Human Factors in Aviation

Eduardo Salas, Dan Maurino, Eduardo Salas, Dan Maurino

• Publisher: Academic Press
• Year: 2010
• ISBN:
  9780080923024
• Edition: 2
• Topic: Tecnología e ingeniería
• Subtopic: Seguridad y salud industriales

Fully updated and expanded, the second edition of Human Factors in Aviation serves the needs of the widespread aviation community - students, engineers, scientists, pilots, managers and government personnel. Offering a comprehensive overview the volume covers topics such as pilot performance, human factors in aircraft design, vehicles and systems and NextGen issues. The need for an up-to-date, scienti?cally rigorous overview is underscored by the frequency with which human factors/crew error cause aviation accidents, pervasiveness of human error in safety breakdowns. Technical and communication advances, diminishing airspace and the priority of aviation safety all contribute to the generation of new human factors problems and the more extensive range of solutions. Now more than ever a solid foundation from which to begin addressing these issues is needed.

• New edition thoroughly updated with 50% new material, offering full coverage of NexGen and other modern issues
• Liberal use of case examples exposes students to real-world examples of dangers and solutions
• Website with study questions and image collection

III

Pilot and Crew Performance Issues

Chapter 6 The Human in Flight

Chapter 7 Information Processing in Aviation

Chapter 8 Managing Workload, Performance, and Situation Awareness in Aviation Systems

Chapter 9 Team Dynamics at 35,000 Feet

Chapter 10 Flight Training and Simulation as Safety Generators

Chapter 11 Understanding and Analyzing Human Error in Real-World Operations

Chapter 12 Cognitive Architectures for Human Factors in Aviation

Chapter 13 Aircrew Fatigue, Sleep Need and Circadian Rhythmicity

Chapter 6

The Human in Flight: David From Kinesthetic Sense to Cognitive Sensibility

Kathleen L. Mosier

San Francisco State University

Introduction

Technological advances since the early days of flight have significantly transformed the aircraft cockpit and have altered the relationships among the human pilot, the aircraft, and the environment. Consistent with technological advances in aviation—many of which occurred after publication of the Wiener and Nagel (1988) volume—the role of the pilot has evolved from one characterized by sensory, perceptual, memory, and motor skills (Liebowitz, 1988) to one characterized primarily by cognitive skills. The flightdeck has evolved into a hybrid ecology comprised of both naturalistic and electronic elements. The environment is deterministic in that much of the uncertainty has been engineered out through technical reliability, but it is naturalistic in that conditions of the physical and social world—including ill-structured problems, ambiguous cues, time pressure, and rapid changes—interact with and complement conditions in the electronic world. Cues and information may originate in either the naturalistic (external, physical) environment or the deterministic systems (internal, electronic).

Different cognitive strategies and goals are required for dealing with each side of the hybrid ecology. Correspondence, or empirical, objective accuracy, is the primary goal in the naturalistic world. A correspondence strategy in the flying task involves evaluating probabilistic cues in the natural world (multiple fallible indicators; see, e.g., Brunswik, 1956; Hammond, 1996; Wickens & Flach, 1988) to formulate judgments with reference to it. In contrast, coherence, or rationality and consistency in judgment and decision making, is the primary goal in the electronic world. Using a coherence strategy, a pilot might evaluate the information displayed inside the cockpit to ensure that system parameters, flight modes, and navigational displays are consistent with each other and with what should be present in a given situation. In the hybrid ecology of the modern cockpit, input from both sides must be integrated to evaluate situations and make decisions. In this environment, both visual and kinesthetic sensing and, to a greater extent, cognitive sensibility are critical to the safety of humans in flight.

The goals of this chapter are: (1) to trace the technological evolution of the aircraft cockpit and of the flying task; (2) to describe issues inherent in the naturalistic side of the hybrid ecology, the need for correspondence, or accuracy in perception and judgment, in dealing with external environmental factors such as ambiguity and probabilism of cues, and the dangers of errors in correspondence; (3) to describe issues inherent in the electronic side of the hybrid ecology, including the need for analytical and consistent use of information, the need for coherence, or rational use of data and information in dealing with the internal, electronic environment, and the dangers of coherence errors; and (4) to discuss the integration of the two sides of the hybrid ecology and challenges for the design of Next Generation (NextGen) aircraft.

The Evolution of the Aircraft Cockpit and of the Pilot’s Task

Piloting an aircraft used to be a very physical- and sensory-oriented task. First generation aircraft were highly unstable, and demanded constant physical control inputs (Billings, 1996). The flight control task was a “stick and rudder” process involving knowing the characteristics of the aircraft and sensing the information necessary for control (Baron, 1988). Early aviation research therefore focused heavily on troubleshooting manual control and operational problems.

The senses—especially sight—were critical for problem diagnosis and navigation as well as for spotting other aircraft or obstacles. Judgments in early days of aviation were made via sensory—visual and kinesthetic—perception of the natural, physical world, in what has been referred to as “contact” flying (Hopkins, 1982). The emphasis was on accurate judgment of objects in the environment—height of obstacles in terrain, distance from ground, severity of storm activity in and around clouds, location of landmarks—and accurate response to them (e.g., using the controls to maneuver around obstacles or storm clouds, or to make precise landings). Features of the environment and of the available cues impacted the accuracy of judgments. Clear weather and concrete, easily discernable cues facilitated judgment. Pilots could easily discern a 5-mile reporting point when it was marked by a tall building. Murky weather, darkness, or ambiguous cues hindered judgment. The reporting point would be harder to find when the building that marked it was covered in fog or overshadowed by a long string of similar buildings. As pilots gained experience, more accurate perception resulted in more accurate response.

Pilots avoided situations that would put the accuracy of their senses in jeopardy, such as clouds or unbroken darkness. Early airmail pilots often relied on railroad tracks to guide their way, and mail planes had one of the landing lights slanted downward to make it easier to follow the railroad at night. Later, a system of beacons and gas lights created a 902-mile illuminated airway for nighttime flight. In 1929, Lieutenant James H. Doolittle of the U.S. Air Corps completed a historic 15-minute flight guided only by instruments (an altimeter, a gyrocompass, and an artificial horizon) and special radio receivers, and demonstrated that flight could be conducted entirely without visual reference to the outside world (Orlady Orlady, 1999). This was a milestone on the road to instrument-guided flight.

Most facets of the flying task have become less sensory-oriented than in the past. As aircraft evolved, flying became physically easier as parts of control task were automated (e.g., through use of an autopilot), and automated systems began to perform many of the flight tasks previously accomplished by the pilot. The demand for all-weather flight capabilities resulted in the development of instruments that would supposedly compensate for any conditions that threatened to erode pilots’ perceptual accuracy. Conflicts between visual and vestibular cues when the ground was not visible could lead to spatial disorientation and erroneous control inputs—but an artificial horizon, or attitude indicator, within the cockpit could help resolve these conflicts. Limitations of night vision could be overcome with navigational displays. These were first steps in the transformation of the cockpit ecology. Soon, more and more information placed inside the aircraft supplemented or replaced cues outside the aircraft (e.g., altitude indicator, airspeed indicator, alert and warning systems) and vastly decreased reliance on perceptual (i.e., probabilistic) cues. The readings inside the cockpit provided more accurate data than could be gleaned from the senses, and pilots became increasingly reliant on them.

As the aviation domain matured, much of the related research was geared toward defining and overcoming human limitations in terms of detection and recognition, night vision, and visual-vestibular interaction (Liebowitz, 1988). The perception and human information processing focus that dominated aviation research for many years was consistent with this era of aviation history. Limitations of the human as perceiver such as the degradation of vision at night and difficulties in detecting and recognizing large airplanes at a distance (e.g., Leibowitz, 1988), or as information processor such as attention and memory limitations (e.g., Wickens and Flach, 1988) were key topics of research. In the modern cockpit, many of these human limitations were addressed by instruments and technological aids.

Figure 6.1 illustrates the advances in automation in the aircraft cockpit since the 1930s. Note that in each successive generation, more data from the outside environment are brought into the cockpit and displayed as highly reliable and accurate information, reducing pilot dependence on ambiguous and probabilistic cues. With each technological advance, the pilot has less reason to look outside the cockpit and more reason to focus on systems and displays within it. In fourth-generation aircraft, all the information required to fly the aircraft and navigate from A to B can be found inside the cockpit, and the need for kinesthetic sensing or searching for cues outside the cockpit is greatly diminished. In fact, with reliable instruments aircraft can operate in low- or no-visibility conditions. Exact location in space can be read from cockpit displays, whether or not visual cues are visible outside of the cockpit. In some aircraft even the need for tactile sensing has been reduced and tactile feedback eliminated as “fly-by-wire” controls, which provide little or no tactile feedback on thrust setting, have replaced conventional hydraulically actuated control columns. Fourth-generation aircraft such as the Airbus A-319/320/321/330/340 and the Boeing 777/787 are qualitatively different entities than early generation aircraft such as the Boeing 707, and issues and requirements for flying them derive not only from sensory and external (naturalistic) aspects of flying, but also from cognitive and internal (electronic/deterministic) factors. Table 6.1 outlines the characteristics of each side of the hybrid ecology, each of which is discussed in the sections that follow.

Figure 6-1 Evolution of technology in civil air transport. Adapted from Fadden (1990) and Billings (1996).

Table 6-1. The Hybrid Ecology of the Modern Flightdeck

Naturalistic World	Electronic World
Sensory and kinesthetic	Cognitive
Correspondence strategies and goals	Coherence strategies and goals
Ambiguity	Reliability
Intuitive processes	Analytical processes
Probabilistic cues	Deterministic data and information
Expertise affords intuitive “short cuts”	Analysis required at all levels of expertise

Correspondence and the Naturalistic World

Aviation has traditionally been described as a correspondence-driven domain in that it exists within and is subject to the constraints of the natural environment (Vicente, 1990), including dynamic, changing condition, ambiguous cues, ill-structured problems, and time pressure (Zsambok & Klein, 1997). Correspondence, or accuracy, in this natural environment involves integration of multiple probabilistic cues. Much of the applied work that has been done on expert processes in aviation has focused on intuitive and sensory-driven correspondence strategies. Klein’s model of expert Recognition-Primed Decision Making (e.g., Klein, 1993, 2000; Zsambok & Klein, 1997), for example, describes expertise as the ability to identify critical cues in the environment, to recognize patterns of cues, and to understand the structural relationships among cues. According to this model, expert pilots look for familiar patterns of relevant cues, signaling situations that they have dealt with in the past, and base their responses on what they know “works” (e.g., Klein, 1993; Klein, Calderwood, & Clinton-Cirocco, 1986). The expert pilot may check to see if the view out the window is as expected with respect to patterns of surrounding and runway lights, and whether the cues match what he or she has previously encountered at this location or point in the flight. Or, the expert pilot may scan the sky ahead, intuitively gauging a safe distance from clouds, estimating their density and the horizontal visibility, and picking out a safe route through them.

Experienced pilots are typically highly competent in correspondence strategies. They are adept at assessing cue validity within specific situational contexts, and they are better than inexperienced pilots at predicting the outcome of a given decision or action. Their expectations have been shaped by a wide array of experiences, and they utilize these experiences to assess patterns of cues. Expertise offers a great advantage in correspondence judgments, as expert pilots are able to quickly recognize a situation from patterns of probabilistic cues, and may be able to use intuitive judgment processes under conditions that would demand analysis from a novice. For example, novice pilots may need to use a combination of computations and cues outside of the aircraft to figure out when to start a descent for landing. Experienced pilots in contrast may look outside the cockpit window and intuitively recognize when the situation “looks right” to start down.

Correspondence Errors

Correspondence errors typically entail misreadings of probabilistic cues or failure to integrate the cues appropriately. One important probabilistic element of flight is weather information. Weather has been identified as a factor in 15% of fatal GA (General Aviation) accidents (Coyne, Baldwin, & Latorella, 2001) and is a significant contributor to airline accidents and incidents. It is also a salient factor in plan continuation errors, in which crews continue with a plan of action despite the presence of cues suggesting that the original plan is not longer optimal and should be modified (Orasanu...