Technical, regulatory and social issues must be overcome if unmanned aircraft are to be successfully integrated into US public airspace.
Those were the main conclusions in a report issued this week by the National Research Council. The 92-page report that identifies key barriers and provides research recommendations that could help answer the serious questions about how drones will be safely and efficiently integrated into the existing civil aviation structure.
The report, requested by NASA’s Aeronautics Research Mission Directorate, uses the term “increasingly autonomous” systems to describe a spectrum of technologies, from unmanned aircraft that are piloted remotely – which describes most such aircraft currently in use -- to advanced autonomous systems for unmanned aircraft that would adapt to changing conditions and require little or no human intervention. Increasingly autonomous systems could also be used in crewed aircraft and air traffic management systems to lessen the need for human monitoring and control.
“Development of such systems is accelerating, prompted by the promise of a range of applications, such as unmanned aircraft that could be used to dust crops, monitor traffic, or execute dangerous missions currently undertaken by crewed planes, such as fighting forest fires. The FAA currently prohibits commercial use of unmanned aircraft without a waiver or special authorization,” the report notes.
According to the report, “ one critical, crosscutting goal that must be achieved before increasingly autonomous aircraft and other systems can reach their full potential is ensuring that they will perform with the high level of safety and reliability expected of civil aviation systems, says the report. It identifies specific technological, regulatory, and other barriers that must be overcome in order to reach that goal.”
The report focused on three key challenges:
- Technological barriers include the inherent difficulty associated with characterizing and predicting the behavior of systems that can adapt to changing conditions. This poses a particular challenge in engineering increasingly autonomous unmanned aircraft to be compatible with already-existing air traffic management systems and other elements of the national airspace system. Also, the ability of systems to operate independently of human operators is currently limited by the capabilities of machine sensory, perceptual, and cognitive systems. The use of increasingly interconnected networks and complex software embedded throughout unmanned systems as well as the potential for cyber attacks threaten the safety and reliability of unmanned technology. The operations of such aircraft could also significantly increase the demand on bandwidth.
- Regulation and certification barriers include the fact that existing processes, criteria, and approaches for certifying aircraft do not adequately address the special characteristics of advanced autonomous systems. In addition, many existing safety standards and requirements, which are focused on ensuring the safety of aircraft passengers and crew, are not well-suited to ensure the safety of unmanned aircraft operations, where the main concern is the safety of people in other aircraft and on the ground.
- Other barriers include social issues, such as public concerns about privacy and safety, and legal hurdles, such as public policy, reflected in law and regulation.
The report recommends a national research agenda that would involve government agencies, industry, and academia. The committee described eight research projects, but said it considered these four to be the most challenging:
- Behavior of adaptive/nondeterministic systems. Technologies that enable aircraft to adapt to uncertain environments and to learn based on experience will be integral to many advanced autonomous aircraft. As autonomous systems take over more functions traditionally performed by humans, there will be a growing need to incorporate autonomous monitoring and other safeguards to ensure that appropriate operational behavior continues. Research is needed to develop new methods and tools to address the inherent uncertainties in airspace system operations due to factors such as weather and conflicting air traffic and thereby enable advanced autonomous systems to improve their performance and provide greater assurance of safety.
- Operation without continuous human oversight. Enabling unmanned aircraft to operate for extended periods of time without real-time human oversight will require that the autonomous systems be able to perform certain critical functions currently provided by humans, such as “detect and avoid” and contingency decision-making. Successful development of these systems and technologies depends on understanding how humans perform their roles currently and how to translate these roles to the autonomous system, particularly for high-risk situations.
- Modeling and simulation. Modeling and simulation capabilities will play an important role in the development of increasingly autonomous systems because they enable researchers, designers, regulators, and operators to get information about how an aircraft -- or one of its systems or components -- performs without actually testing it in real life. For example, computer simulations may be able to test the performance of an autonomous aircraft in millions of scenarios in a short timeframe to produce a statistical basis for determining safety risks. The committee recommended the creation of a distributed suite of modeling and simulation modules developed by disparate organizations with the ability to be interconnected or networked; monolithic modeling efforts that are intended to “do it all” and answer all questions posed tend not to be effective.
- Verification, validation, and certification. The national airspace system’s high levels of safety largely reflect the formal requirements imposed by the FAA for verification, validation, and certification of hardware and software and the certification of people as a condition for entry into the system. Extension of these concepts and principles to highly autonomous aircraft and systems is not a simple matter and will require the development of new approaches and tools.
Many of the National Council’s observations reiterate findings from the Government Accountability Office and others. For example in 2013 the GAO wrote: “The bottom line for now seems to be that while research and development efforts are under way to mitigate obstacles to safe and routine integration of unmanned aircraft into the national airspace, these efforts cannot be completed and validated without safety, reliability, and performance standards, which have not yet been developed because of data limitations.”
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