Flight safety assessment based on a modified human error risk quantification approach

In risk and safety assessments of aviation systems, engineers generally pay more attention to the risks of hardware or software failure and focus less on the risks caused by human errors. In this paper, a (FRAHE) method is proposed for identifying this critical error type and determining the risk severity of human errors. This method accounts for the human error probability as well as the impacts of human errors on the system. The fuzzy inference approach is employed in this paper to address the uncertainty and issues of imprecision that arise from insufficient information and scarce error data and a risk assessment model of human error is developed. The model can be used to precisely describe the relationship between the output risk severity and the input risk indicators, including the human error probability, the error impact probability, and the human error consequence. A case study of the approach task is presented to demonstrate the availability and reasonability of the model. The risk-based modeling method can not only provide valuable information for reducing the occurrence of critical errors but also be used to conduct prospective analyses to prevent unsafe incidents or aviation accidents.

The Untapped Potential of Narrative as a Tool in Aviation Mental Health and Certification

INTRODUCTION: Work-related stress is common in pilots, with broad implications, including the potential development of mental health symptoms and sometimes even psychiatric disease. This commentary argues for the use of narrative as a tool to promote preventive health behaviors in pilots and combat misinformation about aeromedical certification related to mental health.Hoffman WR, McNeil M, Tvaryanas A. The untapped potential of narrative as a tool in aviation mental health and certification. Aerosp Med Hum Perform. 2024; 95(3):165-166.

Effects of distance flown on pilot decision making in continued flight into deteriorating weather conditions

INTRODUCTION

Continuing flight into adverse weather remains a significant problem in general aviation (GA) safety. A variety of experiential, cognitive, and motivational factors have been suggested as explanations. Previous research has shown that adverse weather accidents occur further into planned flights than other types of accident, suggesting that previous investment of time and effort might be a contributing factor. The aim of this study was to experimentally determine the effect of prior commitment on general aviation pilots' decision-making and risk-taking in simulated VFR flights.

METHOD

Thirty-six licensed pilots 'flew' two simulated flights designed to simulate an encounter with deteriorating coastal weather and a developing extensive cloud base underneath the aircraft as it crossed a mountain range. After making a decision to continue or discontinue the flight, pilots completed a range of risk perception, risk taking, and situational awareness measures.

RESULTS

Visual flight rules were violated in 42% of the flights. Prior commitment, in terms of distance already flown, led to an increased tendency to continue the flight into adverse weather in the coastal 'scud running' scenario. Continuing pilots perceived the risks differently and showed greater risk tolerance than others. These 'bolder' pilots also tended to be more active and better qualified than the others.

CONCLUSIONS

There are undoubtedly multiple factors underlying any individual decision to continue or discontinue a flight. The willingness to tolerate a higher level of risk seems to be one such factor. This willingness can increase with time invested in the flight and also seems to be related to individual flight qualifications and experience.

PRACTICAL APPLICATIONS

All pilots might benefit from carefully structured simulator sessions designed to safely teach practical risk management strategies with clear and immediate feedback.

Pilot performance and workload whilst using an angle of attack system

Loss of control in flight is the primary category of fatal accidents within all sectors of aviation and failure to maintain adequate airspeed - leading to a stall - is often cited as a causal factor. Stalls occur when the critical angle of the aircraft is exceeded for a given airspeed. Using airspeed as an indicator of the potential to stall is an unreliable proxy. Systems that measure the angle of attack have been routinely used by military aircraft for over 50 years however rigorous academic research with respect to their effectiveness has been limited. Using a fixed-base flight simulator fitted with a simulated, commercially available angle of attack system, 20 pilots performed normal and emergency procedures during the circuit/pattern in a light aircraft. Experimental results have shown that pilot performance was improved when angle of attack was displayed in the cockpit for normal and emergency procedures during the approach phase of flight in the pattern/circuit. In relation to pilot workload, results indicated that during the approach phase of flight, there was a moderate but tolerable increase in pilot workload. The use of such a display may assist pilots to maintain the aircraft within the optimum range and hence reduce occurrences of unstable approaches. Overall, fewer stall events were observed when angle of attack was displayed and appropriate pilot decisions made during emergencies. These results provide a new perspective on pilot workload and aviation safety.

Analysis on coupling dynamic effect of human errors in aviation safety

Human factors have increasingly been the leading cause of aircraft accidents. In most cases, human factors are not working alone, instead they are coupled with complex environment, mechanical factors, physiological and psychological factors of pilots, and organizational management, all of which form a complex aviation safety system. It is vital to investigate the coupling impact of human errors to avoid the occurrence of aviation accidents. In view that the Human Factors Analysis and Classification System (HFACS) provides a hierarchical classification principle of human errors in aviation accidents, and the System Dynamics (SD) approach is helpful to describe the risk evolution process, this paper establishes a hybrid HFACS-SD model by employing the HFACS and the SD approach to reveal the aviation human factors risk evolution mechanism, in which the HFACS is first used to capture the causal factors of human errors risk, and a coupling SD model is then built to describe the evolution of aviation human factors risk supported by historical data. The eigenvalue elasticity analysis is taken to identify critical loops and parameters that have a substantial impact on the system structural behavior, and the influence of parameters and loops is assessed. Simulation results show that the evolution trend of the accident rate can be replicated by the proposed HFACS-SD model, and the structural dominance analysis can efficiently identify critical loops and parameters. Simulation results further show that, with the recommended safety enhancement measures, the stability of the aviation system is increased, and thus lowering the overall accident rate.

Research on Aviation Safety Prediction Based on Variable Selection and LSTM

Accurate prediction of aviation safety levels is significant for the efficient early warning and prevention of incidents. However, the causal mechanism and temporal character of aviation accidents are complex and not fully understood, which increases the operation cost of accurate aviation safety prediction. This paper adopts an innovative statistical method involving a least absolute shrinkage and selection operator (LASSO) and long short-term memory (LSTM). We compiled and calculated 138 monthly aviation insecure events collected from the Aviation Safety Reporting System (ASRS) and took minor accidents as the predictor. Firstly, this paper introduced the group variables and the weight matrix into LASSO to realize the adaptive variable selection. Furthermore, it took the selected variable into multistep stacked LSTM (MSSLSTM) to predict the monthly accidents in 2020. Finally, the proposed method was compared with multiple existing variable selection and prediction methods. The results demonstrate that the RMSE (root mean square error) of the MSSLSTM is reduced by 41.98%, compared with the original model; on the other hand, the key variable selected by the adaptive spare group lasso (ADSGL) can reduce the elapsed time by 42.67% (13 s). This shows that aviation safety prediction based on ADSGL and MSSLSTM can improve the prediction efficiency of the model while keeping excellent generalization ability and robustness.

Predicting and mitigating failures on the flight deck: an aircraft engine bird strike scenario

Engine damage as a consequence of foreign object debris (FOD) during flight is frequently caused by birds. One approach to minimising disruption caused by this damage is to provide flight crew with accurate information relating to the continuing operational status of the aircraft's engines. Before designing such avionic systems however, understanding of current procedures is needed. Hierarchical Task Analysis (HTA) and Systematic Human Error Reduction and Prediction Approach (SHERPA) were used to identify potential failures that flight crew may make when managing an engine bird strike. Workshops with commercial pilots generated insights into current practice and a commercial pilot SME reviewed outputs for accuracy. Over 200 potential failures were identified, most commonly related to communication. Remedial measures, considering future avionic systems, are proposed to mitigate identified failures. This analysis provides a starting point for future design concepts for assisting flight crew in dealing with engine malfunction due to FOD strikes. Practitioner summary: Hierarchical Task Analysis was conducted to show all tasks involved in dealing with an in-flight aircraft engine bird strike. Systematic Human Error Reduction and Prediction Approach analysis was performed and over 200 possible failures were identified when managing this event. Remedial measures are proposed to help mitigate possible failures.

Cardiovascular Concerns from COVID-19 in Pilots

BACKGROUND: Cardiovascular disease, now complicated by the COVID-19 pandemic, remains a leading cause of death and risk for sudden incapacitation for pilots during flight. The capacity for aeromedically significant cardiovascular sequelae with potentially imperceptible clinical symptoms elicits concern both during and following resolution of acute COVID-19 in pilots.OBJECTIVE: We summarize the current state of knowledge regarding COVID-19 cardiovascular implications as applied to the aviation environment to better understand their significance toward flight safety and application toward a focused cardiovascular screening protocol following recovery from infection.METHODS: A narrative review of the cardiovascular implications of COVID-19 infection was performed using the PubMed literature search engine and existing organizational guidelines. In addition, to established medical aviation benchmarks, surrogate populations examined included high performance athletes (as a correlate for high G-forces), and scuba divers (as an environmental work analog). Conditions of primary concern included myocardial injury, proarrhythmic substrates, risk of sudden death, myopericarditis, pulse orthostatic lability in response to vigorous activity, cardiovagal dysfunction, and thromboembolic disease.LITERATURE REVIEW: Cardiovascular screening guideline recommendations post-infection recovery are suggested based on profile stratification: airperson flight class, tactical military, and aerobatic pilots. This provides an approach to inform aeromedical decision making.CONCLUSION: Aviation medical examiners should remain cognizant of the clinically apparent and occult manifestations of cardiovascular dysfunction associated with COVID-19 infection when applying return-to-work screening guidelines. This will ensure high flight safety standards are maintained and sudden incapacitation risk mitigated during and following the ongoing pandemic.Elkhatib W, Herrigel D, Harrison M, Flipse T, Speicher L. Cardiovascular concerns from COVID-19 in pilots. Aerosp Med Hum Perform. 2022; 93(12):855-865.

The development of a scenario-based human-machine-environment-procedure (HMEP) classification scheme for the root cause analysis of helicopter accidents

The current study analyzed the root causes of 22 helicopter accidents/incidents that took place between 1998 and 2019. Each root cause was coded using three commonly used classification models in aviation HFACS, ATSB, and IATA to identify recurring factors for better targeting of future prevention strategies. The frequency analysis revealed that not following procedure (22 observations), training inadequate or unavailable (17), inadequate regulatory oversight (17), inadequate procedure guidance (16), company management absent or deficient (10) and incorrect manuals/charts/checklists (9) were the most frequent contributing factors. Since none of the existing models could summarize the root causes of 22 occurrences effectively, a scenario-based human-machine-environment-procedure (HMEP) classification scheme was proposed to use organizational influences, people management, technical failure, procedure and document, and environment as the first-layer subcategories. The HMEP scheme was additionally applied to the analysis and coding of 4 helicopter accidents in the USA published by the NTSB. The HMEP scheme revealed that NTSB had identified a significantly greater number of root causes in the manufacturer design, manufacturing & documentation. Overall, HMEP can be used to guide the data collection during accident investigation and subsequently to aggregate aviation accidents to derive recurring factors and compare accident patterns in an efficient manner.

When Outcomes are not Enough: An Examination of Abductive and Deductive Logical Approaches to Risk Analysis in Aviation

While airlines generate massive amounts of operational data every year, the ability to use the collected material to improve safety has begun to plateau. With the increasing demand for air travel, the aviation industry is continually growing while simultaneously being required to ensure the level of safety within the system remains constant. The purpose of this article is to explore whether the traditional analysis methods that have historically made aviation ultra-safe have reached their theoretical limits or merely practical ones. This analysis argues that the underlying logic governing the traditional (and current) approaches to assess safety and risk within aviation (and other safety critical systems) is abductive and therefore focused on creating explanations rather than predictions. While the current "fly-fix-fly" approach has, and will continue to be, instrumental in improving what (clearly) fails, alternative methods are needed to determine if a specific operation is more or less risky than others. As the system grows, so too does the number of ways it can fail, creating the possibility that more novel accidents may occur. The article concludes by proposing an alternative approach that explicitly adds temporality to the concepts of safety and risk. With this addition, a deductive analysis approach can be adopted which, while low in explanatory power, can be used to create predictions that are not bound to analyzing only outcomes that have occurred in the past but instead focuses on determining the deviation magnitude between the operation under analysis and historically commensurate operations.

A Systematic Review of Multilevel Influenced Risk-Taking in Helicopter and Small Airplane Normal Operations

The violation of aviation rules, particularly meteorological flight rules, can have fatal outcomes. Violation can sometimes be explained by intentional risk-taking, alternatively it can be the manifestation of a strategy to enhance performance and influence outcomes, such as saving time or fulfilling customer expectations. The aim of this study was to determine the types of risk-taking behavior within extant empirical research and identify multilevel antecedents related to risk-taking in the context of aviation operations, via a systematic literature review. 4,742 records were identified, which after screening resulted in the detailed consideration of 10 studies, three qualitative and seven quantitative studies, which met the eligibility criteria. Only published works were included in the review, thus the results may have been subject to publication bias, however, the types of risk taking within the research were consistent with that observed in Australian and New Zealand accident reports. The predominate risk-taking behavior was that of continuing Visual Flight Rules (VFR) flight into deteriorating conditions / Instrument Meteorological Conditions (IMC). Multilevel influences could be categorized under two overarching themes, being “continuation influence” and “acceptance of risk / normalization of deviance.” One or both themes was consistently observed across the finding in all studies, although precaution should be given to the relative frequency of the reported associations. This review indicates the value of considering the social and organizational influences on risk-taking, and suggests avenues for future research, in particular exploring the influences through a Self-Determination Theory (SDT) lens.

An Orientation to Aviation Psychiatry: With 30 Case Examples and a 10-Year Follow-up

ABSTRACT

This report orients general psychiatrists to assessment and care for "safety sensitive" aviation workers. Our case study of 30 sequential aviation patients consists of demographic, clinical, and aviation characteristics plus a 10-year follow-up. Relatively few pilots and other aviation workers self-identified their psychiatric condition. Aviation outcomes associated with psychiatric disorder included personnel injury and/or aircraft damage (three cases), imminent risk without injury or damage (nine cases), impaired aviation functioning without imminent risk (15 cases), and neither risk nor psychiatric disorder or impairment (three cases). Mood, anxiety, and substance use disorders comprised the most common diagnoses. Ten years later, 23 patients were employed (21 in aviation); seven were disabled or deceased. General psychiatrists will find aviation cases clinically familiar but requiring added evaluation for aviation safety and potential interaction with the Federal Aviation Agency and airline supervisors.

Fuel Planning Errors in General Aviation from 2015 to 2020

BACKGROUND: Planning, whether preflight or in-flight, is a cause of accident that is presumably almost entirely preventable. Planning skills on the part of the pilot should assist in avoiding dangerous situations with regards to light conditions, weather, fuel shortage, and/or improper weight and balance. Fuel planning is noted as especially unnecessary, as fuel planning is not considered a complex skill but part of proper flight preparation and in-flight planning.METHODS: A total of 196 accident reports from 2015 until 2020 were extracted from the NTSB online database in which the probable cause included either preflight or in-flight planning as a cause attributed to the pilot. Of those accidents, the majority (N = 131, 67%) were attributed to fuel planning and were further analyzed.RESULTS: Fuel-planning related accidents were significantly less often fatal compared to all planning-related accidents and all fuel-related accidents. The majority of fuel planning accidents resulted in fuel exhaustion. Additionally, the cause attributed to the accidents was frequently the skill-based error of "fuel planning (pilot)" and the crew resource management issue of "fuel-fluid level". Specific information regarding the pilot's fuel plan was only available in 52 (40%) of the accident reports.CONCLUSIONS: The frequency of fuel-related planning accidents suggests that this aspect of pilotage is underestimated and requires more attention both in training and in standard operating procedures. In particular, more detailed information regarding the pilot's fuel plan is necessary in order to determine which step in the process most frequently results in an accident.Kalagher H. Fuel planning errors in general aviation from 2015 to 2020. Aerosp Med Hum Perform. 2021; 92(12):970-974.

Aviation Maxillofacial Shields and Blunt Impact Protection in U.S. Army Helicopter Mishaps

BACKGROUND: Maxillofacial shields (MFSs) are an available piece of aviation protective equipment designed to integrate into aircrew helmets and protect the face from wind and flying debris. Aviators have anecdotally reported that MFSs have provided blunt impact protection during impact events (i.e., a crash); however, no such cases have been formally documented in the literature.CASE REPORTS: Two cases were identified where aircrew wearing MFSs were involved in mishaps resulting in maxillofacial blunt impacts. In the first case, an OH-58 pilot struck the cyclic with his head/face during a crash. In the second case, a CH-47 crew chief was struck in the face by a maintenance panel dislodged from the aircraft. In both cases the MFS was damaged, but neither service member experienced injuries as a result of impact to the face.DISCUSSION: The cases illustrate the effectiveness of the MFS against blunt impact during aviation mishaps. While MFS use is currently optional for aircrew, it is believed that increased MFS use would result in fewer or less severe facial injuries as well as decrease the associated time and monetary losses due to injury.Weisenbach CA, McGhee JS. Aviation maxillofacial shields and blunt impact protection in U.S. Army helicopter mishaps. Aerosp Med Hum Perform. 2021; 92(1):5053.

Inventive nesting behaviour in the keyhole wasp Pachodynerus nasidens Latreille (Hymenoptera: Vespidae) in Australia, and the risk to aviation safety

The keyhole wasp (Pachodynerus nasidens Latreille 1812), a mud-nesting wasp native to South and Central America and the Caribbean, is a relatively recent (2010) arrival in Australia. In its native range it is known to use man-made cavities to construct nests. A series of serious safety incidents Brisbane Airport related to the obstruction of vital airspeed measuring pitot probes on aircraft possibly caused by mud-nesting wasps, prompted an assessment of risk. An experiment was designed to determine the species responsible, the types of aircraft most affected, the seasonal pattern of potential risk and the spatial distribution of risk on the airport. A series of replica pitot probes were constructed using 3D-printing technology, representing aircraft with high numbers of movements (landings and take-offs), and mounted at four locations at the airport. Probes were monitored for 39 months. Probes blocked by mud nesting wasps were retrieved and incubated in mesh bags. Emerging wasps were identified to species. Results show that all nests in probes were made by P. nasidens, and peak nesting occurs in the summer months. Nesting success (as proportion of nests with live adult emergents) was optimal between 24 and 31°C and that probes with apertures of more than 3 mm diameter are preferred. Not all areas on the airport are affected equally, with the majority of nests constructed in one area. The proportion of grassed areas within 1000 m of probes was a significant predictor of nesting, and probe volume may determine the sex of emerging wasps.

Spatial Disorientation Impact on the Precise Approach in Simulated Flight

BACKGROUND: The risks posed by flight illusions impacting pilot spatial orientation have been determined as a safety concern from numerous past aviation accident investigations. Early demonstration of the adverse effects of flight illusions on spatial orientation would be desirable for all pilots, especially at the early training stages to deeply embed good practices for onset detection, flight correction, and response mitigation.METHOD: Simulated flights on a disorientation demonstrator were performed by 19 pilots for 3 conditions: no illusion, somatogyral illusion, and Coriolis illusion. An objective approach for assessing pilot performance degradation due to flight illusions can be done by using a defined flight profile: instrument landing system (ILS) flight trajectory during final instrument approach. Deviations to the standard ILS profile were recorded to measure and evaluate the influence of the demonstrated flight illusion on pilot performance.RESULTS: The results show the expectation that the smallest deviations from the ideal trajectory are caused by pilot tracking error (no illusion), and the greatest deviations are caused by the Coriolis illusion. Results demonstrated a statistically significant effect of illusions on performance. According to statements from pilots, training for flight illusion response is essential to complement training in aircraft regulations and aerodynamics.DISCUSSION: Measuring the influence of vestibular illusions on flight profile with a simulator allows assessment of individual differences and improvement of pilot performance under the conditions of no illusion, the somatogyral illusion, and the Coriolis illusion.Boril J, Smrz V, Blasch E, Lone M. Spatial disorientation impact on the precise approach in simulated flight. Aerosp Med Hum Perform. 2020; 91(10):767775.

Blending Human and Machine: Feasibility of Measuring Fatigue Through the Aviation Headset

OBJECTIVE

To determine viability of drowsiness detection, researchers study the feasibility of photoplethysmogram (PPG) data collection from the geography of the aviation headset, correlating to electrocardiogram (ECG) reference.

BACKGROUND

Fatigue has been a probable cause, contributing factor, or a finding in 20% of transportation incidents and accidents studied between January 2001 and December 2012. This operational hazard is particularly troublesome within aviation and airline operations.

METHOD

PPG and ECG data were collected synchronously from Federal Aviation Administration (FAA) commercially rated pilots during flight simulation in the window of circadian low (WOCL). Valid PPG and ECG data from 14 participants were analyzed, which yielded approximately 2 hr of data per participant for fatigue-related analysis.

RESULTS

The results of the study demonstrate clear trends toward decreased heart rate for both ECG and PPG and suggest progression of drowsiness between four separate periods (T1, T2, T3, and T4) selected during the study; however, the mean heart rate change from T1 to T4 was statistically significant.

CONCLUSION

The results suggest that ECG and PPG data can be an important tool to observe conditions where drowsiness or fatigue may add risk to the operation. In addition, the data show high correlation between ECG and PPG data, further suggesting that a simpler PPG sensor, mounted within the geography of the aviation headset, may streamline the operationalization of important physiological data.

APPLICATION

Incorporation of PPG sensors and associated signal processing methods into facilitating equipment, such as the aviation headset, may add a layer to operational safety.

Human Factors Contributions to the Development of Standards for Displays of Unmanned Aircraft Systems in Support of Detect-and-Avoid

OBJECTIVE

The aim is to provide a high-level synthesis of human factors research that contributed to the development of detect-and-avoid display requirements for unmanned aircraft systems (UAS).

BACKGROUND

The integration of UAS into the U.S. National Airspace System is a priority under the Federal Aviation Administration's Modernization and Reform Act. For UAS to have routine access to the National Airspace System, UAS must have detect-and-avoid capabilities. One human factors challenge is to determine how to display information effectively to remote pilots for performing detect-and-avoid tasks.

METHOD

A high-level review of research informing the display requirements for UAS detect-and-avoid is provided. In addition, description of the contributions of human factors researchers in the writing of the requirements is highlighted.

RESULTS

Findings from human-in-the-loop simulations are used to illustrate how evidence-based guidelines and requirements were established for the display of information to assist pilots in performing detect-and-avoid. Implications for human factors are discussed.

CONCLUSION

Human factors researchers and engineers made many contributions to generate the data used to justify the detect-and-avoid display requirements. Human factors researchers must continue to be involved in the development of standards to ensure that requirements are evidence-based and take into account human operator performance and human factors principles and guidelines.

APPLICATION

The research presented in this paper is relevant to the design of UAS, the writing of standards and requirements, and the work in human-systems integration.

Aerodynamic imaging by mosquitoes inspires a surface detector for autonomous flying vehicles

Some flying animals use active sensing to perceive and avoid obstacles. Nocturnal mosquitoes exhibit a behavioral response to divert away from surfaces when vision is unavailable, indicating a short-range, mechanosensory collision-avoidance mechanism. We suggest that this behavior is mediated by perceiving modulations of their self-induced airflow patterns as they enter a ground or wall effect. We used computational fluid dynamics simulations of low-altitude and near-wall flights based on in vivo high-speed kinematic measurements to quantify changes in the self-generated pressure and velocity cues at the sensitive mechanosensory antennae. We validated the principle that encoding aerodynamic information can enable collision avoidance by developing a quadcopter with a sensory system inspired by the mosquito. Such low-power sensing systems have major potential for future use in safer rotorcraft control systems.

Fatigue-Related Aviation Mishaps

INTRODUCTION: Fatigue is a critical safety issue to U.S. Air Force (USAF) flight and ground crew. Nearly 15 yr of mishap reports were analyzed to determine how fatigue affects USAF operations with the goal of improving fatigue risk management policies and tools.METHODS: Summary data for 19,920 aviation mishap reports dating back to 2003 were collected from the Air Force Safety Automated System (AFSAS). Fatigue-related mishaps were identified based on designations provided within AFSAS. Other metrics examined were characteristics such as timing, cost, and aircraft metrics, among others. Contingency tables built from these metrics were used to assess fatigue-related trends across the aviation community.RESULTS: While only 3.88% of all mishaps were identified as fatigue-related, they are associated with 2.1 billion of medical expenses and property damage, or 18% of the 11.7 billion total cost of all mishaps included in the study. Nearly a quarter of the fatigue-related mishaps fall into the most severe mishap category and more than half occurred between 0100 and 0700, local time. Fatigue-related mishaps tended to be more common for Remotely Piloted Aircraft (RPA) and ground operations.DISCUSSION: Fatigue is very costly to the USAF despite the relatively low incidence rate of fatigue-related mishaps. This is because larger proportions of severe mishaps were found to be fatigue-related. RPA and ground maintenance operators might be especially susceptible to fatigue and potentially lack adequate fatigue mitigation support and training tailored to their unique operational environment, suggesting a need to improve upon fatigue mitigation tools and strategies.Gaines AR, Morris MB, Gunzelmann G. Fatigue-related aviation mishaps. Aerosp Med Hum Perform. 2020; 91(5):440447.

Flight safety assessment based on an integrated human reliability quantification approach

Human error is an important risk factor for flight safety. Although the human error assessment and reduction technique (HEART) is an available tool for human reliability derivation, it has not been applied in flight safety assessment. The traditional HEART suffers from imprecise calculation of the assessed proportion of affect (APOA) because it heavily depends on a single expert’s judgment. It also fails to provide remedial measures for flight safety problems. To overcome these defects of the HEART, this study proposes an integrated human error quantification approach that uses the improved analytic hierarchy process method to determine the APOA values. Then, these values are fused to the HEART method to derive the human error probability. A certain flight task is completed to assess human reliability. The results demonstrate that the proposed method is a reasonable and feasible tool for quantifying human error probability and assessing flight safety in the aircraft manipulation process. In addition, the critical error-producing conditions influencing flight safety are identified, and improvement measures for high-error-rate operations are provided. The proposed method is useful for reducing the possibility of human error and enhancing flight safety levels in aircraft operation processes.

Social Acceptance of Increased Usage of the Ballistic Parachute System in a General Aviation Aircraft

BACKGROUND: An airframe parachute ("Chute") available in certain aircraft is designed to lower the airplane safely to the ground for emergency situations that occur 500 ft (152 m) above ground level (AGL): the "Chute altitude envelope." This study will explore the change in Chute use before and after 2012 to better understand factors that increased usage and improved accident outcomes.METHODS: Using the public National Transportation Safety Board (NTSB) accident database from January 1, 2001, through August 31, 2018, a regression model was developed to identify factors that may predict Chute use.RESULTS: In accidents occurring after January 1, 2013, pilots were 5 times more likely to use the Chute, while 2.9 times less likely to use the Chute when the accident involved pilot-related causes. The presence of passengers did not predict Chute use. Injuries were likely to be more severe when the Chute was used outside the Chute altitude envelope.DISCUSSION: In contrast to General Aviation (GA) overall, accidents outcomes in aircraft equipped with a Chute have seen great improvements between 2013 and 2018, with increased use of the Chute and improved injury outcomes. Results suggest that changes to pilot training in 2012 have increased the social acceptance of Chute use. Results highlight increased risk of injury outcomes for Chute use in accidents that occur outside the Chute altitude envelope.Kirby J. Social acceptance of increased usage of the ballistic parachute system in a general aviation aircraft. Aerosp Med Hum Perform. 2020; 91(2):86-90.

Modelling and supporting flight crew decision-making during aircraft engine malfunctions: developing design recommendations from cognitive work analysis

In this article, we analyse flight crew response to an in-flight powerplant system malfunction (PSM) using control task analysis. We demonstrate the application of the decision ladder template and the skills, rules, and knowledge (SRK) framework to this new area of inquiry. Despite the high reliability of turbofan engines, accidents and incidents involving PSM still occur. During these unusual events, flight crew have not always responded appropriately, leading to a reduction in safety margins or disruption of operations. This article proposes recommendations for technological and information system that can support flight crew in responding safely and appropriately to a PSM. These recommendations focus on new ways in which information from engine health monitoring system and other sources of data can be utilised and displayed. Firstly, we conducted knowledge elicitation using Critical Decision Method (CDM) interviews with airline pilots who have experienced real or simulated PSM events. We then developed generic decision ladders using the interview data, operations manual, training manual, and other guideline documents. The generic decision ladders characterise the different stages of responding to PSM identified as part of the research. These stages include: regaining and maintaining control of aircraft, identifying PSM and selecting appropriate checklists to secure the engine, and modifying the flight plan. Using the decision ladders and insights from the CDM interviews, we were able to identify cognitive processes and states that are more prone to errors and therefore more likely to generate an inappropriate response. Using the SRK framework, we propose design recommendations for technological and information systems to minimise the likelihood of such inappropriate response. We conclude that this combination of methods provides a structured and reliable approach to identifying system improvements in complex and dynamic work situations. Our specific contributions are the application of these techniques in the unrepresented area of flight operations, and the development of evidence-based design recommendations to improve flight crew response to in-flight powerplant system malfunctions.

Association of Medical Certification Factors with All-Cause Mortality in U.S. Aviators

INTRODUCTION: The value of aeromedical certification in reducing adverse medical outcomes is an especially important question for this era of increasing flight operations that do not require an FAA medical certificate. The study of this question has previously been thwarted by a lack of information about pilots when their medical certificates are not renewed.METHODS: We matched airmen in the FAA medical certification database to the U.S. Social Security Death Index to identify date of death for deceased pilots. Logistic regression models were used to explore associations of certification data with odds of death while holding a medical certificate and within 4 yr of expiration of a medical certificate.RESULTS: FAA aeromedical waivers were associated with 33% lower odds of death while holding a medical certificate and 35% increased odds of death within 4 yr after expiration of a medical certificate. Denial was associated with 21% increased odds of death in the next 4 yr. Only 13 of 47 medical conditions having significant associations were associated with increased odds of death during certification.DISCUSSION: We found that FAA aeromedical certification reduces the odds of death while holding a medical certificate compared to the 4 yr after certificate expiration. We believe this helps provide a positive answer to the question of whether medical certification reduces medically related events.Mills WD, Greenhaw RM. Association of medical certification factors with all-cause mortality in U.S. aviators. Aerosp Med Hum Perform. 2019; 90(11):938-944.

A Medical Review of Fatal High-G U.S. Aerobatic Accidents

INTRODUCTION: Exposure to high G force is a known safety hazard in military aviation as well as civilian aerobatic flight. Tolerance to high G forces has been well studied in military pilots, but there is little research directed at civilian pilots who may have medications or medical conditions not permitted in military pilots.METHODS: In this case-control study, we identified 89 fatal high-G aerobatic accidents and 4000 fatal control accidents from 1995 through 2018 from the NTSB accident database and the FAA autopsy database. We retrieved medications and medical conditions from the FAA's pilot medical databases. Logistic regression models were used to explore the associations of drugs, medical conditions, height, and medical waivers with high-G accidents.RESULTS: Seven drugs (alprazolam, clonidine, ethanol, meclizine, phentermine, triamterene, and zolpidem) reached statistical significance in our models, but had such small case counts that we consider these findings to be uncertain, except for ethanol, which was found in seven cases. Of these, only triamterene was known to the FAA. Statistically significant medical predictors included only alcohol abuse (seven cases) and liver disease (only two cases).DISCUSSION: Our analysis found that the drug ethanol and the condition alcohol abuse are significantly associated with high-G accidents. Seven other factors were statistically significant, but should only be considered as hypothesis generating due to very low case counts. Our study does not suggest that restricting pilots with otherwise permissible medications or medical conditions from aerobatics is warranted.Mills WD, Greenhaw RM, Wang JMP. A medical review of fatal high-G U.S. aerobatic accidents. Aerosp Med Hum Perform. 2019; 90(11):959-965.

Aviation Safety vs. Medical Confidentiality: Disclosure of Health Information for Accident Prevention and Investigation

INTRODUCTION: In this article an analysis is made of existing legal provisions and policies regarding medical confidentiality and the use of medical information on pilots, for the reporting of unfit pilots and for accident and incident investigation. An overview is given of the applicable international, European and several national legal frameworks in relation to this question. The applicable national legislation and relating policies of the Netherlands, the U.S., and Canada are compared on this subject. These three States (countries) are selected because of the differences between them in legal provisions when it comes to medical confidentiality of pilots' health information. The article will conclude with tools derived from this analysis, which can be used to find a balance between medical confidentiality vs. aviation safety.Schuite JM. Aviation safety vs. medical confidentiality: disclosure of health information for accident prevention and investigation. Aerosp Med Hum Perform. 2019; 90(10):872-881.

Integration of a Vestibular Model for the Disorientation Research Device Motion Algorithm Application

INTRODUCTION: Spatial disorientation (SD) remains a leading cause of Class A mishaps and fatalities in aviation. Motion-based flight simulators and other research devices provide the capacity to rigorously study SD in order to develop effective countermeasures. By applying mathematical models of human orientation perception, we propose an approach to improve control algorithms for motion-based flight simulators to study SD.METHODS: The Disorientation Research Device (DRD), or the Kraken™, is the Department of Defense's newest and most capable aerospace medicine motion-based research device. We implemented an "Observer" model for predicting aircrew spatial orientation perception within the DRD, and perceptions experienced in flight. Further, we propose a framework that uses the model output, in addition to pilot control inputs, to optimize multiaxis motion control including human-in-the-loop control capability.RESULTS: A case study was performed to demonstrate the functionality of the framework. Additionally, the case study highlights both how limitations of human perception are crucial to consider when designing motion algorithms, and the challenges of effective flight simulation with multiple motion axes.DISCUSSION: We implemented a mathematical model for spatial orientation perception to improve the design of control algorithms for motion-based flight simulators, using the DRD as an example application. We provide an example of predicting perceptions, producing quantitative information on the efficacy of motion control algorithms. This mathematical model based approach to validating motion control algorithms aims to improve the fidelity of ground-based SD research.Dixon JB, Etgan CA, Horning DS, Clark TK, Folga RV. Integration of a vestibular model for the Disorientation Research Device motion algorithm application. Aerosp Med Hum Perform. 2019; 90(10):901-907.

Anticipated Negative Emotions Effect on Incident Involvement Among Civil Pilots

INTRODUCTION: Human factors have contributed to a constant increase in the level and numbers of aviation incident involvement. The primary objective of this study is to investigate the relationships between anticipated negative emotions (ANEs) and incident involvement among Chinese civil pilots. Furthermore, this paper examines the role of risk perception and proactive coping within the relationships in order to understand the mechanisms underlying pilots' involvement in air transport incidents.METHODS: A cross-sectional regression design was used to measure ANEs (Anticipated Negative Emotions Scale), proactive coping (Proactive Coping Scale), risk perception (Pilot Risk Perception Scale), and incident involvement (Hazardous Events Scale) among 295 Chinese civil pilots from China Southern Airlines. Mediation and moderating effects were explored using regression analyses and were confirmed by the bootstrapping approach.RESULTS: The results show that ANEs are significantly correlated with risk perception (r = -0.55) and incident involvement (r = 0.28). ANEs have a direct effect on pilot involvement in incidents and have an indirect effect on pilot incident involvement through the influencing of risk perception. Proactive coping was also found to weaken the direct effect of anticipated negative emotions on incident involvement.DISCUSSION: The safety benefits of proactive coping are more pronounced among pilots with high levels of ANEs. The practical implications of the study include recommendations relating to injury prevention efforts in incident involvement. Future research directions are also discussed.Wang H, Xu Q, Yang C, You X, Ji M. Anticipated negative emotions effect on incident involvement among civil pilots. Aerosp Med Hum Perform. 2019; 90(9):774-781.

Self-Assessed Preferred Retraining Intervals of Helicopter Underwater Egress Training (HUET)

BACKGROUND: Royal Netherlands Air Force (RNLAF) helicopter aircrew get Helicopter Underwater Egress Training (HUET) using a Modular Egress Training Simulator (METS™) in order to be prepared for escaping the aircraft when ditching into water. In the current situation the retraining intervals are only chosen on an arbitrary basis for different backgrounds of the crew (maritime and regular flight crew). The frequency of refresher training depends on the expected degree of retention, but evidence-based research on required intervals between refresher courses is scarce. Ideally, training should be based on the amount of retention of acquired competencies.METHODS: Retrospective questionnaires were filled in by 132 helicopter aircrew who followed the HUET course(s) at the Survival Evasion Resistance and Escape (SERE) school in Gilze-Rijen (Netherlands). They assessed themselves on competencies and gave their opinion on the preferred interval.RESULTS: Maritime crew report increasing competence levels with the number of refresher courses followed. According to the opinion of all aircrew, retraining intervals may take longer than 18 (first refresher) to 30 mo (fourth refresher). Maritime and regular flight crew differ in preferred retraining intervals (up to 22 mo and up to 33 mo, respectively).DISCUSSION: This study provides indications to reconsider the retraining interval and to differentiate between maritime and regular flight crew based on aircrew's opinions and self-assessments. As competence levels still increase with the number of courses followed, it is recommended to reconsider the current fixed intervals of once a year or once every 3 yr for maritime and regular flight crew, respectively.Bottenheft C, Oprins EAPB, Houben MMJ, Meeuwsen T, Valk PJL. Self-assessed preferred retraining intervals of Helicopter Underwater Egress Training (HUET). Aerosp Med Hum Perform. 2019; 90(9):800-806.

Preflight Risk Assessment for Improved Safety in Helicopter Emergency Medical Service Operations

INTRODUCTION: Adverse weather and poor visual cues are common elements in night-time Helicopter Emergency Medical Service (HEMS) operations contributing to spatial disorientation and fatal accidents. Pilots are required to make weather-related preflight risk assessments to accept or reject a flight. This study's aim was to develop predictive risk assessment tools based on historical accident data to assist the decision-making process.METHODS: We analyzed 32 single-pilot HEMS night-time visual flight rules fatal accidents to identify contributory risk factors. Logistic regression analysis was used to develop prediction nomograms for nonvisual meteorological conditions (non-VMC), cause and nonsurvivable accidents as dependent variables. Risk factors such as temperature dew point spread, elevation difference, and years of HEMS pilot experience, were entered as continuous variables. Flight crew composition, pilot DTE (domain task experience) and flight rule capability, primary missions, and temperature dew point spread were entered as categorical variables. A point scoring matrix transposed model probability to likelihood and consequence severity.RESULTS: The nomograms correctly predicted the likelihood of entering non-VMC, accident cause, and sustaining a nonsurvivable accident in 75%, 55%, and 94% of cases, respectively. Using data from a recent nonsurvivable HEMS accident, the nomogram estimated a 92% probability (Very Likely) of nonsurvivable accident if visual cues were lost.CONCLUSION: These nomograms can provide preflight information to predict the likelihood of adverse safety outcomes occurring during a planned HEMS mission. While further development work is needed, this approach has the potential to improve HEMS operational safety.Aherne BB, Zhang C, Chen WS, Newman DG. Preflight risk assessment for improved safety in Helicopter Emergency Medical Service operations. Aerosp Med Hum Perform. 2019; 90(9):792-799.

U.S. Army Parachute Mishap Fatalities: 2010-2015

INTRODUCTION: Despite the large number of U.S. military members who conduct parachuting operations, its inherent safety risks, and the introduction of a new military parachute in 2010, little has been published in the last decade on U.S. military parachute fatalities.METHODS: Parachute fatality investigative records maintained by the U.S. Army Combat Readiness Center were reviewed for U.S. Army fatalities resulting from military parachuting operations from January 1, 2010, through December 31, 2015. De-identified data on cases were collected, including causes, lethal injuries, and demographic, environmental, and missional factors. A descriptive analysis was performed.RESULTS: There were 13 cases which met study inclusion criteria. Most occurred during static-line operations and were jumps from a C-17 aircraft using a T-11 parachute. The two most common assigned accident codes were "improper or abnormal exit" and "unstable or improper body position," which combined accounted for 33% of cases. Also noteworthy at 11% each were "entanglement," "parachute malfunction," and "dragged on the drop zone," and at 6% each were "static line injury," "lost or stolen air," and "drop zone hazard." In 69% of cases blunt force trauma was the cause of death.DISCUSSION: Incident factors included human actions, equipment failure, and the environment. Death from blunt force trauma upon impact with the ground as the most frequent lethal injury was expected for parachute operations. This descriptive study provides awareness to military leaders of circumstances in which fatalities occur. Future investigations should include data on the total number of jumps to provide a more comprehensive analysis of risk.Johnson ES, Gaydos SJ, Pavelites JJ, Kotwal RS, Houk JE. U.S. Army parachute mishap fatalities: 2010-2015. Aerosp Med Hum Perform. 2019; 90(7):637-642.

An analysis of human factors in fifty controlled flight into terrain aviation accidents from 2007 to 2017

INTRODUCTION

Controlled Flight Into Terrain (CFIT) account for a considerable amount of fatalities when compared to other accident categories. Human factors are deemed significant contributory causes in these accidents. This paper aims to identify the human factors involved with aviation accidents that resulted in CFIT.

METHOD

The study used the Human Factors Analysis and Classification System (HFACS) framework to determine the factors involved in 50 CFIT accidents from 24 counties over a 10 year period, i.e. 2007-2017. Interviews with five senior aviation safety experts were used to provide a better comprehension of the human factors affecting the flight safety.

RESULTS

The study identified 1289 individual causal and contributory human factors with unsafe actions and preconditions for unsafe actions being the main subcategories of the accidents. The study found that CFIT occur across a range of pilot experience and 44% of accidents occurred in cruise flight. Distraction, complacency and fatigue are all elements that flight crews may experience as contributors to CFIT during cruising.

CONCLUSIONS

Human factors represent a major component of CFIT accidents. The analysis revealed a similar pattern of contributory and causal human factors across the various flight categories, with some noteworthy isolated variations. The prevalent factors were decision and skill-based errors along with communication, coordination and planning issues. Practical applications: Provision of specific CFIT awareness, pilot training focusing on improved decision-making and revision of basic flight skills, development of specific Global Positioning System routes for transiting high terrain areas are necessary to prevent CFIT accidents. Installation of Terrain Avoidance and Warning System and Ground Proximity Warning System and appropriate equipment training, specific CFIT Crew Resource Management training and improvement of organizational knowledge on the elements involved in CFIT are also recommended.

Modafinil as a Stimulant for Military Aviators

INTRODUCTION: Modafinil is a wakefulness-promoting stimulant that has been approved by the Republic of Singapore Air Force (RSAF) as a fatigue countermeasure medication since 2011. Each RSAF aircrew member must undergo a ground test to exclude operationally relevant adverse drug effects prior to consuming the medication for operational reasons. This study describes the RSAF's modafinil ground testing outcomes over a 7-yr period.METHODS: This is a retrospective case series of 243 RSAF aircrew members who underwent modafinil 100-mg test dosing over the 7-yr period from September 2011 to September 2018.RESULTS: The median age was 31 yr (range, 21-53 yr) and mean age was 31.7 yr ± 6.19 yr. Of the aircrew members, 234 (96.3%) were men and all were of Asian ethnicity. Of the subjects, 237 (97.5%) were medically cleared for the operational use of modafinil. Among the six (2.47%) who failed modafinil ground testing, headache (cumulative incidence, 1.65%), anxiety (cumulative incidence, 0.41%), diarrhea (cumulative incidence, 0.41%), and insomnia (cumulative incidence, 0.41%) were reported as the side effects experienced. None of the aircrew members experienced major adverse drug events.DISCUSSION: Our findings suggest a low occurrence of adverse drug effects among military aircrew members who undergo modafinil test dosing prior to using the drug operationally. To our knowledge, this is the single largest published case series of modafinil ground testing outcomes among Asian military aviators.Ooi T, Wong SH, See B. Modafinil as a stimulant for military aviators. Aerosp Med Hum Perform. 2019; 90(5):480-483.

Safety Implications of 6-Month vs. 1-Year First-Class Aeromedical Certificates

INTRODUCTION: This study explores the safety risk due to delayed detection of hazardous health conditions that would result from increasing the duration of U.S. first-class aeromedical certificates from 6 mo to 12 mo for pilots ages 40 yr old through 60 yr old.METHODS: All pilots who submitted a U.S. first-class application in 2014 with no electrocardiogram and with the previous exams 4.5 to 7.5 mo prior were selected from the FAA pilot medical database. Proportions of Federal Aviation Administration (FAA) denial pathology codes and Aviation Medical Examiner (AME) deferrals were compared for these exams within and between age groups from 40 yr old through 75 yr old. The absolute incidence rates for delayed detection were calculated and relative incidence of these proportions was compared graphically.RESULTS: The relative risk between age groups for delayed identification of disqualifying medical conditions showed that the 56-60-yr-old group would be at about twice the risk as the 40-45-yr-old group. The absolute incidence for the 56-60-yr-old group was 0.46% for denial conditions and 0.60% for AME deferrals over 6 mo.DISCUSSION: Increasing FAA first-class medical certificate duration from 6 mo to 12 mo would put 56-60-yr-old pilots at double the currently accepted risk for delayed detection of significant medical conditions. The absolute risk for this 6-mo delayed identification for the 56-60-yr-old group would average 0.53%.Mills WD, DeJohn CA. Safety implications of 6-month vs. 1-year first-class aeromedical certificates. Aerosp Med Hum Perform. 2019; 90(5):484-487.

Systems Safety Risk Analysis of Fatal Night Helicopter Emergency Medical Service Accidents

INTRODUCTION: In the United States, the proportion of Helicopter Emergency Medical Service (HEMS) fatal accidents remained unchanged despite an overall decreasing accident rate. Previous research showed night HEMS operations influenced fatal outcomes. Pilots with <6 yr of HEMS domain task experience (low-DTE) had a higher likelihood of a night operational accident in conditions associated with adverse weather. This study sought to determine whether a difference existed between day and night fatal accident rates and identify influences contributing to night fatal HEMS accidents. Any risk factors identified will be used for a risk analysis to inform future operational safety of the night visual flight rule (VFR) HEMS transport system.METHODS: Historical accident data and industry hours were obtained. Both pilot DTE groups (low and high) and mission VFR and instrument flight rule (IFR) capability were identified using data from 32 night VFR operational fatal HEMS accidents. Accidents were stratified by loss of control and controlled flight into terrain, pilot DTE, and flight rule capability. The effectiveness of both DTE groups and both flight rule capabilities were measured using system safety risk analysis techniques.RESULTS: Night fatal accident rates were statistically different from daytime. Low-DTE pilots and the VFR capability combination had the highest likelihood of night operational nonsurvivable accident.CONCLUSION: Low-DTE pilots and the VFR capability were the least effective mission combination to avoid hazardous conditions at night and maintain spatial orientation, respectively. The analysis identified measures to reduce likelihood of night fatal operational accidents.Aherne BB, Zhang C, Chen WS, Newman DG. Systems safety risk analysis of fatal night Helicopter Emergency Medical Service accidents. Aerosp Med Hum Perform. 2019; 90(4):396-404.

Speech Analysis for Fatigue and Sleepiness Detection of a Pilot

BACKGROUND: Mental fatigue and sleepiness are well recognized determinants of human-error related accidents and incidents in aviation. In Brazil, according to the Center for Investigation and Prevention of Aeronautical Accidents (CENIPA), the rate of accidents in the aerial modal is 1 per 2 d. Human factors are present in 90% of these accidents.CASE REPORT: This paper describes a retrospective study of the communication between a pilot and an air traffic control tower just before a fatal accident. The objective was the detection of fatigue and sleepiness of a pilot, who complained of these signs and symptoms before the flight, by means of voice and speech analysis. The in-depth accident analysis performed by CENIPA indicated that sleepiness and fatigue most likely contributed to the accident. Speech samples were analyzed for two conditions: 1) nonsleepy data recorded 35 h before the air crash (control condition), which were compared with 2) data from samples collected about 1 h before the accident and also during the disaster (sleepy condition). Audio recording analyses provided objective measures of the temporal organization of speech, such as hesitations, silent pauses, prolongation of final syllables, and syllable articulation rate.DISCUSSION: The results showed that speech during the day of the accident had significantly low elocution and articulation rates compared to the preceding day, also indicating that the methodology adopted in this study is feasible for detection of fatigue and sleepiness through speech analysis.de Vasconcelos CA, Vieira MN, Kecklund G, Yehia HC. Speech analysis for fatigue and sleepiness detection of a pilot. Aerosp Med Hum Perform. 2019; 90(4):415-418.

What went right? An analysis of the protective factors in aviation near misses

Learning from successful safety outcomes, or what went right, is an important emerging component of maintaining safe systems. Accordingly, there are increasing calls to study normal performance in near misses as a part of safety management activities. Despite this, there is limited guidance on how to accomplish this in practice. This article presents a study in which using Rasmussen's risk management framework to analyse 16 serious incidents from the aviation domain. The findings show that a network of protective factors prevents accidents with factors identified across the sociotechnical system. These protective networks share many properties with those identified in accidents. The article demonstrates that is possible to identify these networks of protective factors from incident investigation reports. The theoretical implications of these results and future research opportunities are discussed. Practitioner Statement: The analysis of near misses is an important part of safety management activities. This article demonstrates that Rasmussen?s risk management framework can be used to identify networks of protective factors which prevent accidents. Safety practitioners can use the framework described to discover and support the system-wide networks of protective factors.

Maintenance and inspection as risk factors in helicopter accidents: Analysis and recommendations

In this work, we establish that maintenance and inspection are a risk factor in helicopter accidents. Between 2005 and 2015, flawed maintenance and inspection were causal factors in 14% to 21% of helicopter accidents in the U.S. civil fleet. For these maintenance-related accidents, we examined the incubation time from when the maintenance error was committed to the time when it resulted in an accident. We found a significant clustering of maintenance accidents within a short number of flight-hours after maintenance was performed. Of these accidents, 31% of these accidents occurred within the first 10 flight-hours. This is reminiscent of infant mortality in reliability engineering, and we characterized it as maintenance error infant mortality. The last quartile of maintenance-related accidents occurred after 60 flight-hours following maintenance and inspection. We then examined the "physics of failures" underlying maintenance-related accidents and analyzed the prevalence of different types of maintenance errors in helicopter accidents. We found, for instance, that the improper or incomplete (re)assembly or installation of a part category accounted for the majority of maintenance errors with 57% of such cases, and within this category, the incorrect torquing of the B-nut and incomplete assembly of critical linkages were the most prevalent maintenance errors. We also found that within the failure to perform a required preventive maintenance and inspection task category, the majority of the maintenance programs were not executed in compliance with federal regulations, nor with the manufacturer maintenance plan. Maintenance-related accidents are particularly hurtful for the rotorcraft community, and they can be eliminated. This is a reachable objective when technical competence meets organizational proficiency and the collective will of all the stakeholders in this community. We conclude with a set of recommendations based on our findings, which borrow from the ideas underlying the defense-in-depth safety principle to address this disquieting problem.

Using Neural Networks to predict HFACS unsafe acts from the pre-conditions of unsafe acts

Human Factors Analysis and Classification System (HFACS) is based upon Reason's organizational model of human error which suggests that there is a 'one to many' mapping of condition tokens (HFACS level 2 psychological precursors) to unsafe act tokens (HFACS level 1 error and violations). Using accident data derived from 523 military aircraft accidents, the relationship between HFACS level 2 preconditions and level 1 unsafe acts was modelled using an artificial neural network (NN). This allowed an empirical model to be developed congruent with the underlying theory of HFACS. The NN solution produced an average overall classification rate of ca. 74% for all unsafe acts from information derived from their level 2 preconditions. However, the correct classification rate was superior for decision- and skill-based errors, than for perceptual errors and violations. Practitioner Summary: A model to predict unsafe acts (HFACS level 1) from their preconditions (HFACS level 2) was developed from the analysis of 523 military aircraft accidents using an artificial NN. The results could correctly predict approximately 74% of errors.

Eye tracking as a debriefing tool in upset prevention and recovery training (UPRT) for general aviation pilots

Upset prevention and recovery training (UPRT) is intended to improve the ability of pilots to recognize and avoid situations that can lead to airplane upsets and to improve their ability to recover control of an airplane that has exceeded the normal flight envelope. To this end, a set of different training contents - from theoretical knowledge of aerodynamics and human factors to practice-based flight training - is necessary. In order to support the debriefing with an objective feedback, and because visual scanning is a core competence, two studies on subjective evaluation of aviation pilots - one conducted in a flight simulator and the other one in-flight - focussed on the practical application of eye tracking as a debriefing tool in UPRT. From a practitioner's perspective, eye tracking appeared to be a useful method in terms of visualising instrument scanning techniques, supporting the instructor with objective debriefing material and fostering self-awareness in human processes. The discussion recommends adjusted UPRT instructor training and further improvements to eye tracking hardware and software. Practitioner Summary: The article focuses on pilot evaluations of eye tracking as a debriefing tool in UPRT and the identification of critical elements in its use. Eye tracking is a promising debriefing tool for UPRT. The discussion points to desirable improvements of eye tracking hardware and software as well as adjustments to instructor training that are pertinent.

Modelling distributed crewing in commercial aircraft with STAMP for a rapid decompression hazard

Changes to crewing configurations in commercial airlines are likely as a means of reducing operating costs. To consider the safety implications for a distributed crewing configuration, system theoretic accident model and processes (STAMP) was applied to a rapid decompression hazard. High level control structures for current operations and distributed crewing are presented. The CONOPS generated by STAMP-STPA for distributed crewing, and design constraints associated with unsafe control actions (UCAs) are offered to progress in the route to certification for distributed crewing, and improve safety in current operations. Control loops between stakeholders were created using system-theoretic process analysis (STPA). The factors leading to the Helios 255 incident demonstrated the redundancy that a ground station could offer without the risk of hypoxia, during a decompression incident. STPA analysis also highlighted initial UCAs that could occur within the hypothetical distributed crewing configuration, prompting consideration of design constraints and new CONOPS for ground station design. Practitioner Summary: SPO in commercial aircraft is likely as a means to reduce costs. This paper makes a case for distributed crewing using STAMP-STPA. Comparing current operations with a distributed crewing configuration, the redundancy offered by a ground station is demonstrated. Design constraints and new CONOPs for distributed crewing, and current operations are proposed.

Parachute use to prevent death and major trauma when jumping from aircraft: randomized controlled trial

OBJECTIVE

To determine if using a parachute prevents death or major traumatic injury when jumping from an aircraft.

DESIGN

Randomized controlled trial.

SETTING

Private or commercial aircraft between September 2017 and August 2018.

PARTICIPANTS

92 aircraft passengers aged 18 and over were screened for participation. 23 agreed to be enrolled and were randomized.

INTERVENTION

Jumping from an aircraft (airplane or helicopter) with a parachute versus an empty backpack (unblinded).

MAIN OUTCOME MEASURES

Composite of death or major traumatic injury (defined by an Injury Severity Score over 15) upon impact with the ground measured immediately after landing.

RESULTS

Parachute use did not significantly reduce death or major injury (0% for parachute v 0% for control; P>0.9). This finding was consistent across multiple subgroups. Compared with individuals screened but not enrolled, participants included in the study were on aircraft at significantly lower altitude (mean of 0.6 m for participants v mean of 9146 m for non-participants; P<0.001) and lower velocity (mean of 0 km/h v mean of 800 km/h; P<0.001).

CONCLUSIONS

Parachute use did not reduce death or major traumatic injury when jumping from aircraft in the first randomized evaluation of this intervention. However, the trial was only able to enroll participants on small stationary aircraft on the ground, suggesting cautious extrapolation to high altitude jumps. When beliefs regarding the effectiveness of an intervention exist in the community, randomized trials might selectively enroll individuals with a lower perceived likelihood of benefit, thus diminishing the applicability of the results to clinical practice.

A modified accident analysis and investigation model for the general aviation industry: Emphasizing on human and organizational factors

INTRODUCTION

Currently, there is a lack of specific analytical tools for general aviation accidents (GAAs). This has led to loopholes in the prevention of GAAs.

METHODS

A Swiss Cheese model for general aviation (SCM-GA) is proposed to identify the human and organizational factors involved in GAAs. In the proposed SCM-GA, 5 categories, 45 subcategories, a general aviation safety management system (GA-SMS) and safety culture were developed based on the classic accident causation models combined with the laws and regulations and safety management practices in the general aviation industry.

RESULTS

One GAA was analyzed using SCM-GA. The human and organizational causes revealed by SCM-GA were more complete than the causes revealed through the accident report. The identification results of the deficiencies in the subcategories of GA-SMS and the safety culture were more consistent with the requirements in the general aviation laws and regulations than the organizational factors in the accident report. Based on the subcategories of SCM-GA, 41 GAAs that occurred between 1996 and 2010 in China were statistically analyzed and χ² test analyses were performed to estimate the statistical strength of the association between two adjacent subcategories of SCM-GA. The results showed that two adjacent subcategories of SCM-GA were significantly associated. They helped to determine the hidden problems in the accident report based on the path of accident.

CONCLUSIONS

SCM-GA is an accident analysis tool that can comprehensively analyze the human and organizational deficiencies involved in GAAs. The accident causes revealed by SCM-GA were more consistent with the general aviation safety management practices.

PRACTICAL APPLICATIONS

General aviation companies should establish their own GA-SMS and safety culture based on the subcategories developed herein. Using SCM-GA for routine safety inspection and accident investigation will help the management and the staff make effective safety decisions to effectively prevent GAAs.

Parallels in safety between aviation and healthcare

Aviation and healthcare are complex industries and share many similarities: the cockpit and the operating theater, the captain and the surgeon. While North American commercial aviation currently enjoys a tremendous safety record, it was not always this way. A spike of accidents in 1973 caused 3214 aviation-related fatalities. Over the past 20years, the rate of fatal accidents per million flights fell by a factor of five, while air traffic increased by more than 86%. There have been no fatalities on a U.S. carrier for over 12years. Last year, there were 251,454 deaths in the United States owing to medical error. Pilots pioneered ways to address risks through crew resource management (CRM), and threat and error management (TEM). Both strategies, which are aimed at minimizing risk and optimizing safety, are applicable to surgery and the healthcare industry. These strategies as well as the Swiss Cheese Model, Checklists and the Normalization of Deviance will be reviewed in this article.

Concurrent Pilot Instrument Monitoring in the Automated Multi-Crew Airline Cockpit

INTRODUCTION

Pilot instrument monitoring has been described as "inadequate," "ineffective," and "insufficient" after multicrew aircraft accidents. Regulators have called for improved instrument monitoring by flight crews, but scientific knowledge in the area is scarce. Research has tended to investigate the monitoring of individual pilots when in the pilot-flying role; very little research has looked at crew monitoring, or that of the "monitoring-pilot" role despite it being half of the apparent problem.

METHODS

Eye-tracking data were collected from 17 properly constituted and current Boeing 737 crews operating in a full motion simulator. Each crew flew four realistic flight segments, with pilots swapping between the pilot-flying and pilot-monitoring roles, with and without the autopilot engaged. Analysis was performed on the 375 maneuvering-segments prior to localizer intercept.

RESULTS

Autopilot engagement led to significantly less visual dwell time on the attitude director indicator (mean 212.8-47.8 s for the flying pilot and 58.5-39.8 s for the monitoring-pilot) and an associated increase on the horizontal situation indicator (18-52.5 s and 36.4-50.5 s).

DISCUSSION

The flying-pilots' withdrawal of attention from the primary flight reference and increased attention to the primary navigational reference was paralleled rather than complemented by the monitoring-pilot, suggesting that monitoring vulnerabilities can be duplicated in the flight deck. Therefore it is possible that accident causes identified as "inadequate" or "insufficient" monitoring, are in fact a result of parallel monitoring.Jarvis SR. Concurrent pilot instrument monitoring in the automated multi-crew airline cockpit. Aerosp Med Hum Perform. 2017; 88(12):1100-1106.

Debiasing visual pilots' weather-related decision making

Pilots who decide to continue a flight into deteriorating weather conditions, rather than turn back or divert, are a significant cause of fatal crashes in general aviation. Earlier research has suggested that cognitive biases such as the anchoring effect and confirmation bias are implicated in many decisions to continue into worsening weather. In this study, we explored whether a simple debiasing technique, 'considering the alternative', reduced the effect of these two potentially fatal biases. Despite the study being adequately powered, our attempts to reduce the effects of biases were both unsuccessful. Negative findings such as these are particularly useful in aviation, as they can provide information on what does not work in this high stakes industry, even though such strategies may work elsewhere.

Rates and causes of accidents for general aviation aircraft operating in a mountainous and high elevation terrain environment

BACKGROUND

Flying over mountainous and/or high elevation terrain is challenging due to rapidly changeable visibility, gusty/rotor winds and downdrafts and the necessity of terrain avoidance. Herein, general aviation accident rates and mishap cause/factors were determined (2001-2014) for a geographical region characterized by such terrain.

METHODS

Accidents in single piston engine-powered aircraft for states west of the US continental divide characterized by mountainous terrain and/or high elevation (MEHET) were identified from the NTSB database. MEHET-related-mishaps were defined as satisfying any one, or more, criteria (controlled flight into terrain/obstacles (CFIT), downdrafts, mountain obscuration, wind-shear, gusting winds, whiteout, instrument meteorological conditions; density altitude, dust-devil) cited as factors/causal in the NTSB report. Statistics employed Poisson distribution and contingency tables.

RESULTS

Although the MEHET-related accident rate declined (p<0.001) 57% across the study period, the high proportion of fatal accidents showed little (40-43%) diminution (χ²=0.935). CFIT and wind gusts/shear were the most frequent accident cause/factor categories. For CFIT accidents, half occurred in degraded visibility with only 9% operating under instrument flight rules (IFR) and the majority (85%) involving non-turbo-charged engine-powered aircraft. For wind-gust/shear-related accidents, 44% occurred with a cross-wind exceeding the maximum demonstrated aircraft component. Accidents which should have been survivable but which nevertheless resulted in a fatal outcome were characterized by poor accessibility (60%) and shoulder harness under-utilization (41%).

CONCLUSION

Despite a declining MEHET-related accident rate, these mishaps still carry an elevated risk of a fatal outcome. Airmen should be encouraged to operate in this environment utilizing turbo-charged-powered airplanes and flying under IFR to assure terrain clearance.

Fatigue proofing: The role of protective behaviours in mediating fatigue-related risk in a defence aviation environment

In the military or emergency services, operational requirements and/or community expectations often preclude formal prescriptive working time arrangements as a practical means of reducing fatigue-related risk. In these environments, workers sometimes employ adaptive or protective behaviours informally to reduce the risk (i.e. likelihood or consequence) associated with a fatigue-related error. These informal behaviours enable employees to reduce risk while continuing to work while fatigued. In this study, we documented the use of informal protective behaviours in a group of defence aviation personnel including flight crews. Semi-structured interviews were conducted to determine whether and which protective behaviours were used to mitigate fatigue-related error. The 18 participants were from aviation-specific trades and included aircrew (pilots and air-crewman) and aviation maintenance personnel (aeronautical engineers and maintenance personnel). Participants identified 147 ways in which they and/or others act to reduce the likelihood or consequence of a fatigue-related error. These formed seven categories of fatigue-reduction strategies. The two most novel categories are discussed in this paper: task-related and behaviour-based strategies. Broadly speaking, these results indicate that fatigued military flight and maintenance crews use protective 'fatigue-proofing' behaviours to reduce the likelihood and/or consequence of fatigue-related error and were aware of the potential benefits. It is also important to note that these behaviours are not typically part of the formal safety management system. Rather, they have evolved spontaneously as part of the culture around protecting team performance under adverse operating conditions. When compared with previous similar studies, aviation personnel were more readily able to understand the idea of fatigue proofing than those from a fire-fighting background. These differences were thought to reflect different cultural attitudes toward error and formal training using principles of Crew Resource Management and Threat and Error Management.