A team from Helios and the University of York has been investigating the changing aviation safety risk landscape associated with the advent of autonomous and electric powered vertical take-off and landing (eVTOL) aircraft and drones.
The work was commissioned by the Future Flight (FF) Challenge, a UK Research and Innovation initiative to advance new aviation technologies such as drones, urban air mobility aircraft and hybrid-electric regional aircraft that will transform the way people and goods fly. The FF challenge is looking at the big picture, not just future aircraft themselves but also the system they fit into, such as ground infrastructure, regulations and the control systems behind safe operations. The aim of this particular study is to de-risk the development of the future aviation system by identifying and proposing solutions to key safety issues early on.
How do you begin this kind of project? The scope is potentially so broad that an essential first step is to agree a framework for moving forwards. We began by enlisting the help of a working group of industry experts – fifteen in total - representing many different types of organisations within the aviation community. Their role was to validate the study outputs at key points throughout the project. We then set out the baseline – a description of today's system, the actors within it, and the regulatory structure.
To shape the analysis, we developed three future scenarios representing the evolution of the aviation system over different time horizons out to 2035. Each scenario moved the baseline forwards, including a 'map' of the expected actors within the aviation system at that point and a description of how the system might be regulated and managed. The scenarios were not meant to be fixed points of development but rather tools to show the evolution of systems and operations.
Within those scenarios, we explored three use cases aligned with the objectives of the wider future flight challenge: Drones, initially remotely piloted but becoming fully autonomous, including drones for delivery, inspection, monitoring or broadcast and drones that perform robotic functions (e.g. repair, crop spraying); Urban Air Mobility (UAM) expanding from today's helicopter transport to eVTOL aircraft and eventually autonomous air taxis for example; and finally Regional Air Mobility (RAM), larger forms of UAM aircraft accommodating 10 to 100 passengers (or cargo equivalent) and making city-city hops. Similar to UAM, these aircraft will make use of new technologies to reduce the carbon footprint of the vehicle and may include pure or hybrid electric and hydrogen fuel cell forms of propulsion.
Four transversal safety themes
It was evident that there were some core themes running across all use cases and scenarios that deserved specific attention from a safety management perspective.
- 1. Safety management of complex systems - The complexity of systems and the role of humans and organisations means that accurate predictive quantitative safety analysis is challenging - and will become even more challenging in the future. This is an emerging area of expertise and one that our study partners from the University of York have been developing alongside the Royal Academy of Engineering and the Lloyds Register Foundation.
- 2. Integrated risk and safety management - There are many participants in the aviation system that together contribute toward safety outcomes. If not well managed, safety objectives within one organisation can be in contradiction with safety objectives in another organisation. Whilst tools already exist for considering risk across organisational boundaries, as new FF service providers join the aviation system it will be important for all participants to understand how their operations might impact aviation safety risks. The theme also includes a broader appreciation of risk across the different risk outcomes (e.g. safety, security, environment) and how they can be managed in a more integrated way.
- 3. Role of the human and autonomy - Increasing autonomy, the use of artificial intelligence and machine learning will change the role of the human in operations. Humans will oversee autonomous systems in their own organisation and also interact with external autonomous systems. How will humans adapt to this? And how can we ensure that autonomous systems are capable of maintaining control and safely resolving the situation under all failure modes?
- 4. Supporting infrastructure - Physical and digital infrastructure will need to evolve to meet the FF operations and be resilient to cyber security threats. The scenarios envisage the development of 'vertiports' and charging infrastructures to accommodate new aircraft. The main challenge perhaps is that there will always be mixed equipage in aircraft and mixed infrastructure. What safety implications are there across such a diverse system of users that at least partially share the same airspace?
Exploring these transversal themes with our working group, the study team has begun to develop a safety case framework, with a particular focus on the strategic aspects of the argument and constructed in the goal structuring notation (GSN) language that is familiar to many safety professionals.
The framework is a means to identify principal activities and tasks necessary to demonstrate that the future aviation system is 'tolerably' safe. These activities and tasks can then be used to build a roadmap to develop the safety case in a collaborative and practical manner. We'll be sharing some of the outputs of this work and actively inviting reader feedback in the weeks ahead!
Want to learn more? Project lead Richard Derrett-Smith will be speaking on the progress and key challenges associated with the development of the Future Flight Safety Case Framework, on the 13th of November 2020 at 13:00. (In partnership with the Knowledge Transfer Network and UK Research & Innovation) you can register for the webinar here.
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