General Aviation Accidents Research Articles

Evolution Mechanism on the Unsafe Behavioural Risks of General Aviation Pilots

The unsafe behaviour prevention and control of general aviation pilots has become an emphasis in the general aviation safety management with the increasing number of general aviation enterprises, lengthening of flight time and frequent occurrence of public safety events caused by general aviation accidents. How to identify the factors influencing the unsafe behaviours of general aviation pilots and clarify the inter factor evolution mechanism is hot issue in the general aviation. To accurately identify the key factors influencing the unsafe behaviours of general aviation pilots and define the interaction mechanism between factors, using the unsafe behaviours of pilots in 200 global general aviation accidents during 2015-2019 and the association rule method, the bottom-layer factors of the Human Factors Analysis and Classification System (HFACS) model were analysed. Furthermore, the influence degree, influenced degree, centrality and causality of the influencing factors in the HFACS model were calculated, and the risk transfer path at different layers was determined on the basis of the integrated decision-making trial and evaluation laboratory (DEMATEL) and fuzzy theory. Results show that the poor individual ready state is strongly associated with skill error, decision-making error and habitual violation. Moreover, 11 factors, such as poor physical environment, physical/intelligence limitation and poor technical environment, constitute the factors in the cause group for pilot unsafe behaviours. 7 factors, such as insufficient supervision, improper operation plan and failure to discover and correct problems, are the factors in the result group. Illegal behaviour, failure to discover and correct problems and decision-making error of pilots, which are of high centrality, are key factors influencing the unsafe behaviours of general aviation pilots. The conclusions obtained from this study compensate the deficiencies for the linear statistical model of risk factors and provide a novel method for regulating and controlling the unsafe behaviours of general aviation pilots.

Severity-Mapped Vibrotactile Cues to Support Interruption Management with Weather Messaging in the General Aviation Cockpit

Despite the increasing availability of technologies that provide access to aviation weather information in the cockpit, weather remains a prominent contributor to general aviation (GA) accidents. Pilots fail to detect the presence of new weather information, misinterpret it, or otherwise fail to act appropriately on it. When cognitive demands imposed by concurrent flight tasks are high, the risks increase for each of these failure modes. Previous research shows how introducing vibrotactile cues can help ease or redistribute some of these demands, but there is untapped potential in exploring how vibratory cues can facilitate “interruption management”, i.e., fitting the processing of available weather information into flight task workflow. In the current study, GA pilots flew a mountainous terrain scenario in a flight training device while receiving, processing, and acting on various weather information messages that were displayed visually, in graphical and text formats, on an experimental weather display. Half of the participants additionally received vibrotactile cues via a connected smartwatch with patterns that conveyed the “severity” of the message, allowing pilots to make informed decisions about when to fully attend to and process the message. Results indicate that weather messages were acknowledged more often and faster when accompanied by the vibrotactile cues, but the time after acknowledgment to fully process the messages was not significantly affected by vibrotactile cuing, nor was overall situation awareness. These findings illustrate that severity-encoded vibrotactile cues can support pilot awareness of updated weather as well as task management in processing weather messages while managing concurrent flight demands.

The Effects of Display Type, Weather Type, and Pilot Experience on Pilot Interpretation of Weather Products

The majority of general aviation (GA) accidents involving adverse weather result in fatalities. Considering the high weather-related fatality rate among GA flight operations, it is imperative to ensure that GA pilots of all experience levels can incorporate available weather information into their flight planning. In the past decade, weather product development has incorporated increasing levels of automation, which has led to the generation of high-resolution, model-based aviation displays such as graphical turbulence guidance and current icing potential, which rival the resolution of radar and satellite imagery. This is in stark contrast to the traditional polygonal-based displays of aviation weather hazards (G-AIRMETs and SIGMETs). It is important to investigate the effects of these changes on the end user. Therefore, the purpose of this study was to compare the interpretability of weather products for two areas of interest: display type (traditional polygons vs. model-based imagery) and type of weather phenomena (ceiling/visibility, turbulence, and icing), across a range of pilot experience levels. Two hundred and four participants completed a series of weather product interpretation questions. The results indicated significant effects of product display type, as well as significant effects of weather phenomena and pilot experience on product interpretation. Further investigation is needed to assess possible extraneous variables.

A comparison of general aviation accidents involving airline pilots and instrument-rated private pilots

Introduction: The extremely low accident rate for U.S air carriers relative to that of general aviation (∼1 and ∼60/million flight hours respectively) partly reflects advanced airman certification, more demanding recurrency training and stringent operational regulations. However, whether such skillset/training/regulations translate into improved safety for airline pilots operating in the general aviation environment is unknown and the aim of this study. Methods: Accidents (1998–2017) involving airline pilots and instrument-rated private pilots (PPL-IFR) operating non-revenue light aircraft were identified from the NTSB accident database. An online survey informed general aviation flight exposure for both pilot cohorts. Statistics used proportion testing and Mann-Whitney U tests. Results: In degraded visibility, 0 and 40% (χ2p = 0.043) of fatal accidents involving airline and PPL-IFR airmen were due to in-flight loss-of-control, respectively. For landing accidents, airline pilots were under-represented for mishaps related to airspeed mismanagement (p = 0.036) relative to PPL-IFR but showed a dis-proportionate count (2X) of ground loss-of-directional control accidents (p = 0.009) the latter likely reflecting a preference for tail-wheel aircraft. The proportion of FAA rule violation-related mishaps by airline pilots was >2X (7 vs. 3%) that for PPL-IFR airmen. Moreover, airline pilots showed a disproportionate (χ2p = 0.021) count of flights below legal minimum altitudes. Not performing an official preflight weather briefing or intentionally operating in instrument conditions without an IFR flight plan represented 43% of airline pilot accidents involving FAA rule infractions. Conclusions: These findings inform safety deficiencies for: (a) airline pilots, landing/ground operations in tail-wheel aircraft and lack of 14CFR 91 familiarization regulations regarding minimum operating altitudes and (b) PPL-IFR airmen in-flight loss-of-control and poor landing speed management. Practical Applications: For PPL-IFR airmen, training/recurrency should focus on unusual attitude recovery and managing approach speeds. Airline pilots should seek additional instructional time regarding landing tail-wheel aircraft and become familiar with 14CFR 91 rules covering minimum altitudes.

General Aviation Weather Hazards:Current Human Factors Research, Pilot Practices, and Tools

When General Aviation (GA) pilots encounter unexpected weather hazards in-flight, the results are typically deadly. It is unsurprising that the National Transportation Safety Board repeatedly lists weather related factors in GA flight operations as an unsolved aviation safety challenge. Solving this problem requires multidisciplinary perspectives. Fortunately, in the past several years innovative laboratory research and industry products have become available. This panel discussion brings together Human Factors and Ergonomics researchers and practitioners to discuss and describe the current work and future directions to avoid weather related accidents in GA.

HFACS Analysis of U.S. General Aviation Accidents Using Bayesian Network

Safety is one of the most important factors that affects the sustainable development of the aviation industry. With the increasing robustness of technologies, humans have played a progressively more important causal role in aviation accidents. This paper applies an HFACS-BN model (HFACS: Human Factors Analysis and Classification System; BN: Bayesian Network) to analyze the root causes of aviation accidents. General aviation (GA) accident reports were collected from the U.S. National Transportation Safety Board (NTSB) accident database. The authors encoded the human factors of sample cases based on the HFACS framework and constructed a corresponding BN. From this work, parameter estimation associated with a conditional probability table (CPT) was conducted to determine prior probabilities of contributing factors, and a sensitivity test was conducted to determine the most significant factors. This study provides guidance to the federal government to facilitate risk management in order to reduce fatal general aviation accidents.

Flying Solo

Abstract. The paper examines general aviation (GA) pilot risk perception and decision-making via an online vignette study. GA is a high-risk area of aviation with many GA accidents considered to be the result of pilot performance rather than mechanical failure. Pilots ( n = 101) were presented with 12 go/no-go take-off decision scenarios across four risk categories (compromised performance, environment, faulty equipment, missing equipment). Scenarios depicting a missing checklist, missing sunglasses, and stress were considered less risky than illness, a faulty airspeed indicator (ASI), and a broken seatbelt. Pilots weighed their take-off decisions against mitigating factors, protective measures, and flight parameters. Situation awareness training and a focus on pre-flight planning may help to enhance flight safety within this group.

Accident Rates, Causes, and Occupant Injury Involving High-Performance General Aviation Aircraft.

BACKGROUND: Spatial disorientation, poor situational awareness, and aerodynamic stalls are often causal/contributory to general aviation accidents. To mitigate against the occurrence of these mishaps Cirrus Aircraft has, since 2002, introduced advanced avionics into their piston airplanes (Cirrus SR20/22). These airplanes are also certificated to more rigorous crashworthiness tests than legacy aircraft approved prior to these standards being codified. Herein, using for comparison two legacy aircraft fleets manufactured prior to 2002, we determined whether a reduced mishap rate for all accidents or relating to the aforementioned causes/contributing factors and/or diminished injury severity for survivable accidents were evident for Cirrus SR20/22 airplanes.METHODS: Accidents (2008-2017) involving Cirrus SR20/22 airplanes (manufactured 2002 or later) and Beechcraft 35/36 (Bonanza) and Mooney 20 models (both manufactured no later than 2001) (14CFR Part 91 rules) were identified (N = 136, 259, 164, respectively) from the NTSB database. Statistical analyses used Poisson distribution/contingency tables/ t- and Mann-Whitney tests.RESULTS: For each year within the 2013-2017 timespan the Cirrus SR20/22 all-accident rate was diminished 39-75% relative to both legacy fleets. Temporally, the fraction of fatal Cirrus SR20/22 accidents, initially higher, declined 50% achieving a lower, or comparable, proportion to the two legacy airframes. Fatal accident rates involving spatial disorientation/situational awareness/aerodynamic stalls were > 80% lower for Cirrus SR20/22 airplanes. For survivable mishaps, Cirrus SR20/22 aircraft showed a lower proportion (0.13 compared with 0.20-0.35) of fatal/serious injuries.CONCLUSION: Toward improving legacy aircraft safety, owners should be encouraged to upgrade their avionics for mitigating against the occurrence of such human-factor-related mishaps and install airbags to minimize injury severity.Boyd DD, Howell C. Accident rates, causes, and occupant injury involving high-performance general aviation aircraft. Aerosp Med Hum Perform. 2020; 91(5):387-393.

Visual Flight into Instrument Meteorological Condition: A Post Accident Analysis

The phenomenon of encountering instrument meteorological conditions (IMCs) while operating an aircraft under visual flight rules (VFRs) remains a primary area of concern. Studies have established that pilots operating under VFRs that continue to operate under IMCs remains a significant cause of accidents in general aviation (GA), resulting in hundreds of fatalities. This research used the Australian Transport Safety Bureau (ATSB) database, which contained a total of 196 VFR to IMC occurrences, from 2003 to 2019, with 26 having formal reports. An explanatory design was adopted, commencing with a qualitative study of the 26 occurrences with reports followed by a quantitative study of all 196 occurrences. Factors investigated included the locations and date of the occurrences, involved aircraft (manufacturer, model, type), pilot details (licenses, ratings, h, and medical), number of fatalities, and causal factors. Fisher’s exact tests were used to highlight significant relationships. Results showed occurrences were more likely to end fatally if (1) they involved private operations, (2) pilots only had a night VFR rating, (3) the pilot chose to push on into IMCs, (4) the pilot did not undertake proper preflight planning consulting aviation weather services, and (5) the pilot had more than 500 h of flight experience. Further results showed occurrences were less likely to end fatally if the meteorological condition was clouds without precipitation, if the pilot held a full instrument rating, or the pilot was assisted via radio. Analysis of the data using the Human Factors Analysis and Classification System (HFACS) framework revealed that errors and violations occur with slightly greater frequency for fatal occurrences than non-fatal occurrences. Quantitative analyses demonstrated that the number of VFR to IMC occurrences have not decreased even though initiatives have been implemented in an attempt to address the issue.

A QUANTITATIVE TEST OF THE PREDICTIVE VALIDITY OF HEINRICH’S ACCIDENT PYRAMID

Herbert W. Heinrich, a pioneer researcher in the field of occupational safety, published a book on occupational accidents in 1931. In the publication, Heinrich presented an Accident Pyramid, which affirmed that one workplace fatality would occur after 300 no-injury accidents have been recorded in a workplace. Heinrich’s Accident Pyramid has since been adopted as a standard for predicting the likelihood that fatalities will occur. Moreover, Heinrich’s claim on occupational accidents was adopted as a standard because of his reputation as a pioneer of occupational safety research. This study seeks to test the statistical hypothesis put forward by Heinrich in reference to General Aviation (GA) accidents and does so with a random subsample of the National Transportation Safety Board (NTSB) data. Retrospective data published for public use by NTSB was collected from 2004 to 2013 for 15,119 GA accidents (with a mean fatal accident count of ≈ 282). The pyramid was initially recommended for use in predicting all forms of accidents, including GA accidents. Notwithstanding, the analysis of an independent variable x, the number of total accidents, and a dependent variable y, the number of fatalities, produced a p-value of approximately 0.821, which indicates no correlation between the variables. There was no statistically significant relationship found between the total number of accidents and fatal accidents, as asserted by Heinrich. This study, therefore, demonstrates that Heinrich’s Accident Pyramid is statistically invalid. Consequently, this means that a fatality may still occur even if the total number of accidents is reduced.

Significance of Incorporating Weather Technology Training for GA Pilots to Curb Fatalities

Weather is considered to be the main threat to aviation safety from the early 1900s. Despite advanced technologies available at present, the weather still poses a risk to the ever-growing aviation industry. This research gives an overview of weather-related accidents with special reference to Part 91 operation in the United States from 1982 and 2017 based on the NTSB database. The analysis shows that 14 CFR Part 91 operations experienced more accidents than Part 121 operations, and weather was a cause or a contributing factor in 35 % of fatal general aviation accidents. The study also identified the main weather hazards that were associated with general aviation accidents are high-density altitude, icing, carburetor icing, turbulence, thunderstorms, wind, and precipitation. The purpose of this research is to identify which weather hazard has to be given more emphasis during pilot training so that it will help pilots to develop the proper skills required to manage emergencies during actual flight. Based on the gaps identified, this study provides several recommendations to enhance pilot training like providing education and training of weather technology products, using advanced technology like Simulation/ Virtual reality-based training with different weather hazards, and changing the examination requirements for pilot certifications.

A state-based approach to modeling general aviation accidents

This paper develops a state-based accident model that we apply to General Aviation (GA) accidents recorded in the National Transportation Safety Board (NTSB) accident database. We demonstrate our approach on 6180 helicopter accidents that occurred in the United States between 1982 and 2015, with emphasis on inflight loss of control (LOC-I) accidents. Our model helps remove the redundancies in the NTSB coding system by logically grouping various NTSB accident codes that convey the same meaning. Further, this model checks for logical gaps or omissions in NTSB accident records, and potentially fills the omissions in. This approach uses NTSB coding data to define a set of states (safe or hazardous) for a system and triggers that move the system into (or out of) these states. We identify the most frequent triggers for LOC-I and compare the results from the state-based approach with those obtained from a conventional analysis of NTSB accident codes.

Quantifying the Safety Benefits of a Digital Copilot in General Aviation

Digital Copilot is a prototype information system providing cognitive assistance to pilots in general aviation. This paper presents the methods and results of an analysis quantifying the expected safety benefits of the system. The methods include a cognitive performance analysis, to quantify pilot workload in flight activities; a human reliability analysis, to quantify pilot error probabilities; and a probabilistic risk assessment, to quantify accident sequence frequencies. These methods are used to model flight risk with and without pilots’ use of Digital Copilot, and the comparison provides a quantitative measure of expected safety benefits, assuming the prototype system is adopted by pilots. The results suggest that Digital Copilot technology has the potential to significantly reduce the rates of total and fatal accidents in general aviation. The same methods also enable a detailed analysis of individual pilot actions and system features to quantify their risk importance and identify the most promising opportunities for further system improvements.

Occupant Injury Severity in General Aviation Accidents Involving Excessive Landing Airspeed.

BACKGROUND: Of all phases of flight operations, accidents during landings are the most frequent. Of these, poor speed management during landing has ramifications for injury severity since: 1) impact forces increase as a square of forward velocity; and 2) an aerodynamic stall, associated with inadequate landing speed, imparts high vertical G forces. Herein, the proportion of landing accidents involving deficient airspeed control and occupant injury severity was determined.METHODS: General aviation landing accidents (1997-2016) were identified from the NTSB database. An accident involving high-airspeed (high-energy) was one for which the NTSB cited airplane porpoising, multiple bounces, or floating, whereas an inadequate airspeed related (low energy) mishap was one citing this term or in which an aerodynamic stall occurred. An anonymous online survey of certificated pilots was used to inform landing technique. Statistical analyses used Poisson distribution and Chi-squared tests.RESULTS: Relative to the earliest period (1997-2001), the landing accident rate was undiminished for more recent years (2007-2016). Of 235 accidents, 38% involved high-energy, whereas 4% were inadequate airspeed-related. For the former, 17% resulted in occupants with fatal-serious injuries, twofold higher than for mishaps with no evidence of mis-speed. Of 1392 survey respondents, 73% selected a landing airspeed higher than required for an under-maximum weight airplane.CONCLUSION: For landing accidents involving airspeed mismanagement, those related to excessive energy predominate and are associated with more severe injuries. Two mitigating strategies are advanced: 1) pilot training should discuss landing airspeed adjustment for aircraft weight; and 2) installation of inflatable restraints for reducing injury severity should be encouraged.Boyd DD. Occupant injury severity in general aviation accidents involving excessive landing airspeed. Aerosp Med Hum Perform. 2019; 90(4):355-361.

The Analysis of Spatial Pattern and Hotspots of Aviation Accident and Ranking the Potential Risk Airports Based on GIS Platform

Aviation accident analysis is an important task to ensure aviation safety. The existing researches mainly focus on the analysis of aviation accident time characteristics and accident causes and less analysis of the spatial characteristics of aviation accidents. The spatial characteristics analysis of aviation accidents can identify hot spots of aviation accidents, improve the accuracy of aviation accident emergency management, and provide decision support for airport route planning. This study established the severity index of aviation accident based on aviation accident data, using GIS spatial analysis methods to study the spatial distribution characteristics of aviation accidents. The hot spots were identified in the aviation accidents. Finally, airports around the accident hot spots were ranked to obtain the airports with high potential aviation risks based on RI, taking Florida as an example. It was found that in the Florida aviation accident, general aviation accidents accounted for the majority, but the aviation accident severity index for air route flight was far greater than general aviation accidents. From the spatial distribution point of view, accidents with high severity index were distributed around large international airports. The Density Center for Aviation Accidents was located in Tampa, Miami, and some airports link areas in Florida. In terms of the Moran’s I index, the distribution of aviation accidents tended to aggregate in the region as a whole. However, aviation accident severity index was randomly distributed for each year separately. At the level of significance of 0.01, there were a total of 75 accident hotspots in the Florida region, mainly in the north and southwest. Airports with high RI in the Florida area were mainly concentrated in the Miami area and the Tampa Bay area, and Orlando Airport was ranked outside the top 10.

Fatal General Aviation Accidents in Furtherance of Business (1996–2015): Rates, Risk Factors, and Accident Causes

Fatal General Aviation Accidents in Furtherance of Business (1996–2015): Rates, Risk Factors, and Accident Causes

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

IntroductionCurrently, there is a lack of specific analytical tools for general aviation accidents (GAAs). This has led to loopholes in the prevention of GAAs. MethodsA 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. ResultsOne 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. ConclusionsSCM-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 applicationsGeneral 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.

Evaluation of preconditions affecting symptomatic human error in general aviation and air carrier aviation accidents

Human error remains the leading cause of accidents in the aviation industry, as technological reliability and system safety have undergone significant improvements. Improved methods are required to model the events resulting in human error incidents. In this study, aviation accident data are evaluated to model the association between the latent and symptomatic causal factors resulting in aviation mishaps. We comparatively analyze National Transportation Safety Board accident data for general aviation and air carrier pilots in order to evaluate potential causal factors. The demonstrated methodology leverages previous work in causal relationships by using multiple-variable logistic regression to model the relationships among latent causal factors, symptomatic causal factors, and accident severity. The Human Factors Analysis and Classification System is applied to define a framework intended to identify focal areas for the safety community to mitigate similar future system failures. The results demonstrate an effective methodology for evaluating the quantitative relationships between symptomatic and latent causal factors, which are not readily apparent based solely on occurrence rates. Furthermore, the results also clarify the differences in causal factors between the selected general aviation and air carrier pilot operations. The usefulness of the framework, transferability to other domains, and possibilities for future research are discussed.

Prediction of U.S. General Aviation fatalities from extreme value approach

General Aviation is the main component of the United States civil aviation and the most aviation accidents concern this aviation category. Between early 2015 and May 17, 2016, a total of 1546 general aviation accidents in the United States has left 466 fatalities and 384 injured. Hence, in this study, we investigate the risk of U.S. General Aviation accidents by examining historical U.S. General Aviation accidents. Using the Peak Over Threshold approach and Generalized Pareto Distribution, we predict the number of fatalities resulting in extreme GA accidents in the future operations. We use a graphical method and intensive parameters estimates to obtain the optimal range of the threshold. In order to assess the uncertainty in the inference and the accuracy of the results, we use the nonparametric bootstrap approach.

Hazards in the Polish Civil Aviation resulting from engines failures

Published by the Civil Aviation Authority in May 2017, the State Safety Programme 2017-2020 in the appendix A presents "Events Data - 2016". Detailed description of the hazard arising from the technical condition of aircraft limits to the general presentation of the events in terms of SCF-NP (System Component Failure Non Powerplant) and SCF-PP (System Component Failure Powerplant). The analysis of these events performed in the Institute of Aviation (aviation events reports are collected in the European Coordination Center for Accident and Incident Reporting System database - ECCAIRS) has shown that the general aviation and commercial aviation (CAT) should be treated separately. Especially events caused by the powerplants failures must be considered separately for piston, turbofan, turboshaft, turboprop types and also their each installation has to be taken into account. Events caused by the technical condition of aircraft, especially engines, are the most common cause of accidents in general aviation. The aim of the article is to improve risk awareness and, ultimately, reduce the number of the aviation events associated with exploitation of the piston engines. Particularly significant impact on reducing the number of accidents in general aviation can be achieved by the implementation of modern technical solutions to control the technical condition of the engines and reduce their operating costs, while operators are fully aware of the risks resulting from the possibility of extending engine time on wing. In conclusion: reversing the dangerous trend of piston engine failures causing aviation safety hazards requires, above all, changes in the way these engines are operated.