UMD Guest Post: Human Factors in UAS

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By Grant Williams | Engineer, University of Maryland UAS Test Site
 

IMSAFE, check! This acronym is what a normal pilot would talk through with themselves before a flight to ensure that they are personally ready to fly. IMSAFE: illness, medications, stress, alcohol, fatigue, and eating. Simple enough, right? Though these are great considerations to ensure a base-level of risk mitigation, the truth is that human factors (in all aspects of aviation) are much more complex and more important than many UAS pilots probably realize. If we look to manned aviation, somewhere between 60-80% of aviation accidents are due to or related to human factors (Shappell, 2006). This is a staggering number of accidents that could presumably be mitigated by autonomy or a higher level of risk understanding and management. We need to explore the human aspect of UAS and how we can deeply analyze ourselves and our organizations to be safer operators through the FAA’s HFACS system (Shappell, 2006) and the SHELL model (Moriarty, 2015).
 

There are four categories that surround the operator (in the middle of the model) that are what make up the SHELL model of human factors (Moriarty, 2015). Each category, including the operator themselves, have many human factors considerations that comprise each operation, whether consciously or not. We must take into consideration not only the operator’s personal condition, but also the interaction between the operator and the environment, other liveware entities, software, and hardware as well. This is a very good overview model of human factors in UAS, but we can even further our understanding. Below, we will analyze human factors with the HFACS system. This is a framework of an organization that ranges from the organizational influences down to the operators themselves. We will look at the preconditions for unsafe acts, the unsafe acts themselves, and the organizational culture that have a large role in UAS human factors.
 

Preconditions for unsafe acts

Where UAS human factors considerations are typically and routinely addressed is in the category of preconditions. This sets the stage for every operation, and what could eventually lead to an accident or unsafe act. This is where our IMSAFE checklist is utilized, but it is only one piece of the puzzle. Other considerations for this category are environmental and personnel factors. Environmental factors include the obvious temperature, wind speed, and changing conditions, but also include the technological environment surrounding the pilot. Personnel factors are more than just the personal considerations but more encompassing fields including crew resource management. All these factors need to be examined and challenged in order to mitigate potential accidents.
 

Unsafe acts

Unsafe acts are where our pilot skill and knowledge can be the best (and sometimes only) accident mitigation. These acts can be broken down into two groups: errors and violations. Errors can be distinguished into three sub-categories which are decision-based errors, skill-based errors, and perceptual errors (shappell, 2006). Most of these errors can be mitigated with training and practice. Examples of skill-based errors are failing to give proper wind correction, setting up a flight plan dangerously or incorrectly, or putting an aircraft into an inadvertent attitude or stall. Examples of perceptual errors would include losing aircraft orientation, depth perception miscalculation, or any of the various night illusions. All these need to be addressed to help prevent accidents due to pilot error.

Violations can be distinguished into two sub-categories being routine and exceptional violations. Routine violations are often a habitual “bending of the rules” (shappell, 2006). A good example would be visual line of sight operations. Though it is required to have a waiver or only brief periods for the operator to not have eyes on the aircraft, we often see fpv and photography pilots fly without eyes on the aircraft for the entire duration of a flight. Exceptional violations would be beyond the small habitual violations. An example of this would be climbing to 3000 ft AGL to get a view of a city or flying in front of an active runway. Both routine and exceptional violations should be avoided to keep accidents from occurring.
 

Organizational Culture and Influences

The final topic we will cover in UAS human factors is the organization influences. One of the largest pieces of the human factors puzzle is the organization itself. Whether it is extremely careless oversight or rigorous control, the climate of the organization can determine a pilot’s performance and abilities. On one side, an operator might not care very much about the rules or get proper training because no one will hold them accountable. On the other hand, an operator might struggle with stress and fatigue due to time pressures and a supervisor scrutinizing everything they do. This can be managed through a system of SOPs, checklists, chain of command, and resource management. It is important to have a balanced organizational culture where operators can be held accountable but also given proper direction and training to succeed at a manageable pace.
 

References
Shappell SA, Detwiler CA, Holcomb KA, Hackworth CA, Boquet AJ, Wiegmann DA “Human Error and Commercial Aviation Accidents: A Comprehensive, Fine-Grained Analysis Using HFACS” Federal Aviation Administration, DOT/FAA/AM-06/18, July 2006, PP. 1-22 Retrieved from: https://www.faa.gov/data_research/research/med_humanfacs/oamtechreports/...

Practical Human Factors for Pilots by David Moriarty (2015) ISBN-13: 978-0124202443

Contact the author
Grant Williams
UAS Test Engineer/Pilot
University of Maryland UAS Test Site
grant1o1@umd.edu 
(301) 862-7824

Learn more about how the UMD UAS Test Site's work supports the development of drone regulations, commercialization, and airspace integration in AUVSI's July 2021 article, "Fearless Flight: The UMD UAS Test Site."

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