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Unalerted air-to-air visual acquisition
November 26, 1991
Project Report
Published in:
MIT Lincoln Laboratory Report ATC-152
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Summary
A series of flight tests were flown to measure pilot air-to-air visual acquisition performance for pilots employing unalerted visual search. Twenty-four general aviation subject pilots flew a cross-country route while an intercepting aircraft was controlled to produce three intercepts with altitude separation of 500 feet. Pilots received no traffic advisory information to alert them to the possible presence of the intercepting aircraft. Results were analyzed to estimate the instantaneous rate of visual acquisition for a visual target of specified size and contrast. The results were used to calibrate a mathematical model of visual acquisition that can be used to predict pilot performance under a range of conditions.
Summary
A series of flight tests were flown to measure pilot air-to-air visual acquisition performance for pilots employing unalerted visual search. Twenty-four general aviation subject pilots flew a cross-country route while an intercepting aircraft was controlled to produce three intercepts with altitude separation of 500 feet. Pilots received no traffic advisory...
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Role of FAA/NWS terminal weather sensors and terminal air traffic automation in providing a vortex advisory service
October 29, 1991
Conference Paper
Published in:
FAA Int. Wake Vortex Symp., Washington, DC, 29-31 October 1991.
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The Federal Aviation Administration (FAA) is developing a number of terminal weather sensors and a terminal weather information system which can make important contributions toward an operational wake vortex advisory service. Although these systems have been developed to meet other important weather information needs, their existence/development offers the possibility of a more cost effective wake vortex advisory system than would be possible with a standalone system such as was tested in the 1970's. Specifically, we postulate an advisory system in which the aircraft separation during IFR conditions is adjusted to account for the advection of vortices by the wind on the approach path and/or the breakup of vortices due to air instability and in which the desired aircraft separation is achieved by the Terminal Air Traffic Automation (TATCA) system. When reduced separations are obtained with such a system, it is important to be able to anticipate that the winds/vortex stability in the terminal area will continue to meet the reduced spacing criteria for an appropriate time interval (e.g., at least 15 minutes) in the future.
Summary
The Federal Aviation Administration (FAA) is developing a number of terminal weather sensors and a terminal weather information system which can make important contributions toward an operational wake vortex advisory service. Although these systems have been developed to meet other important weather information needs, their existence/development offers the possibility of...
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The 1990 Airport Surveillance Radar Wind Shear Processor (ASR-WSP) operational test at Orlando International Airport
July 17, 1991
Project Report
Published in:
MIT Lincoln Laboratory Report ATC-178
Summary
Lincoln Laboratory, under sponsorship from the Federal Aviation Administration (FAA), is conducting a program to evaluate the capability of the newest Airport Surveillance Radars (ASR-9) to detect hazardous weather phenomena -- in particular, low-altitude wind shear created by thunderstorm-generated microbursts and gust fronts. The ASR-9 could provide coverage at airports not slated for a dedicated Terminal Doppler Weather Radar (TDWR) and could augment the TDWR at high-priority (high traffic volume, severe weather) facilities by providing a more rapid update of wind shear products, a better viewing angle for some runways, and redundancy in the event of a TDWR failure. An operational evaluation of a testbed ASR Wind Shear Processor (ASR-WSP) was conducted at the Orlando International Airport in Orlando, FL during August and September 1990. The ASR-WSP operational system issued five distinct products to Air Traffic Control: microburst detections, gust front detections, gust front movement predictions, precipitation reflectivity and storm motion. This document describes the operational system, the operational products, and the algorithms employed. An assessment of system performance is provided as one step in evaluating the operational utility of the ASR-WSP.
Summary
Lincoln Laboratory, under sponsorship from the Federal Aviation Administration (FAA), is conducting a program to evaluate the capability of the newest Airport Surveillance Radars (ASR-9) to detect hazardous weather phenomena -- in particular, low-altitude wind shear created by thunderstorm-generated microbursts and gust fronts. The ASR-9 could provide coverage at airports...
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Characteristics of gust fronts
July 1, 1991
Conference Paper
Published in:
Fourth Int. Conf. on Aviation Weather Systems, 24-28 June 1991, pp. 387-392.
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Summary
A gust front is the leading edge of a thunderstorm outflow. A gust frontal passage is typically characterized by a drop in temperature, a rise in relative humidity and pressure, and an increase in wind speed and gustiness. Gust front detection is of concern for both Terminal Doppler Weather Radar (TDWR) and Next Generation Weather Radar (NEXRAD) systems. In addition, airborne systems using radar, lidar, and infrared sensors to detect hazardous wind shears are being developed. The automatic detection of gust fronts is desirable in the airport terminal environment so that warnings of potentially hazardous gust front-related wind shears can be delivered to arriving and departing pilots. Information about estimated time of arrival and accompanying wind shifts can be used by an Air Traffic Control (ATC) supervisor to plan runway changes. Information on expected wind shifts and runway changes is also important for terminal capacity programs such as Terminal Air Traffic Control Automation (TATCA) and wake vortex advisory systems. In addition, the convergence associated with gust fronts is often a factor in thunderstorm initiation and intensification. Knowledge of gust front locations, strengths, and movement can aid forecasters with thunderstorm-specific predictions. Current gust front detection systems generally are reliable in that the probability of false alarms is low. However the probability of detecting gust fronts with these systems is less than desired. Improved characterization of gust fronts is a key element in improving detection capability. Typically, the basic products from the algorithms are the location of the gust front (for hazard assessment) and its propagation characteristics (for forecasting). This paper discusses the thermodynamic and radar characteristics of gust fronts from three climatic regimes, highlighting regional differences and similarities of gust fronts. It also compares propagation speeds, estimated by two techniques, to measured propagation speeds.
Summary
A gust front is the leading edge of a thunderstorm outflow. A gust frontal passage is typically characterized by a drop in temperature, a rise in relative humidity and pressure, and an increase in wind speed and gustiness. Gust front detection is of concern for both Terminal Doppler Weather Radar...
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Performance results and potential operational uses for the prototype TDWR microburst prediction product
July 1, 1991
Conference Paper
Published in:
Proc. 25th Int. Conf. on Radar Meteorology, 24-28 June 1991, pp. J33-J36.
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The Terminal Doppler Weather Radar (TDWR) is a ground-based system for providing automated warnings of aviation wind shear hazards. This paper describes a proposed new TDWR product for microburst prediction. The proposed Microburst Prediction (MBP) product provides the ability to predict microbursts prior to the onset of surface outflow. The MBP product uses the ability of the TDWR to scan aloft for precursor signatures which indicate that a microburst is about to occur. The proposed MBP product provides a complementary capability to the other TDWR wind shear detection and prediction algorithms. As shown in Figure 1, the Microburst and Gust Front algorithms provide safety benefits by detecting wind shear hazards. The Wind Shift Prediction product provides an economic benefit by predicting runway wind shifts up to 20 minutes in advance. The MBP product provides both safety and economic benefits by predicting microburst hazards about 5 minutes in advance. The development of the MBP product is intended to be evolutionary. The initial implementation of the product relies on TDWR radar data only. Later versions are expected to also employ thermodynamic information, as part of the Integrated Terminal Weather System (ITWS). However, the radar-only version discussed in this paper will provide a useful interim capability. The organization of the paper is as follows. Section 2 provides a discussion of the potential operational benefits of the MBP product in improving safety and reducing delay. Section 3 describes the current MBP product algorithm, and section 4 provides performance results for two environments: Kansas City, KS and Orlando, FL. Section 5 provides an example of the product operation in predicting a 50 knot microburst which had substantial impact on airport operations. Section 6 will provide a summary and discuss future work.
Summary
The Terminal Doppler Weather Radar (TDWR) is a ground-based system for providing automated warnings of aviation wind shear hazards. This paper describes a proposed new TDWR product for microburst prediction. The proposed Microburst Prediction (MBP) product provides the ability to predict microbursts prior to the onset of surface outflow. The...
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Weather information requirements for terminal air traffic control automation
June 24, 1991
Conference Paper
Published in:
Fourth Int. Conf. on Aviation Weather Systems, 24-28 June 1991, pp. 208-214.
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Aviation operations in the airport terminal area, where flights converge from a number of directions onto one or two active runways, create a fundamental limitation on the capacity of the national airspace system. The U.S. Federal Aviation Administration (FAA) has recognized that the throughput of existing terminals can be increased significantly by providing the terminal air traffic control team with Terminal Air Traffic Control Automation (TATCA) tools that increase the efficiency of individual controller tasks and provide a dynamic, overall plan for traffic management throughout the terminal control region (Andrews and Welch, 1989). This latter function relies on accurate projection of traffic flow into the future (0-30 minutes) in order to automatically examine the many possible permutations of control actions. The result is a coordinated plan for the multiple (four to ten) control positions involved in the decision making processes that determine end-capacity at the runways. The FAA has launched an intensive effort to develop and implement TATCA capabilities by taking advantage of preparatory work done at NASA Ames Research Center, MITRE Corporation, and M.I.T. Lincoln Laboratory. An initial TATCA configuration, the Final Approach Spacing Tool (FAST), will be evaluated in the field beginning in 1993 and will be scheduled for possible national implementation two years later. Estimates of the economic value of TATCA-generated operational improvements, when implemented at major airports nationwide, are expected to be over $1 billion yearly by the year 2000 in reduced fuel consumption, other air carrier operating costs, and passenger time (Boswell et al., 1990). Since TATCA is first and foremost a planning system, the primary impacts of weather upon T ATCA performance involve disruption of planning. This can occur because of sudden or unexpected changes in routing, runway availability, or separation standards. In addition, errors in estimated wind produce errors in time-to-fly predictions made by the TATCA planning logic. The TATCA system must be robust with respect to weather events that commonly occur in its region of operation. This paper describes an initial study of the weather information requirements for TATCA, and their relationship to current and future systems for measurement, integration, forecasting and dissemination of meteorological data in the terminal area. A major goal is to stress the need for close coupling between ongoing initiatives in weather sensing/forecasting in the airport terminal area, and air-space capacity enhancement programs.
Summary
Aviation operations in the airport terminal area, where flights converge from a number of directions onto one or two active runways, create a fundamental limitation on the capacity of the national airspace system. The U.S. Federal Aviation Administration (FAA) has recognized that the throughput of existing terminals can be increased...
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Terminal Doppler Weather Radar operational test and evaluation Orlando 1990
April 9, 1991
Project Report
Published in:
MIT Lincoln Laboratory Report ATC-179
Summary
Lincoln Laboratory conducted an evaluation for hte Federal Aviation Administration (FAA) Terminal Doppler Weather Radar (TDWR) system in Orlando, Florida during the cummer of 1990. In previous years, evaluations have been conducted at airports in Kansas City, MO (1989) and Denver, CO (1988). Since the testing at the Kansas City International Airport, the radar was modified to operate in C-band, which is the intended frequency band for the production TDWR systems. The objectives of the 1990 evaluation period were to evaluate TDWR system performance in detecting low-altitude wind shear, specifically microbursts and gust fronts, at the Orlando International Airport and in the surrounding area; to refine the system's wind shear detection capabilities; and to evaluate elements of the system developed by the contractor, which were new for this C-band system and therefore not available for evaluation in previous years. Some performance comparisons are made among results from the vastly different weather environments of Denver, Kansas City, and Orlando. The report discusses and presents statistics for the performance of the system in detecting and predicting microbursts and gust fronts. A significant use of the prediction capability is its potential use for air traffic control (ATC) personnel to plan aitport operations when hazardous weather is predicted. Issues such as low-velocity ground clutter (from tree leaves, road traffic, and dense urban areas) that affect prediction performance are discussed, along with possible software modifications to account for them. FInally, the ATC personnel and pilots who took part in the evaluation provide the users' perspectives on the usefulness of the system's capabilities.
Summary
Lincoln Laboratory conducted an evaluation for hte Federal Aviation Administration (FAA) Terminal Doppler Weather Radar (TDWR) system in Orlando, Florida during the cummer of 1990. In previous years, evaluations have been conducted at airports in Kansas City, MO (1989) and Denver, CO (1988). Since the testing at the Kansas City...
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Automated flight strip management system functional description
November 19, 1990
Project Report
Published in:
MIT Lincoln Laboratory Report ATC-174
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This document gives a high level functional overview of an automated flight strip management system. The current manual flight strip system at Boston's Logan Airport is reviewed and described in detail for both the Tower Cab and TRACON with emphasis on the information flow as an aircraft progresses through the system. The interfaces between the ATC elements, as they related to flight data, are explained. Finally, the system requirements are described including specific requirements for Tower Cab positions.
Summary
This document gives a high level functional overview of an automated flight strip management system. The current manual flight strip system at Boston's Logan Airport is reviewed and described in detail for both the Tower Cab and TRACON with emphasis on the information flow as an aircraft progresses through the...
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A prototype microburst prediction product for the terminal doppler weather radar
October 22, 1990
Conference Paper
Published in:
16th Conf. on Severe Local Storms/Conf. on Atmospheric Electricity, 22-26 October 1990, pp. 393-396.
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This paper describes a prototype microburst prediction product for the Terminal Doppler Weather Radar (TDWR). The prediction product was evaluated for microbursts observed during the spring and summer of 1989 at Kansas City. Results are presented demonstrating reliable prediction of high reflectivity microbursts of at least 15 m/s outflow intensity from single-Doppler radar data. The ability of the algorithm to predict microbursts approximately five minutes prior to the onset of surface outflow could be used to improve air traffic control (ATC) planning and to improve hazard warning time to pilots. In particular, this product could allow aircraft to avoid an impending microburst hazard, rather than penetrating it. The present TDWR microburst recognition algorithm uses features aloft such as reflectivity cores and convergence to recognize microburst precursors. The algorithm uses precursors to make a microburst declaration while the surface outflow is still weak, thereby improving the hazard warning time (Campbell, 1989). The microburst prediction product is an extension of the algorithm to predict microbursts from these precursor signatures. The prototype prediction product is tuned to predict the high reflectivity microburst typical of humid regions of the United States. The paper begins by reviewing conceptual models for microburst development and comparing them to the observed characteristics of Kansas City microbursts. The prototype prediction product is then described, and performance statistics are presented. Finally, failure mechanisms and future work are discussed.
Summary
This paper describes a prototype microburst prediction product for the Terminal Doppler Weather Radar (TDWR). The prediction product was evaluated for microbursts observed during the spring and summer of 1989 at Kansas City. Results are presented demonstrating reliable prediction of high reflectivity microbursts of at least 15 m/s outflow intensity...
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Planning horizon requirements for automated terminal scheduling
October 1, 1990
Conference Paper
Published in:
Proc. 35th Annual Air Traffic Control Association Mtg., 16-20 September 1990, pp. 438-451.
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This paper presents the results of an engineering analysis of the ability of an automated terminal scheduling process to achieve efficient use of runways. The motivation for the analysis is the need to understand possible architectures for an implementation of the proposed Terminal Air Traffic Automation (TATCA) system. The performance of TATCA is dependent upon metering precision and the controllability that TATCA can apply to aircraft entering the scheduling process. Controllability refers to the amount of time by which the flight time of an aircraft can be lengthened or shortened between the scheduling horizon and the chosen runway. The analysis concludes that when current en route metering mechanisms are used to deliver traffic to the terminal, the terminal scheduler meets a controllability window of 300 seconds or so in order to achieve full runway utilization. Because this amount of controllability is often achievable within the terminal area itself, a TATCA system can provide significant benefits prior to the implementation of further improvements in the en route metering process.
Summary
This paper presents the results of an engineering analysis of the ability of an automated terminal scheduling process to achieve efficient use of runways. The motivation for the analysis is the need to understand possible architectures for an implementation of the proposed Terminal Air Traffic Automation (TATCA) system. The performance...
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