Airworthiness Criteria: Special Class Airworthiness Criteria for the Joby Aero, Inc. Model JAS4-1 Powered-Lift

<RULE> DEPARTMENT OF TRANSPORTATION <SUBAGY>Federal Aviation Administration</SUBAGY> <CFR>14 CFR Part 21</CFR> <DEPDOC>[Docket No. FAA-2021-0638]</DEPDOC> <SUBJECT>Airworthiness Criteria: Special Class Airworthiness Criteria for the Joby Aero, Inc. Model JAS4-1 Powered-Lift</SUBJECT> <HD SOURCE="HED">AGENCY:</HD> Federal Aviation Administration (FAA), DOT <HD SOURCE="HED">ACTION:</HD> Issuance of final airworthiness criteria. <SUM> <HD SOURCE="HED">SUMMARY:</HD> The FAA announces the special class airworthiness criteria for the Joby Aero, Inc. (Joby) Model JAS4-1 powered-lift. This document sets forth the airworthiness criteria the FAA finds to be appropriate and applicable for the powered-lift design. </SUM> <EFFDATE> <HD SOURCE="HED">DATES:</HD> These airworthiness criteria are effective April 8, 2024. </EFFDATE> <FURINF> <HD SOURCE="HED">FOR FURTHER INFORMATION CONTACT:</HD> James Clary, Emerging Technology Coordination Section, AIR-611, Policy and Standards Division, Aircraft Certification Service, Federal Aviation Administration, 10101 Hillwood Parkway, Fort Worth, TX 76177; telephone 817-222-5138; email <E T="03">james.clary@faa.gov</E> . </FURINF> <SUPLINF> <HD SOURCE="HED">SUPPLEMENTARY INFORMATION:</HD> <HD SOURCE="HD1">Background</HD> The Joby Model JAS4-1 (Model JAS4-1) powered-lift has a maximum gross takeoff weight of 4,800 lbs. and is capable of carrying a pilot and four passengers. The aircraft uses six tilting electric engines with 5-blade propellers attached to a conventional wing and V-tail. <SU>1</SU> <FTREF/> The aircraft structure and propellers are constructed of composite materials. As a powered-lift, the Model JAS4-1 has characteristics of both a rotorcraft and an airplane. The Model JAS4-1 is intended to be used for Title 14, Code of Federal Regulations (14 CFR) parts 91 and 135 operations, with a single pilot onboard, under visual flight rules (VFR). <FTNT> <SU>1</SU>  A V-Tail aircraft design incorporates two slanted tail surfaces instead of the horizontal and vertical fins of a conventional aircraft empennage. The two fixed tail surfaces of a V-Tail act as both horizontal and vertical stabilizers and each has a moveable flight-control surface referred to as a ruddervator. </FTNT> On November 2, 2018, Joby applied for a type certificate for the Model JAS4-1 powered-lift. Under 14 CFR 21.17(c), Joby's application for type certification is effective for three years. Section 21.17(d) provides that, where a type certificate has not been issued within that three-year time limit, the applicant may file for an extension and update the designated applicable regulations in the type certification basis. Because the project was not certificated within three years after the application date above, the FAA approved the applicant's request to extend the application for type certification. As a result, the date of the updated type certification basis is June 14, 2022. The FAA issued a notice of proposed airworthiness criteria for the Model JAS4-1 powered-lift, which published in the <E T="04">Federal Register</E> on November 8, 2022 (87 FR 67399). The FAA issued a notice extending the comment period to December 22, 2022, which published in the <E T="04">Federal Register</E> on December 7, 2022 (87 FR 74994). <HD SOURCE="HD1">Discussion</HD> Because the FAA has not yet established powered-lift airworthiness standards in 14 CFR, the FAA type certificates powered-lift as special class aircraft. Under the procedures in § 21.17(b), the airworthiness requirements for special class aircraft, including the engines and propellers installed thereon, are the portions of the requirements in 14 CFR parts 23, 25, 27, 29, 31, 33, and 35 found by the FAA to be appropriate and applicable to the specific type design and any other airworthiness criteria found by the FAA to provide an equivalent level of safety to the existing standards. These final airworthiness criteria announce the applicable regulations and other airworthiness criteria developed, under § 21.17(b), for type certification of the Model JAS4-1 powered-lift. The Model JAS4-1 powered-lift has characteristics of both a rotorcraft and an airplane. It is designed to function as a rotorcraft for takeoff and landing, and as an airplane cruising at speeds higher than a rotorcraft during the enroute portion of flight operations. The electric engines on the Model JAS4-1 powered-lift will use electrical power instead of air and fuel combustion to propel the aircraft through six 5-bladed composite variable-pitch propellers. Accordingly, the Model JAS4-1 powered-lift proposed airworthiness criteria contained standards from parts 23, 33, and 35 as well as other proposed airworthiness criteria specific for a powered-lift and the engines and propellers installed thereon. For the existing regulations that were included without modification, the proposed airworthiness criteria included all amendments to the existing parts 23, 33, and 35 airworthiness standards in effect as of the application date of June 14, 2022. These are part 23, amendment 23-64, part 33, amendment 33-34, and part 35, amendment 35-10. The Model JAS4-1 powered-lift proposed airworthiness criteria also included new performance-based airworthiness criteria. The FAA developed these criteria because no existing standard captured the powered-lift's various flight modes and electric engines, and some unique characteristics of their propellers. The new requirements specific to the Model JAS4-1 in the proposed airworthiness criteria used a “JS4.xxxx” section-numbering scheme. Because many of the proposed airworthiness criteria are performance-based, like the regulations found in part 23, the FAA has proposed to adopt § 23.2010 by reference, which would require that the means of compliance used to comply with the airworthiness criteria be accepted by the Administrator. Because no powered-lift consensus standards are currently accepted by the Administrator, the means of compliance will be accepted through the issue paper process. <SU>2</SU> <FTREF/> <FTNT> <SU>2</SU>  See Order 8110.112A, <E T="03">Standardized Procedures for Usage of Issue Papers and Development of Equivalent Levels of Safety Memorandums</E> . </FTNT> <HD SOURCE="HD1">Summary of Changes From the Proposed Airworthiness Criteria</HD> These final airworthiness criteria reflect the following changes, in addition to others as explained in more detail under Discussion of Comments: The FAA made changes to the aircraft performance section to incorporate an optional, “increased performance” approval, which requires greater aircraft performance capabilities beyond that of the baseline “essential performance” approval. The expectations for aircraft performance at both levels are clearly defined at the requirement level. Requirements to address various scenarios involving failures that can lead to loss of thrust were clarified and consolidated into a consistent terminology across all airworthiness criteria. Expectations were added for the aircraft to be capable of a controlled emergency landing following any condition where the aircraft can no longer provide the commanded power or thrust required for continued safe flight and landing (CSFL). The proposed requirement to incorporate a bird strike deterrent system was not adopted in these final airworthiness criteria, nor were other requirements not applicable to the Model JAS4-1, such as requirements for operations on water, approval for aerobatic flight, and others, as discussed in further detail under Discussion of Comments. The FAA modified and developed revised aeroelasticity criteria to more directly address concerns expressed by commenters related to “whirl flutter” and aeromechanical stability. The FAA revised requirements in response to numerous comments requesting clarification or recommending changes to address safety gaps in the proposed criteria, particularly in the areas of aircraft handling and control, structural airframe loads and durability, flight controls, protection of occupants, and protection of systems from high-intensity radiated fields (HIRF) and lightning. The FAA updated requirements for electric engines in response to requests for improved clarity on applicability and relationship to the airframe requirements. The FAA also updated definitions for “controlled emergency landing,” “CSFL,” and “sources of lift” and added a definition for “local events.” Lastly, the FAA clarified that, should Joby apply to amend the type certificate to include another model powered-lift, these airworthiness criteria would apply to that model also, provided the criteria remain appropriate to the changed aircraft in accordance with part 21, subpart D. This change was necessary so that each future change to the aircraft will not necessarily require an application for a new type certificate. <HD SOURCE="HD1">Discussion of Comments</HD> The FAA received responses from 46 commenters. The majority of commenters were government agencies, private companies, and organizations as follows: Alaka'i Technologies Corporation (Alaka'i); Aerospace Industries Association (AIA); AIBOT LLC (AIBOT); Airbus; Air Line Pilots Association (ALPA); Agência Nacional de Aviação Civil (ANAC); Archer Aviation Inc. (Archer); Ascot Aviation Associates (Ascot); Aerospace, Security and Defense Industries Association of Europe (ASD-Europe); Association for Uncrewed Vehicle Systems International (AUVSI); BETA Technologies, Inc. (Beta); United Kingdom Civil Aviation Authority (UKCAA); Civil Aviation Administration of China (CAAC); Diamond Aircraft; EASA; End State Solutions; General Aviation Manufacturers Association (GAMA); Hartzell Propeller (Hartzell); LDR; Japan Civil Aviation Bureau (JCAB); Lilium eAircraft GmbH (Lilium); Martin Aerotech; MTLS Aerostructure (MTLS); National Business Aviation Association (NBAA); Od ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ Preview showing 10k of 247k characters. Full document text is stored and available for version comparison. ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━