NAA Network Releases First Roadmap for Advanced Air Mobility Aircraft Type Certification

The Paris Air Show included the exciting unveiling of the National Aviation Authorities (NAA) Network's first "Roadmap for Advanced Air Mobility Aircraft Type Certification" (the Roadmap). U.S. Secretary of Transportation Sean Duffy, alongside Federal Aviation Administration (FAA) Acting Administrator Chris Rocheleau, presented the Roadmap, which provides a first-of-its-kind plan for collaboration of aviation authorities and alignment of overall standards and approaches for type certification of Advanced Air Mobility (AAM) aircraft, all in the interest of increasing efficiency throughout the review process.¹

The Roadmap marks a significant milestone in collaboration of aviation authorities from Australia, Canada, New Zealand, the United Kingdom (U.K.) and the United States. Aviation authorities from each of the five authorities declared their support for the Roadmap. These authorities' issuance of the Roadmap occurred alongside their declaration of intent to foster development at a fast pace. They each agreed with the "importance of fostering cooperation and building resilience" and declared their intention to deliver solutions for the challenges of "safely type certifying Advanced Air Mobility aircraft and rapidly evolving aviation technologies."

The Roadmap emphasizes six key principles to guide certification of AAM technologies, including aircraft:

1. safety and innovation
2. harmonized type certification
3. collaboration and alignment
4. collaborative multi-authority validation
5. incremental approach
6. AAM inclusive bilateral agreements

The Roadmap contains information concerning each of the six principles. For example, in the interest of collaboration and alignment, NAA Network authorities will exchange Means of Compliance information as part of the overall validation effort of ensuring an aircraft fulfills the relevant airworthiness standard. Through prioritization of each of the above-listed principles, the Roadmap indicates the NAA Network's overall goal is to reduce the certification burden on those seeking type certification for a novel design of an aircraft.² But perhaps the most salient points in the Roadmap are those that touch each of the above-listed principles – the use of the safety continuum model and upcoming efforts to achieve overall harmonization of approaches.

Safety Continuum and Performance-Based Standards

The Roadmap is consistent with the overall mindset of adopting a risk-based framework in a manner that pervades all certification projects for novel types of aircraft. The Roadmap states the NAA Network will "focus type certification effort proportionate to operational risk resulting in a simplification of type certification effort." It also commits to using a "tiered approach" that aligns with the safety continuum, in which NAA Network authorities will assess and address risk in a tailored manner that considers the type of AAM operation and maximum number of passengers that an aircraft might carry.

The Roadmap states that the NAA Network not only recognizes the safety continuum approach but also plans to use it "when seeking convergence on airworthiness requirements" and when applying airworthiness standards. Use of this safety continuum approach means authorities will generally increase their levels of scrutiny or analysis of the applicability of appropriate airworthiness standards in a manner that is proportionate to the level of risk that an aircraft (and a prospective operation of that aircraft) would present. The Roadmap cites the FAA's Policy Statement PS-AIR-21.17-03, "Safety Continuum for Powered-Lift," as background material that is relevant to the Roadmap.

The FAA has historically engaged in the type certification approach governed by 14 C.F.R. 21.17(b), which applies to special classes of aircraft. When airworthiness standards do not exist under the subchapter that applies to aircraft design, Section 21.17(b) has long allowed those designing aircraft to apply a collection of various requirements from 14 C.F.R. parts 23, 25, 27, 29, 31, 33 or 35, as long as such proposed requirements are appropriate for the aircraft and applicable to a specific type design or consist of airworthiness criteria that the FAA finds will provide a level of safety that is equivalent to the level of safety that compliance with existing standards would reach.

Notably, among the parts listed above, 14 C.F.R. Part 23, which applies to Normal Category Airplanes, employs the helpful approach of using performance-based, rather than prescriptive, regulations. As such, obtaining type certification that reaches the necessary level of safety is possible and can provide the flexibility to propose a novel means of compliance for achieving the applicable standards. Designers and manufactures can request acceptance of such a means of compliance with certain criteria codified in Part 23; as long as the means indeed achieves the standard, the FAA has a process for accepting it. The model of accepting a means of compliance provides inherent flexibility – development and acceptance of a means of compliance indicates approval of one way, but not the only way, of fulfilling an airworthiness requirement.

Understanding the approach of carefully selecting applicable airworthiness criteria or requirements in a manner consistent with Section 21.17(b) is fundamental to understanding the approach of the Roadmap.³ The NAA Network regards Section 21.17(b) as the basis for not only the FAA's approach for type certification but also the general approach of Australia's Civil Aviation Safety Authority, the Transport Canada Civil Aviation and U.K.'s Civil Aviation Authority (CAA). Similarly, the Roadmap describes the Civil Aviation Authority of New Zealand as planning to utilize a flexible regulatory approach in accepting design standards on a case-by-case basis.

Harmonization Among NAA Network Authorities

The Roadmap indicates NAA Network authorities are aware of distinctions between airworthiness criteria and means of compliance, as well as procedures for obtaining acceptance of means of compliance. In response to potential divergence between NAA Network authorities' standards or means of compliance, the NAA Network commits to making efforts to achieve harmonization of type certification using a three-phased approach:

1. Adopt a performance-based approach by using flexibility that already exists in regulatory frameworks. Overall, the Roadmap states the NAA Network intends to use AAM-specific certification requirements set forth in Appendix A of FAA Advisory Circular (AC) 21.17-4, "Type Certification – Powered-Lift," along with airworthiness criteria published by NAA Network authorities and the U.K. CAA's adoption of the European Union Aviation Safety Agency's (EASA) Special Condition for Vertical Take-off and Landing (SC-VTOL) Aircraft.
2. Address differences between NAA Network authorities' AAM requirements by "converging" on airworthiness requirements. This convergence will entail increased collaboration and sharing of type certification knowledge. The Roadmap estimates that approximately 60 percent of certification requirements for AAM "are already known" to the NAA Network; for the remaining 40 percent, the NAA Network anticipates the introduction of certification requirements for AAM. The Roadmap further indicates that the NAA Network has realized the primary differences that currently exist in airworthiness requirements are between the FAA Airworthiness Criteria published in FAA AC 21.17-4 and the U.K. CAA SC-VTOL. The Roadmap contains a commitment to harmonizing such requirements. In the event that NAA Network authorities are unable to reach agreement on any airworthiness requirement, the NAA Network intends to use consensus standards by coordinating participation in AAM-related work of industry Standards Development Organizations.
3. Mutually accept means of compliance with airworthiness requirements. In achieving such mutuality, NAA Network authorities will maximize the use of industry-driven consensus standards. NAA Network authorities will also develop common guidelines and procedures for demonstrating compliance, with the ultimate goal of increasing efficiency.

Next Steps

The NAA Network will engage in an incremental approach throughout its efforts to align standards to minimize differences among airworthiness criteria. NAA Network authorities will develop supplemental airworthiness criteria and special conditions over time to support type certification of AAM aircraft that are increasingly complex and innovative. The Roadmap indicates piloted AAM will be the first type of aircraft that will achieve type certification, followed by remotely piloted AAM and finally autonomous AAM. As the complexity or risk of each type of aircraft and operation increases, NAA Network authorities plan to share Means of Compliance information and employ industry consensus standards to address risk.

According to the Roadmap's Timeline of Activities, the NAA Network plans to begin several activities at present or at least by July 2025: the NAA Network will converge differences in airworthiness requirements for electric vertical take-off and landing (eVTOL) certification; exchange information across the NAA Network; and review, update and initiate bilateral agreements for AAM certification and validation. The NAA Network will begin development of hydrogen or hybrid electric airworthiness requirements in January 2026 after reviewing involvement with standards development organizations across the NAA Network and after initiating opportunities for multi-authority eVTOL validation. The NAA Network will begin developing a second edition of the Roadmap in January 2026.

Throughout the Roadmap, the NAA Network acknowledges the quickly evolving nature of the industry. In this regard, the NAA Network characterizes the Roadmap as a "living document" in which authorities in the NAA Network seek to collaborate to align standards that address the "ever-evolving landscape" of aviation technology.

Please reach out to the author with any questions about the Roadmap or its potential impact to your business.

Notes

¹ As used throughout the Roadmap, Advanced Air Mobility (AAM) is "a sector that encompasses new aerial transportation technologies, including electric Vertical Take-off and Landing (eVTOL) aircraft."

² A type certificate refers to design approval that an authority issues upon finding an applicant has demonstrated that a product complies with applicable regulations. Validation is the process used by one authority to approve the type certificate that another authority has issued; processes and requirements for such validation are contained in bilateral agreements.

³ Airworthiness criteria are portions of airworthiness standards codified in FAA regulations or other criteria identified by the authority to provide an equivalent level of safety to the existing standards that the authority has found are appropriate. Airworthiness requirements are comprehensive and detailed sets of airworthiness codes that the authority has established for specific type design; this term includes airworthiness standards and airworthiness criteria.