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Administration 

Subject: TYPE CERTIFICATION—FIXED- nwe: n/10/93 AC No: 21.17-2A 


WING GLIDERS (SAILPLANES), Initiated by: ACE-100 chai*e: 


INCLUDING POWERED GLIDERS 


1. PURPOSE• This advisory circular (AC) provides information and 


guidance concerning acceptable means, but not the only means, of 


showing compliance with § 21.17(b) of part 21 of the Federal Aviation 


Regulations (FAR) for type certificatioTi of gliders and powered 


gliders. Accordingly, this material is neither mandatory nor 


regulatory in nature and does not constitute a regulation. General 


guidance relative to glider type certification is also provided. 


NOTE: The term glider is used interchangeably with the term 


sailplane throughout the AC. This includes both unpowered and 


powered gliders and sailplanes. Although JAR-22 uses the terms 


"sailplanes and powered sailplanes," the FAA will continue to use the 


terrainology that was used in the previous AC and is currently used in 


other parts of Title 14 of the Code of Federal Regulations (CFR). 
 The term "self-launching" has been left out of the title to avoid 


confusion between self-launching and self-sustaining, which are both 


considered powered gliders in this AC. (Self-sustaining gliders have 


low power engines that are not intended for self-launching 


operations.) 


2. CANCELLATION. AC 21.17-2, "Type Certification—Fixed-Wing 


Gliders (Sailplanes), Including Self-Launching (powered) Gliders," 


dated July 13, 1989, is cancelled. 


3. RELATED FEDERAL AVIATION REGULATIONS. 


a. Section 21.5—Airplane or Rotorcraft Flight Manual. 


b. Section 21.17—Designation of applicable regulation. 


c. Section 21.21—Issue of type certificate; normal, utility, 
 acrobatic, commuter, and transport category aircraft; manned free 


balloons, special classes of aircraft; aircraft engines; propellers. 


d. Section 21.29—Issue of type certificate; import products. 


e. Part 23—Airworthiness Standards: Normal, Utility, 
 Acrobatic, and Commuter Category Airplanes-


f. Part 33-Airworthiness Standards: Aircraft Engines. 

AC 21.17-2A 2/10/93 

g. Part 35—Airworthiness Standards: Propellers. 

h. Part 45, Subpart C—Nationality and Registration Harks. 

i. Section 91.9—Civil aircraft flight manual, marking, and 

placard requirements. 


j. Section 91.205—Powered civil aircraft with standard 


category U.S. airworthiness certificates: Instrument and equipment 


requirements. 


4. OTHER RELATED DOCUMENTS. 


a. SN 050-011-00004-6—"FAA Basic Glider Criteria Handbook," 


may be purchased from the Superintendent of Documents, U.S. 
 Government Printing Office, Washington, DC 20402. 


b. JAR-22—"Joint Airworthiness Requirements Sailplanes and 


Powered Sailplanes," may be purchased f rom T:he Civil Aviation 


Authority, Printing and Publication Services, Greville House, 37 


Gratton Road, Cheltenham Glos. GL 50 2BN, England. 


c. AC 21.17-2A, "Type Certification—Fixed-Wing Gliders 

(Sailplanes), Including Powered Gliders,n may be obtained from the 

U.S. Department of Transportation, Utilization and Storage Section, 
 M-443.2, Washington, DC 20590. 


5. BACKGROUND. On April 13, 1987, part 21 of the FAR was amended 


to provide procedures for the type certification and airworthiness 


certification of special classes of aircraft. Special classes of 


aircraft include gliders and powered gliders, airships, and other 


kinds of aircraft, which would be eligible for a standard 


airworthiness certificate, but for which no airworthiness standards 


have as yet been established as a separate part of chapter I, 
 subchapter C, Title 14 of the CFR. Airworthiness standards for 


these special classes of aircraft are designated in § 21.17(b). 


6. DISCUSSION. This AC contains a list of design criteria found 


acceptable to the Administrator for the type certification of 


gliders and powered gliders. The following is a discussion of some 


of the acceptable means of showing compliance with § 21.17(b). 


a- JAR-22. Joint Airworthiness Requirements (JAR) for 


Sailplanes and Powered Sailplanes. 


(1) origin. On April 1, 1980, certain European Civil 


Aviation Authorities agreed to Joint Airworthiness Requirements for 


Sailplanes and Powered Sailplanes (JAR-22). JAR-22 is based on the 


Federal Republic of Germany national airworthiness code 


(Lufttuechtigkeitsforderungen fuer Segelflugzeuge and Motorsegler 


(LFSM) published by the Luftfahrt-Bundesamt), and was developed 


through joint participation of the Civil Aviation Authorities of 


Belgium, th© Federal P.epublic of Germany, France, Italy, the 

2/10/93 AC 21.17-2A 


Netherlands, Sweden, and the United Kingdom. After the original 


issuance, JAR-22 was amended to add new subparts H and J which set 


forth criteria for the type certification of sailplane engines and 


propellers, respectively. 


(2) Acceptability of JAR-22. After reviewing JAR-22 as 


amended, the FAA has determined that the criteria of JAR-22 


provides an acceptable level of safety and is appropriate for the 


type certification of gliders and powered gliders. 


b. other Airworthiness Criteria. Section 21.17(b) provides 


authority for the development and application of airworthiness 


standards and criteria for special classes of aircraft, which 


include gliders and powered gliders. The applicable requirements 


for gliders and powered gliders may be based on the appropriate 


portions of those airworthiness standards published in chapter I, 
 subchapter C, Title 14 of the CFR, which include parts 1 thru 49, 
 or such other airworthiness criteria as" the Administrator may find 


to provide an equivalent level of safety to those standards. 


c. operational Provisions of Part 91. In addition to the type 


certification requirements of part 21 of the FAR, gliders must also 


comply with certain operational provisions of part 91 of the FAR. 
 Applicants for type certification of gliders, particularly powered 


gliders, should ensure that these requirements are considered in 


their designs. 


7. ACCEFT^LE CRITERIA ­

a. Criteria for Gliders. Applicants may utilize one or both of 


the following means of showing compliance for type certification of 


gliders and powered gliders. 


(1) JAR-22 as amended and accepted by the FAA at the date 


of application for type certification. However, in the event that 


the Administrator finds the compliance with airworthiness criteria 


prescribed in JAR-22 is inadequate as a certification basis of a 


glider or powered glider due to its unique design or design 


features, the Administrator may require an applicant to comply with 


additional conditions. 


(2) Other Airworthiness Criteria. 


(i) In the event that the airworthiness criteria 


prescribed in (1) are inadequate or otherwise inappropriate as a 


certification basis of a glider due to its unique design or design 


features, other criteria may be developed. Such criteria may 


utilize the appropriate airworthiness criteria contained in parts 


23, 33, 35 of the FAR and in JAR 22, as well as any additional 


conditions that may be prescribed by the Administrator. Guidance 


for preparation and approval of these criteria are outlined below: 

AC 21.17-2A 2/10/93 

(A) These criteria must provide for a level of 


safety equivalent to that prescribed in § 21.17(b). Any proposed 


airworthiness criteria submitted to the FAA should be comparable to 


part 23 of the FAR. It is envisaged by the FAA that, to achieve a 


feasible set of airworthiness criteria, an engineering staff 


experienced in glider design, in conducting certification programs, 
 and with the development of procedures and standards will be 


necessary. If the Administrator finds that there is a need, the 


FAA may participate in the development of such criteria depending 


on the feasibility of completing the project and the availability 


of personnel. 


(B) The applicant should submit their 


airworthiness criteria for approval to the Aircraft Certification 


Office (ACO) having jurisdiction, who will submit them, with 


recommendations, to the Small Airplane Directorate, Aircraft 


Certification Service, ACE-100. Upon receipt, ACE-100 will review 


the airworthiness criteria for applicability to the type design and 


for completeness. After the criteria are determined by ACE-100 to 


be acceptable, they will be announced in the Federal Register for 


public comment as a proposed revision to this AC. The disposition 


of public comments will be kept on file. Once approved, these 


criteria may be used as the certification basis for other gliders. 
 The approved set of criteria will be listed in the Federal 


Register, as an amendment to this AC, along with information on 


where they may be obtained. ACE-100 will maintain a file of these 


criteria. 


(ii) The approval procedures for significant changes or 


additions to any previously approved airworthiness criteria 


proposed for a new project will follow the procedures outlined in 


(B) above established for a complete set of airworthiness criteria. 


(iii) Previously approved airworthiness criteria, when 


proposed for a new project, should be evaluated against current 


glider design, service experience, and amendments to appropriate 


regulations such as part 23 of the FAR. 


(iv) An applicant may make a case for exemption from 


§ 21.17(b) and the approved airworthiness criteria, which is 


incorporated by reference. The preferred procedure, however, is 


for the applicant to approach the FAA during the process of 


establishing the certification basis to make its case for not 


imposing a particular rule or criterion. If the airworthiness 


criteria has already been approved, the applicant may apply for an 


amendment to these criteria. 


(v) The procedures for equivalent safety findings 


provided in § 21.21(b)(1) may be used for glider airworthiness 


criteria. The reference to equivalent safety findings for glider 


criteria must be done through § 21.17(b) and the glider 


airworthiness criteria incorporated by reference. In such cases, a 


showing of equivalent safety findings should be required nf the 

.1/10/93 AC 21.17-2A 


applicant and approved by ACE-100. Such equivalent safety findings 


should be part of the type certification basis and noted on the 


type certificate data sheet. 


(vi) These criteria shall also provide for instructions 


for continued airworthiness to show compliance with § 21.50. 


b- Additional Criteria for Powered Gliders. 


(1) Powered fixed-wing gliders may be type certificated 


under Section 21.17(b) if: 


(i) The number of occupants does not exceed two; 


(ii) Maximum weight does not exceed 850 kg (1874 


pounds); and 


(iii) The maximum weight to wing span squared £w/bJ) 


does not exceed 3.0 kg/ma (0.62 lb./ft.1). 


NOTE: These criteria originated from JAR-22. 


(2) Engines and propellers intended for use on powered 


gliders may be type certificated in accordance with parts 33 and 35 


of the FAR, respectively; under § 21.29 for import products; or may 


be approved as an integral part of the glider using such other 


airworthiness criteria approved by the FAA. 


Engines and/or propellers that are approved as an integral part of 


the glider will be certificated as a part of the glider and will be 


limited to installation on that specific type glider. Separate 


type certificates will not be issued for these engines and 


propellers. Type certification of an engine and/or propeller 


installed in one JAR-22 design does not in and of itself constitute 


type certification of the same engine and/or propeller in another 


JAR-22 type design. Maximum credit will, however, be given for the 


use of FAA approved data developed in an earlier certification 


project as well as engines and propellers certificated by other 


agencies to JAR-22, subparts H and J. If either the engine or the 


propeller is certificated as an integral part of the glider, the 


applicant has two ways in which to obtain approval: 


(i) For Engines: JAR-22, subpart H - Engines, or 


other requirements that may be based on part 33 of the FAR. 


(ii) For Propellers: JAR-22, subpart J - Propellers, 
 or other requirements that may be based on part 35 of the FAR. 


(3) Part 36 of the FAR does not contain noise requirements 


for gliders and powered gliders. A finding under the Noise Control 


Act of 1972 is to be made by the FAA for all aircraft before a new 


type certificate can be issued. The finding may consist of the 

AC 21.17-2A 2/10/93 

rationale as to why it would be impractical to decrease the 


aircraft's noise level. Amended type certificates do not require 


determinations. 


c. JAR-22. If JAR-22 is selected by the applicant— 


(1) The national variants identified by individual 


countries need not be applied. 


(2) The "ACJ" (interpretative material) is considered 


acceptable to the FAA. 


d. JAR Section 22.1581. The flight manual requirements of 


§ 22.1581 apply to all gliders. In addition, compliance with 


§ 21.29(a)(3) of the FAR is required. Manuals, placards, listings, 
 and instrument markings are to be presented in the English 


language. 


e. Section 21.17(c^ of the FAR. An application for type 


certification is effective for three years, as specified by 


§ 21.17(c), unless an applicant shows at the time of application 


that his product reguires a longer period of time for design, 
 development, and testing, and the Administrator approves a longer 


period. 


f. Section 21.21(bH21 of the FAR. Gliders may be designed for 


quick removal and installation of the wing and tail surfaces by the 


pilot in accordance with JAR 22.611, 22.612, and 22.685. 


g. Part 45. Subpart C of the FAR. Registration marking 


requirements for U.S. registered gliders are provided in part 45 of 


the FAR, subpart C. 


h. Section 91.205 of the FAR. Powered gliders are considered 


to be powered aircraft for the purpose of complying with § 91,205. 


8. OTHER INFORMATION. 


a. Compliance with JAR-22. United States designers and 


manufacturers of gliders and powered gliders should be advised that 


strict compliance with JAR-22, including adherence to the national 


variants, will probably be required by participating countries of 


the JAA group for import airworthiness acceptance. Accordingly, 
 the FAA will consider strict compliance with JAR-22 required for 


issuance of a U.S. Class I Export Certificate of Airworthiness for 


export to a JAR participating country, unless specifically notified 


to the contrary by the authority of the importing country on an 


individual case basis. 


b. Certification Basis. An FAA letter may be used by the 


certificating ACO to inform the applicant of the airworthiness 


criteria, selected in accordance with paragraph 6, that were found 


tc be acceptable to the Administrator for showing compliance with 


§ 21.17(b) of the FAR. These airworthiness criteria should be 


identified by title, number, revision, and date of FAA approval. 

AC 21.17-2A 


c. Type Certificate Data Sheet (TDCS1. Section 21.17(b) of the 

FAR will be cited as the certification basis for gliders and 

powered gliders. The TCDS will list, as the certification basis, 

§ 21.17(b), the airworthiness criteria established in paragraph 7b 

above, and any other additional conditions proposed by the 

Administrator. These criteria need to be identified by title, number, revision, and date of approval. 

d. Basic Glider Criteria Handbook. Originally designed for 


individual glider designers, the glider industry, and glider 


operating organizations in 1962, the Basic Glider Handbook is no 


longer an acceptable means of compliance for type certification of 


gliders and powered gliders. This handbook does, however, provide 


useful information on design practices and design criteria. 


.^Q 

PT£&CE 

Acting Manager, Small Airplane Directorate 


Aircraft Certification Service