An experiment has been done to study the effects on divided attention of visual shifts and long-t... more An experiment has been done to study the effects on divided attention of visual shifts and long-term memory retrieval during a monitoring task. A concurrent vigilance task was standardized under all experimental conditions. The results show that subjects can perform nearly perfectly on all of the time-shared tasks if long-term memory retrieval is not required for monitoring. With the requirement of memory retrieval, however, there was a large decrease in accuracy for all of the timeshared activities. It was concluded that the attentional demand of longterm memory retrieval is appreciable (even for a well-learned motor sequence), and thus memory retrieval results in a sizable reduction in the capability of subjects to divide their attention. Also, a selected bibliography on the divided attention literature is provided.
Subjective estimates of the threat posed by a ;jingle intruder aircraft were determined by showin... more Subjective estimates of the threat posed by a ;jingle intruder aircraft were determined by showing pilots photographs of a cockpit display of traffic information. The time the intruder was away from the point of minimum separation was found to be the major determinant of the Perception of threat. When asked to choose a maneuver to reduce the conflict, pilooL, selected maneuvers with a bias toward those that would have kept the intruders in sipbt had they been visible out the cockpit window.
This paper focuses on the application of data link for communication between air traffic manageme... more This paper focuses on the application of data link for communication between air traffic management and FMSequipped aircraft. Based on requirements and guidelines for data link usage, a general philosophy for automated data exchange and the distribution of tasks between the human operators and the automation is presented. Many different areas are affected by the introduction of data link, including the role of the flight crew and the controllers as well as procedures and training requirements. In particular, the design of a flight crew interface providing for the necessary flight crew support is a crucial factor for data link efficiency. This paper introduces a concept addressing these areas and concludes with an outlook to upcoming experiments at NASA’s research facilities that are aimed at validating the proposed concept. Ultimately, safety and cost-effectiveness of the air transport system should be significantly improved by exploiting the capabilities of automation tools like CT...
This paper focuses on the application of data link for communication between air traffic manageme... more This paper focuses on the application of data link for communication between air traffic management and FMSequipped aircraft. Based on requirements and guidelines for data link usage, a general philosophy for automated data exchange and the distribution of tasks between the human operators and the automation is presented. Many different areas are affected by the introduction of data link, including the role of the flight crew and the controllers as well as procedures and training requirements. In particular, the design of a flight crew interface providing for the necessary flight crew support is a crucial factor for data link efficiency. This paper introduces a concept addressing these areas and concludes with an outlook to upcoming experiments at NASA's research facilities that are aimed at validating the proposed concept. Ultimately, safety and cost-effectiveness of the air transport system should be significantly improved by exploiting the capabilities of automation tools like CTAS on the ground and the FMS in the aircraft through the utilization of digital data connections.
This study investigated how pilots resolved potential conflicts in the horizontal plane when the ... more This study investigated how pilots resolved potential conflicts in the horizontal plane when the only information available on the other aircraft was presented on a Cockpit Display of Traffic Information (CDTI). The intruder aircraft appeared on the CDTI with various programmed minimum miss distances, times ho minimum miss distance, crossing angles, velocities, and turn rates. The pilot's task was to assess the situation and if necessary maneuver so as to avoid the other aircraft. No instructions were given on evasive strategy or on what was considered to be an acceptable minimum separation. The results indicate that pilots had a strong bias of turning toward the intruder aircraft in ordez to pass behind it. In more than 50% of the encounters with a 90 degree crossing angle in which the intruder aircraft was programmed to pass either 2000 or 4000 feet behind ownship, the pilots maneuvered so as to pass behind the intruder. This bias was not as strong with the display which showed a prediction of the intruder's relative velocity. The average miss distance for all encounters was about 4500 feet. mane,_,er commands to the pilot to avert possible midair collisions. In this latter system, to reduce the number of false alarms, commands are not issued until an immediate evasive maneuver is required to prevent physical contact between two aircraft. More complex collision avoidance systems also include an electronic display very simillar to a CDTI. There are a number of potential advantages and disadvantages to presenting the pilot with situation information with a CDTI and command information with a CAS. The CDTI may interfere with the CAS by encouraging the pilot to assess th_ validity of alarms and commands and thereby exceed
IEEE Transactions on Systems, Man, and Cybernetics, 1978
A simulator study was undertaken to compare and evaluate the design features of the electronic di... more A simulator study was undertaken to compare and evaluate the design features of the electronic displays for possible use in V/STOL aircraft: a combined transition display (Display A), a perspective display (Display B), and a hover display (Display C). Display B presents height information via integrated elements; Displays A and C present information similarly except that Display C presents vertical and lateral guidance via conventional cross pointers. High pilot work load was attained by evaluating the displays only as situational guidance displays in a simulated vehicle without stability augmentation. Glide slopes of 6 and 15 deg were used, and steady-state and no-wind conditions were randomly presented. Six pilots participated, and fifty-five objective performance measures were taken along with pilot opinions
This cooperative agreement supported Dr. Peter Polson's participation in two interrelated researc... more This cooperative agreement supported Dr. Peter Polson's participation in two interrelated research programs. The first was the development of the Situation-Goal-Behavior (SGB) Model that is both a formal description of an avionics system's logic and behavior and a representation of a system that can be understood by avionics designers, pilots, and training developers. The second was the development of a usability inspection method (Nielsen and Mack, 1994) based on an approximate model, RAFIV, of pilot interactions with the Flight Management System (FMS). The main purpose of this report is to integrate the two models and provide a context in order to better characterize the accomplishments of this research program. A major focus of both the previous and this Cooperative Agreement was the development of usability evaluation methods that can be effectively utilized during all phases of the design, development, and certification process of modern avionics systems. The current efforts to validate these methods have involved showing that they generate useful analyses of known operational and training problems with the current generation of avionics systems in modern commercial airliners. This report is organized into seven sections. Following the overview, the second section describes the Goal-Situation-Behavior model and its applications. The next section summarizes the foundations of the RAFIV model and describes the model in some detail. The contents of both these sections are derived from previous reports referenced in footnotes. The fourth section integrates these two models into a complete design evaluation and training development framework. The fifth section contains conclusions and possible future directions for research. References are in Section 6. Section 7 contains the titles and abstracts of the papers paper describing in more detail the results of this research program.
A simulator study was conducted to determine the usefulness of adding flight path vector symbolog... more A simulator study was conducted to determine the usefulness of adding flight path vector symbology to a head-up display designed to improve glide-slope tracking performance during steep 7.5" visual approaches in STOL aircraft. All displays included a fixed attitude symbol, a pitch-and roll-stabilized horizon bar, and a glide-slope reference bar parallel to and 7.5" below the horizon bar. The displays differed with respect to the flight-path marker (FPM) symbol: display I had no FPM symbol; display I1 had an air-referenced FPM, and display I11 had a ground-referenced FPM. No differences between displays I and I1 were found on any of the performance measures. Display I11 was found to decrease height error in the early part of the approach and to reduce descent rate variation over the entire approach. Two measures of workload did not indicate any differences between the displays.
2005 International Symposium on Aviation Psychology, 2005
Controller workload, recognized as a significant bottleneck to capacity increase in the future Na... more Controller workload, recognized as a significant bottleneck to capacity increase in the future National Airspace System, has been researched extensively in air traffic management. Unfortunately, subjective workload has been an unreliable predictor of a controller's ability to safely manage the traffic, leading to attempts at replacing workload with more objective metrics, such as task load (e.g. number of clearances) and traffic density (e.g. aircraft count). A significant caveat to substituting these metrics for workload ratings, however, is that their relationships are nonlinear. More specifically, when the objective metrics, such as aircraft count, increase linearly, the controller's perceived workload remains low until the traffic and associated task load increase to a critical threshold. From this point, the workload increases at a much faster rate with each added task. In a series of informal studies conducted as a precursor to testing Distributed Air Ground Traffic Management (DAG-TM) concepts, researchers at NASA Ames Research Center manipulated aircraft count in real-time human-in-the-loop simulations to determine the maximum traffic levels at which the controllers stated that traffic would no longer be manageable. As hypothesized, traffic scenarios that elicited moderate levels of controller workload quickly became unmanageable when only a few aircraft were added. Feedback from the controllers further supported the non-linear nature of subjective workload. Task load data partially supported the above findings but the results were inconclusive due to individual differences and varying results from different task load metrics. The non-linear relationship between subjective workload and aircraft count has been further examined using data collected from the Free Maneuvering concept feasibility study in June 2004, which shows a step-function relationship between the two. The combined results suggest that any estimation on workload should not be extrapolated linearly from a set of workload measures taken from an experiment since the extrapolated workload is likely to significantly underestimate workload.
... Sheryl L. Chappell* Everett A. Palmer Tufts University NASA Arnes Research Center Medford, Ma... more ... Sheryl L. Chappell* Everett A. Palmer Tufts University NASA Arnes Research Center Medford, Mass. Moffett Field, Calif, Abstract ... Low Profile Descent Chart, Denver Colo., Plate No. 10-2, Dated 7/27/79. Jeppesen Sanderson Inc., Denver (1978). Page 5. ...
Simulated night visual approaches were flown into two airports with and without a head up display... more Simulated night visual approaches were flown into two airports with and without a head up display in a transport aircraft. The HUD featured pitch stabilized vertical scales which displayed the glide slope angle to the runway aim point and a horizontal bar which aided the pilot in his control of the aircraft flight path angle. One airport was located on flat terrain with numerous foreground lights, the second airport had no foreground lights and the terrain sloped up behind the airport. With the HUD glide slope tracking precision was equally good for either runway. With no HUD glide slope tracking was about three times worse with the flat airport and about eight times worse with the airport with no foreground lights and up-sloping terrain beyond the runway. Details of illusira&tionl ~s this document may be better gudap in anrthA
Situation and command head-up displays were evaluated for both standard and two segment noise aba... more Situation and command head-up displays were evaluated for both standard and two segment noise abatement night visual approaches in a fixed base simulation of a DC-8 transport aircraft. The situation display provided glide slope and pitch attitude information. The command display provided glide slope information and flight path commands to capture a 3 deg glide slope. Landing approaches were flown in both zero wind and wind shear conditions. For both standard and noise abatement approaches, the situation display provided greater glidepath accuracy in the initial phase of the landing approaches, whereas the command display was more effective in the final approach phase. Glidepath accuracy was greater for the standard approaches than for the noise abatement approaches in all phases of the landing approach. Most of the pilots preferred the command display and the standard approach. Substantial agreement was found between each pilot's judgment of his performance and his actual performance.
Proceedings of the Human Factors Society annual meeting, Oct 1, 1990
A s our aircraft cockpits become more complex, pilots are becoming overwhelmed by the vast amount... more A s our aircraft cockpits become more complex, pilots are becoming overwhelmed by the vast amount of information available. The following video will set the stage for this panel which will look at current research and advanced concepts associated with improving pilot-vehicle interface. Topics include pilot-vehicle interface, system design, prediction and decision aids, automation, error-tolerant systems, and task-oriented display design. Audience members will have an opportunity to ask questions and explore other associated areas of study.
Twelve airline pilots participated in a fixed-base simulator study to determine the effect of inc... more Twelve airline pilots participated in a fixed-base simulator study to determine the effect of increased pictorial display realism on the frequency of control reversals made with an inside-out landing display. Display conditions included the effects of collimation and scale (headup versus head-down presentation), horizon symbology (simple line versus white-black sky-ground surfaces), and ground plane realism (computer generated perspective versus a TV picture of a realistic model). The number of control reversals was moderately high on all displays. Control reversals to roll disturbances occurred nearly twice as frequently as reversals to either pitch or lateral rate disturbances. Though there were no significant differences among the numbers of small control reversals for the different displays, there was some evidence that this conclusion may not apply to large control reversals. Pilots who were prone to make control reversals made considerably more large control reversals when using the two displays which did not have the white-black sky-ground surfaces; however, due to the low occurrence of large reversals, this observation was not amenable to statistical test. Details of illustrations in this document may be better studied on microfiche
The concept of a cockpit display of traffic information (CDTI) includes the integration of air tr... more The concept of a cockpit display of traffic information (CDTI) includes the integration of air traffic, navigation, and other pertinent information in a single electronic display in the cockpit. Concise display symbology was developed for use in later full-mission simulator evaluations of the CDTI concept. Experimental variables used included the update interval motion of the aircraft, the update type, (that is, whether the two aircraft were updated at the same update interval or not), the background (grid pattern or no background), and encounter type (straight or curved). Only the type of encounter affected performance.
An experiment has been done to study the effects on divided attention of visual shifts and long-t... more An experiment has been done to study the effects on divided attention of visual shifts and long-term memory retrieval during a monitoring task. A concurrent vigilance task was standardized under all experimental conditions. The results show that subjects can perform nearly perfectly on all of the time-shared tasks if long-term memory retrieval is not required for monitoring. With the requirement of memory retrieval, however, there was a large decrease in accuracy for all of the timeshared activities. It was concluded that the attentional demand of longterm memory retrieval is appreciable (even for a well-learned motor sequence), and thus memory retrieval results in a sizable reduction in the capability of subjects to divide their attention. Also, a selected bibliography on the divided attention literature is provided.
Subjective estimates of the threat posed by a ;jingle intruder aircraft were determined by showin... more Subjective estimates of the threat posed by a ;jingle intruder aircraft were determined by showing pilots photographs of a cockpit display of traffic information. The time the intruder was away from the point of minimum separation was found to be the major determinant of the Perception of threat. When asked to choose a maneuver to reduce the conflict, pilooL, selected maneuvers with a bias toward those that would have kept the intruders in sipbt had they been visible out the cockpit window.
This paper focuses on the application of data link for communication between air traffic manageme... more This paper focuses on the application of data link for communication between air traffic management and FMSequipped aircraft. Based on requirements and guidelines for data link usage, a general philosophy for automated data exchange and the distribution of tasks between the human operators and the automation is presented. Many different areas are affected by the introduction of data link, including the role of the flight crew and the controllers as well as procedures and training requirements. In particular, the design of a flight crew interface providing for the necessary flight crew support is a crucial factor for data link efficiency. This paper introduces a concept addressing these areas and concludes with an outlook to upcoming experiments at NASA’s research facilities that are aimed at validating the proposed concept. Ultimately, safety and cost-effectiveness of the air transport system should be significantly improved by exploiting the capabilities of automation tools like CT...
This paper focuses on the application of data link for communication between air traffic manageme... more This paper focuses on the application of data link for communication between air traffic management and FMSequipped aircraft. Based on requirements and guidelines for data link usage, a general philosophy for automated data exchange and the distribution of tasks between the human operators and the automation is presented. Many different areas are affected by the introduction of data link, including the role of the flight crew and the controllers as well as procedures and training requirements. In particular, the design of a flight crew interface providing for the necessary flight crew support is a crucial factor for data link efficiency. This paper introduces a concept addressing these areas and concludes with an outlook to upcoming experiments at NASA's research facilities that are aimed at validating the proposed concept. Ultimately, safety and cost-effectiveness of the air transport system should be significantly improved by exploiting the capabilities of automation tools like CTAS on the ground and the FMS in the aircraft through the utilization of digital data connections.
This study investigated how pilots resolved potential conflicts in the horizontal plane when the ... more This study investigated how pilots resolved potential conflicts in the horizontal plane when the only information available on the other aircraft was presented on a Cockpit Display of Traffic Information (CDTI). The intruder aircraft appeared on the CDTI with various programmed minimum miss distances, times ho minimum miss distance, crossing angles, velocities, and turn rates. The pilot's task was to assess the situation and if necessary maneuver so as to avoid the other aircraft. No instructions were given on evasive strategy or on what was considered to be an acceptable minimum separation. The results indicate that pilots had a strong bias of turning toward the intruder aircraft in ordez to pass behind it. In more than 50% of the encounters with a 90 degree crossing angle in which the intruder aircraft was programmed to pass either 2000 or 4000 feet behind ownship, the pilots maneuvered so as to pass behind the intruder. This bias was not as strong with the display which showed a prediction of the intruder's relative velocity. The average miss distance for all encounters was about 4500 feet. mane,_,er commands to the pilot to avert possible midair collisions. In this latter system, to reduce the number of false alarms, commands are not issued until an immediate evasive maneuver is required to prevent physical contact between two aircraft. More complex collision avoidance systems also include an electronic display very simillar to a CDTI. There are a number of potential advantages and disadvantages to presenting the pilot with situation information with a CDTI and command information with a CAS. The CDTI may interfere with the CAS by encouraging the pilot to assess th_ validity of alarms and commands and thereby exceed
IEEE Transactions on Systems, Man, and Cybernetics, 1978
A simulator study was undertaken to compare and evaluate the design features of the electronic di... more A simulator study was undertaken to compare and evaluate the design features of the electronic displays for possible use in V/STOL aircraft: a combined transition display (Display A), a perspective display (Display B), and a hover display (Display C). Display B presents height information via integrated elements; Displays A and C present information similarly except that Display C presents vertical and lateral guidance via conventional cross pointers. High pilot work load was attained by evaluating the displays only as situational guidance displays in a simulated vehicle without stability augmentation. Glide slopes of 6 and 15 deg were used, and steady-state and no-wind conditions were randomly presented. Six pilots participated, and fifty-five objective performance measures were taken along with pilot opinions
This cooperative agreement supported Dr. Peter Polson's participation in two interrelated researc... more This cooperative agreement supported Dr. Peter Polson's participation in two interrelated research programs. The first was the development of the Situation-Goal-Behavior (SGB) Model that is both a formal description of an avionics system's logic and behavior and a representation of a system that can be understood by avionics designers, pilots, and training developers. The second was the development of a usability inspection method (Nielsen and Mack, 1994) based on an approximate model, RAFIV, of pilot interactions with the Flight Management System (FMS). The main purpose of this report is to integrate the two models and provide a context in order to better characterize the accomplishments of this research program. A major focus of both the previous and this Cooperative Agreement was the development of usability evaluation methods that can be effectively utilized during all phases of the design, development, and certification process of modern avionics systems. The current efforts to validate these methods have involved showing that they generate useful analyses of known operational and training problems with the current generation of avionics systems in modern commercial airliners. This report is organized into seven sections. Following the overview, the second section describes the Goal-Situation-Behavior model and its applications. The next section summarizes the foundations of the RAFIV model and describes the model in some detail. The contents of both these sections are derived from previous reports referenced in footnotes. The fourth section integrates these two models into a complete design evaluation and training development framework. The fifth section contains conclusions and possible future directions for research. References are in Section 6. Section 7 contains the titles and abstracts of the papers paper describing in more detail the results of this research program.
A simulator study was conducted to determine the usefulness of adding flight path vector symbolog... more A simulator study was conducted to determine the usefulness of adding flight path vector symbology to a head-up display designed to improve glide-slope tracking performance during steep 7.5" visual approaches in STOL aircraft. All displays included a fixed attitude symbol, a pitch-and roll-stabilized horizon bar, and a glide-slope reference bar parallel to and 7.5" below the horizon bar. The displays differed with respect to the flight-path marker (FPM) symbol: display I had no FPM symbol; display I1 had an air-referenced FPM, and display I11 had a ground-referenced FPM. No differences between displays I and I1 were found on any of the performance measures. Display I11 was found to decrease height error in the early part of the approach and to reduce descent rate variation over the entire approach. Two measures of workload did not indicate any differences between the displays.
2005 International Symposium on Aviation Psychology, 2005
Controller workload, recognized as a significant bottleneck to capacity increase in the future Na... more Controller workload, recognized as a significant bottleneck to capacity increase in the future National Airspace System, has been researched extensively in air traffic management. Unfortunately, subjective workload has been an unreliable predictor of a controller's ability to safely manage the traffic, leading to attempts at replacing workload with more objective metrics, such as task load (e.g. number of clearances) and traffic density (e.g. aircraft count). A significant caveat to substituting these metrics for workload ratings, however, is that their relationships are nonlinear. More specifically, when the objective metrics, such as aircraft count, increase linearly, the controller's perceived workload remains low until the traffic and associated task load increase to a critical threshold. From this point, the workload increases at a much faster rate with each added task. In a series of informal studies conducted as a precursor to testing Distributed Air Ground Traffic Management (DAG-TM) concepts, researchers at NASA Ames Research Center manipulated aircraft count in real-time human-in-the-loop simulations to determine the maximum traffic levels at which the controllers stated that traffic would no longer be manageable. As hypothesized, traffic scenarios that elicited moderate levels of controller workload quickly became unmanageable when only a few aircraft were added. Feedback from the controllers further supported the non-linear nature of subjective workload. Task load data partially supported the above findings but the results were inconclusive due to individual differences and varying results from different task load metrics. The non-linear relationship between subjective workload and aircraft count has been further examined using data collected from the Free Maneuvering concept feasibility study in June 2004, which shows a step-function relationship between the two. The combined results suggest that any estimation on workload should not be extrapolated linearly from a set of workload measures taken from an experiment since the extrapolated workload is likely to significantly underestimate workload.
... Sheryl L. Chappell* Everett A. Palmer Tufts University NASA Arnes Research Center Medford, Ma... more ... Sheryl L. Chappell* Everett A. Palmer Tufts University NASA Arnes Research Center Medford, Mass. Moffett Field, Calif, Abstract ... Low Profile Descent Chart, Denver Colo., Plate No. 10-2, Dated 7/27/79. Jeppesen Sanderson Inc., Denver (1978). Page 5. ...
Simulated night visual approaches were flown into two airports with and without a head up display... more Simulated night visual approaches were flown into two airports with and without a head up display in a transport aircraft. The HUD featured pitch stabilized vertical scales which displayed the glide slope angle to the runway aim point and a horizontal bar which aided the pilot in his control of the aircraft flight path angle. One airport was located on flat terrain with numerous foreground lights, the second airport had no foreground lights and the terrain sloped up behind the airport. With the HUD glide slope tracking precision was equally good for either runway. With no HUD glide slope tracking was about three times worse with the flat airport and about eight times worse with the airport with no foreground lights and up-sloping terrain beyond the runway. Details of illusira&tionl ~s this document may be better gudap in anrthA
Situation and command head-up displays were evaluated for both standard and two segment noise aba... more Situation and command head-up displays were evaluated for both standard and two segment noise abatement night visual approaches in a fixed base simulation of a DC-8 transport aircraft. The situation display provided glide slope and pitch attitude information. The command display provided glide slope information and flight path commands to capture a 3 deg glide slope. Landing approaches were flown in both zero wind and wind shear conditions. For both standard and noise abatement approaches, the situation display provided greater glidepath accuracy in the initial phase of the landing approaches, whereas the command display was more effective in the final approach phase. Glidepath accuracy was greater for the standard approaches than for the noise abatement approaches in all phases of the landing approach. Most of the pilots preferred the command display and the standard approach. Substantial agreement was found between each pilot's judgment of his performance and his actual performance.
Proceedings of the Human Factors Society annual meeting, Oct 1, 1990
A s our aircraft cockpits become more complex, pilots are becoming overwhelmed by the vast amount... more A s our aircraft cockpits become more complex, pilots are becoming overwhelmed by the vast amount of information available. The following video will set the stage for this panel which will look at current research and advanced concepts associated with improving pilot-vehicle interface. Topics include pilot-vehicle interface, system design, prediction and decision aids, automation, error-tolerant systems, and task-oriented display design. Audience members will have an opportunity to ask questions and explore other associated areas of study.
Twelve airline pilots participated in a fixed-base simulator study to determine the effect of inc... more Twelve airline pilots participated in a fixed-base simulator study to determine the effect of increased pictorial display realism on the frequency of control reversals made with an inside-out landing display. Display conditions included the effects of collimation and scale (headup versus head-down presentation), horizon symbology (simple line versus white-black sky-ground surfaces), and ground plane realism (computer generated perspective versus a TV picture of a realistic model). The number of control reversals was moderately high on all displays. Control reversals to roll disturbances occurred nearly twice as frequently as reversals to either pitch or lateral rate disturbances. Though there were no significant differences among the numbers of small control reversals for the different displays, there was some evidence that this conclusion may not apply to large control reversals. Pilots who were prone to make control reversals made considerably more large control reversals when using the two displays which did not have the white-black sky-ground surfaces; however, due to the low occurrence of large reversals, this observation was not amenable to statistical test. Details of illustrations in this document may be better studied on microfiche
The concept of a cockpit display of traffic information (CDTI) includes the integration of air tr... more The concept of a cockpit display of traffic information (CDTI) includes the integration of air traffic, navigation, and other pertinent information in a single electronic display in the cockpit. Concise display symbology was developed for use in later full-mission simulator evaluations of the CDTI concept. Experimental variables used included the update interval motion of the aircraft, the update type, (that is, whether the two aircraft were updated at the same update interval or not), the background (grid pattern or no background), and encounter type (straight or curved). Only the type of encounter affected performance.
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Papers by Everett Palmer