# ATC Human Factors Involved in RPAS Contingency Management in Non-Segregated Airspace
## 1 Introduction
ADS technologies are dependent because, in contrast with other surveillance sensors such as radar, the surveillance data are obtained from the onboard sensors. Two different approaches have been designed: ADS-Broadcast (ADS-B) and ADS-Contract (ADS-C). Among others, ADS-C can provide the aircraft-projected intent, a set of 4-dimensional points describing the aircraft's predicted flight trajectory. The flight-intent mechanism seems to be the perfect way for the RPAS to inform the ATC controller about its whereabouts. The flight intent can even support the lost-link contingency, as the lost-link per se does not imply the failure of the onboard FMS or ADS-C equipment. This research combines different subjective and objective performance ratings to accurately measure the ATCO workload impact when managing contingencies potentially supported by information exchange systems. Under the umbrella of the Evaluation of the RPAS-ATM Interaction in Non-Segregated Airspace project (ERAINT) [8], we created flight trajectories, missions, interfaces, and flight operations to measure the ATC human factor impact in an environment where RPASs operate while intermixed with other manned aircrafts within a realistic air traffic management simulation environment. The ATCO performance and the evaluation of unreasonable workload increases have been performed in two steps. First, RPAS operations were inserted in a high-density non-segregated airspace. Once it was observed that the workload levels did not rise beyond unreasonable levels, a second iteration expanded the complexity of the scenarios by evaluating the workload increases in the case of RPAS contingencies. A contingency is any situation in which an aircraft suffers an unexpected situation affecting the normal development of the flight. In extreme cases, a contingency may develop into an emergency declaration by the pilots, which grants them special priority status and the full attention of the ATC system. This paper reports the analysis strategy and results achieved when evaluating the ATCO workload increases while managing RPAS contingencies. In order to perform our evaluation, we identified several relevant human factors that may affect the ATCO workload when an RPAS flies across the ATC sector within nominal conditions but also when the RPAS is in an emergency state. Among all the possible situations, two relevant contingencies have been selected as the most representative: (a) loss of the command-and-control link and (b) failure of the RPAS engine as a case of urgent flight termination. The paper is structured as follows: Section 1 briefly shows the main human factor evaluation methods used in the aviation domain and details the specific human factor concerns in current RPAS operations, including two different kinds of RPAS contingencies. Section 3 outlines the simulation setup, information flows, human-machine interfaces involved in the actuation of the system, and general RPAS operational scenarios. The section will also detail the experiments that were carried out and the involved procedures to measure the ATCO task load and workload. Section 4 features the results. Finally, Section 5 discusses the attained experimental results.