UAS Mishaps and Accidents
Feature Photo: Freya SmartPlanes Drone. Reprinted from "Drone impact from a safety perspective," by Öhlund, 2017, SmartPlanes. Copyright 2017 by Öhlund
Aviation has an inherent risk every time someone or something takes flight. There is a possibility of an incident or mishap to occur during any portion of the flight. These risks associated with aviation are shared between manned and unmanned aviation. The human factors are different for manned and unmanned aircraft due to the difference between having a pilot either on the ground or onboard the aircraft.
Hazards and Risks in Aviation Operations
Flight Hazards in aviation from the FAA cover a broad spectrum. The FAA lists the top ten most frequent flight hazards:
Inadequate preflight preparation and planning.
Failure to obtain/maintain flying speed.
Failure to maintain directional control.
Improper level off.
Failure to see and avoid objects or obstructions.
Mismanagement of fuel.
Improper in-flight decisions or planning.
Misjudgment of distance and speed.
Selection of unsuitable terrain.
Improper operation of flight controls.
(FAA, n,d,)
These hazards cover almost all areas of flight from the beginning of a flight, to the middle of the flight, to landing and shutdown. These hazards carry an inherent risk to the aircraft and the operator when operations are taking place. According to Joslin (2015), Unmanned Aircraft Systems (UAS) have some specific hazards associated with the unmanned aircraft that are not shared with manned aircraft. Unmanned aircraft have the capability for the pilot to fly the aircraft from the ground using Line of Sight (LOS) or Beyond Visual Line of Sight (BVLOS) command and control links.
Joslin investigated 274 accidents between October 2009 -August 2014 to determine any trends or anomalies that indicate trends in specific areas for mishaps (Joslin, 2015). UAS specific incidents showed a trend that indicated that the incidents were primarily caused by equipment failure (Joslin, 2015). Equipment failure in this study was categorized between Command and Control Link, communications link, and other equipment such as avionics, structural, electrical, and more, as seen in Figure 1 (Joslin, 2015).
Tools to mitigate Risk in BVLOS
Beyond Visual Line of Sight or BVLOS is the use of satellite command and control links to fly a UAS from a location where the control station where the operator is sitting cannot see the aircraft (Heppe, 2015). A problem with using BVLOS is latency. Latency and communication transaction time is the maximum time to send a one way or two-way message for a communication system (Heppe, 2015).
Another risk for BVLOS is the loss of command and control link between the aircraft and the operator. The first risk for a loss link situation of a UAS is the inability of the aircraft to follow Air Traffic Control (ATC) instructions (Kaliardos & Lyall, 2015). Along with the lack of ability to follow ATC instructions is the inability to communicate with ATC and unpredictability of the aircraft (Kaliardos & Lyall, 2015). These risks are part of the concern for operating UAS in the National Airspace System (NAS).
One of the tools to mitigate these risks is a contingency plan. With the ability to lose the command and control link to the aircraft, the UAS must ensure predictability through an understandable set of preset flight planned points and altitudes that are pre-coordinated with ATC before the flight (Kaliardos & Lyall, 2015). Having a contingency plan in the event of a loss link scenario allows ATC controllers to ensure they can maintain safe separation between the unmanned aircraft and other aircraft that are operating nearby.
Human Factors Contributions to UAS Mishaps and Accidents
One major human factor with UAS mishaps is the loss of “Shared Fate” between the operator and the aircraft. Pilot complacency and the loss of shared fate can be caused by pilot isolation from the aircraft they are operating (Kaliardos & Lyall, 2015). This separation can increase pilot complacency, boredom, and loss of attentiveness (Kaliardos & Lyall, 2015). With the lack of shared fate, it is possible that the pilots would be more willing to take risks and discard some perceived risks that manned aircraft pilots would be concerned with due to the lack of survival instinct (Kaliardos & Lyall, 2015).
References
FAA. (n.d.). Aeronautical information publication - AIP - ENR 5.7 potential flight hazards. Retrieved from .https://www.faa.gov/air_traffic/publications/atpubs/aip_html/part2_enr_section_5.7.html
Heppe, S. B. (2015). Problem of UAV communications. Handbook of unmanned aerial vehicles, 530-576.
Joslin, R. (2015). Insights into Unmanned Aircraft Systems Accidents and Incidents (2009–2014). In Aviation, Aeronautics, Aerospace International Research Conference-2015, Phoenix, AZ.
Kaliardos, B., & Lyall, B. (2015). Human factors of unmanned aircraft system integration in the national airspace system. Handbook of Unmanned Aerial Vehicles. Dordrecht: Springer Netherlands, 2135-2158.