# ATC Human Factors Involved in RPAS Contingency Management in Non-Segregated Airspace
## 3 Experiments
### Systems and Human-machine Interfaces in the ERAINT Project  
In the context of manned aviation, a \"machine\" primarily relates to an aircraft flown by pilots and to work stations used by air traffic controllers. However, the concept of \"machine\" more broadly encompasses any device that the pilots and controllers are interfacing with, be it a mobile phone, laptop computer, RPAS system, etc. Interfacing with a machine is mastering the physical interface between the human user and the system and the mental model implemented in the machine's architecture and logic. If the machine's design has been well thought out and user-centred, this should mirror the user's mental model. In order to interface with/supervie an RPAS, the ERAINT project [24] provides a set of HMI and simulation environments such as the ATC traffic interface, the ATC-RPAS pilot communication system, and the command-and-control system of the RPAS, etc. The simulation environment comprises two main components, the RPAS simulation system and the ATM simulation system. The RPAS simulation architecture includes both the simulation of the RPA air vehicle and its onboard components and the provision of a ground control station for the PiC that supports real-time interactions. The real-time manned traffic and ATC control within the selected airspace was carried out by the Early Demonstration and Evaluation Platform (eDEP) provided by Eurocontrol [30]. eDEP provides real-time air traffic management simulation tools, air traffic controllers positions, and pseudo-pilot positions per sector with a model of controller behaviour and a replay mechanism to record simulation data. Airspace sectorization, structure, and historical manned traffic were extracted from the Eurocontrol's Network Strategic Tool (NEST) [31], which also helps to analyse the traffic density and the sector capacity. NEST is a Eurocontrol stand-alone desktop application that combines dynamic Air Traffic Flow with airspace design and capacity planning analysis functionalities. We implemented changes to the original NEST dataset to model operational traffic and the RPAS in the shared airspace. The traffic was extracted from the planned flights instead of the actual flights to avoid including the actual ATCO interventions in  
Figure 3: ISA management interface employed in the ERAINT project. the simulations. Then, we add a random schedule time to avoid participating ATCOs to memorise repeated conflicts. To analyse the task load, we employed a task-based metric from Eurocontrol called the Capacity Analyser method (CAPAN) [20]. With CAPAN, we evaluated the task load of the operational controllers at the air traffic control by identifying the most relevant events that occur along the operation (sector coordination, separation provision, changes in altitudes and speeds, etc.). Each one of these events has an assigned time duration (statistically known by the day-to-day operation of the ATCO), which, combined with using the CAPAN methodology, provides a measure of the task load of the controller positions for a given actual traffic sample in different ATM scenarios (see in Section 3.1). The task load should be confronted by the actual ATCO workload estimated by several mechanisms such as TLX, ISA, number of aircraft per controller/scenario/sector, percentage of time a controller spends to handle aircraft, issuing instructions, and receiving read-back/requests from the pilot-in-command (from voice recording), etc. The interface between the RAISE [8] simulation component and eDEP component is designed to be as realistic as possible. The RPAS exchanges Mode-S and ADS-B Out data with the ATM system. The RPAS can detect the surrounding traffic via ADS-B In positioning flows. The RPAS also has the capability to send flight-intent data directly to the ATM system via a simulated ADS-C link. The flight intent is generated as a short-term prediction of the RPAS trajectory computed by the onboard FMS.