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Good weather-related decision making is critical for the safe conduct of general aviation flights. A number of tools have been developed in recent years to help pilots visualize the actual and forecast weather for their planned flight. In this study we compare the effectiveness of a graphic weather visualization tool designed for preflight decision making with conventional coded reports and plain English translations. Qualified pilots from several aero clubs were asked to view 4 hypothetical cross-country flights. Departure and destination weather reports (METARs) were provided for each flight in 1 of 4 formats—code, plain English, graphic, or both graphic and plain English. Following a short interference task, the pilots were asked to recall as much of the weather information as possible. Results showed that pilots correctly recalled most information from the dual graphic and plain English display but this was largely attributable to the additional time required to process the 2 displays. Although the fo...

The objectives of this study were to assess the effects of differing formats of forward-looking primary flight display (PFD; electronic attitude-direction indicator, full-color terrain, uniformly brown terrain) on general aviation (GA) pilot recoveries from unknown attitudes and to determine if recovery assistance embodied in the display could be useful. Total recovery times and control reversals were examined as indexes of performance for 40 GA pilots, and the recovery times were subjected to a comparative analysis using both a parametric difference analysis and an equivalence testing technique. Results suggest that for the specific conditions investigated, terrain-depicting PFDs supported performance that was equivalent to that observed with the standard attitude indicator. Equivalence testing is recommended for cases where it is desirable to determine if one device or system provides for performance that is equivalent to another.

Perspective flight-path displays allow pilots to accurately follow complex curved approach trajectories. The current practice to define the tunnel reference trajectory as a concatenation of straight and circular segments, however, leads to difficult transition maneuvers between these segments, strongly contributing to pilot workload. To achieve a smooth interception, clothoid transition paths can be inserted between the straight and circular sections. A clothoid function defines a trajectory curvature that changes from 0 (a straight trajectory) to the desired curvature (the circular trajectory) in a certain amount of space traveled. Because the reference path better matches the natural aircraft response, the clothoid transients are hypothesized to make the task of flying complex curved approaches easier. A pilot-in-the-loop experiment, conducted in a fixed-base flight simulator, confirms this hypothesis and shows that clothoid-augmented trajectories yield improved path-following performance, requ...

Cognitive complexity is a term that appears frequently in air traffic control research literature, yet there is little principled investigation of the potential sources of cognitive complexity. Three distinctly different sources of cognitive complexity are proposed: environmental, organizational, and display. Two experiments were conducted to explore whether these proposed components of complexity could be effectively partitioned, measured, and compared. The findings demonstrate that sources of complexity can be decomposed and measured and furthermore, the use of color in displays, a display design intervention meant to reduce environmental complexity, can actually contribute to it. Language: en

Cockpit displays of traffic information are designed to support pilots' abilities to perform conflict detection and resolution tasks. Three experiments investigated the effects of display dimensionality, conflict geometry, and time pressure of in-flight conflicts on performance. The results indicated that interactive viewpoints in 2 3-D displays eliminated ambiguity costs, resulting in performance on both tasks comparable to a 2-D coplanar display. Viewpoint interactivity in the 3-D displays was vulnerable to increased workload, although corresponding performance was no worse than the 2-D coplanar. All 3 display formats showed performance decrements for nonlevel conflict geometries and increased time pressure. Language: en

An operational evaluation of the automatic dependent surveillance system and cockpit display of traffic information (CDTI) provided an opportunity to examine how pilot use of CDTI enabled them to maintain predefined spacing intervals from other aircraft. Seventy percent of the controller -issued traffic calls resulted in positive visual acquisitions (83% displayed on CDTI). Approximately 55% of the approach clearances that included instructions to "follow that traffic" involved communication problems and operational concerns. In light of the findings and the participants' comments, changes to proposed procedures and supporting phraseology will be constructed and evaluated for the approach spacing application.

One of the most difficult aspects of manually controlled flight is the coupling between the control over the aircraft speed and altitude. These states cannot be changed independent of each other through the aircraft control devices, the elevator and the throttle. Rather, to effectively change an aircraft's speed and altitude, the controls have to be coordinated. The mediating mechanism that underlies the coordination of the controls is the management of the aircraft's energy state. This article shows that the abstraction hierarchy (AH; Rasmussen, 1986) framework can be effectively used to gain more insight into the underlying structure of the aircraft energy management problem. The derived AH representation is based on the analysis of the energy constraints on the control task. It reveals the levels of abstraction necessary to link the aircraft's physical controls to the speed and altitude goals and also how the aircraft energy is a critical mediating state of the control problem. Energy awareness can be ...

In 3 experiments, we examined maneuver choice, flight safety, and mental workload across 3-dimensional (3D) perspective and 2-dimensional coplanar cockpit displays of traffic information in a free-flight simulation. In Experiment 1 (30 pilots), we examined dimensionality issues; in Experiments 2 and 3 (18 pilots each), we examined the effects of traffic density, dimensionality, and vertical profile orientation. Collectively, these data may be modeled by trade-offs between the display types: The coplanar suite suffers from scanning-related integration that increases with conflict density; the 3D display suffers from perceptual ambiguity. This research informs our understanding of how displays modulate performance in free-flight environments.

An operational evaluation of the automatic dependent surveillance system and cockpit display of traffic information (CDTI) was performed in October 2000. It provided an opportunity to examine how the use of a CDTI influences pilot/controller operational communications. Departure profiles were established to evaluate the ability of flight crews and air traffic controllers to manage long (6 nautical miles [nm]) and short (4.5 nm) spacing intervals between departing aircraft. Approximately 4% of the departures conducted when CDTI was not used and 9% when it was involved communication problems. Fortunately, controllers and pilots detected and corrected these problems in midstream. When pilots executed CDTI departures, there was an overall increase in time on frequency, more time spent under local control during the day, and departures were completed in less time when assigned the short spacing interval.

Synthetic vision information systems (SVIS) are the next generation of cockpit display systems that will become an integral part of the commercial flight deck in the future. The goal of this study was to evaluate SVIS against conventional glass cockpit displays to assess whether or not SVIS can improve pilot performance, situation awareness (SA), and workload. The evaluation was conducted in a fixed-base laboratory flight simulator located in the Operator Performance Laboratory at the University of Iowa. A total of 12 pilot evaluators hand-flew fairly difficult approaches into the Eagle County, Colorado, airport. Specially designed questionnaires were used in various phases of the flights to estimate workload, SA, and user preference. Information relating to SA was collected using the Situation Awareness Global Assessment Technique and workload estimates were obtained using the NASA Task Loading Index technique. Eye movement data were collected using a modified IScan ETL 500 system, and analyzed to find a...

Visual displays often employ the onset or flashing of an element to notify users of important events. Recent research findings and operational experiences in data-rich, event-driven domains, such as aviation, suggest that this design approach, which was supported by findings from early basic research on attention capture, is not always successful. The goal of this study was to examine how display context affects the effectiveness of abrupt onset signals. Participants in this study performed an externally paced visual task while trying to detect abrupt-onset stimuli, which were presented against 5 different display backgrounds and at 2 different eccentricities. The display background varied in terms of its dynamics and its color similarity to the target. Color similarity, the movement of background elements, and increasing target eccentricity resulted in reduced detection performance. The findings from this study help explain why pilots on modern flight decks sometimes miss changes in the status and behavi...

The retrofit question concerns whether useful and effective synthetic vision displays are usable in aircraft that have limited-size display spaces. Two experiments were conducted to examine the efficacy of these displays and develop field-of-view and terrain texture recommendations for design. The first experiment examined issues of field of view and display size using an Asheville, North Carolina, synthetic vision database and fixed-based simulator. The second experiment was conducted on the NASA B-757 aircraft at Dallas/Fort Worth International Airport and investigated the efficacy of both head-down and head-up displays and generic and photorealistic terrain texture. Both experiments confirmed the retrofit capability and that all sizes and texturing methods were found to be viable candidates for synthetic vision displays. These results, future directions, and implications for meeting national aeronautic safety and capacity goals are discussed.

The aviation community is interested in how use of cockpit displays of traffic information (CDTI) may enable pilots to acquire, identify, verify, and maintain predefined spacing intervals from other aircraft and influence air traffic control (ATC)-pilot communication and workload. In July 1999, as part of an operational evaluation, pilots flew 67 airport traffic patterns (20 CDTI not in use, 47 CDTI in use). Routine ATC procedures were retained. Pilots were trained to augment responses to ATC traffic calls with traffic call signs. An analysis of 1,127 pilot-controller messages revealed CDTI increased collaboration, reduced frequency congestion, resulted in more responsive pilot reports, and increased visual acquisitions. However, 4% of the traffic-related messages contained problems stemming from the call sign procedure. In light of the findings, the call sign procedure is undergoing modification and reevaluation before implementation.

The effectiveness of three different data link interfaces, involving auditory, visual, and redundant presentation of Air Traffic Control (ATC) information, was evaluated in a single pilot general aviation simulator. Fifteen certified flight instructor pilots flew a Frasca flight simulator with full visual display of the outside world, through a series of ATC-instructed maneuvers, while scanning outside for traffic. ATC instructions, of various lengths, were delivered through a text based data link display, through synthesized voice (similar to the current system), or through a redundant voice-text format. Pilots read back the instructions and then complied with whatever maneuver was instructed, while monitoring for traffic. Visual scanning was measured. The results revealed that the visual display provided greatest accuracy of communications readback, and was least disruptive of both traffic monitoring and flight path tracking. The auditory-only condition was most disruptive of these tasks, in part becaus...

Ergavionic principles governing the design and operation of an airplane cockpit were discovered through simulator and flight experiments starting during World War II and continuing through the 1970s, but their systematic application has not happened. These principles deal with control location and operation, display integration and pictorial realism, and control/display direction-of-motion relationships. Systematic application of these principles would make the job of flying an airplane so much easier and safer that hundreds of lives would be saved every year, and in the decades to come, thousands of lives.

The Human Effectiveness Directorate of the Air Force Research Laboratory is developing and evaluating human-machine interface concepts to enhance overall weapon system performance by embedding knowledge of the operator's state inside the interface, enabling the interface to make informed, automated decisions regarding many of the interface's information management display characteristics. Some of these characteristics include information modality, spatial arrangement, and temporal organization. By increasing the ability of the interface to respond, or adapt, to the changing requirements of the human operator in real time-in essence closing the loop-the interface provides intuitive information management to the operator and provides real-time human engineering.

The overall goal for the design of complex sociotechnical systems is to maintain human-machine system performance. One advanced interface design concept that attempts to do so is the dynamically adaptive interface (DAI). DAI is a computer interface that changes the display or control characteristics of the system, or both, in real time. The goal of DAI is to anticipate informational needs or desires of the user and provide that information without the requirement of an explicit control input by the user. This article explores both theoretical and practical issues in the design of DAIs. The relation of the DAI concept to decision aiding and automation is discussed, and a theoretical framework for design is outlined. A preliminary investigation of the DAI design concept was conducted in the domain of aviation (precision, low-level navigation). Nontraditional controls, such as a force reflecting stick, and displays, such as a configural flight director, were developed to support performance at the task. A standard interface, with conventional controls and displays, a candidate interface, with alternative controls and displays, and an adaptive interface, dynamically alternating between the standard and candidate displays, were evaluated. The results indicate that significant performance advantages in the quality of route navigation were obtained with the candidate adaptive interfaces relative to the standard interface. There were no significant differences between the candidate and adaptive interfaces. The implications of these results are discussed, with special emphasis on their relation to fundamental challenges that must be met for the DAI concept to be a viable design alternative.

This study compared the effect of alternative graphic or numeric vertical navigation aircraft cockpit displays on horizontal and vertical flight technical error, workload, and subjective preference. Displays included (a) a moving map with altitude range arc; (b) the same format, supplemented with a push-to-see profile view, including a vector flight-path predictor; (c) an equivalent numeric display; and (d) a numeric nonvertical navigation display. Sixteen pilots each flew 4 different approaches with each format in a Frasca 242 simulator. Our vertical navigation displays reduced vertical flight technical error by as much as a factor of 2 without increasing workload. Relative advantages of the graphics formats are discussed.

Thirty-six participants were tested in a flight simulator on their ability to decide which of two airports was furthest from a storm front, based on the manner in which information was presented on a navigational display. Results indicated that use of a moving-map display was superior to either a tabular, text-only display or a text display with an additional orienting symbol. In addition, in contrast to an earlier study (Williams, 1999), pilots performed better using a north-up map than when using a track-up map. Discussion of the results focuses on recommendations for moving-map displays and the display requirements for support of the nearest-airport function within a navigational display in particular.

Three prototype displays are contrasted for aircraft navigation and tactical hazard awareness: a conventional 2-D coplanar display, an exocentric (God's eye) 3-D display, and an immersed (pilot's eye) 3-D display coupled with a small scale global display. Strengths and weaknesses of each display type are discussed, related particularly to the ambiguity of perspective displays and to attention allocation problems with dual-display suites. In Experiment 1, 8 pilots flew with each of the displays around an airspace populated by waypoints, hazards, and traffic. Performance measures revealed the anticipated costs and benefits of each display type. In Experiment 2, cognitive engineering techniques of performance and cognitive task analysis were applied to remediate the weaknesses of each display type. Emphasis was placed on display enhancements to resolve 3-D ambiguity and visual momentum and cueing techniques to facilitate attention allocation and switching. Analysis of performance of 27 additional participant...

Modern aerial combat represents a highly complex task domain that imposes many significant challenges on aviators. In modern cockpits there are more sources of dynamic information than any single pilot has the ability to attend to, let alone comprehend, all at once. As technological developments lead to the deployment of new weapons systems, the future aerial battlefield will inevitably yield increased levels of complexity. A significant challenge for cockpit designers is to devise pilot-vehicle interfaces that take full advantage of the parallel information extraction capabilities of humans through the use of integrated multisensory displays. This article describes an approach to multisensory display development that uses human performance evaluations as a design tool, and concludes with a description of a multisensory crew station designed by an interdisciplinary team.

In a variety of domains, automation technology has evolved from passive tools to highly autonomous agents that can initiate actions independent of user input and without explicit operator consent. This evolution brings with it an increased need for effective human-automation communication and coordination to ensure that both agents stay informed about each others' goals, activities, and limitations. Yet, most modern systems are not equipped with the skills required to contribute effectively and in a timely manner to the exchange of information on commitments and actions. In particular, systems fail to provide external attentional guidance to their operators in the case of uncommanded changes and events, which can lead to automation surprises and, sometimes, incidents and accidents. To a large extent, these problems can be explained by designers' increasing reliance on automation feedback that requires focal visual attention. This article explores the potential of multisensory displays to better support at...

A simulation study was performed to evaluate helmet-mounted display symbology for fighter aircraft ground collision avoidance systems. Four visual alert symbologies were tested: an iconic cue, an aircraft-fixed (AF) guidance cue, a head-fixed (HF) guidance cue, and an HF guidance cue with a pitch ladder. Participants were given audio and visual side tasks and responded to alerts in different aircraft attitudes. Shorter reaction times were observed when a HF visual alert was given in addition to the standard audio alert. No significant differences in recovery performance (measured by response time and altitude loss) were observed between display formats. However, the display format had a significant effect on participant head motion. With HF guidance cues, pilots were able to perform the recovery maneuver with their heads off axis; with AF guidance cues or no guidance cues, pilots consistently turned their heads to face forward before maneuvering the aircraft.

Thirty-six participants were tested on their ability to orient toward the nearest airport based on the manner in which information was presented on a global positioning system (GPS) area navigation display. Results indicated that use of the tabular, text-only format normally found on such displays was significantly slower and less accurate than either a map display of nearest airport information or a text display that included an orientation symbol. Additionally, pilots ignored information from the heading indicator, focusing on the GPS to perform the task. Discussion focuses on the need to support pilot decision making.

A major portion of the research conducted throughout the history of aviation psychology has been devoted to the analysis and design of cockpit displays. Military and commercial aviators, as well as the travelling public, have significantly benefited from many years of research that have produced displays that facilitate safe and effective crewmember performance. As Koonce (1984) pointed out, the human performance issues raised in the early days of aviation attracted the research attention of some of the most prominent experimental psychologists of the day. As we enter the 21st century, aviation psychology remains one of the most vital areas in applied psychological research, and the design of advanced cockpit displays still serves as a focal point for innovative research programs and paradigms.