight of 1,323 pounds (600 kilograms).

EASA type certificated the Model ASK 21 B glider in the utility and aerobatic categories and issued Type Certificate No. EASA.A.221, dated August 9, 2018. The associated EASA Type Certificate Data Sheet (TCDS) No. EASA.A.221 defined the certification basis, which Alexander Schleicher submitted to the FAA for review and acceptance.

Gliders are type certificated by the FAA as special class aircraft for which airworthiness standards have not yet been established by regulation. Under the provisions of 14 CFR 21.17(b), the airworthiness standards for special class aircraft are those found by the FAA to be appropriate and applicable to the specific type design. FAA Advisory Circular (AC) 21.17-2A [1] provides guidance on acceptable design criteria for the type certification of gliders and powered gliders in the United States. AC 21.17-2A allows applicants to utilize the Joint Aviation Requirements (JAR)-22,[2] other airworthiness criteria comparable to 14 CFR part 23, or a combination of both as the means for showing compliance for glider certification.


Airworthiness Criteria: Glider Design Criteria for Alexander Schleicher GmbH & Co. Segelflugzeugbau Model ASK 21 B Glider was published in the Federal Register on April 2, 2019 (84 FR 12529). No comments were received and the airworthiness design criteria are adopted as proposed.

Type Certification Basis

The certification basis for the Model ASK 21 B will be the same as the certification basis for the Model ASK 21 as shown on TCDS No. G47EU, Revision 1, except for areas affected by the change, which will use EASA Certification Specification (CS)-22 [3] as shown in these airworthiness design criteria.


The authority citation for these airworthiness design criteria is as follows:

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Authority: 49 U.S.C. 106(g), 40113, and 44701.

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The Airworthiness Design Criteria

Applicable Airworthiness Criteria Under 14 CFR 21.17(b)

Based on the Special Class provisions of § 21.17(b), the following airworthiness requirements form the FAA certification basis for the Model ASK 21 B:

1. 14 CFR part 21, effective February 1, 1965, including amendments 21-1 through 21-53.

2. Lufttuechtigkeitsforderungen fuer Segelflugzeuge and Motorsegler (LFSM) Airworthiness Requirements for Sailplanes and Powered Sailplanes, dated October 23, 1975.

3. JAR-22, dated April 1, 1980, including amendment 1, dated May 18, 1981.

4. CS-22, amendment 2, dated March 5, 2009, for the following regulations: CS 22.147, 22.455, 22.477, 22.561 except (b)(2), 22.595, 22.597, 22.629, 22.677, 22.685, 22.689, 22.721, 22.771, 22.773, 22.777, 22.779, 22.780, 22.781, 22.785, 22.786, 22.787, 22.788, 22.807, and 22.831.

5. AC 21.23-1, section 5(e)(6), dated January 12, 1981.

6. Operations are limited to Day VFR and to flying in Instrument Meteorological Conditions (IMC) if the glider is equipped as required under 14 CFR 91.205. Night operation is prohibited.

7. FAA Type Certificate Application Date: August 16, 2018.

8. EASA Type Certificate No. EASA.A.221, Issue 05, dated August 9, 2018.

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Issued in Kansas City, Missouri, on June 5, 2019.

Pat Mullen,

Manager, Small Airplane Standards Branch, Policy & Innovation Division, Aircraft Certification Service.

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1.  Ref AC 21.17-2A, “Type Certification—Fixed-Wing Gliders (Sailplanes), Including Powered Gliders,” dated February 10, 1993.

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2.  Ref JAR-22, “Sailplanes and Powered Sailplanes.”

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3.  Ref EASA CS-22, “Certification Specifications for Sailplanes and Powered Sailplanes,” amendment 2, dated March 5, 2009.

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[FR Doc. 2019-12626 Filed 6-13-19; 8:45 am]