Air transportation is undergoing a rapid evolution globally with the introduction of Advanced Air Mobility (AAM) and with it comes novel challenges and opportunities for transforming aviation. As AAM operations introduce increasing heterogeneity in vehicle capabilities and density, increased levels of automation are likely necessary to achieve operational safety and efficiency goals. This paper focuses on one example where increased automation has been suggested. Autonomous operations will need contingency management systems that can monitor evolving risk across a span of interrelated (or interdependent) hazards and, if necessary, execute appropriate control interventions via supervised or automated decision making. Accommodating this complex environment may require automated functions (autonomy) that apply artificial intelligence (AI) techniques that can adapt and respond to a quickly changing environment. This paper explores the use of Deep Reinforcement Learning (DRL) which has shown promising performance in complex and high-dimensional environments where the objective can be constructed as a sequential decision-making problem. An extension of a prior formulation of the contingency management problem as a Markov Decision Process (MDP) is presented and uses a DRL framework to train agents that mitigate hazards present in the simulation environment. A comparison of these learning-based agents and classical techniques is presented in terms of their performance, verification difficulties, and development process.
I. IntroductionT he air transportation system is currently undergoing a rapid evolution with the introduction of novel concepts and the demand for an increase in operational efficiency. One of those novel concepts is Advanced Air Mobility (AAM), which foresees the transport of cargo and passengers across cities, as well as communities currently under-served by aviation. These AAM operations may include electric vertical take-off and landing (eVTOL) aircraft, high-density operations, and a combination of piloted (i.e., remote or on-board) and autonomous flights. Across the world, organizations such as the FAA, NASA, and EASA expect these operations to increase in density from a single operation per hour to over 100 simultaneous operations per hour over a local region [1][2][3][4]. The FAA and NASA refer to the increasing phases of complexity for AAM operations as Urban Air Mobility (UAM) Maturity Levels (UML). Low-density human piloted airspace operations are classified as UML 1, while highly autonomous and dense operations are described as UML 4 and beyond. Evident in NASA's and the FAA's concepts of operations, is an expectation that some types of operations will transition from human piloted to fully autonomous operations. Artificial Intelligence (AI) techniques are viewed as one way to enable higher levels of autonomy because the operations will need to make safety critical DISTRIBUTION STATEMENT A. Approved for public release. Distribution is unlimited.