Standardization News

From The Jetsons to Back to the Future, visions of the 21st century created in the 20th century often depict metropolitan areas of the future with modes of transportation that seem to have escaped the bonds of gravity. Flying cars that look more like personal spacecraft and all manner of other flying vehicles flit about in different directions, at different levels, seemingly at random. Of course, since this was the future, we all assumed that some undreamt-of technology was controlling the flow and keeping everyone safe.

Here in the real world of 2025, however, the situation is more complicated. Civil airspace that was once the exclusive realm of human pilots and navigators is now shared with an ever-expanding fleet of unmanned fellow travelers. The numbers tell the story: As of early December 2024, the U.S. Federal Aviation Administration (FAA) reported that more than one million drones were registered in the U.S. alone, with commercial aircraft representing a little over 400,000 of that total. The agency also counted over 420,000 certified remote pilots.

Managing this increasingly crowded airspace is the job of the FAA and similar civilian aviation authorities (CAAs) around the world. These regulators rely on standards like the ones created by ASTM International and its overseas counterparts to assess the safety and airworthiness of unmanned aerial vehicles (UAV), the preferred industry term for everything from tiny micro-drones to full-sized pilotless aircraft.

FOR YOU: A New Era for UAS Standards

Standards are also crucial to the development and evaluation of functional requirements for unmanned aircraft systems (UAS), which encompass all the elements that enable UAVs to operate: GPS and ground-control modules; transmission and software systems; cameras; and more. [Note that in the case of both UAV and UAS, much of the industry is moving to replace the term “unmanned” with “uncrewed.”]

Unmanned traffic management (UTM) systems designed to facilitate safe integration of UAS into the existing air traffic control (ATC) infrastructure are another focus of standards-development activity.

ASTM’s committee on unmanned aircraft systems (F38) is working with international CAAs and other stakeholders to shape a consistent set of UAS/UTM standards that can be used to help manage the rapid proliferation of unmanned aircraft. Standards developed by the committee on general aviation aircraft (F44) apply to UAVs as part of the airworthiness certification for larger aircraft. What follows is a closer look at this important work.

Understanding UTM

While the ubiquity of recreational drones – and the swooping viral videos shot by camera-equipped UAS – has propelled awareness of this technology beyond the realm of tech-obsessed hobbyists and into the public consciousness, the concept of unmanned traffic management is less well understood.

“UTM is the system that will allow unmanned aircraft to operate safely in airspace that is already shared by manned aircraft,” explains F38 vice chair Philip Kenul. “UTM acts as a digital infrastructure that supports things like flight planning, real-time monitoring, collision avoidance, and coordination between drones, and is essential for scaling up unmanned aircraft operations, especially in urban environments where large numbers of drones may be flying simultaneously.”

Why is UTM so important? F44 member Anna Mracek Dietrich points out that existing FAA-provided ATC services are not designed to accommodate the high volume of smaller drones that operate at lower altitudes. “Larger unmanned aircraft flying at higher altitudes will interface with the existing air traffic management systems [ATM]. UTM is intended to provide supplemental airspace services outside of this system.”

European Collaboration

According to Kenul, other organizations working with ASTM to develop industry-approved consensus standards that will support consistent international UTM regulations include the European Union Aviation Safety Agency (EASA); the European Organisation for the Safety of Air Navigation (commonly referred to as Eurocontrol); Switzerland’s Federal Office of Civil Aviation (FOCA); and the United Kingdom’s Civil Aviation Authority (CAA).

“EASA plays a central role in the regulatory aspects of UAS integration into European airspace, harmonizing standards for UTM and ensuring that these standards align with European safety requirements,” says Kenul. “Eurocontrol is responsible for pan-European air-navigation services and integration of unmanned systems into the broader ATM framework, particularly in terms of coordination across different national systems. These agencies are integral to ensuring that UTM systems are not only standardized and interoperable, but also aligned with the operational realities of managing both manned and unmanned aircraft across the continent.”

Kenul notes that ASTM and European regulators have been working together on these issues for several years, with two primary objectives in mind: 1) Creating a robust framework that allows unmanned aircraft to safely coexist with manned aviation, particularly in congested airspace; and 2) Harmonizing UTM standards globally by aligning U.S. and European technological and regulatory approaches to UAS operations. “This collaboration aims to ensure that operators, regulators, and manufacturers can rely on a unified set of standards, regardless of geographic location,” he says.

Though there is a shared vision for the future of UTM, Kenul points out that different regulatory environments and technological approaches in the U.S. and European countries can pose challenges. “For instance, the European U-Space framework focuses on the operational management of drones in specific airspace categories, with a particular emphasis on safety zones and operational requirements,” he says. “In contrast, ASTM standards focus more on the technological aspects of UTM, such as communication, monitoring, and data exchange, and have a more global focus.” [Note: The term “U-Space” is the European equivalent of UTM in the United States.]

A key component of the collaboration is project SHEPHERD, an initiative launched by the EASA in 2022 with the goal of identifying and developing UAS standards. European regulators have since adopted a number of ASTM standards through SHEPHERD.

The evolution of these standards flows both ways. As an example, Kenul cites ASTM aviation committees that are currently refining their standards and addressing areas where harmonization is needed, in particular with regard to beyond visual line of sight (BVLOS) operation of unmanned aircraft.

Harmonizing UAS standards will allow them to become an integral part of daily life. 

Specific UTM Standards

The following ASTM standards focus on key aspects of UTM:

• Standard specification for UAS traffic management (UTM) UAS service supplier interoperability (USS) (F3548);
• Standard specification for remote ID and tracking (F3411);
• Standard specification for surveillance supplementary data service providers (F3623);
• Standard specification for performance for weather information reports, data interfaces, and weather information providers (WIPs) (F3673).

Kenul describes the purpose of these standards and the context in which they are intended to operate:

F3548: “Addresses the communication and interoperability standards for UAS, which are integral to safe and efficient UTM operations. Clear communication protocols are the backbone of any UTM system, ensuring that unmanned aircraft can communicate with other systems as necessary. This standard provides a framework for the operational requirements of UTM systems, focusing on the technology and processes needed to safely manage UAS in shared airspace, and is pivotal in ensuring that UTM solutions are compatible across borders.”

F3411: “Defines requirements for remote identification (Remote ID) of UAS, a security feature for integrating drones into the broader ATM system that ensures unmanned aircraft can be identified in real-time, enhancing safety and security.”

F3623: “Defines minimum performance requirements for surveillance supplemental data service providers (SDSPs) and associated equipment and services. Surveillance SDSPs may provide aircraft track information to detect-and-avoid systems and situational awareness tools to enable BVLOS UAS operations and support visual line of sight (VLOS) operations. This specification also defines requirements on users of the Surveillance SDSP’s services.”

F3673: “Addresses the standard of performance for weather information reports, analyses, and services performed by a weather information provider (WIP) in support of extensible traffic management (xTM) systems, unmanned aircraft systems (UAS), and vertical takeoff and landing (VTOL) systems operating from the surface to 5,000 ft (1524 m) above ground level.

F3548 and F3411 have particular relevance to ASTM’s collaborative interactions with civil aviation authorities around the world. Kenul notes the influence of these standards in Europe, where the issues they address are under discussion, and also that they are being used as references by other international aviation regulatory bodies.

“The global reach of F38’s standards is a testament to their broad applicability. By collaborating with European regulators, we are making sure that these standards are applicable not just in the U.S. but across borders, providing a universal safety framework for UAS operations that supports both UTM and advanced air mobility systems,” Kenul concludes.

The Evolution of Part 23

The discussion thus far has focused on the aerial environment, where UAVs share the skies with piloted aircraft. But what about the UAVs themselves? How are standards evolving to keep up with advances in drone technology and functionality? Before answering these questions, some history might be useful, and it starts with FAA regulation 14 CFR Part 23, known within the industry simply as “Part 23.”

“Part 23 is an airworthiness certification regulation,  which is a technical specification that airplanes need to comply with in order to be awarded a type certificate and to be brought into service,” explains F44 chair Christoph Genster. “This specification ensures that the airplanes meet safety standards appropriate for the class of aircraft. For many years, these specifications were very prescriptive and maintained by each individual CAA. This meant that any change would have to go through the prescribed rulemaking processes of the respective countries before it could be applied, a process that typically took many years.”

As far back as 2009, the FAA realized that its airworthiness regulations were not keeping pace with rapid improvements in traditional aircraft technology, and in subsequent years, initiated a shift from very specific, prescriptive design requirements to performance-based airworthiness standards that went into effect in 2017.

The committee on general aviation aircraft was formed in 2012 in response to these developments. “The committee was founded and charged with extracting the prescriptive details from the airworthiness regulations and maintaining and developing the content to address available technology and also technology that is anticipated in the near future,” Genster says. “The airworthiness specifications maintained by the CAAs were changed to performance-based rules that stated the high-level safety objectives.”

READ MORE: Standards Up in the Air

But what exactly does a performance-based standard look like in this context? According to the Aircraft Owners and Pilots Association (AOPA), “A performance-based standard establishes a level of performance that must be achieved through the airplane’s design, rather than dictating how a manufacturer should arrive at a particular level of performance.”

AOPA uses the example of airplane cabin exit design to illustrate the difference. The performance-based standard that was proposed and ultimately approved by the FAA requires the design to enable “evacuation of the airplane within 90 seconds in conditions likely to occur following an emergency landing,” but does not say anything about specific ways to achieve this result (such as cabin lighting, signage, etc.).

Mracek Dietrich sums up the Part 23 shift this way: “The F44 standards provide an accepted set of prescriptive details, developed through the consensus of technical experts. This information allows the CAAs to focus on setting the required level of safety with their regulatory requirements, and for these regulations to be relatively stable in the face of innovation.”

Part 23 and Unmanned Aircraft

The preceding summary of the evolution of Part 23 was presented in the context of traditional aircraft (i.e., those with pilots). But what did this change in approach toward airworthiness standards mean to the unmanned aircraft industry?

“The ASTM standards contain technical requirements for manned general aviation airplanes,” says Genster. “However, the majority of content can be used as airworthiness requirements for unmanned aircraft. This also allows optionally manned aircraft using the same airframe as a basis,” he says.

Mracek Dietrich echoes this opinion. “The vast majority, if not all, of the work in both F44 and the committee on light sport aircraft (F37)  is directly relevant to UAVs of similar size and complexity to the manned versions that were the original focus of those committees. Having a mature standards base from established portions of the general aviation industry definitely has helped the unmanned aircraft industry move faster than it would have without that library. Initially focused on smaller UAVs, F38 has done a lot of work to provide a requirements context that the FAA and industry can draw upon.”

It’s important to note that ASTM has multiple committees focused on aviation (F37, F38, F39, F44, and F46) and each of these groups is producing standards applicable to specific types of aircraft, operations, and/or people. These committees have also developed standards that, in the words of F38 chair Mark Blanks, “May be suitable to UAS across a wide safety continuum, from low-risk, small aircraft to passenger-carrying systems. One size standard doesn’t fit all, but ASTM is working across a very broad portfolio.”

“Since many entrants into the UAV space are coming from non-aviation backgrounds, the entire standards set developed by these committees is important for both efficient development and safety,” notes Mracek Dietrich, emphasizing that the UAS industry is forging ahead even as UTM standards continue to be proposed, vetted, and ultimately approved.

“Additional airspace-management tools and services have the potential to make more complex operations possible and to make current operations simpler to get authorization for,” she concludes. “But the unmanned aircraft industry is already doing a lot of great things in the airspace.” today.” ●

Jack Maxwell is a freelance writer based in Westmont, NJ.