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Proposed Rule

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.


Notice of proposed design criteria.


This notice announces the availability of and requests comments on the proposed design criteria for the Alexander Schleicher GmbH & Co. Segelflugzeugbau Model ASK 21 B glider. The administrator finds the proposed design criteria for the Model ASK 21 B acceptable.These final design criteria will be published in the Federal Register.


Comments must be received on or before May 2, 2019.


Send comments identified by docket number FAA-2019-0197 using any of the following methods:

Federal eRegulations Portal: Go to and follow the online instructions for sending your comments electronically.

Mail: Send comments to Docket Operations, M-30, U.S. Department of Transportation (DOT), 1200 New Jersey Avenue SE, Room W12-140, West Building Ground Floor, Washington, DC, 20590-0001.

Hand Delivery of Courier: Take comments to Docket Operations in Room W12-140 of the West Building Ground Floor at 1200 New Jersey Avenue SE, Washington, DC, between 9 a.m., and 5 p.m., Monday through Friday, except Federal holidays.

Fax: Fax comments to Docket Operations at 202-493-2251.

Privacy: The FAA will post all comments it receives, without change, to, including any personal information the commenter provides. Using the search function of the docket website, anyone can find and read the electronic form of all comments received into any FAA docket, including the name of the individual sending the comment (or signing the comment for an association, business, labor union, etc.). DOT's complete Privacy Act Statement can be found in the Federal Register published on April 11, 2000 (65 FR 19477-19478), as well as at

Docket: Background documents or comments received may be read at at any time. Follow the online instructions for accessing the docket or go to the Docket Operations in Room W12-140 of the West Building Ground Floor at 1200 New Jersey Avenue SE, Washington, DC, between 9 a.m., and 5 p.m., Monday through Friday, except Federal holidays.

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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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Comments Invited

We invite interested people to take part in this rulemaking by sending written comments, data, or views. The most helpful comments reference a specific portion of the design criteria, explain the reason for any recommended change, and include supporting data. We ask that you send us two copies of written comments.

We will consider all comments received on or before the closing date for comments. We will consider comments filed late if it is possible to do so without incurring expense or delay. We may change these airworthiness design criteria based on received comments.


On August 16, 2018, Alexander Schleicher GmbH & Co. Segelflugzeugbau (Alexander Schleicher) 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.

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 Start Printed Page 125301, except for areas affected by the change, which will use EASA Certification Specification (CS)-22[3] as shown in these proposed airworthiness criteria.

The Proposed 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 March 21, 2019.

Pat Mullen,

Manager, Small Airplane Standards Branch, 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. 2019-06395 Filed 4-1-19; 8:45 am]