Electrified Powertrain Flight Demonstrations (EPFD)
HS Advanced Concepts LLC continues to support the ASTM and SAE committees in the areas of electrified aircraft propulsion and alternative fuels for conventional propulsion.
Along with participation in the following six committees, HS Advanced Concepts LLC chairs the ASTM F44.40 Powerplant Subcommittee’s Working Group WK66028 on Distributed Electric Propulsion. The objective of the working group is to revise ASTM F3239 to make the standard applicable to Distributed Electric Propulsion systems.
HS Advanced Concepts LLC supports three committees in ASTM:
Committee F44 on General Aviation Aircraft — addresses issues related to design and construction, systems and performance, quality acceptance tests, and safety monitoring for general aviation aircraft (also known as Part 23, Normal Category Airplanes) that are less than 19,000 pounds and 12 passengers.
Committee F39 on Aircraft Systems — develops standards for electrical wiring system design, fabrication, modification, inspection, and maintenance procedures and processes.
Committee D02 on Petroleum Products, Liquid Fuels, and Lubricants — was formed in 1904, and meets twice a year, in June and December. The committee, with a current membership of 2,374 industry professionals and experts, currently has jurisdiction over 863 standards, published in five volumes of the Annual Book of ASTM Standards. These standards have played, and continue to play, a preeminent role in all aspects of the standardization of Petroleum Products and Lubricants.
HS Advanced Concepts LLC supports four committees in SAE:
E-40 Electrified Propulsion Committee — was established in 2018, and its membership counts over 400 experts from 18+ countries. E-40 develops and maintains standards, recommended practices, and information reports covering hybrid and electric propulsion for aircraft.
AE-10 High Voltage Committee — is a technical committee to develop and maintain SAE Technical Reports for use in aircraft and engine electrical systems in support of applications for voltage levels as defined in SAE AIR7502 for level 4 and higher.
G-35A Pilot Training and Certification Committee — was formed to address the need for pilot training and qualification required to obtain the certificate/license necessary to operate vertical takeoff and landing (VTOL)-capable aircraft (VCA) (also referred to as powered-lift [PL]), which are part of the ecosystem of advanced air mobility (AAM).
G-35C Modeling Simulation for Aircraft Certification Committee — brings together experts from academia, design, manufacturing, operations, regulators, and testing to develop consensus-based standards to be used as a means of compliance for certification.
HS Advanced Concepts LLC supported the Electrified Powertrain Flight Demonstrations (EPFD) project through its untimely cancellation in September 2025. The focus was to help the EPFD effort in the Regulations and Standards Development (R&SD) team develop standards that support the Means and Methods of Compliance (MOC) for integrated MW-class powertrain systems for large transport-category airplanes.
The support included managing the Regulations and Standards Working Group (RASWG), which comprises subject-matter experts in electrified aircraft propulsion (EAP) and related efforts. All of them support the development of standards in ASTM, SAE, RTCA, and other standards development organizations (SDOs).
The support included working with industry partners in EPFD, supporting the EPFD R&SD Team Lead by learning best practices from industry teams, and sharing concepts to advance the state of the art in standards for integrated MW-class powertrain system technologies.
In July 2026, HS Advanced Concepts LLC, together with Mr. Chris Baczynski of BAC Aerospace Inc. and Mr. Zach Kaufman, formerly with magniX, developed a report with a comprehensive comparison of the regulatory text of the European Union Aviation Safety Agency (EASA) Special Condition (SC) E-19 and the Federal Aviation Administration (FAA) special conditions for the certification of electric engines.
The report provides a regulatory gap assessment of the special conditions for electric engines from both the FAA and EASA. This information is presented to support ongoing international harmonization efforts for electric engine certification, to establish a level of safety consistent across regulatory bodies and equivalent to that of existing combustion engines.
The Assessment of Aircraft Electric Engine Regulatory Special Conditions is a NASA Contractor Report, NASA/CR-20260004921.
In August 2023, HS Advanced Concepts LLC, together with the NASA EPFD Regulations and Standards Development Team Lead, provided a webinar to the Advanced Air Mobility (AAM) Ecosystem Crosscutting Working Group on Aircraft Electrification Gap Analysis and its potential application to AAM.
Watch the webinar on this YouTube channel.
In September 2024, HS Advanced Concepts LLC chaired a panel at the 34th Congress of the International Council of the Aeronautical Sciences (ICAS) on A Call to Action to Engage the Technical Community to Make Aircraft Electrification Real through Regulations and Standards. The panel was comprised of:
V.P. Schultz, NASA Langley Research Center, United States
H. Schlickenmaier, HS Advanced Concepts LLC, United States
L. Daelemans, European Union Aviation Safety Authority, Germany (absent)
C. Genster, Diamond Aircraft, Austria
M. Walz, Federal Aviation Administration, United States
E. Holtz, Harbour Air, Canada
Dr. Susan Ying, Ampaire, United States
The thesis was that more is needed to implement novel electrified aircraft than simply reduce technology risk. These novel Electrified Aircraft Propulsion (EAP) companies plan to certify their novel aircraft where no current regulations exist. The NASA Electrified Powertrain Flight Demonstration (EPFD) project has partnered with two companies to build upon their approaches to close these gaps in regulations and standards in their EAP technologies.
A copy of the ICAS paper can be found here.
Initial Assessment of Aircraft Certification Procedures for Emerging Technologies
NASA Langley Research Center and the National Institute for Aerospace tasked HS Advanced Concepts LLC to… “Identify gaps that may exist due to emerging technologies in both new certification rules and existing standards used as means of compliance to these rules for Normal Category Aircraft.”
HS Advanced Concepts LLC has published three NASA reports supporting the NASA X-57 Distributed Electric Propulsion flight demonstrator’s primary objectives associated with airworthiness certification:
Certification Gap Analysis, “…describes a generic method for addressing any new technology to its associated set of regulations and certification criteria. The result is a framework under which a detailed assessment can be conducted. Using just such a framework, the report maps the detailed updated regulations and evolving ASTM standards to the particular technology planning and tests. As a result, a roadmap of NASA technology is documented that shows clear transfer of technology data to industry (standards developers, as well as technology developers) and the FAA regulatory policy and certification staff upon whom certification and policy will be data-driven. A clear description of benefits and gaps are identified, as well.”
Certification Rules and Standards Review, “…characterizes the certification practices for electric propulsion systems by modeling changes to current engine and propeller certification practices (14 CFR 23, 33 and 35 and means of compliance in standards developed by ASTM Committee F39 and F44). Industry technology paths are varied, so this report focuses on insights from the NASA X-57 Maxwell Distributed Electric Propulsion flight demonstrator system technology project. There are 122 sections of the regulation reviewed, where 28 needed tailoring or revision. A second report will examine the regulations to the X-57 system development products. A final report will describe a general regulatory gaps method for new vehicle concepts.”
Certification Coordination Roadmap, “Innovative technology has to prove itself in the context of legacy regulations. The knowledgeable technologist must engage standards process and regulating authorities to understand their roles and to advise the effect of new technology, and with manufacturers to demonstrate technology benefit. A model for Innovative Technology Environment relating NASA to industry, standards and regulation is described. The needs of the standards community of the X-57 are identified, and a NASA standards structure is described. No NASA project works with standards and regulatory organizations like the X-57.”
NASA X-57 Airworthiness Validation Plan Report
NASA Langley Research Center and the National Institute for Aerospace tasked HS Advanced Concepts LLC to… “develop an airworthiness validation plan for an advanced aircraft with distributed electric propulsion, using the X-57 as an example application. ”
There are four related activities to support this development:
Development of an Example Certification Basis
Development of a Cross-Reference of X-57 Requirements to the Compliance Checklist and Verification Artifacts
Support NASA Standards Development of Gaps and Cross-References
Support an Airworthiness Certification Workshop
HS Advanced Concepts LLC published a NASA report supporting the NASA X-57 Distributed Electric Propulsion Airworthiness Validation Plan. The report simulates a Certification Plan by assessing the variety of novel technologies in the X-57 against 14 CFR Parts 23, Normal Category Airplanes, 33, Aircraft Engines, and 35, Propellers, along with the associated standards for those regulations. HS Advanced Concepts LLC was supported by Designated Engineering Representatives (DER) and other subject matter experts in the development of the Airworthiness Validation Report.
X-57 Maxwell Airworthiness Validation Plan, “This report is a Final Airworthiness Validation Plan (AVP) and describes how an aircraft like X-57 does (and does not) meet current airworthiness standards. The objective of this report is to create an example certification basis, associated means of compliance (MoC), and method of compliance for a distributed electric propulsion airplane under 14 Code of Federal Regulations (CFR) Part 21, “Certification Procedures for Products and Articles,” and its associated relevant sections of 14 CFR for “Airworthiness Standards” of Part 23, “Normal Category Airplanes,” Part 33 “Aircraft Engines,” and Part 35 “Propellers.” The approach to meet the objective is to use NASA’s X-57 Modification (Mod) IV flight demonstrator as an example and categorize its applicability to the regulations and standards according to the following three conditions: 1. Identify, where applicable, that the MoC and methods of compliance can be associated with existing Standard Specifications and Standard Practices of (ASTM) Committee F39 on Aircraft Systems and ASTM Committee F44 on General Aviation Aircraft; 2. If relevant ASTM standards do not exist, identify means and-or methods of compliance from appropriate Federal Aviation Administration (FAA) Advisory Circulars and other sources to use for the X-57 Mod IV vehicle; or 3. If no relevant certification rule, MoC, or method of compliance exists, highlight this omission and provide recommendations.”
SUbsonic Single Aft eNgine (SUSAN) Electrofan
HS Advanced Concepts LLC supported the civil aviaiton Regulations and Standards analysis of the SUbsonic Single Aft eNgine (SUSAN) Electrofan initiative under the Convergent Aeronautics Solutions (CAS) project.
Support the X-57 Project Office on Management of Standards Development
NASA Langley Research Center and the National Institute for Aerospace tasked HS Advanced Concepts LLC to… “Provide the NASA X-57 PO with support on project- related technology transfer associated with certification and regulations under FAR 23 Normal Category Airplanes, FAR 33 Aircraft Engines, and FAR 35 Propellers, as well as the associated Means of Compliance to those regulations being developed by the ASTM Committees F44 on General Aviation Aircraft and F39 on Aircraft Systems.…”
There are seven tasks:
Produce a Monthly Project Technology Standards Report based on NASA-furnished X-57 Project Progress Reports
Establish Structure for Standards Practice
Conduct Quarterly Review and Recommendation
Support ASTM F44 Committee Meetings in Brussels, Houston and Prague
Communicate Standards Progress to the Technical Community at the AIAA Aviation Conference and Exposition in 2019 and 2020, and the AIAA Propulsion & Energy Conference 2019, including the AIAA-IEEE Electric Aircraft Technology Symposium
Airworthiness Validation Plan Development
Reviews and Reporting
