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At least 487 records · Page 27

The influence of ATC message length and timing on pilot communication

Pilot-controller communication is critical to safe and efficient flight. It is often a challenging component of piloting, which is reflected in the number of incidents and accidents involving miscommunication. Our previous field study identified communication problems that disrupt routine communication between pilots and controllers. The present part-task simulation study followed up the field results with a more controlled investigation of communication problems. Pilots flew a simulation in which they were frequently vectored by Air Traffic Control (ATC), requiring intensive communication with the controller. While flying, pilots also performed a secondary visual monitoring task. We examined the influence of message length (one message with four commands vs. two messages with two commands each) and noncommunication workload on communication accuracy and length. Longer ATC messages appeared to overload pilot working memory, resulting in more incorrect or partial readbacks, as well as more requests to repeat the message. The timing between the two short messages also influenced communication. The second message interfered with memory for or response to the first short message when it was delivered too soon after the first message. Performing the secondary monitoring task did not influence communication. Instead, communication reduced monitoring accuracy.

Morrow, Daniel↗

Contextual specificity in perception and action

The visually guided control of helicopter flight is a human achievement, and, thus, understanding this skill is, in part, a psychological problem. The abilities of skilled pilots are impressive, and yet it is of concern that pilots' performance is less than ideal: they suffer from workload constraints, make occasional errors, and are subject to such debilities as simulator sickness. Remedying such deficiencies is both an engineering and a psychological problem. When studying the psychological aspects of this problem, it is desirable to simplify the problem as much as possible, and thereby, sidestep as many intractable psychological issues as possible. Simply stated, we do not want to have to resolve such polemics as the mind-body problem in order to contribute to the design of more effective helicopter systems. On the other hand, the study of human behavior is a psychological endeavor and certain problems cannot be evaded. Four related issues that are of psychological significance in understanding the visually guided control of helicopter flight are discussed. First, a selected discussion of the nature of descriptive levels in analyzing human perception and performance is presented. It is argued that the appropriate level of description for perception is kinematical, and for performance, it is procedural. Second, it is argued that investigations into pilot performance cannot ignore the nature of pilots' phenomenal experience. The conscious control of actions is not based upon environmental states of affairs, nor upon the optical information that specifies them. Actions are coupled to perceptions. Third, the acquisition of skilled actions in the context of inherent misperceptions is discussed. Such skills may be error prone in some situations, but not in others. Finally, I discuss the contextual relativity of human errors. Each of these four issues relates to a common theme: the control of action is mediated by phenomenal experience, the veracity of which is context specific.

Proffitt, Dennis R.↗

A Comparison of Active Sidestick and Conventional Inceptors for Helicopter Flight Envelope Tactile Cueing

This paper will compare the results of two ground-based piloted simulation studies of helicopter flight envelope tactile cueing. The objective of these trials was to develop methods of assisting the pilot in respecting flight envelope limits in a high workload environment. Both trials looked at the same aggressive hover and forward-flight tasks, the difference being that in the first trial, large-displacement programmable force-feel inceptors were used while in the second programmable short active sidesticks were used.

Whalley, Matthew S.↗

Orion Handling Qualities During ISS Proximity Operations and Docking

NASA's Orion spacecraft is designed to autonomously rendezvous and dock with many vehicles including the International Space Station. However, the crew is able to assume manual control of the vehicle s attitude and flight path. In these instances, Orion must meet handling qualities requirements established by NASA. Two handling qualities assessments were conducted at the Johnson Space Center to evaluate preliminary designs of the vehicle using a six degree of freedom, high-fidelity guidance, navigation, and control simulation. The first assessed Orion s handling qualities during the last 20 ft before docking, and included both steady and oscillatory motions of the docking target. The second focused on manual acquisition of the docking axis during the proximity operations phase and subsequent station-keeping. Cooper-Harper handling qualities ratings, workload ratings and comments were provided by 10 evaluation pilots for the docking study and 5 evaluation pilots for the proximity operations study. For the docking task, both cases received 90% Level 1 (satisfactory) handling qualities ratings, exceeding NASA s requirement. All ratings for the ProxOps task were Level 1. These evaluations indicate that Orion is on course to meet NASA's handling quality requirements for ProxOps and docking.

Stephens, John-Paul↗

Extending Validated Human Performance Models to Explore NextGen Concepts

To meet the expected increases in air traffic demands, NASA and FAA are researching and developing Next Generation Air Transportation System (NextGen) concepts. NextGen will require substantial increases in the data available to pilots on the flight deck (e.g., weather,wake, traffic trajectory predictions, etc.) to support more precise and closely coordinated operations (e.g., self-separation, RNAV/RNP, and closely spaced parallel operations, CSPOs). These NextGen procedures and operations, along with the pilot's roles and responsibilities, must be designed with consideration of the pilot's capabilities and limitations. Failure to do so will leave the pilots, and thus the entire aviation system, vulnerable to error. A validated Man-machine Integration and design Analysis System (MIDAS) v5 model was extended to evaluate anticipated changes to flight deck and controller roles and responsibilities in NextGen approach and Land operations. Compared to conditions when the controllers are responsible for separation on decent to land phase of flight, the output from these model predictions suggest that the flight deck response time to detect the lead aircraft blunder will decrease, pilot scans to the navigation display will increase, and workload will increase.

Gore, Brian Francis↗

Development and Evaluation of the Active Response Gravity Offload System as a Lunar and Martian EVA Simulation Environment

In preparation for future exploration missions, NASA seeks the ability to simulate partial-gravity operations for use in ground-based research, crew training, and engineering design evaluations. The Active Response Gravity Offload System (ARGOS) at the Johnson Space Center (JSC) is designed to simulate reduced gravity environments, such as lunar, Martian, or microgravity, using a robotic system similar to an overhead bridge crane. ARGOS continuously offloads a portion of a suited human’s weight during all dynamic motions within the test facility, which can include basic functional movements such as walking, running, and jumping, as well as a wide range of planetary surface activities. This system will be used as part of a metabolic-rate task characterization study to determine the workload associated with partial-gravity extravehicular activity (EVA). Pilot testing was conducted using the MKIII prototype planetary space suit and two gimbal designs to determine the ability of the ARGOS test environment to simulate planetary EVA operations. This paper will describe the lessons learned from the feasibility testing, simulation-environment mockup design, and the results from the pilot tests and their influence into the final study design. Being able to effectively simulate partial-gravity environments and characterize the performance of crewmembers will have an impact on multiple domains including suit design, task design, thermal models, and life-support-system capacity verification plans, among others.

Omar S Bekdash↗

Crew Autonomy through Self-Scheduling: Scheduling Performance Pilot Study

Within the domain of human spaceflight, crew scheduling for International Space Station (ISS) remains a human-driven planning task. Large teams of flight controllers (called Ops Planners) spend weeks creating violation-free schedules for all crewmembers. As NASA considers long-duration exploration missions, the necessary shift of scheduling and planning management from Ops Planners to crew members requires significant research and investigation of crew performance to complete these scheduling tasks. This pilot study was conducted to evaluate non-expert human performance for the task of planning and scheduling, focusing on scheduling problems that increased in complexity based on the number of activities to be scheduled and the number of planning constraints. Nine non-expert planners were recruited to complete scheduling tasks using Playbook, a scheduling software. The results of this pilot study show that scheduling performance decreased as scheduling workload (i.e. number of activities and percent of activities with planning constraints) increased. This paper provides evidence towards developing a model for scheduling task difficulty and identifies potential implications for future automated aids for flight crew scheduling.

planning↗

Crew Autonomy Through Self-Scheduling: Scheduling Performance Pilot Study

Within the domain of human spaceflight, crew scheduling for International Space Station (ISS) remains a human-driven planning task. Large teams of flight controllers (called Ops Planners) spend weeks creating violation-free schedules for all crewmembers. As NASA considers long-duration exploration missions, the necessary shift of scheduling and planning management from Ops Planners to crew members requires significant research and investigation of crew performance to complete these scheduling tasks. This pilot study was conducted to evaluate non-expert human performance for the task of planning and scheduling, focusing on scheduling problems that increased in complexity based on the number of activities to be scheduled and the number of planning constraints. Nine non-expert planners were recruited to complete scheduling tasks using Playbook, a scheduling software. The results of this pilot study show that scheduling performance decreased as scheduling workload (i.e. number of activities and percent of activities with planning constraints) increased. This paper provides evidence towards developing a model for scheduling task difficulty and identifies potential implications for future automated aids for flight crew scheduling.

planning↗

Cognitive and affective components of mental workload: Understanding the effects of each on human decision making behavior

Human factors and ergonomics researchers have recognized for some time the increasing importance of understanding the role of the construct of mental workload in flight research. Current models of mental workload suggest that it is a multidimensional and complex construct, but one that has proved difficult to measure. Because of this difficulty, emphasis has usually been placed on using direct reports through subjective measures such as rating scales to assess levels of mental workload. The NASA Task Load Index (NASA/TLX, Hart and Staveland) has been shown to be a highly reliable and sensitive measure of perceived mental workload. But a problem with measures like TLX is that there is still considerable disagreement as to what it is about mental workload that these subjective measures are actually measuring. The empirical use of subjective workload measures has largely been to provide estimates of the cognitive components of the actual mental workload required for a task. However, my research suggests that these measures may, in fact have greater potential in accurately assessing the affective components of workload. That is, for example, TLX may be more likely to assess the positive and negative feelings associated with varying workload levels, which in turn may potentially influence the decision making behavior that directly bears on performance and safety issues. Pilots, for example, are often called upon to complete many complex tasks that are high in mental workload, stress, and frustration, and that have significant dynamic decision making components -- often ones that involve risk as well.

Nygren, Thomas E.↗

The Primary Flight Display and Its Pathway Guidance: Workload, Performance, and Situation Awareness

In two experiments carried out in a high fidelity general aviation flight simulator, 42 instrument rated pilots flew a pathway-in-the-sky (tunnel) display through a series of multi-leg curved stepdown approaches through mountainous terrain. Both experiments examined how properties of the tunnel influenced flight path tracking performance, traffic awareness, terrain awareness and workload (assessed both by subjective and secondary task performance measures). Experiment 1, flown in simulated VMC, compared high and low intensity tunnels, with a less cluttered follow-me-airplane (FMA). The results revealed that both tunnels supported better flight path tracking than the FMA, because of the availability of more preview information. Increasing tunnel intensity, while reducing subjective workload, had no benefit on tracking, and degraded traffic detection performance. In Experiment 2, flown mostly in IMC, the low intensity tunnel was flown with a large (10 inch x 8 inch) and small (8 inch x 6.5 inch) display, representing a geometric field of view (GFOV) of either 30 degrees or 60 degrees. Most measures of flight path tracking performance favored the smaller display, and particularly the 60 degree GFOV, which presented a smaller appearing tunnel, and a wider range of terrain depiction. The larger GFOV also supported better terrain awareness, and yielded a lower secondary task assessment of workload. In both experiments, the final landing approach was terminated by a runway obstruction, and the tunnel guided pilots on a missed approach. In nearly all cases, pilots failed to notice an air hazard that lay in the missed approach path, but was only depicted in the outside view.

Wickens, Christopher D.↗

Methods to Reduce Communication Workload for UAM Operations

Implementation of Urban Air Mobility (UAM) operations, or air passenger transportation systems within densely populated metropolitan areas, seeks to mitigate increasing traffic congestion. However, the development and integration of UAM operations into the national airspace system comes with its own unique challenges, such as vehicle requirements, flight planning and scheduling, and coordination between UAM flights and air traffic controllers. In particular, verbal coordination will play an integral part in the determined success of UAM operations and its ability to meet projected high consumer demands. In order to meet demands and higher traffic volumes on UAM routes, verbal communication between the UAM pilot and controller must be streamlined to reduce the controller's workload while helping to maintain safety within a given airspace. One method of reducing verbal workload are Letters Of Agreement (LOAs) that outline responsibilities and procedures for operations in an airspace. These LOAs will specify the operations, procedures, and routes for UAM flights. The proposed study will examine the usability of two route formatting styles for LOAs; (i) Verbal route descriptions and (ii) Tower En Route Control (TECs) routes. Verbal route descriptions will include the route name and associated visual cues on the route. The TEC route versions will include relevant waypoints and charts outlining the route with waypoints marked. The study will be part of a UAM X1 human in the loop (HITL) simulation. Controller participants will handle traditional air traffic including moderate levels of UAM traffic on current and modified helicopter routes within the Dallas Fort-Worth area. Scenarios will be counterbalanced and repeated to test both route formatting versions. After each trial, participants will rate the usability of the LOA used in the previous trial via a subjective questionnaire. We expect that controllers will prefer the LOA with TEC routes due to simplicity and visual elements available.

aerospace human factors↗

Synergistic Allocation of Flight Expertise on the Flight Deck (SAFEdeck): A Design Concept to Combat Mode Confusion, Complacency, and Skill Loss in the Flight Deck

This paper presents a new design and function allocation philosophy between pilots and automation that seeks to support the human in mitigating innate weaknesses (e.g., memory, vigilance) while enhancing their strengths (e.g., adaptability, resourcefulness). In this new allocation strategy, called Synergistic Allocation of Flight Expertise in the Flight Deck (SAFEdeck), the automation and the human provide complementary support and backup for each other. Automation is designed to be compliant with the practices of Crew Resource Management. The human takes a more active role in the normal operation of the aircraft without adversely increasing workload over the current automation paradigm. This designed involvement encourages the pilot to be engaged and ready to respond to unexpected situations. As such, the human may be less prone to error than the current automation paradigm.

Schutte, Paul↗

Stereo 3-D and non-stereo presentations of a computer-generated pictorial primary flight display with pathway augmentation

Stereo 3-D was researched as a means to present cockpit displays which enhance a pilot's situational awareness while maintaining a desirable level of mental workload. The initial study at the NASA Langley Research Center used two different pathways-in-the-sky to augment a computer-generated pictorial primary flight display. One pathway resembled the outline of signposts, while the other pathway resembled a monorail. That display was configured for a curved approach to a landing such as could be used in a Microwave Landing System (MLS) approach. It could also be used for military transports which would have to fly a precision curved pathway. Each trial was initialized with the pilot on the desired flight path. After 2 seconds, he suddenly was shifted to one of eight flight path offsets. The pilot was then required to make the initial pitch and/or roll input to correct back to the nominal flight path. As soon as the input was made, the trial was over. No input was required for control trials with no flight path offset. Pilots responded statistically significantly faster when the display was presented in the stereo version than when it was presented in the nonstereo version.

Nataupsky, Mark↗

Evaluation of advanced displays for engine monitoring and control

The relative effectiveness of two advanced display concepts for monitoring engine performance for commercial transport aircraft was studied. The concepts were the Engine Monitoring and Control System (EMACS) display developed by NASA Langley and a display by exception design. Both of these concepts were based on the philosophy of providing information that is directly related to the pilot's task. Both concepts used a normalized thrust display. In addition, EMACS used column deviation indicators; i.e., the difference between the actual parameter value and the value predicted by an engine model, for engine health monitoring; while the Display by Exception displayed the engine parameters if the automated system detected a difference between the actual and the predicted values. The results showed that the advanced display concepts had shorter detection and response times. There were no differences in any of the results between manual and auto throttles. There were no effects upon perceived workload or performance on the primary flight task. The majority of pilots preferred the advanced displays and thought they were operationally acceptable. Certification of these concepts depends on the validation of the engine model. Recommendations are made to improve both the EMACS and the display by exception display formats.

Summers, L. G.↗

Experimental Study of Collision Detection Schema Used by Pilots During Closely Spaced Parallel Approaches

An experimental flight simulator study was conducted to examine the mental alerting logic and thresholds used by subjects to issue an alert and execute an avoidance maneuver. Subjects flew a series of autopilot landing approaches with traffic on a closely-spaced parallel approach; during some runs, the traffic would deviate towards the subject and the subject was to indicate the point when they recognized the potential traffic conflict, and then indicate a direction of flight for an avoidance maneuver. A variety of subjects, including graduate students, general aviation pilots and airline pilots, were tested. Five traffic displays were evaluated, with a moving map TCAS-type traffic display as a baseline. A side-task created both high and low workload situations. Subjects appeared to use the lateral deviation of the intruder aircraft from its approach path as the criteria for an alert regardless of the display available. However, with displays showing heading and/or trend information, their alerting thresholds were significantly lowered. This type of range-only schema still resulted in many near misses, as a high convergence rate was often established by the time of the subject's alert. Therefore, the properties of the intruder's trajectory had the greatest effect on the resultant near miss rate; no display system reliably caused alerts timely enough for certain collision avoidance. Subjects' performance dropped significantly on a side-task while they analyzed the need for an alert, showing alert generation can be a high workload situation at critical times. No variation was found between subjects with and with out piloting experience. These results suggest the design of automatic alerting systems should take into account the range-type alerting schema used by the human, such that the rationale for the automatic alert should be obvious to, and trusted by, the operator. Although careful display design may help generate pilot/automation trust, issues such as user non-conformance to automatically generated commands can remain a possibility.

Pritchett, Amy R.↗

Cross coupling in pilot/vehicle systems

Multiloop pilot/vehicle analysis is applied to the problem of determining crossfeed techniques which may be employed by pilots in minimizing the effects of vehicle cross coupling. As used here, cross coupling refers to unwanted vehicle motion which occurs in one control axis or loop as the result of pilot control actuation in another control axis or loop. The minimization or elimination of such cross coupling can contribute significantly to the 'workload' associated with tasks like nap-of-the-earth helicopter flight. In contrast, situations arise in which pilot's may use vehicle cross coupling to improve performance by coordinating two control actuations in the control of a single response variable. A crossfeed model is developed based upon simple control system design principles and configured in a manner amenable to pilot pursuit or precognitive control activity. A handling qualities theory developed to analyze single loop tasks is applied to the multiloop problem. The crossfeed model is applied to five different vehicles/configurations ranging from helicopters to fighter aircraft. Results indicate relatively simple crossfeed commands can significantly reduce cross coupling and, in some improve handling qualities as predicted by the single loop theory.

Hess, R. A.↗

Individual differences in strategic flight management and scheduling

A group of 30 instrument-rated pilots was made to fly simulator approaches to three airports under conditions of low, medium, and high workload conditions. An analysis is presently conducted of the difference in discrete task scheduling between the group of 10 highest and 10 lowest performing pilots in the sample; this categorization was based on the mean of various flight-profile measures. The two groups were found to differ from each other only in terms of the time when specific events were conducted, and of the optimality of scheduling for certain high-priority tasks. These results are assessed in view of the relative independence of task-management skills from aircraft-control skills.

Wickens, Christopher D.↗

Comparison of Controller and Flight Deck Algorithm Performance During Interval Management with Dynamic Arrival Trees (STARS)

Managing the interval between arrival aircraft is a major part of the en route and TRACON controller s job. In an effort to reduce controller workload and low altitude vectoring, algorithms have been developed to allow pilots to take responsibility for, achieve and maintain proper spacing. Additionally, algorithms have been developed to create dynamic weather-free arrival routes in the presence of convective weather. In a recent study we examined an algorithm to handle dynamic re-routing in the presence of convective weather and two distinct spacing algorithms. The spacing algorithms originated from different core algorithms; both were enhanced with trajectory intent data for the study. These two algorithms were used simultaneously in a human-in-the-loop (HITL) simulation where pilots performed weather-impacted arrival operations into Louisville International Airport while also performing interval management (IM) on some trials. The controllers retained responsibility for separation and for managing the en route airspace and some trials managing IM. The goal was a stress test of dynamic arrival algorithms with ground and airborne spacing concepts. The flight deck spacing algorithms or controller managed spacing not only had to be robust to the dynamic nature of aircraft re-routing around weather but also had to be compatible with two alternative algorithms for achieving the spacing goal. Flight deck interval management spacing in this simulation provided a clear reduction in controller workload relative to when controllers were responsible for spacing the aircraft. At the same time, spacing was much less variable with the flight deck automated spacing. Even though the approaches taken by the two spacing algorithms to achieve the interval management goals were slightly different they seem to be simpatico in achieving the interval management goal of 130 sec by the TRACON boundary.

Battiste, Vernol↗