# ATC Human Factors Involved in RPAS Contingency Management in Non-Segregated Airspace
## 3 Experiments
### Pre-Planned RPAS Flight Trial Scenarios  
The experiments contemplate six pre-planned flight trial scenarios that use actual sectorization with various levels of traffic density and the RPAS operating within those sectors. The six scenarios are:  
Scenario (a). This scenario does not have an RPAS operating in the area of interest. This scenario is our baseline to compare the results of scenarios that include RPAS flights. The DDR2 database provided the traffic samples operating in the intended mission area, which were slightly randomised to avoid exact repetitions. Scenario (b). Traffic samples are the same as the baseline scenario (a) but with an RPAS operating nominally over the mission area without suffering any contingency. Only transponder and primary ADS-B data are available to the ATC. Voice communications are the primary mode of communication between the RPAS pilot and the ATCO. The communication latency changed according to the distance between the RPAS and its ground segment (LOS/BLOS communication infrastructure). Scenario (c). The traffic samples and RPAS operating over the mission area as in scenario (b). In this scenario, an RPAS suffers an engine failure that requires immediate recovery procedures to avoid a crash. Scenario (d). The traffic samples and RPAS operating over the mission area as in scenario (b). In this scenario, an RPAS suffers an engine failure that requires immediate \begin{table}
\begin{tabular}{l} \hline \hline \(\bullet\) & The RPAS pilot must select the intended airport that complies with the requirements to perform a safe landing (weather conditions, feasibility of the approximation, fire protection, and any circumstance at the pilot’s discretion that can affect safety, such as people or ground infrastructures). \\ \(\bullet\) & The pilot-in-command may determine if diverting to a more distant airport instead of the nearest airport is the safest course of action. The safest course of action typically requires the earliest possible descent and landing, but other alternatives may also be feasible given the RPAS gliding capabilities. \\ \(\bullet\) & In case, during the gliding process, the landing cannot be performed, then flight termination must be executed. The RPAS pilots should immediately share an update decision with the ATC controller: call sign, aircraft type (emphasizing that the aircraft is an RPAS), current position, speed, altitude, updated situation, and updated plan. \\ \(\bullet\) & If the engine failure occurs close to an alternative landing site, then it may be necessary to increase the descent rate, or even circle close to the airfield to lose altitude before starting final descent. \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Flight-specific procedures for urgent flight termination contingency. recovery procedures to avoid a crash. The RPAS has flight-intent support and datalink capabilities along with contingency management, allowing it to provide intentions and request alternative trajectories through a datalink infrastructure. Scenario (e). The traffic samples and RPAS operating over the mission area as in scenario (b). In this scenario, RPAS suffers a C2 communication failure that requires a non-urgent recovery procedure to avoid extensive negative impact on the ATM system. Other systems (flight management system, ADS-B, and transponder) remain operative and flight data are available to the ATC. The RPAS planned trajectory is available to the ATC, including agreed recovery routes (equivalent to the radio loss in manned aviation). Scenario (f). The traffic samples and RPAS operating over the mission area as in scenario (b). In this scenario, the RPAS suffers a C2 communication failure with the pilot-in-command that requires a non-urgent recovery procedure to avoid an extensive negative impact on the ATM system. The flight management system, ADS-B, and flight-intent capabilities allow the RPAS to provide flight data and intentions and to request an alternative trajectory to the ATC via a datalink infrastructure.