Alan Hobbs

National Aeronautics and Space Administration

This chapter will chronicle the journey of the community of operators, regulators, and researchers who embarked upon the task of identifying critical human factors of maintenance and inspection, establishing a database and research tools, developing practical strategies for reducing the risks of maintenance and inspection errors, and understanding...

Remotely piloted aircraft range from quadcopter “drones” with endurance measured in minutes, to large, long endurance aircraft powered by jet turbine engines. This chapter is focused on remotely piloted aircraft that can operate beyond the line of sight of the pilot, in civil airspace in compliance with air traffic control. While this chapter draws...

Without the intervention of maintenance personnel, equipment used in complex technological systems such as aviation, rail transport, and medicine would deteriorate towards a level of unreliability that would threaten safety and profitability. After fuel, maintenance is the largest cost facing airlines. Despite recent technological advances, mainten...

This chapter begins with a brief overview of remotely piloted aircraft, follows with a review of their accident record, and then focuses on human factors principles for Remote Pilot Stations (RPS).

Without the intervention of maintenance personnel, equipment used in complex technological systems such as aviation, rail transport, and medicine would deteriorate toward a level of unreliability that would threaten safety and profitability. After fuel, maintenance is the largest cost facing airlines. Despite recent technological advances, maintena...

It could be said that in complex technological systems such as aviation, accidents do not happen to people, but to entire organisations. There has long been an acknowledgment that system breakdowns or safety occurrences typically reflect not only individual human failings, but also systemic or organisational problems. In recent years there has been...

Maritime piloting operations involve on-call work schedules that may lead to sleep loss and circadian misalignment. Our study documented pilot work scheduling practices (n = 61) over a one-year period. Most pilots worked a week-on/week-off schedule. Work periods averaged 7.6 hours in duration and pilots worked up to four ship assignments during a g...

The purpose of this study was to evaluate the extent of fatigue among Bar Pilots and its potential impact on safety, and to make recommendations concerning how the risk of fatigue could be managed. Information was gathered via a literature review, observations of Bar Pilots at work, surveys, a task analysis, and an analysis of dispatch records.

This chapter focuses on organizational factors as they relate to safety beginning with the consideration of organizational factors in the investigation and analysis of accidents and incidents. But organizational factors not only may contribute to accidents, they also point to ways in which safety can be enhanced and accidents prevented. Examples fr...

This document contains a list of human factors guidelines for remote pilot stations (RPS) arranged within an organizing structure. The guidelines are intended for the RPS of remotely piloted aircraft systems (RPAS) that are capable of operating beyond visual line-of-sight in all classes of civil airspace. Numerous human factors guidelines and stan...

Confidential reports of maintenance incidents are a valuable source of information on maintenance errors and the contexts within which they occur. NASA’s Aviation Safety Reporting System has been receiving an increasing number of maintenance incident reports since a specialized maintenance reporting form was introduced in 1996. In a series of studi...

The pilot control stations of some unmanned aircraft systems (UASs) have been plagued by poor human-machine interfaces. Human factors guidelines focused on the unique challenges of unmanned aviation will be essential if UASs are to gain unrestricted access to civil airspace. We present a systematic approach that can assist in the development and or...

A human factors team was tasked with assessing best practices for developing a crewed space vehicle that is both reliable and robust. The team identified two broad dimensions of human factors relevant to reliability and robustness, namely, the attributes of the product, and the processes used to develop the product. The “product” includes hardware,...

The ground control stations (GCS) of some UAS have been characterized by less-than-adequate human-system interfaces. In some cases this may reflect a failure to apply an existing regulation or human factors standard. In other cases, the problem may indicate a lack of suitable guidance material. NASA is leading a community effort to develop recommen...

The FAA’s Fatigue Risk Management Program is developing a Fatigue Risk Management System that will include science-based shift scheduling and other strategies designed to maintain air traffic controllers’ alertness over the 24-hour clock and to reduce negative impacts of fatigue on Air Traffic Control (ATC) operations. NASA was tasked with conducti...

This panel will address the role of fatigue in air traffic control (ATC) operations and strategies for developing evidence-based fatigue risk mitigation strategies. Following an introduction to the history of ATC fatigue research, panelists will describe a two-part study with current air traffic controllers involving a web-based survey (available t...

The unregulated hours and frequent night work characteristic of maintenance can produce significant levels of employee fatigue, with a resultant risk of maintenance error. Fatigue Risk Management Systems (FRMS) are widely used to manage fatigue among flight crew and drivers of commercial vehicles, but comprehensive approaches to fatigue risk manage...

The need to fly Unmanned Aircraft Systems (UAS) in the National Airspace System (NAS) is increasing at a rapid pace. In order to address some of the issues impeding regular UAS access to the NAS, the National Aeronautics and Space Administration has begun a new program to assist the FAA and stakeholder community in establishing requirements for rou...

Unmanned aviation may appear to be a recent development, but its history stretches back to the beginnings of aviation. The first unmanned glider flew a century before the Wright Flyer, and unpiloted, powered aircraft made their appearance in the first decades of the 20th century. Over the last 100 years, a series of technological innovations have e...

Shift handovers occur in many safety-critical environments, including aviation maintenance, medicine, air traffic control, and mission control for space shuttle and space station operations. Shift handovers are associated with increased risk of communication failures and human error. In dynamic industries, errors and accidents occur disproportionat...

In workplaces where activity continues around the clock, human error has been observed to exhibit a circadian rhythm, with a characteristic peak in the early hours of the morning. Errors are commonly distinguished by the nature of the underlying cognitive failure, particularly the level of intentionality involved in the erroneous action. The Skill-...

This handbook provides an overview of the emerging human factors relevant to the maintenance of small UAS. Its purpose is to raise issues that will be important in future FAA advisory material or rulemaking. The content is based on interviews with UAS maintenance personnel, and observations of UAS operations. Small UA have many potential uses, incl...

Confidential reports of maintenance incidents are a valuable source of information on maintenance errors and the contexts within which they occur. NASA's Aviation Safety Reporting System has been receiving an increasing number of maintenance incident reports since a specialized maintenance reporting form was introduced in 1996. In a series of studi...

Maintenance error is a persistent contributor to accidents and incidents in a range of industries. The errors and violations that lead to serious consequences may reflect longstanding system problems that can be identified before they have an opportunity to cause harm. The Maintenance Environment Questionnaire (MEQ) was developed to evaluate the pr...

The accident rate for UAVs is higher than for conventional aircraft. A significant proportion of these accidents are associated with human error. If UAVs are to be permitted to operate in the National Airspace System, it will be necessary to understand the human factors associated with these vehicles. Unlike conventional aircraft maintenance, UAV o...

It has been claimed that human factors emerged as a significant challenge to flight safety only after the frequency of technical failures diminished in the early years of aviation. An examination of 100 aircraft accidents that occurred between 1921 and 1932 revealed that pilot factors contributed to most accidents, whereas technical failures contri...

In recent years cognitive error models have provided insights into the unsafe acts that lead to many accidents in safety-critical environments. Most models of accident causation are based on the notion that human errors occur in the context of contributing factors. However, there is a lack of published information on possible links between specific...

Road safety studies using the Driver Behaviour Questionnaire (DBQ) have provided support for a three-way distinction between violations, skill-based errors and mistakes, and have indicated that a tendency to commit driving violations is associated with an increased risk of accident involvement. The aims of this study were to examine whether the thr...

Advances in aviation technology have not necessarily been matched by improvements in the way we organise the work of the people who maintain aircraft. While striving for perfect performance by those maintaining aircraft, we should recognise that making mistakes is an unfortunate but unavoidable consequence of being human. The remarkable aspect abou...

Advances in aviation technology have not necessarily been matched by improvements in the way we organize the work of the people who maintain aircraft. While striving for perfect performance by maintainers, we should recognize that making mistakes is an unfortunate but unavoidable consequence of being human. The remarkable aspect about maintenance i...

Automatic or skill-based behaviour is generally considered to be less prone to error than behaviour directed by conscious control. However, researchers who have applied Rasmussen's skill-rule-knowledge human error framework to accidents and incidents have sometimes found that skill-based errors appear in significant numbers. It is proposed that thi...

The circumstances leading up to 619 safety occurrences that occurred during aircraft maintenance were examined. Ninety-six per cent of the occurrences were at least partly attributable to human actions and in most cases, these actions took the form of errors. The most frequent errors were memory lapses, rule violations and skill-based slips. Worker...

Originally published in March 1995, this article examines how apparently simple maintenance oversights can contribute to major disasters.

Numerous limitations, including those of the human visual system, the demands of cockpit tasks, and various physical and environmental conditions combine to make see-and-avoid an uncertain method of traffic separation. This report provides an overview of the major factors which limit the effectiveness of unalerted see-and-avoid. Cockpit workload an...

SUMMARY Six hundred and nineteen aircraft maintenance occurrences were analysed to determine the types of errors that preceded them, and the contributing factors that were associated with each error form. Ninety six percent of the occurrences resulted in whole or in part from human actions. The occurrences were analysed using a cognitive error mode...