Investigating Human Error: Incidents, Accidents, and Complex Systems

Barry Strauch

• Publisher: Routledge
• Year: 2017
• Topic: Psychology
• eBook ISBN:
  9781351926294
• Subtopic: Industrial Engineering
• Index: Psychology

In this book the author applies contemporary error theory to the needs of investigators and of anyone attempting to understand why someone made a critical error, how that error led to an incident or accident, and how to prevent such errors in the future. Students and investigators of human error will gain an appreciation of the literature on error, with numerous references to both scientific research and investigative reports in a wide variety of applications, from airplane accidents, to bus accidents, to bonfire disasters. Features include: - an easy to follow step by step approach to conducting error investigations that even those new to the field can readily apply. - summaries of recent transportation accidents and human factors literature and relates them to the cause of human error in accidents. - an approach to investigating human error that will be of interest to both human factors psychology and industrial engineering students and instructors, as well as investigators of accidents in aviation, mass transportation, nuclear power, or any industry that is to the adverse effects of error. Based on the author's over 18 years of experience as an accident investigator and instructor of both aircraft accident investigation techniques and human factors psychology, it reviews recent human factors literature, summarizes major transportation accidents, and shows how to investigate the types of errors that typically occur in high risk industries. It presents a model of human error causation influenced largely by James Reason and Neville Moray, and relates it to error investigations with step by step guidelines for data collection and analysis that investigators can readily apply as needed.

Part I
Errors and Complex Systems

1 Introduction

The ValuJet accident continues to raise troubling questions—no longer about what happened but about why it happened, and what is to keep something similar from happening in the future. As these questions lead into the complicated and human core of flight safety, they become increasingly difficult to answer. (Langewiesche, 1998)

The Atlantic Monthly

Introduction

“To err is human” it is said, and people make mistakes-it is part of the human condition. When people err they may be embarrassed or angry with themselves, but often the errors are minor and they pay little attention to the consequences. However, sometimes the errors lead to more serious consequences. Occasionally people in settings such as hospitals, airlines, power stations, or refineries commit errors-errors that lead to accidents with catastrophic consequences to those who played no part in the error. These settings establish high standards of employment and performance, and those who committed the errors may have gained highly responsible positions in these domains.

These settings, known as “complex systems” (Perrow, 1999), generate electricity, refine crude oil, manage air traffic, transport products and people, and treat the sick, to name a few. They have brought substantial benefits to our way of life, and permitted a standard of living to which many have become accustomed, but when someone who works in these systems makes an error, the consequences may be severe.

A new catastrophe seems to occur somewhere in the world with regularity, one that is later attributed to someone doing something wrong. Whether it is an airplane accident, a train derailment, a tanker grounding, or any of the myriad events that seem to occur regularly, the tendency of often-simple errors to wreak havoc continues. Despite the progress made in advancing technology, systems have not yet been developed that are immune to the errors of those who operate them. The genetic structure has been mapped and the Internet developed, but human error has not yet been eliminated.

The Crash of ValuJet Flight 592

To illustrate how even simple errors can lead to a catastrophic accident, let us look at an event in one of the safest systems-commercial air transportation. Despite numerous measures that had been developed to prevent the very types of errors that occurred, several people, including some who were not even involved in the conduct of the flight, committed critical errors that led to the accident.

On May 11, 1996, just minutes after it had taken off from nearby Miami, Florida, a McDonnell Douglas DC-9 crashed into the Florida Everglades (NTSB, 1997a). Investigators determined that the cause of this crash was relatively simple and straightforward; an intense fire broke out in the airplane’s cargo compartment and within minutes burned through the compartment into the cabin. The pilots were unable to land before the fire raged through the cabin. All who were onboard were killed in the crash.

The investigation led to considerable worldwide media attention that increased over time. As with any large-scale event that is accompanied by a substantial loss of life, this was understandable. But other factors played a part as well. The airline had been operating for less than three years, and it had employed non-traditional airline practices. It had expanded rapidly, and in the months before the accident, had experienced two non-fatal accidents. After the accident of flight 592, many criticized the airline, questioning its management practices and its safety record. Government officials initially defended the airline’s practices, but then reversed themselves. Just over one month after the accident, government regulators, citing deficiencies in the airline’s operations, forced it to cease operations until it could satisfy their demands for reform. This led to even more media attention.

As details about the crash emerged and more was learned, the scope of the tragedy increased. Minutes after takeoff, the pilots had declared an emergency, describing smoke in the cockpit. Within days of the accident, investigators learned that despite strict prohibitions, canisters of chemical oxygen generators had been loaded onto the aircraft. It was believed that the canisters, the report of smoke in the cockpit, and the accident were related.

Oxygen generators are harmless when properly installed in protective housings in aircraft cabins. However, if the canisters are not packaged properly or without locks to prevent oxygen generation, they could begin to generate oxygen inadvertently. The process also creates heat as a byproduct, bringing the surface temperature of the canisters to as high as 500° F (250° C). Investigators believed that boxes of canisters were placed into the airplane’s cargo hold, and that the canisters began generating oxygen. This heated the canisters to the point that they ignited adjacent material in the cargo compartment. The canisters then fed pure oxygen to the fire, producing one of extraordinary intensity.

Because of the potential danger that unprotected oxygen generators pose, they are considered hazardous and airlines are prohibited from loading unexpended and unprotected canisters of oxygen generators onto an aircraft. Yet, after the accident it was clear that someone had placed the canisters on the airplane. As a result, a major focus of the investigation emerged, to determine how the canisters were loaded onto the airplane.

Investigators learned that no single error led to loading the canisters onto the aircraft. To the contrary, several individuals had committed relatively insignificant errors, in a particular sequence, errors that had been committed about two months before the accident. Each error, in itself, was seemingly minor-the type that people may commit when rushed, for example. Rarely do these types of errors cause catastrophic consequences. However in this accident, despite government-approved standards and procedures designed and implemented to prevent them, people still committed the errors.

However, although the errors may have appeared insignificant, a complex system such as aviation has little room for even insignificant errors. Investigators seeking to identify the errors and relate them to the cause of the accident faced multiple challenges. Many specialists had to methodically gather and examine a vast amount of information, then analyze it to identify the critical errors, the persons who committed them, and the context in which the errors occurred.

Although it took substantial effort to understand the errors that led to this accident, investigators succeeded in learning how the errors were committed. The benefits of their activities were substantial. By meticulously collecting and analyzing necessary data, investigators were able to learn what happened and why-information that managers and regulators then applied to system operations to make them safer. Many learned lessons from this accident, and they applied what they learned to their own operations. Although the tragedy of the accident cannot be diminished, it made the aviation industry a safer one. Although there have been other accidents since this accident occurred, the aviation industry has not witnessed a similar one. This is the hope that guides investigations into error, that circumstances similar to the event being investigated will not recur.

Investigating error

Today, in many industrialized countries, government agencies or commissions generally investigate major incidents and accidents. Some countries have established agencies that are dedicated to that purpose. For example, the National Transportation Safety Board (NTSB) in the U.S., the Transportation Safety Board of Canada and the Australian Transport Safety Bureau, investigate incidents and accidents across transportation modes in their respective countries. In other countries, government agencies investigate accidents in selected transportation modes, such as the Air Accidents Investigation Branch of Great Britain and the Bureau Enquetes Accidents of France, which investigate events in commercial aviation.

However, when relatively minor accidents or incidents occur, organizations with little, if any, experience may conduct the investigations, if investigations are even carried out. Without the proper understanding those investigating error may apply investigative procedures incorrectly and fail to understand how the error came about. Although researchers have extensively examined error (e.g., Reason, 1990, 1997; Woods, Johannesen, Cook, and Sarter, 1994), there is little material that is available to guide those wishing to investigate error. Despite the high proportion of accidents and incidents in complex systems that are caused by operator error, it appears that few understand how to apply a formal process of inquiry to investigate error.

This text presents a general method of investigating errors believed to have led to an event. The method can be applied to error investigations in any complex system, although most of the examples presented are aviation-related. This primarily reflects the long tradition and experience of agencies that investigate aviation accidents, and the author’s experience participating in such investigations. Please consider the examples presented as tools to illustrate points made in the text and not as reflections on the susceptibility of any one complex system or transportation mode to incidents or accidents. Neither the nature of the errors nor the process of investigating errors differs substantially among systems.

This book is intended to serve as a roadmap to those with little or no experience in human factors or in conducting investigations. It is designed for practitioners and investigators, as well as for students of error. Though formal training in human factors, psychology, or ergonomics, or experience in formal investigative methodology is helpful, it is not required. The ability to understand and effectively apply an investigative discipline to the process is as important as formal training and experience.

Chapters begin with reviews of the literature and, where appropriate, follow with explicit directions on documenting data specific to the discussion in that chapter. Most chapters also end with “Helpful techniques,” designed to serve as quick investigative references.

Outline of the text

The text is divided into five sections, each addressing a different aspect of error in complex systems. The first defines concepts that are basic to the text, error and complex systems, the second focuses on types of antecedents to error, the third describes data sources and analysis techniques, the fourth section discusses two contemporary issues in human error, and the final section reviews an accident in detail and presents thoughts on selected issues important to error investigations.

Chapter 2 defines error in complex systems and introduces such critical concepts as operator, incident, accident, and investigation. Contemporary error theories are discussed, with particular attention devoted to Perrow’s conception of system accidents (1999) and Moray (1994) and Reason’s (1990, 1997), models of error in complex systems. Changes in views of error over the years are reviewed.

Chapter 3 begins the focus on antecedents to error by examining the role of equipment in creating antecedents to error, the source of much of the early scientific work in the field of human factors. Information display and control features that affect operator performance are discussed and illustrations of their relationship to operator errors in selected accidents are presented.

Antecedents pertaining to the system operator, historically the primary focus of those investigating error, are addressed in Chapter 4. Behavioral and physiological antecedents to error are examined, and antecedents that are operator initiated or caused are differentiated from company-influenced antecedents.

Antecedents pertaining to companies that operate complex systems, and regulators that oversee the work of those companies, are examined in Chapter 5. These antecedents incorporate many that are discussed in earlier chapters, including operating procedures and company oversight of the application of those procedures to system operations. The role of regulators, who establish and approve the rules governing system operations and oversee compliance with those rules, is reviewed.

Chapter 6 reviews antecedents that are exclusive to the maintenance and inspection environment. With the exception of Reason (1997) and Drury (1998), researchers have generally paid little attention to the role of maintenance and inspection in creating antecedents to error. These antecedents include environmental factors, tool design, the tasks themselves, and other factors related to the distinctive demands of system maintenance and inspection.

Features of multi-operator systems and their role in operator error are reviewed in Chapter 7. The complexities of contemporary systems often call for teams of operators with diverse skills and backgrounds to operate the systems. System features that necessitate the use of multi-operator teams, the errors that members of these teams could commit, and their antecedents, are examined.

Chapter 8 assesses the impact of culture on error antecedents. Two types of culture, national and company-related, are examined. Although they are distinct in terms of their relationship to antecedents, they share many characteristics that influence operator performance. Several accidents, which illustrate the types of antecedents that can arise from cultural factors, are reviewed.

Chapter 9 addresses the first of the data sources investigators rely on, data that systems recorders capture and record. Types of recorders used in different systems are examined and their contribution to the investigation of error in those systems discussed. A recent accident is presented to illustrate how recorded data can provide a comprehensive view of system state and an understanding of the errors leading to an accident.

Written documentation, an additional data source for investigators, is examined in Chapter 10. These include records that companies and government agencies maintain and factors that affect the quality of their information. Several accidents are reviewed to illustrate how written documentation can help investigators understand both the errors that may have led to events in complex systems and their antecedents.

Chapter 11 focuses on a third type of data for investigators, interview data, and their use in error investigations. Memory and memory errors are reviewed, and their relationship to error investigations discussed. Types of interviewees are discussed and factors pertaining to each, such as the type of information expected, the interview location, and the time since the event, examined. Suggestions to enhance interview quality and maximize the information they can provide are offered.

Chapter 12 discusses the analysis of data obtained in a human error investigation. Different types of analyses are described and their relationship to human error explored. A hypothetical illustration of the application of the analysis methodology to an accident involving human error is presented, with the logic involved in each of the steps examined.

The fourth section of the text, the discussion of two contemporary issues in error in complex systems, begins with Chapter 13. This chapter examines situation awareness and decision mak...

Table of contents

• Cover Page
• Investigating Human Error
• Copyright Page
• Contents
• List of Figures
• List of Tables
• Foreword
• Preface
• Part I Errors and Complex Systems
• Part II Antecedents
• Part III Data and Data Analysis
• Part IV Issues
• Part V Applying the Data
• References
• Index