Three Human Factors for UAS
Human Factors Issues
Human factors can fall into multiple categories for unmanned systems. This can include the Human-Computer Interface (HCI) or even the control links that allow the pilot to control the aircraft in flight. In the module, we are focused on selecting three human factors issues that have the most effect on safe Unmanned Aircraft System (UAS) operations and give an in-depth analysis of why they were chosen. Areas that are included are one or more methods to safely mitigate its effects on a mission and describing if and how these issues affect UAS differently than they would a manned aircraft pilot or crewmember.
Control Station Environment
The control station environment is the interface that the operator or pilot uses to operate their system. This is also referred to as the Control Station. This control station is where the pilot flies their system. According to Landry (2017), The GCS is required to accommodate not only pilots but other crew members such as technicians, sensor operators, and maintenance crewmembers. With the large amount of crew that can be a part of the mission, it can be expected to have personnel entering and exiting the GCS throughout the entirety of the mission. Landry (2017) explains that there have been reports that personnel will gather around a GCS during an inflight emergency to try and lend aid.
The Control Station Environment was chosen as one of the major factors affecting Human Factors because of the routine change of crewmembers throughout the course of a flight. The continuous entering and exiting of technicians and maintenance personnel can be distracting for the crew that is flying. This is an area that manned aircraft are not affected by during flight. A way to mitigate this problem is to set a maximum number of people that are allowed in the GCS at any given time. The crewmembers that enter the GCS must be predesignated and must avoid bothering the crews to the max extent possible.
Command and Control (C2) Links
Controlling an unmanned aircraft over a radio link create latencies that do not exist for manned aircraft. Radio links cannot be guaranteed to be 100% reliable for a flight. In the event of a loss link situation, the UAS should hopefully activate a loss link profile that would ensure it operates in a safe manner until it either regains contact with the pilot or lands safely on its own.
A way in which this is mitigated is the use of multiple connections to an aircraft. Some aircraft like the RQ-4B utilizes a satellite link and a line of sight link. These allow for a more stable connection in the terminal area during operations. Another mitigation is the use of a loss link procedure for the UAS. According to Landry (2017), onboard timers can be used to allow the aircraft to wait until it reaches a certain time or location before activating its loss link procedures. This can allow the aircraft to maintain Air Traffic Control (ATC) instructions or remain predictable for ATC and the UAS operator during the situation.
The implications for loss link against manned aircraft are that the crew can simply continue to fly the aircraft under No Radio (NORDO) conditions. This means the crews can continue flying their flight planned route and continue to their destination if need be. The crews would then follow light signals from the tower, which will indicate if they are cleared to land or not.
Sense and Avoid (SAA)
Unmanned aircraft have a disadvantage when it comes to avoiding other aircraft in the sky. Detect and Avoid is an area in which efforts have been made to determine the best way to ensure UAS are safely integrated into the National Airspace System (NAS) (Landry, 2017) A way to ensure that highly autonomous aircraft like the RQ-4B Global Hawk can avoid other aircraft is the Airborne Collision Avoidance System (ACAS Xu). ACAS Xu can interact with manned aircraft TCAS system to maneuver the UAS away from other traffic. (Landry, 2017)
This type of automation can cause distrust with the operator if it does not perform in the way in which it is expected. According to Marshall et al. (2016), The benefit of having automation is to reduce the workload on the crewmembers, however, due to the imperfections of automation, crewmembers may start to form distrust with the automation, and this can cause more workload for the crewmembers. The pilots may spend more time confirming the aircraft is performing correctly and less time on other critical tasks.
The comparison between manned and unmanned for see and avoid is blatant. A manned pilot can simply look outside to ensure they do not collide with another aircraft. Unmanned systems do not have this capability, and they must rely on cameras or sensors. These sensors do not replace the ability to simply look outside of a window and see what is happening around you in clear conditions.
References
Landry, S. J. (2017). Handbook of human factors in air transportation systems. CRC Press.
Marshall, D. M., Barnhart, R. K, Shappee, E., & Most, M. T. (2016). Introduction to unmanned aircraft systems. Crc Press.