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.

In plane sight: Inattentional blindness affects visual detection of external targets in simulated flight

Aviation places significant demands on pilots' perceptual and attentional capacities. The avoidance of other objects both on the ground and in the air is critical to safe flight. Research on automobile driving has revealed the occurrence of 'inattentional blindness' (IB) whereby objects clearly located within the visual field may not detected when drivers are concurrently engaged in another attention capturing task such as a cellphone conversation. Almost no comparable research has been conducted within the aviation domain despite the significance of both ground-based and mid-air collisions. The present study was designed to investigate the effects of diverting attentional resources away from the primary task of safely flying a simulated light aircraft from takeoff to cruising. Flight naïve students were trained to proficiency in a flight-simulator and flew two simulated flights with and without a competing attentional task. Detection of a variety of objects placed in the background was measured. The results showed that when distracted by an engaging cellphone conversation novice pilots failed to detect many of the objects located within the visual scene. Recognition accuracy was greater when pilots' attention was not diverted elsewhere. There was a reduction in time spent looking at some key flight instruments but not on others. Inattentional blindness poses significant flight safety risks and further research into both the stimulus and perceiver characteristics that promote or reduce inattentional blindness would be of significant benefit to aviation safety.

Responding to an Unexpected In-Flight Event: Physiological Arousal, Information Processing, and Performance

OBJECTIVE

The study was designed to investigate whether a simulated unexpected abnormal flight event can lead to startle and explore differences in behavioral responses between expected and unexpected abnormal flight events.

BACKGROUND

Recent research suggests startle (an autonomic response to an acute stimulus) following unexpected abnormal flight events can impact pilot performance and can increase the probability of a negative outcome following the event.

METHOD

Information processing, physiological measures, and performance differences between responses to expected and unexpected flight events were compared. General aviation (GA) pilots flew a series of flights in a fixed-base flight simulator including two experimental flights which included an unexpected and an expected, engine failure. During the flights, heart rate, eye tracking, and flight data were recorded.

RESULTS

During the unexpected engine failure, pilots showed greater increases in heart rate and pupil dilation. Significant differences in scanning were evident with fewer areas scanned following the unexpected event. During the unexpected engine failure, performance was impaired when compared to the expected events. However, poor performance was not associated with higher levels of arousal.

CONCLUSION

The study provides an empirical demonstration of impaired pilot response to unexpected events with associated symptoms consistent with the induction of startle. The present research builds on Landman et al.'s conceptual model of startle and surprise.

APPLICATION

Standardized training protocols may not adequately prepare pilots to deal with the unexpected effects of startle in real-world encounters. Introducing greater variety into training events may be useful. The effects of startle in disrupting well-trained responses may also occur in areas other than aviation where critical events may occur unexpectedly or present in an unfamiliar manner.

How to Observe Users' Movements in Virtual Environments: Viewpoint Control in a Power Wheelchair Simulator

OBJECTIVE

We describe a networked, two-user virtual reality (VR) power wheelchair (PWC) simulator system in which an actor (client) and an observer (clinician) meet. We then present a study with 15 observers (expert clinicians) evaluating the effect of three principal forms of viewpoint control (egocentric-egomotion, egocentric-tethered, and client-centric) on the observer's assessment of driving tasks in a virtual environment (VE).

BACKGROUND

VR allows for the simulation and assessment of real-world tasks in a controlled, safe, and repeatable environment. Observing users' movement behavior in such a VE requires appropriate viewpoint control for the observer. The VR viewpoint user interface should allow an observer to make judgments equivalent or even superior to real-world situations.

METHOD

A purpose-built VR PWC simulator was developed. In a series of PWC driving tasks, we measured the perceived ease of use and sense of presence of the observers and compared the virtual assessment with real-world "gold standard" scores, including confidence levels in judgments.

RESULTS

Findings suggest that with more immersive techniques, such as egomotion and tethered egocentric viewpoints, judgments are both more accurate and more confident. The ability to walk and/or orbit around the view significantly affected the observers' sense of presence.

CONCLUSION

Incorporating the observer into the VE, through egomotion, is an effective method for assessing users' behavior in VR with implications for the transferability of virtual experiences to the real world.

APPLICATION

Our application domain serves as a representative example for tasks where the movement of users through a VE needs to be evaluated.

Zirconium arene triple-decker sandwich complexes: synthesis, electronic structure and bonding

Reduction of a permethylpentalene zirconium(iv) chloride complex [η⁸-Pn*Zr(μ-Cl)_3/2]₂(μ-Cl)₂Li·THF_x with KC₈ in benzene results in activation of the aromatic solvent to yield an "inverted sandwich" complex, [η⁸-Pn*Zr]₂(μ-η⁶:η⁶-C₆H₆) (1). The reactions in toluene, cumene, o-xylene and m-xylene also yield analogous solvent activated triple-decker sandwich complexes, which have been structurally characterised by single-crystal X-ray diffraction. Edge energies in the Zr K-edge XANES spectra are not distinguishable between 1 and formally Zr(ii) and Zr(iv) reference compounds, suggesting a broad edge structure. DFT calculations best describe the bonding in 1 as highly covalent with frontier molecular orbitals showing almost equal contributions from benzene and the Zr-permethylpentalene fragments.

The role of cue utilisation in reducing the workload in a train control task

Skilled performance has been characterised, in part, by the capacity to accurately identify and respond to patterns as cues in the environment. The outcome is a reduction in cognitive load and a greater residual capacity to undertake concurrent tasks. The present study was designed to examine the relationship between cue utilisation and temporal pattern recognition in the context of a simulated, rail control task. Sixty-one university students undertook an assessment of cue utilisation and engaged in a rail control simulation. The appearance and movement of trains followed a consistent but implicit (undisclosed) pattern. Throughout the second half of the rail task, a secondary task was included. The results indicated that participants with relatively higher cue utilisation were more likely to identify the implicit pattern of rail movements, were more accurate and responded more rapidly under increased workload conditions. The results suggest that a propensity to identify patterns as cues may provide an opportunity to reduce cognitive demands, thereby facilitating performance in a novel task. Implications for selection and system design are discussed. Practitioner Summary: This study was designed to explain differences in the way in which people learn, particularly when tasks involve recurring patterns. Using simulated rail control, the results indicated that participants who display behaviour that is indicative of the utilisation of cues also recognise patterns in the movement of simulated trains. This enables them to manage trains more effectively, even while undertaking other tasks.

Immersion factors affecting perception and behaviour in a virtual reality power wheelchair simulator

Virtual Reality based driving simulators are increasingly used to train and assess users' abilities to operate vehicles in a controlled and safe way. For the development of those simulators it is important to identify and evaluate design factors affecting perception, behaviour, and driving performance. In an exemplary power wheelchair simulator setting we identified the three immersion factors display type (head-mounted display v monitor), ability to freely change the field of view (FOV), and the visualisation of the user's avatar as potentially affecting perception and behaviour. In a study with 72 participants we found all three factors affected the participants' sense of presence in the virtual environment. In particular the display type significantly affected both perceptual and behavioural measures whereas FOV only affected behavioural measures. Our findings could guide future Virtual Reality simulator designers to evoke targeted user behaviours and perceptions.

Cue Utilization and Cognitive Load in Novel Task Performance

This study was designed to examine whether differences in cue utilization were associated with differences in performance during a novel, simulated rail control task, and whether these differences reflected a reduction in cognitive load. Two experiments were conducted, the first of which involved the completion of a 20-min rail control simulation that required participants to re-route trains that periodically required a diversion. Participants with a greater level of cue utilization recorded a consistently greater response latency, consistent with a strategy that maintained accuracy, but reduced the demands on cognitive resources. In the second experiment, participants completed the rail task, during which a concurrent, secondary task was introduced. The results revealed an interaction, whereby participants with lesser levels of cue utilization recorded an increase in response latency that exceeded the response latency recorded for participants with greater levels of cue utilization. The relative consistency of response latencies for participants with greater levels of cue utilization, across all blocks, despite the imposition of a secondary task, suggested that those participants with greater levels of cue utilization had adopted a strategy that was effectively minimizing the impact of additional sources of cognitive load on their performance.

Can a glass cockpit display help (or hinder) performance of novices in simulated flight training?

The analog dials in traditional GA aircraft cockpits are being replaced by integrated electronic displays, commonly referred to as glass cockpits. Pilots may be trained on glass cockpit aircraft or encounter them after training on traditional displays. The effects of glass cockpit displays on initial performance and potential transfer effects between cockpit display configurations have yet to be adequately investigated. Flight-naïve participants were trained on either a simulated traditional display cockpit or a simulated glass display cockpit. Flight performance was measured in a test flight using either the same or different cockpit display. Loss of control events and accuracy in controlling altitude, airspeed and heading, workload, and situational awareness were assessed. Preferences for cockpit display configurations and opinions on ease of use were also measured. The results revealed consistently poorer performance on the test flight for participants using the glass cockpit compared to the traditional cockpit. In contrast the post-flight questionnaire data revealed a strong subjective preference for the glass cockpit over the traditional cockpit displays. There was only a weak effect of prior training. The specific glass cockpit display used in this study was subjectively appealing but yielded poorer flight performance in participants with no previous flight experience than a traditional display. Performance data can contradict opinion data. The design of glass cockpit displays may present some difficulties for pilots in the very early stages of training.

The effects of individual differences, prior experience and cognitive load on the transfer of dynamic decision-making performance

Situational awareness is recognised as an important factor in the performance of individuals and teams in dynamic decision-making (DDM) environments (Salmon et al. 2014 ). The present study was designed to investigate whether the scores on the WOMBAT™ Situational Awareness and Stress Tolerance Test (Roscoe and North 1980 ) would predict the transfer of DDM performance from training under different levels of cognitive load to a novel situation. Participants practised a simulated firefighting task under either low or high conditions of cognitive load and then performed a (transfer) test in an alternative firefighting environment under an intermediate level of cognitive load. WOMBAT™ test scores were a better predictor of DDM performance than scores on the Raven Matrices. Participants with high WOMBAT™ scores performed better regardless of their training condition. Participants with recent gaming experience who practised under low cognitive load showed better practice phase performance but worse transfer performance than those who practised under high cognitive load.

PRACTITIONER SUMMARY

The relationship between task experience, situational awareness ability, cognitive load and the transfer of dynamic decision-making (DDM) performance was investigated. Results showed that the WOMBAT™ test predicted transfer of DDM performance regardless of task cognitive load. The effects of cognitive load on performance varied according to previous task-relevant experience.

The effects of Crew Resource Management (CRM) training on flight attendants' safety attitudes

INTRODUCTION

A number of well-known incidents and accidents had led the aviation industry to introduce Crew Resource Management (CRM) training designed specifically for flight attendants, and joint (pilot and flight attendant) CRM training as a way to improve teamwork and communication. The development of these new CRM training programs during the 1990s highlighted the growing need for programs to be evaluated using research tools that had been validated for the flight attendant population.

METHOD

The FSAQ (Flight Safety Attitudes Questionnaire-Flight Attendants) was designed specifically to obtain safety attitude data from flight attendants working for an Asia-Pacific airline. Flight attendants volunteered to participate in a study before receiving CRM training (N=563) and again (N=526) after CRM training.

RESULTS

Almost half (13) of the items from the 36-item FSAQ showed highly significant changes following CRM training. Years of experience, crew position, seniority, leadership roles, flight attendant crew size, and length of route flown were all predictive of safety attitudes.

PRACTICAL APPLICATIONS

CRM training for flight attendants is a valuable tool for increasing positive teamwork behaviors between the flight attendant and pilot sub-groups. Joint training sessions, where flight attendants and pilots work together to find solutions to in-flight emergency scenarios, provide a particularly useful strategy in breaking down communication barriers between the two sub-groups.

Putting the "we" into teamwork: effects of priming personal or social identity on flight attendants' perceptions of teamwork and communication

OBJECTIVE

The study was designed to investigate the effectiveness of a manipulation derived from social categorization and social identity theory to promote greater cabin crew willingness to engage in intergroup communication and teamwork in airline operations.

BACKGROUND

Failures of communication and teamwork between airline crew have been implicated in a number of airline crashes.

METHOD

Flight attendants based domestically (n = 254) or overseas (n = 230) received a manipulation designed to prime either their social identity or personal identity and then read a brief outline of an in-flight event before completing a teamwork questionnaire.

RESULTS

Flight attendants who received a social identity prime indicated increased willingness to engage in coordinated team action compared with those who received a personal identity prime.

CONCLUSION

Priming social identity can enhance attitudes toward teamwork and communication, potentially leading to increased willingness to engage in intergroup cooperation.

APPLICATION

Social categorization and social identity theories can be used to inform joint training program development for flight attendants and pilots to create increased willingness for group members to participate in effective communication and teamwork behaviors.

An objective approach to identifying diagnostic expertise among power system controllers

OBJECTIVE

The present study investigated whether performance across a range of cue-based cognitive tasks differentiated the diagnostic performance of power control operators into three distinct groups, characteristic of novice, competence, and expertise.

BACKGROUND

Despite its increasing importance in the contemporary workplace, there is little understanding of the cognitive processes that distinguish novice, competent, and expert performance in the context of remote diagnosis. However, recent evidence suggests that cue acquisition and utilization may represent a mechanism by which the transition from novice to expertise occurs.

METHOD

The study involved the application of four distinct cue-based tasks within the context of power system control. A total of 65 controllers, encompassing a range of industry experience, completed the tasks as part of an in-service training program.

RESULTS

Using a cluster analysis, it was possible to extract three distinct groups of operators on the basis of their performance in the cue-based tasks, and these groups corresponded to differences in diagnostic performance.

CONCLUSION

The results indicate assessments of the capacity to extract and utilize cues were able to distinguish expert from competent practitioners in the context of power control.

APPLICATION

Assessments of the capacity to extract and utilize cues may be used in the future to distinguish expert from nonexpert practitioners, particularly in the context of remote diagnosis.

Situational and personal characteristics associated with adverse weather encounters by pilots

Weather conditions are significant hazards impacting the safe and efficient operation of aircraft. In this study, a large number of pilots were surveyed regarding weather events, and the circumstances associated with those events. Pilots completed a web-based questionnaire containing demographic questions, a risk perception scale, a hazardous events scale, and a pilot judgment scale. The pilots who reported a flight in which they penetrated weather without authorization or were concerned about the weather also completed 53 questions regarding their weather encounter. Usable data were obtained for 364 participants: 144 who reported flying into weather, 114 who experienced a flight on which weather was a concern, and 106 who reported no flights on which weather was entered or was a major concern. Significant differences were evident between the three groups on the measures of pilot judgment, personal minimums, and hazardous events where pilots flying into weather recorded the poorest scores (least conservative minimums, most hazardous events, and poorest judgment). Significant differences were also noted between the two weather groups for a number of circumstances surrounding the events. Compared to the in-weather group, pilots in the near-weather group had acquired greater instrument hours, were older, and were more likely to have an instrument rating. Their aircraft were more likely to have an autopilot. More pilots in the in-weather group (28%) reported that they would be much more careful in the future regarding weather, compared to 17% of the near-weather group. The study provides data not previously obtained on both the situational and personal characteristics that are related to involvement in different degrees of weather-related encounters. These data should promote a better understanding of these individuals and the situations in which they are involved, and should inform future research and intervention efforts.

Under the weather: an evaluation of different modes of presenting meteorological information for pilots

Understanding current and forecast weather conditions for a planned route of flight is vital for general aviation (GA) pilots. Weather information can be obtained from multiple sources and in multiple formats, ranging from abbreviated code provided by aviation weather forecasters to animated graphical displays available on TV and the Internet. The present study investigated the effectiveness of graphical displays of meteorological information. A commercially available graphical display was ergonomically redesigned and the original and redesigned displays were compared with an ordinary text statement. Recall of information was significantly affected by display type. Comparisons showed the ergonomically redesigned display to be superior to the ordinary text statement. Performance was affected by participants' general level of familiarity with evaluating data displays as measured by their area of study (sciences or humanities). The generalizability of the results to the pilot population is discussed.

Localization of the equine IgG-binding domain in the fibrinogen-binding protein (FgBP) of Streptococcus equi subsp. equi

Fibrinogen-binding protein (FgBP, also termed SeM) is a cell-wall-associated anti-phagocytic M-like protein of the equine pathogen Streptococcus equi subsp. equi, and binds fibrinogen (Fg) and IgG. FgBP binds Fg avidly through residues located at the extreme N terminus of the molecule, whereas the IgG-binding site is more centrally located between the A and B repeats. FgBP binds equine IgG4 and IgG7 subclasses through interaction with the CH2-CH3 interdomain region of IgG-Fc, and possesses overlapping Fc-binding sites with protein A and protein G. In this study, FgBP truncates containing defined internal deletions were used to identify a stretch of 14 aa (residues 335-348) critical for IgG binding. Protein chimeras consisting of the non-IgG-binding alpha-helical coiled-coil M5 protein fused to FgBP sequences were used to identify a minimal equine IgG-binding domain consisting of residues 329-360. Competition ELISA tests suggested that IgG does not compromise Fg binding and vice versa.

Implicit perceptions of risk and anxiety and pilot involvement in hazardous events

OBJECTIVE

The aim of the studies was to examine the role of implicit processes in aeronautical risk perception and risk taking.

BACKGROUND

Aeronautical decision making consists of both explicit processes (e.g., comparing options, seeking information) and implicit, or intuitive, processes (e.g., immediate affective reactions). The present studies utilized a novel methodology, adapted from studies in social cognition, to examine the relationship between general aviation pilots' implicit reactions toward risk and their involvement in hazardous events.

METHOD

The Implicit Association Test was used to measure pilots' (Study 1: N= 23; Study 2: N= 32) implicit associations between good and bad weather conditions and perceptions of risk and anxiety.

RESULTS

There was a relationship between the pilots' implicit perceptions and previous involvement in hazardous aeronautical events as measured by D. R. Hunter's (1995, 2002) Hazardous Events Scale. The more weather-related hazardous events the pilots had been involved in, the less they associated implicit risk with adverse weather (Study 1) and the less implicitly anxious they were toward adverse weather (Study 2).

CONCLUSION

The results show a relationship between implicit associations and risk-taking behavior.

APPLICATION

Pilots may be involved in risk-taking behavior because they perceive less risk in, and are implicitly less afraid of, hazardous conditions.

Risk tolerance and pilot involvement in hazardous events and flight into adverse weather

INTRODUCTION

According to Lopes [Lopes, L.L. (1987). Between hope and fear: The psychology of risk. Advances in Experimental Social Psychology, 20, 255-295] tolerance of risk may be governed by sensitivity to either the opportunities for gain or threats of loss involved.

METHODS

In the initial study, qualified pilots were presented with 36 written flight scenarios that varied in the levels of opportunity and threat present. The pilots rated the likelihood that they would undertake each flight. Pilots were largely risk averse, as their ratings were all significantly influenced by threat.

RESULTS

The pilots whose ratings were significantly influenced by opportunity had been involved in more hazardous aviation incidents than the other pilots. In the final study, 32 qualified pilots completed both the risk tolerance measure and a simulated flight into adverse weather. The pilots who continued flying into adverse weather were less risk averse compared to the pilots who diverted. This further highlighted the link between risk tolerance and risk-taking, and suggested that some pilots may fly into adverse weather because of a greater tolerance of risk.

IMPACT ON INDUSTRY

The studies provide evidence that a measure of risk tolerance can predict potential accident involvement amongst general aviation pilots.

Situational awareness ability and cognitive skills training in a complex real-world task

Successful performance in complex dynamic environments depends on domain-dependent factors, such as situational awareness (SA). Underlying SA in a domain are domain-independent cognitive abilities in perception, memory, attention and executive control. Individuals with lower underlying ability perform relatively poorly in complex dynamic real-world tasks. The first experiment examined whether cognitive skills training could overcome limitations in underlying SA ability that impact on complex dynamic task performance. Participants were taught a mix of cognitive management strategies (e.g. divided and focused attention and visual search) in a simulated air traffic control task. A second experiment investigated the link between underlying SA ability, TRACON and SAGAT, a widely used measure of domain-specific SA. In a third experiment, the focus was on encouraging participants to plan ahead and consider the interrelations of elements (aircraft) in the environment. Whilst both training methods ameliorated the negative impact that lower SA ability had on complex dynamic task performance, the results of the third study indicated that this may have been achieved through improved planning behaviour. Finally, participants with higher underlying SA ability performed well irrespective of training condition.

Developing a tissue perfusion sensor

The development of a electrochemical tissue perfusion sensor is presented. The sensor is a platinum/platinum ring-disc microelectrode that relies on the principle of collector-generator to monitor mass transport within its vicinity. Tissue perfusion is a mass transport mechanism that describes the movement of respiratory gases, nutrients and metabolites in tissue. The sensor's capability of detecting perfusion at the cellular level in a continuous fashion is unique. This sensor will provide insight into the way nutrients and metabolites are transported in tissue especially in cases were perfusion is low such as in wounds or ischemic tissue. We present experimental work for the development and testing of the sensors in vitro. Experimental flow recordings in free steam solutions as well as the flow through tissue-like media are shown. Tests on post operative human tissue are also presented. The sensor's feature such as the continuous recoding capacities, spatial resolution and the measurement range from ml/min to microl/min are highlighted.

Effects of age on feeding behavior and chemosensory processing in the pond snail, Lymnaea stagnalis

This study used behavioral and electrophysiological techniques to examine age-related changes in the feeding behavior and chemosensory processing in the pond snail, Lymnaea stagnalis. Increasing age was associated with a 50% decrease in long-term food consumption. Analysis of short-term sucrose-evoked feeding bouts showed an age-related increase in the number of animals that failed to respond to the stimulus. Of the animals that did respond increasing age was associated with a decrease in the number of sucrose-evoked bites and a increase in the duration of the swallow phase. These changes were observed with both 0.01 and 0.05M sucrose stimuli but were not seen when 0.1M sucrose was used as the stimulus. Electrophysiological analysis of the chemosensory pathway in semi-intact lip-CNS preparations failed to demonstrate a significant change in the neuronal information entering the cerebral ganglia from the lips via the median lip nerve, but did demonstrate an age-related deficit in the neuronal output from the cerebral ganglia. This deficit was also dependent on the sucrose concentration and mirrored the concentration-dependent changes in feeding behavior. In summary, aging appeared to affect central but not peripheral processing of chemosensory information and suggests that this deficit contributes to the age-related changes in feeding behavior.

Improving pilots' risk assessment skills in low-flying operations: the role of feedback and experience

Risk assessment is one of the most important skills that pilots are expected to acquire to ensure the safe and successful management of flight. The traditional approach to the development of these skills requires pilots to directly engage with potentially hazardous events. Using low-flying as a context, the present study sought to test whether engagement with hazards in a simulated environment, together with feedback concerning performance, would improve pilots' risk assessment during a subsequent simulated test flight. The results indicated that engagement with the hazards, rather than the provision of feedback per se, was associated with behavior that reduced the risk to the aircraft, while maintaining operational performance. It was concluded that exposure to hazards within a simulated environment could provide the basis for the development of risk assessment skills amongst less experienced pilots.

Case-control study of risk factors for fatal and non-fatal injury in crashes of rotary-wing aircraft

INTRODUCTION

There have been few studies of the risk factors for fatal injury in air crashes of rotary-wing aircraft, and none of risk factors for all serious injury (fatal and non-fatal) in these aircraft. The aim of the study was to identify the potentially modifiable risk factors for injury in civil rotary-wing aircraft crashes in New Zealand.

METHOD

We analyzed records from all reported civil rotary-wing aircraft crashes in New Zealand between 1988 and 1994. Air crash data from the official databases were merged with nationwide injury records and information obtained from Coroner's files. Crashes where the pilot-in-command was fatally injured were compared with crashes where the pilot-in-command was not fatally injured on 50 variables, covering pilot, aircraft, environmental, and operational characteristics. A second analysis compared crashes where the pilot-in-command was seriously injured (either fatally or non-fatally) with crashes where the pilot-in-command was not hospitalized with an injury. A series of multivariate logistic regression analyses were conducted to estimate the odds associated with each of the factors identified by the univariate analyses.

RESULTS

The most significant risk factors for all serious injury were: (a) not obtaining a weather briefing, (b) off-airport location of the crash site, (c) flights carried out for air transport purposes, and (d) non-solo flights. Other risk factors, significant for fatal injury only, included post-crash fire and the nature of the crash terrain. Factors within the control of the pilot, environmental, and flight characteristics are the key determinants of the injury outcome of civil rotary-wing aircraft crashes.

Changes in the properties of the modulatory cerebral giant cells contribute to aging in the feeding system of Lymnaea

This study examined whether electrophysiological changes in the endogenous properties and connectivity of the modulatory serotonergic cerebral giant cells (CGCs) contributed to the age-related changes in feeding behavior of the pond snail, Lymnaea. With increasing age there was a decrease in spontaneous CGC firing rates and decreased excitability of the CGCs to both chemosensory stimulation (0.05M sucrose applied to the lips) and direct intracellular current injection. These changes could be accounted for by a decrease in the input resistance of the neuron and an increase in the amplitude and the duration of the after-hyperpolarization. Decreases were also seen in the % of CGC pairs that were electrically coupled causing asynchronous firing. Together these changes would tend to reduce the ability of the CGCs to gate and control the frequency of the feeding behavior. Part of the ability of the CGCs to gate and frequency control the feeding network is to provide a background level of excitation to the feeding motor neurons. Recordings from B1 and B4 motor neurons showed an age-related hyperpolarization of the resting membrane potential consistent with a deficit in CGC function. Increases were seen in the strength of the evoked CGC-->B1 connection, however, this increase failed to compensate for the deficits in CGC excitability. In summary, age-related changes in the properties of the CGCs were consistent with them contributing to the age-related changes in feeding behavior seen in Lymnaea.

Pilot behaviors in the face of adverse weather: A new look at an old problem

INTRODUCTION

Weather-related general aviation accidents remain one of the most significant causes for concern in aviation safety. Previous studies have typically compared accident and non-accident cases. In contrast, the current study does not concentrate on occurrence outcome. Instead, the emphasis is on the different behaviors that pilots exhibit in the face of adverse weather and, by inference, on the decision-making processes that underlie those behaviors.

METHODS

This study compares three weather-related behaviors that reflect different levels of risk: visual flight rules flight into instrument meteorological conditions ('VFR into IMC'); precautionary landing; and other significant weather avoidance actions. Occurrence data (n=491) were drawn from the Australian Transport Safety Bureau database of aviation occurrences, and included weather-related accidents, incidents, and 'normal operationsd.'

RESULTS

There were few significant differences between the three weather-related behavior groups in terms of pilot demographics, aircraft characteristics, geographic or environmental factors, or absolute flight distances. The pattern of relative flight distances (a psychological construct) was markedly different for the three groups, with pilots in the weather avoidance group being distinguished by taking timely action.

DISCUSSION

The relative distance results suggest that the mid-point of the flight can be a 'psychological turning point' for pilots, irrespective of the absolute flight distance involved. Hence, pilots' behavior was sometimes influenced by psychological factors not related to any particular operational aspect of the flight. The results of the weather avoidance group indicate that a safe pilot is a proactive pilot. Dealing with adverse weather is not a one-off decision but a continually evolving process. This aspect is discussed in terms of the concept of 'mindfulness'.

Remembrance of cases past: who remembers what, when confronting critical flight events?

Recent "naturalistic" theories of decision making emphasize the role of stored prior experiences or cases as a guide to current action. However, there is little empirical evidence on the role that case-based remindings play in real-life decision making. The present study utilized a Web-based survey to collect data about the role of prior cases in pilot decision making about critical flight events. Results showed that more than half of the 1081 pilots who responded could provide details about utilizing a previous case in responding to a critical flight event. These events were most likely to involve weather or equipment failure. The cases were found to be useful in situational assessment rather than option evaluation. The use of cases increased with age and experience. Data obtained from a concurrent conventional survey showed broadly similar results. The implications of these results are that case-based remindings play an important role in expert pilot decision making and that a training system that incorporates case-based learning would be a potentially useful means of improving pilot decision making. Actual or potential applications of this research include the development of case-based training systems to enhance flight training.

Case-control study of risk factors for fatal and non-fatal injury in crashes of civil aircraft

BACKGROUND

There have been few studies of the risk factors for fatal injury in air crashes, and none of risk factors for all serious injury (fatal and non-fatal).

OBJECTIVE

To identify the potentially modifiable risk factors for fatal and non-fatal injury in civil aircraft crashes in New Zealand.

METHODS

We analyzed records from all reported civil aircraft crashes in New Zealand (1988-1994). Air crash data from the official databases were merged with nationwide injury records and information obtained from coroners' files. Pilots-in-command who were fatally injured were compared with pilots-in-command who were not fatally injured using 50 variables covering pilot, aircraft, environmental, and operational characteristics. A second analysis compared pilots-in-command who were seriously injured (either fatally or non-fatally) with those who were involved in a crash but not hospitalized with an injury. Univariate and multivariate logistic regression analyses were then conducted to estimate the odds associated with each of the factors identified by the above comparisons.

RESULTS

The most significant risk factors for fatal and serious injury were aerobatic flight, post-crash fire, not having a certificate of airworthiness, and off-airport location. Environmental characteristics including terrain type, wind, rain, and elevation of the crash site were identified as risk factors, as was being under instruction. Flying a twin-engine aircraft was a risk factor for fatal injury, while piloting a microlight aircraft was a risk factor for all serious injury.

CONCLUSION

Environmental and operational factors, rather than pilot or aircraft characteristics, are the key determinants of the injury outcome of civil aircraft crashes.

Weatherwise: evaluation of a cue-based training approach for the recognition of deteriorating weather conditions during flight

Inappropriate and ineffective weather-related decision making continues to account for a significant proportion of general aviation fatalities in the United States and elsewhere. This study details the evaluation of a computer-based training system that was developed to provide visual pilots with the skills necessary to recognize and respond to the cues associated with deteriorating weather conditions during flight. A total of 66 pilots were assigned to one of two groups, and the evaluation process was undertaken at both a self-report and performance level. At the self-report level, the results suggested that pilots were more likely to use the cues following exposure to the training program. From a performance perspective, there is evidence to suggest that cue-based training can improve the timeliness of weather-related decision making during visual flight rules flight. Actual or potential applications of this research include the development of computer-based training systems for fault diagnosis in complex industrial environments.

Direct and indirect cost of general aviation crashes

BACKGROUND

There have been few well-designed studies which estimate the costs inflicted on society from injuries, fatalities, and property damage caused by aviation crashes. Furthermore, indirect cost estimates from the human capital (HC) approach tend to be substantially smaller than those obtained from the willingness-to-pay (WTP) approach.

OBJECTIVES

To estimate the direct and indirect costs of general aviation crashes in New Zealand, and to contrast the HC and WTP approaches used to estimate indirect costs.

METHODS

The incidence, morbidity, and mortality from aviation crashes between 1988 and 1997 were estimated from national health and aviation records. Direct costs included medical treatment, damage to aircraft and property, and the cost of crash investigation. For the HC approach, we valued losses to society as the value of lost production from both employed work and household activity. For the WTP approach, we used the Land Transport Safety Authority's estimated values of society's willingness to pay to avoid a fatality or injury.

RESULTS

The annual average direct cost of aviation crashes was $9.1 m (range: $8.0 m to $11.4 m). The annual average indirect cost using the HC approach was $13.6 m ($5.6 m to $32.2 m). Using the WTP approach the annual average indirect costs was $49.3 m ($20.6 m to $106.5 m). Indirect costs from premature deaths were the key cost drivers. A sensitivity analysis showed that these values were relatively robust to changes in parameters.

CONCLUSION

The annual average cost of general aviation crashes in New Zealand was between $22.6 m and $58.4 m. Indirect costs using the WTP approach were 3.5 times greater than those estimated using the HC approach.

Mortality and morbidity in white water rafting in New Zealand

OBJECTIVES

This study provides the first descriptive overview of fatal and non-fatal injury associated with white water and other recreational river rafting in New Zealand. The current study sought to identify the nature and causes of hospitalisable injuries and to identify the causes of fatal injuries to white water rafters.

DESIGN

The data were obtained from the New Zealand Health Information Service (NZHIS) mortality and morbidity files. Mortality data for the period from 1983 to 1995 and morbidity data from 1983-1996 were used.

PARTICIPANTS

Members of the public who took part in white water and other recreational river rafting activities throughout the above periods.

RESULTS

Of the 33 fatalities, over 80% were male. Almost all the fatalities involved drowning, more than a third resulting from the raft capsizing. Nearly half of the 215 hospitalisations resulted from fractures, victims spending an average of 3.3 days in hospital. The effects of submersion, and intracranial injuries were the next most common categories.

CONCLUSIONS AND IMPLICATIONS

In relation to fatalities, the potentially modifiable risk factors involve improved resistance to raft capsizing, and equipment and skills required to stay afloat. In relation to injuries, the potentially modifiable risk factors relate mainly to preventing slipping and falling through the design of footwear, protective equipment, and procedures for entry and egress.

Cross-country VFR crashes: pilot and contextual factors

BACKGROUND

General Aviation (GA) cross-country crashes, particularly those involving weather, continue to be a major source of fatalities, with a fatality rate more than four times greater than for GA crashes in general. There has been much speculation and little solid evidence on the causes of these crashes.

METHODS

We have designed a program of laboratory and database research into the causes of cross-country weather-related crashes including an analysis of air crashes in New Zealand between 1988 and 2000. There were 1308 reported occurrences in this period. We examined in detail 77 crashes where it could be determined that the aircraft was on a cross-country flight.

RESULTS

In our first analysis we compared the characteristics of crashes that occurred in response to externally driven failures with crashes where the aircraft continued to be flown at the pilot's discretion up until the point of the crash. Clear differences were found for visibility, altitude, crash severity, and for several pilot characteristics. These differences are highly consistent with those found for previous research on pilot characteristics and crash involvement. In the second analysis we made comparisons between the weather-related and nonweather-related crashes in the discretionary control group and between subcategories of weather-related crashes.

CONCLUSIONS

These data show that weather-related crashes occur further into the flight and closer to the planned destination than other kinds of cross-country crashes in GA. Pilots involved in these crashes are younger and have more recent flight time than pilots involved in other crashes. Their increased involvement cannot be explained simply by exposure (flight-time) but must be due to other factors.

The role of situation assessment and flight experience in pilots' decisions to continue visual flight rules flight into adverse weather

Visual flight rules (VFR) flight into instrument meteorological conditions (IMC) is a major safety hazard in general aviation. In this study we examined pilots' decisions to continue or divert from a VFR flight into IMC during a dynamic simulation of a cross-country flight. Pilots encountered IMC either early or later into the flight, and the amount of time and distance pilots flew into the adverse weather prior to diverting was recorded. Results revealed that pilots who encountered the deteriorating weather earlier in the flight flew longer into the weather prior to diverting and had more optimistic estimates of weather conditions than did pilots who encountered the deteriorating weather later in the flight. Both the time and distance traveled into the weather prior to diverting were negatively correlated with pilots' previous flight experience. These findings suggest that VFR flight into IMC may be attributable, at least in part, to poor situation assessment and experience rather than to motivational judgment that induces risk-taking behavior as more time and effort are invested in a flight. Actual or potential applications of this research include the design of interventions that focus on improving weather evaluation skills in addition to addressing risk-taking attitudes.

Real time observation of the hydrothermal crystallization of barium titanate using in situ neutron powder diffraction

The hydrothermal crystallization of barium titanate, BaTiO3, has been studied in situ by time-resolved powder neutron diffraction methods using the recently developed Oxford/ISIS hydrothermal cell. This technique has allowed the formation of the ferroelectric ceramic to be followed in a noninvasive manner in real time and under genuine reaction conditions. In a first set of experiments, Ba(OD)2-8D2O was reacted with two different titanium sources, either crystalline TiO2 (anatase) or amorphous TiO2-H2O in D2O, at 100-140 degrees C and the reaction studied using the POLARIS time-of-flight neutron powder diffractometer, at the ISIS Facility. In a second series of experiments, the reaction between barium chloride and crystalline TiO2 (anatase) in NaOD/D2O was studied at temperatures between 100 and 200 degrees C and at different deuterioxide concentrations using the constant-wavelength D20 neutron powder diffractometer at the Institut Laue Langevin. Quantitative growth and decay curves were determined from analysis of the integrated intensities of Bragg reflections of starting materials and product phases. In both sets of experiments the rapid dissolution of the barium source was observed, followed by dissolution of the titanium source before the onset of crystallization of barium titanate. Using a nucleation-growth model we are able to simulate the growth curve of barium titanate at three temperatures. Our results indicate the predominance of a homogeneous dissolution-precipitation mechanism for the hydrothermal formation of barium titanate, rather than other possible mechanisms that have been discussed in the literature. Analysis of the line widths of the Bragg reflections in the neutron diffraction data indicates that the particle size of the BaTiO3 product phase prepared from the amorphous TiO2-H2O is smaller than that prepared from crystalline TiO2 (anatase).

Intercalation and controlled release of pharmaceutically active compounds from a layered double hydroxide

A series of pharmaceutically active compounds including diclofenac, gemfibrozil, ibuprofen, naproxen, 2-propylpentanoic acid, 4-biphenylacetic acid and tolfenamic acid can be reversibly intercalated into a layered double hydroxide, initial studies suggest that these materials may have application as the basis of a novel tuneable drug delivery system.

High resolution imaging of the distribution and permeability of methyl viologen dication in bovine articular cartilage using scanning electrochemical microscopy

Scanning electrochemical microscopy (SECM) has been used in the induced transfer (SECMIT) mode to image the permeability of a probe cation, methyl viologen (MV(2+)), in samples of articular cartilage. An ultramicroelectrode (UME), scanned just above the surface of a sample, is used to amperometrically detect the probe solute. The resulting depletion of MV(2+) in solution induces the transfer of this cation from the sample into the solution for detection at the UME. The current provides quantitative information on local permeability, provided that the sample-UME distance is known. It is shown that the necessary topographical information can be obtained using the amperometric response for the oxidation of Ru(CN)(4-)(6), which does not permeate into the cartilage matrix. This procedure was validated by marking samples in situ, after electrochemical imaging, with subsequent examination by ex situ interferometry and optical microscopy. Wide variations in the permeability of MV(2+) have been detected by SECMIT. These observations represent the first demonstration of the inhomogeneous permeability of a cation in cartilage on a micrometre scale. The permeability maps show similar features to the proteoglycan distribution, identified by toluidine blue staining, and it is likely that proteoglycans are the main determinant of MV(2+) permeability in articular cartilage.

(eta 5-Cyclopentadienyl)(kappa 3-hydrotris(pyrazolyl)borate)cobalt(II)--the first high-spin cobalt organometallic complex

(eta 5-Cyclopentadienyl)(kappa 3-hydrotris(pyrazolyl)borate)-cobalt(II) has been synthesised; magnetic and crystallographic data indicate this to be the first example of a high-spin cobalt organometallic complex whilst its pentamethylcyclopentadienyl analogue is found to have a low-spin electronic configuration.