Airside Operations Safety: Understanding the Effects of Human Factors (2022)

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18 The Risks to Airports According to the ACRP project request for proposals, one of the objectives of the project was to “identify risks associated with reduced cognitive ability and SA caused by fatigue or overload.” Identifying these risks was determined to be unachievable given the lack of data specific to fatigue or overload. Even for those investigation narratives with enough informa- tion for HFACS coding per the taxonomy, the analysis required the research team to default to one unsafe act for the largest percentage of the events—that act being decision error. The next most prevalent unsafe act was violations, but in no cases was there enough information available to code the act as a routine violation or an exceptional violation. The coding did allow for the identification of additional underlying human factors, the most prevalent being communication, coordination, and planning (CCP); adverse mental state (AMS); inadequate supervision (IS); and tools and technology (TT). Of note, the research team decided to use the second-level category condition of operators (CO) in place of AMS. CO includes the following factors: mental states (including AMS), physiological state, and physical/mental limitations. The team felt that CO would better convey the category to the reader of the final report. The research team decided to pursue a different approach in deter- mining human factors risks that could be of value to airport decision makers. Within the framework of an SMS and the SRM component of an SMS, the risk presented by a safety hazard is defined as the composite of predicted severity and likelihood of the potential effect of a hazard. Severity is the measure of how bad the results of an event are predicted to be and is usually determined by the worst credible outcome. Likelihood is the estimated probability or frequency, in quantitative or qualitative terms, of a hazard’s effect; it is often an expression of how often an effect is expected to occur (FAA, 2016). From a risk perspective, a V/PD event is unique in two ways. First, the risks associated with these events can, in general, be determined using likelihood as the sole determining component, given that in only a small number of cases will the severity of the outcome involve damage or injuries. Second, given the lack of outcome severity, a V/PD could be considered a safety hazard where specific guidance is in place on how the event should be addressed by the airport. Thus, the processes used by the airport to address V/PDs might serve as a model for how other safety hazards could be investigated, evaluated, and mitigated before the hazard could result in an accident. C H A P T E R   3 Risk: The composite of predicted severity and likelihood of the potential effect of a hazard. Severity is the measure of how bad the results of an event are predicted to be and is usually determined by the worst credible outcome. Likelihood is the estimated probability or frequency, in quantitative or qualitative terms, of a hazard’s effect; it is often an expression of how often an effect is expected to occur (FAA, 2016).

The Risks to Airports 19   3.1 Human Factors Risks Leading to V/PDs The research team determined that the risk posed by the human factors behind V/PDs is a function of the frequency of the human factor since the severity of the events is viewed as a constant. Of the 847 events analyzed, only eight resulted in any damage to airport facilities; seven of those eight (one not able to be assessed) were the result of a person not associated with the airport gaining unauthorized access (trespassing) or being pursued by police, with the result being the vehicle caused damage to airport property. In the remaining 839 events, the outcome was an observed incursion onto the movement area. While the category of each incursion (A, B, C, or D) was not evaluated, the outcome of each event was considered as a constant from a risk assessment standpoint; for each event, no damage or injury occurred. The first step in the risk assessment was to determine the frequency of the human factors issues. With the variance in the quality and quantity of the human factors information available in the investigation narratives, some assumptions were required. The process started with the unsafe acts causing the V/PD. Figure 3-1 depicts these steps of the research process, and Figure 3-2 illustrates the breakdown of the unsafe acts. A - 20% B - 61% C - 11% D - 1% E - 7% A - No Data B - Decision Errors C - Violations D - Decision Errors + Violations E - Other Figure 3-1. Risk assessment research steps leading to unsafe acts. Figure 3-2. Frequency of V/PD unsafe acts per HFACS.

20 Airside Operations Safety: Understanding the Effects of Human Factors The next step was to determine the level of airport effort that should be focused on mitigating violations. As a start, the events coded as violations were analyzed for second-level contributing factors. The results of this analysis are illustrated in Figure 3-3. The analysis showed that, of the 100 events involving violations, over half provided insufficient investigation information to determine a second-level contributor. For the remainder of the violations, 20% indicated that CO (AMS in the figure) was an issue, 12% were the result of CCP issues, 11% involved TT, 5% included inadequate supervision (IS), and one event involved a skill-based error (SBE). The team felt that additional evaluation of the events was needed to explore the role airport personnel played in the violation events. Thus, a more detailed examination of the event narra- tives coded as violations was performed. 3.2 Violations in Greater Detail In the HFACS framework, the category of violations includes two subcategories: routine violations and exceptional violations. Routine violations are often referred to as “bending the rules.” This type of violation tends to be habitual by nature and is often enabled by a system of supervision and management that tolerates such departures from the rules. Exceptional violations are isolated departures from authority, neither typical of the individual nor condoned by management (Shappell and Wiegmann, 2001). With these categories in mind, the violation events were examined to determine the extent to which airports had control over those committing the violations. The investigation narratives of 93 events were analyzed again to find out whether the violator was authorized to be on airport property, and if so, whether the violator was an employee of the airport or an airport tenant. If the answer to each query was yes, the research team postulated that the V/PD was a safety- related event likely requiring human factors risk mitigations. If the answer to either query was no, the event was determined to be airport security–related, with the human factors affecting the violator outside the control of the airport. Figure 3-4 illustrates this research step. A - 51% B - 20% C - 12% D - 5% E - 11% F - 1% A - Violation Only B - Violations + Adverse Mental States C - Violations + Communication, Coordination, & Planning D - Violations + Inadequate Supervision E - Violations + Tools/Technology F - Violations + Skill Based Errors Figure 3-3. Second-level human-factor contributors to violations. Figure 3-4. Violation evaluation step.

The Risks to Airports 21   The results of this analysis are depicted in Figure 3-5. The investigation narratives showed that in 62 of the 100 events assessed, the person or persons violating the rules were trespassing on airport property (two were being chased by police vehicles). Thus, two-thirds of the viola- tions were the result of someone not affiliated with or not authorized to be on the property by the airport. Another quarter of the events were characterized as negligence—that is, a person authorized to be on the airport did not comply with the rules and regulations, thus leading to the V/PD. In roughly 60% of these events, an airport employee or tenant employee was involved. Approxi- mately 10% of these events involved a contractor working on an airport project. The remaining 30% of the narratives were inconclusive as to the violator’s affiliation. These personnel groups can be considered under the control and authority of the airport, and steps could be taken to minimize the number of violations. This analysis illustrates one of the areas where airport safety and airport security mesh. The largest percentage of the risk-mitigation responsibility for V/PDs that result from violations appeared to fall under airport security policy and practices. In addition, for the 62 V/PDs falling under the trespassing/police pursuit category, 28 occurred at general aviation airports, with another 14 events occurring at small-hub or non-hub airports. The analysis shows that the number of violation-coded events where the person(s) involved fell under the control of the airport made up approximately 4% of the HFACS coded as V/PDs during the 2-year period examined. This led the research team to conclude that the risk of a V/PD violation is exceptionally low. Therefore, airport efforts and resources would more effectively be employed in mitigating other risks. 3.3 Decision Errors Decision errors are thinking errors. They represent conscious, goal- intended behavior that proceeds as designed, yet the plan proves inadequate or inappropriate for the situation. These errors typically manifest as poorly executed procedures, improper choices, or simply the mis interpretation or misuse of relevant information (Shappell and Wiegmann, 2001). As shown in Figure 3-2, the data analysis revealed that in roughly two-thirds of the events evaluated, a decision error was determined to Figure 3-5. Violations leading to V/PDs, by category. Decision errors present the highest risk to airport management. In two of every three V/PDs, a decision error was the unsafe act that led to the event. The top second-level contributing factors to decision errors were as follows: CCP (32%), condition of operators (AMS in Figure 3-7 – 18%), IS (18%), and TT (6%).

22 Airside Operations Safety: Understanding the Effects of Human Factors be the unsafe act that led to the V/PD. In accordance with the risk assessment methodology dis- cussed, the underlying human factors leading to these decision errors present the highest levels of human performance risk to airport management working to minimize V/PD occurrences. This step of the Phase II research process is illustrated in Figure 3-6. When viewing decision errors through the lens of safety risk, the team looked at how often the second-level contributors were able to be determined from the V/PD data. Figure 3-7 illustrates the breakdown of the contributors. It is important to note that 529 (or 78%) of the 679 events coded using the HFACS taxonomy involved a decision error. In 25% of these coded events, insufficient information existed to determine a second-level contributor. How the research team addressed this finding is discussed later in the report. The HFACS analysis of decision errors revealed that the three greatest second-level con- tributors fell under the preconditions level of the taxonomy—that is, conditions that existed prior to and could be considered causal factors leading to the unsafe act. These factors, in order of frequency, are as follows: • CCP • TT • CO (AMS in Figure 3-7) An additional contributor to decision errors accounted for in a significant percentage of the events was IS. This code falls under the unsafe supervision level of the HFACS taxonomy and can be a forerunner to the preconditions for the unsafe act. 3.4 Decision Error Events Without Second-Level Contributors As depicted in Figure 3-7, 25% (or 170 of the 679 coded events) of the decision error–coded events lacked information in the investigation narrative to determine a human-cause factor beyond the unsafe act itself. While arming airport leadership with the knowledge that a large A - 25% B - 18% C - 32% D - 18% E - 6% F - 1% A - Decision Errors Only B - Decision Errors + Adverse Mental States C - Decision Errors + Communication, Coordination, & Planning D - Decision Errors + Inadequate Supervision E - Decision Errors + Tools/Technology F - Decision Errors + Skill Based Errors Figure 3-6. Decision error analysis research step. Figure 3-7. Second-level human-factor contributors to decision errors.

The Risks to Airports 23   number of V/PDs are the result of a decision error by someone involved in the event provides some level of insight, it does little to guide them toward the development and implementation of mitigations to prevent future occurrences. The research steps to address this shortfall are illustrated in Figure 3-8. The approaches that apply to fill this gap included one long- term solution and one short-term, stopgap solution. The long-term solution is to improve the investigation processes used to find the causes of V/PDs. Enhanced investigations improve the quality of human factors data on V/PDs collected by the FAA, which lead to greater insight into the national trends and mitigations. Addition- ally, improved investigations at the local level can provide better information to airport leadership. The research efforts to address investigation improvement are addressed in Chapter 8. In order to provide the airport industry with knowledge that may aid its efforts in the short term, the decision-making section of Chapter 2 was included. The intent of including information on this topic is to enrich the human factors knowledge base of airport leaders so that they might enhance risk-based deci- sion making on airport issues involving human cognitive performance. 3.5 Mitigating the Risks Posed by Decision Errors With the breakdown of underlying causes of decision errors as a foundation, Chapter  4 through Chapter 7 address means by which airports can mitigate decision error risks. The team considered these areas of interest to be categories of human-factor risk mitigation or risk controls. The areas are airport personnel traits and hiring practices, airside driver training, fatigue risk management (FRM), and technology solutions that may reduce human error. The most frequent underlying factors that lead to decision errors and the risk controls are illustrated in Figure 3-9. Figure 3-8. Research steps to address decision error–coded events with no second-level contributors. The knowledge that a large number of V/PDs are the result of a decision error provides some level of insight, but it does little to guide airport leaders toward mitigations to prevent future occurrences. The long-term solution was to improve the investigation processes used to find the causes of V/PDs. Figure 3-9. Decision error risks and risk-mitigation areas.