Why did the pilots shut down the wrong engine? Explaining errors in context using Schema Theory and the Perceptual Cycle Model

Although human error remains a dominant issue in aviation research, methods that predict human error have been criticised for not providing adequate causal explanations, rather they have focused on classification. The concept of Schemata has prevailed in the literature and has been shown to describe the contextual causes of human error. The purpose of this paper is to review the recent error literature and demonstrate that Schema Theory (as incorporated in the Perceptual Cycle framework) offers a compelling causal account of human error. Schema Theory offers a system perspective with a focus on human activity in context to explain why apparently erroneous actions occurred, even though they may have appeared to be appropriate at the time. This is exemplified in a case study of the pilots’ actions preceding the 1989 Kegworth accident. Schema Theory is presented as a promising avenue for further exploration into the context of human error in aviation.     

Learning from incidents – A method for assessing the effectiveness of the learning cycle

This paper describes a method for assessing the effectiveness in the steps of the learning cycle: the 1st loop with reporting – analysis – decision – implementation – follow-up, and the 2nd loop on an aggregated basis. For each step, the dimensions considered the most relevant for the learning process (scope, quality, timing and information distribution) and for each dimension the most relevant aspects (e.g. completeness and detail) were defined. A method for a semi-quantitative assessment of the effectiveness of the learning cycle was developed using these dimensions and aspects and scales for rating. The method will give clear indications of areas for improvement when applied. The results of the method can also be used for correlation with other safety parameters, e.g. results from safety audits and safety climate inquiries. The method is intended to be used on a sample of the broad range of incidents normally seen in process industry companies. The method was tested on a two-year incident reporting material from six companies from various types of process industries. It was found that the method and the tools worked very well in practice. The results gave interesting insights into the effectiveness of learning from the incidents.     

How does the social context fuel the proactive fire? A multilevel review and theoretical synthesis

The role of social context (e.g., leadership, team climate, and organizational support) in shaping employee proactive behavior has received considerable attention and has been investigated across multiple forms of proactive behavior. However, the research has not been well integrated. In this review, we adopt a multilevel approach to synthesize what is known about how social context factors influence employees' proactive behavior, as well as what mechanisms underpin these effects. Our analyses show that leader‐, team‐, and organization‐related social context factors mainly influence employee proactivity through shaping “reason to,” “can do,” and “energized to” states (i.e., proactive motivational states) via individual‐, team‐, and cross‐level processes. That has been most frequently investigated is the effect of the discretionary social context, particularly leadership, on proactive behavior. We also review the interaction effects between social context factors and other factors on employee proactive behavior and found inconsistent support for the motivational‐fit perspective that stimuli with the same directions enhance each other's effect. We offer a research agenda to advance theoretical insights on this important topic.     

Revisiting the trustworthiness–trust relationship: Exploring the differential predictors of cognition- and affect-based trust

We seek to develop a better understanding of interpersonal trust by bridging the gap between two heretofore distinct paradigms of trust. One paradigm views trust in terms of two dimensions: cognition- and affect-based. The other paradigm views trust as being distinct from trustworthiness, which has four dimensions: ability, behavioral integrity, benevolence, and values congruence. Currently, theoretical consensus is lacking about the antecedents of cognition- and affect-based trust in the first paradigm that incorporates insights from research on trustworthiness in the second paradigm. We show that this lack of consensus is problematic for internal knowledge development and external knowledge expansion. Thus, we join both paradigms by theorizing that ability and behavioral integrity are the most important predictors of cognition-based trust, whereas benevolence and values congruence are the most important predictors of affect-based trust. Across two samples, we found that our predictions were largely supported. Based on relative weights analysis, ability and behavioral integrity were more important than values congruence in predicting cognition-based trust, and benevolence was more important than ability in predicting affect-based trust. Furthermore, we found evidence that these relationships were largely robust to changes in the referent of analysis.     

Risk and characteristics analysis of the flow-induced vibration of the dip tube in opposed multi-burner gasifier

The vibration of dip tube in multi-burner gasifier changes the stress at the connection, causing flange seal failures and high temperature gas erosions with heavy economic losses and industrial accidents. This work aims to reveal the dip tube vibration mechanism, with special focus on obtaining the effect of operational parameters on the fatigue damage and long-term stable operation of gasifiers. A three-dimensional numerical simulation of the water-scrubbing cooling chamber was conducted to obtain the excitation source in the flow field. Then a FSI (fluid-structure interaction) transient dynamics simulation was carried out to investigate the vibration characteristics. Two major flow forms were found: a vertical annular flow near the dip tube outlet in the water-scrubbing cooling chamber; and a gas-liquid coupled flow caused by the syngas entrained the liquid. These two unstable multiphase flow forms exerted an energy excitation on the dip tube, resulting in a self-excited flutter. The dip tube vibration was similar to the first mode of a cantilever beam. The peak frequency was less affected by the initial liquid level and the syngas stream inlet velocity, which was close to its own first natural frequency. Note that, the alternating load generated by vibration may cause fatigue damage, which needs to be specifically considered in the design and manufacturing process of opposed multi-burner gasifier.     

Analysis of the experimental results of the initiation of detonation in short tubes with kerosene–oxidizer mixtures

The paper describes the experimental investigation of detonation initiation in a mixture of kerosene–oxidant in a short test tube. Various mixtures of oxygen and nitrogen were used as an oxidant, from pure oxygen to the composition of air. The goal of the study was to determine the minimum diameter of the tube and the minimum level of energy needed for the direct initiation of detonation. As a result of the measurements the pressure courses were obtained for two kinds of cases: with and without (only shock waves) of fuel injection. The results of both kinds of measurements were compared, providing information about the initiation of detonation in a fuel–oxidizer mixture. Brief analyses of the results for different initiators and different oxidizers were performed and compared with the shock wave and Chapman–Jouget velocity.     

Exploring the linkage between the home domain and absence from work: Health,motivation, or both?

The aim of this study was twofold. First, we examined depleting and enriching effects of employees' home domain (home demands and quality time spent at home) on unscheduled absence from work. Second, we tested the assumption of the medical and withdrawal models that absence duration and frequency are uniquely predicted by respectively health condition and job motivation. We used longitudinal, different‐source data from 1014 employees. The results showed that home quality time was negatively related to absence frequency and duration in the following year through a physical pathway (less physical stress symptoms and health complaints) and through a psychological pathway (less psychological stress symptoms, increased job motivation). Employees with heavy home demands reported more physical and psychological stress symptoms, more health complaints, and lower job motivation. Accordingly, they had longer and more frequent sick leaves in the consecutive year. We conclude that the home domain adds to our understanding of absence from work. In addition, the model including cross pathways between health complaints and job motivation on the one hand, and absence frequency and duration on the other, best fitted the data. Thus, a clear distinction between volitional absence (frequency) and absence due to illness (duration) seems hard to justify. Copyright © 2012 John Wiley & Sons, Ltd.     

Does homesickness undermine the potential of job resources? A perspective from the work–home resources model

Rapid economic development in recent decades has resulted in a considerable increase in the number of people working far away from their home locations. Homesickness is a common reaction to the separation from home. Our research uses the work–home resources model to explain how the experience of homesickness can undermine the positive effect of job resources on job performance (i.e., task performance and safety behavior). In addition, we hypothesize that emotional stability and openness are key resources that can buffer the negative interference of homesickness with the job resources–performance relationship. We conducted two studies to test our hypotheses. Study 1 was a two‐wave longitudinal study using a migrant manufacturing worker sample. In this study, homesickness was measured at the between‐person level, and performance was measured three months later. Study 2 was a daily diary study conducted in a military trainee sample. In this study, homesickness was measured at the within‐person level to capture its fluctuations over 20 days, and daily job performance was assessed using supervisor ratings. Both studies showed evidence of the hypothesized moderating effect of homesickness and three‐way interaction effects of job resources, homesickness, and key resources (i.e., emotional stability and openness) on task performance and safety behavior.     

STAMP-based analysis on the railway accident and accident spreading: Taking the China–Jiaoji railway accident for example

Each hazard analysis technique is based on a model of accident causation. Most accident models regard accidents as resulting from a chain or sequence of events, such models are fit for accidents caused by failures of physical components and for relatively simple systems, but suffer from serious deficiencies when they are applied to software-intensive, complex engineering systems. Recently, a new accident model called System-Theoretic Accident Models and Process (STAMP) for system safety has been proposed, it is based on control theory and enforces constraints on hazards and thereby prevent accidents. In this paper, taking the China–Jiaoji railway accident happened on April 28, 2008 as an example, the STAMP approach has been used to analyze the railway accident and some improvement measures have been proposed. As the occurrence of one accident can cause many other accidents happen, based on the STAMP-based analysis, the accident spreading processes have also been discussed and modeled, which will be helpful to analyze accidents spreading in a broad sense and establish effective emergent measures for accident response management.     

Does the built environment affect when American teens become drivers? Evidence from the 2001 National Household Travel Survey

Problem

Motor vehicle crashes are the most common cause of death for American adolescents. However, the impact of where teens live on when they begin driving has not been studied.

Method

Data from the 2001 National Household Travel Survey were used to estimate the effect of residential density on the driver status of teens aged 16 to 19 years after matching on demographic characteristics.

Results

Controlling for demographic characteristics, 16 and 17 year old teens in high density neighborhoods had driver rates 15 percentage points below teens living in less dense areas (p < 0.001). The effect for 18 and 19 year olds was a 9 percentage point decrease (p < 0.001).

Summary

These results suggest teens living in less dense and more sprawling communities initiate driving at a younger age than comparable teens in compact areas, placing them at increased risk for crash related injuries. Impact on Industry: The role of environmental factors, such as neighborhood walkability and provision of transit, should be considered in young driver programs.     

Study on Lockout Procedures for the Safety of Workers Intervening on Equipment in the Municipal Sector in Québec

In Québec, workers intervening in hazardous zones of machines, equipment and processes during maintenance, repairs and unjamming activities have to apply lockout procedures. Lockout procedures involve shutting down the equipment, isolating it, applying individual locks, releasing residual energies and verifying the absence of energies. Lockout has mostly been linked to industrial sectors. However, the municipal sector also faces challenges when it comes to controlling hazardous energies. The objectives of this research are to study serious accidents linked to our subject, study the application of lockout in different municipalities in Québec, identify the specificities for the municipal sector and propose some means to support the application of lockout. We will show that lockout procedures are required in different locations in municipalities and that they are currently being implemented in the municipal sector in Québec. Moreover, we propose a model which aims at facilitating the implementation of lockout procedures in the municipal sector.     

Bund overtopping — the consequence of catastrophic tank failure

The Health and Safety Executive (HSE) has considerable interest in predicting the consequence of releases of hazardous liquids from storage tanks (HSE, 1998), because of its responsibilities as a statutory adviser to local planning authorities on the siting of hazardous installations and on the control of development in their vicinity, and because of its responsibilities alongside the Environment Agencies as the Competent Authority in the assessment of COMAH safety reports. As a result, HSE has commissioned a number of studies, including: experimental studies of the behavior of liquid spills (Lee and Kountouris, 1992, Skitt and Wheeler, 1989, Bentinck and Crow, 1991, Clark and Savery, 1993, Law and Johnskareng, 1994, Ruddle and Widowson, 1985, Ruddle and Elms, 1985, Cleaver, Cronin, Evans and Hirst, 2001), a review of overtopping data and theoretical models used to study liquid flow (Thyer & Jagger, 1997), the characterization of the profile of the leading edge of the spreading liquid (Thyer, MacMillan, & Jagger, 1999), and the development and use of complex mathematical models to predict overtopping fractions and liquid spill behavior (Daish et al., 1998, Ivings and Webber, 2001).This paper summarizes the consequences of catastrophic tank failure, the current position on the availability of liquid spill data for model validation, and indicates how such data may be used to predict the often considerable fraction of liquid that could overtop retaining bunds around real tanks.     

Effects of controller-pilot communication medium,flight phase and the role in the cockpit on pilots’ workload and situation awareness

This study explores the effects of communication medium, flight phase, and the role in the cockpit on pilots’ workload and situation awareness. Eight pilots with the experience of Controller-Pilot Data Link Communications (CPDLCs) participated in this simulated experiment. Two types of communication medium (voice and datalink), three types of flight phase (departure, cruise, and arrival), and two types of role (pilot flying and pilot non-flying) were investigated in the experiment. The results indicated that flight phase is a significant factor and cruise is the most suitable phase for datalink use on pilots’ acceptance, workload, and situation awareness performance. Both medium and role were not the significant factors. Since there is no significant difference on medium when no extra tasks and interferences involved in a normal flight, that the use of CPDLC can be justified during all phases of a no-event flight. In addition, the results of usability indicated that the simulated CPDLC with command selection functions proposed in this study provides good utility for the participants. In order to use the CPDLC for all phases of flight in the future, adding more command selection functions in place of typing messages by pilots and accommodating appropriate interfaces for different phases are recommended to enhance the usability of the CPDLC unit.     

Testing the validity of the “value of a prevented fatality” (VPF) used to assess UK safety measures

The “value of a prevented fatality” (VPF), the maximum amount that it is notionally reasonable to pay for a safety measure that will reduce by one the expected number of preventable premature deaths in a large population, is published by the UK Department for Transport (DfT). The figure, updated for changes in GDP per head, is used by the DfT, the Health and Safety Executive and other UK regulatory bodies as well as very widely in the process, nuclear and other industries as the standard by which to judge how much to spend to reduce harm to humans. The paper tests the validity of the 1999 study on which the VPF is based and finds that that study fails numerous tests of its validity. It is concluded that there is no evidential base for the VPF that has been used for many years in the UK and is still in standard use today. Given the difficulties evident in the interpretation of survey results, an urgent re-appraisal is needed of alternative statistical methodologies that can allow robust regulatory and industry safety decision making and, vitally, give adequate protection to the UK public and to those working in the UK's transport, process, nuclear and other industries.     

Does the Maryland graduated driver licensing law affect both 16-year-old drivers and those who share the road with them?

PROBLEM: To assess effects of the 1999 Maryland graduated driver licensing (GDL) law on both 16-year-old drivers and other road users. METHOD: Calculation and comparison of crash involvement rates and non-fatal injury rates pre-GDL (1996-1998) and post-GDL (2001-2003) by type of road user, per population, and per licensed driver, with adjustment for trends among 30-59-year-old drivers. RESULTS: Post-GDL, prevalence of licensure decreased 24% among 16-year-olds, and rates of 16-year-old drivers involved in crashes significantly decreased per 16-year-old population (corrected rate ratio (RRc) 0.82; 95% CI (0.71, 0.96)). A significant decrease also was observed for non-fatal injuries per 16-year-old population among 16-year-old drivers involved in crashes (RRc 0.63; 95% CI (0.41, 0.98)). Similarly, decreases, albeit not statistically significant, were observed among their passengers and other vehicle occupants. Per 16-year-old licensed driver, a slight non-significant increase was observed in crash involvement rates; non-fatal injury rates per 16-year-old licensed driver suggest decreased risk (non-significant) among 16-year-old drivers, their passengers, and other vehicle occupants. SUMMARY: Maryland's GDL delayed licensure and reduced crashes and non-fatal injuries among 16-year-old drivers per population. Trends in injuries among other road users involved in crashes with 16-year-old drivers were suggestive of a benefit from GDL, although observed decreases were not significant. Per licensed driver, findings were not significant, but suggested little change in crash involvement and decreased non-fatal injuries. Because one-third fewer 16-year-olds were licensed post-GDL, these results may suggest a selection effect in licensure. IMPACT ON INDUSTRY: Because Maryland had nighttime restrictions for new drivers before 1999, this study suggests other components of GDL are beneficial for drivers and possibly for other road users. States with weak GDL laws should strongly consider revising them.     

Paperwork at the service of safety? Workers’ reluctance against written procedures exemplified by the concept of ‘seamanship’

Efforts to reduce accidents in seafaring have led to a proliferation of procedures such as workplace assessments and checklists. Unfortunately, the demand for written procedures is perceived by many seafarers as counteracting the use of common sense, experience, and professional knowledge epitomized in the concept of seamanship. Their objections suits well in Dreyfus and Dreyfus’ model of skill acquisition: while novices steadily follow context-independent rules, the expert’s behaviour goes beyond analytical rationality, and is situational, experience-based, and intuitive. The Aristotelian concept of phronesis brings us further by adding a reflexive, social and ethical dimension to the expert’s knowledge. Phronesis is, like expertise, contextual, experience-based knowledge; but it is also value- and action-oriented. While phronesis rests on value rationality, ‘techne’ (know how’), another Aristotelian concept, is based on instrumental rationality and is production-oriented. Phronesis is, inter alia, choosing the proper techne for the circumstances. However, the seamen fear a development where techne predominates at the expanse of phronesis. The case raises issues on which conditions are enabling or hindering written procedures to be perceived as a tool at the service of safety.