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Daniel Guggenheim School of Aerospace Engineering

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https://hdl.handle.net/1853/70742

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College of Engineering

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Aerospace Design Group

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Aerospace Systems Design Laboratory (ASDL)

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Air Transportation Laboratory

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Cognitive Engineering Center

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Space Systems Design Laboratory (SSDL)

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https://finding-aids.library.gatech.edu/agents/corporate_entities/106

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Publication Search Results

Now showing 1 - 10 of 15

Context dependent total energy alerting system for the detection of low energy unstabilized approaches

(Georgia Institute of Technology, 2019-07-05) Portman, Michael Aaron

This thesis examines context dependent total energy alerting to protect against low energy unstable approaches in commercial aviation operations. Currently, many individual states are monitored independently to identify unstable approaches, rather than an integrated single assessment of total energy. An alert would also have to be context dependent, integrating the individual states with awareness of phase of flight, approach profile modeling, and expected pilot response to individualize the alert’s activation threshold for each approach. This thesis details a design of such a context dependent total energy alerting system. First, a preliminary analysis examines when such an alert would have been given in a case study of Asiana Airlines Flight 214. This flight’s crash on approach into San Francisco International Airport was attributed to lack of pilot situational awareness and understanding of the aircraft’s autoflight systems, leading to the aircraft having sufficiently low total energy that it stalled into the seawall just before the runway threshold. Analysis shows the total energy alert would have sounded roughly 14-41 seconds before impact, earlier than any currently installed system and potentially early enough for corrective action. Next, the context dependent total energy alert is analyzed to assess its performance in real flight as captured by Flight Operations Quality Assurance (FOQA) data. The analysis examines how alerting parameters impact when and how often the alert is triggered, and the thesis concludes with recommendations for the design and application of a context dependent total energy alert, along with recommendations for future work.
Enhanced flight vision systems: Portrayal of runway markings and sensor range effects on pilot performance

(Georgia Institute of Technology, 2018-04-26) Greenhill, Andrew

This thesis investigates the effects of two specific sensor limitations in enhanced flight vision systems (EFVS) on general aviation pilot performance during approach and landing: sensor range and EFVS portrayal of runway markings. The background section of this thesis describes current sensor technologies with EFVS: millimeter wave radar, forward-looking infrared, and light detection and ranging (LiDAR). In addition, the connections between pilot tasks, information requirements, visual cues and information processing level are identified. These connections show how limitations of sensor technologies could affect pilot performance. These effects were then assessed in a fixed base flight simulator of a general aviation aircraft with an EFVS system. The sensor range and portrayal of runway markings was varied while measuring pilot performance. Pilot performance during approach was measured according to FAA instrument certification standards. Landing performance was measured using standards taught during private pilot training. The results show that pilot performance in tracking an instrument approach is negatively affected by reductions in EFVS sensor range, while the vertical speed and distance from centerline had exceedances beyond acceptable standards when the EFVS did not portray runway markings. These results identify the key minimum specifications of EFVS sensor range and ability to portray runway markings for their implementation in general aviation.
Analysis and synthesis of allocations of authority and responsibility in novel air traffic concepts of operation

(Georgia Institute of Technology, 2016-08-01) Bhattacharyya, Raunak Pushpak

The Next Generation Air Transportation System (NextGen) in the US and the Single European Sky Air Traffic Management (ATM) Research (SESAR) program in Europe are redefining ATM, allowing for transformative new concepts of operation that may radically re-allocate authority and responsibility between air and ground. There is a need for methods that can systematically incorporate innovative allocations of authority and responsibility in the design of novel concepts of operations to enable them to meet their specified performance and safety goals. This need translates to two objectives: 1) Create the methodology and tools for analysis of allocation of authority and responsibility in novel air traffic concepts of operation, and 2) Create the methodology and tools for synthesis of allocation of authority and responsibility in novel air traffic concepts of operation. This thesis first establishes concrete definitions of capability, authority and responsibility in the context of function allocations in the design of concepts of operations. Then, it addresses the first objective by proposing a computational modeling and simulation methodology to assess allocations of authority and responsibility with respect to the performance and safety goals of the concept of operations. Subsequently, it addresses the second objective by proposing a methodology based on network modeling and optimization to systematically synthesize allocations of authority under specified allocations of responsibility to meet performance and safety goals. The proposed methodologies are demonstrated on a case study designing of allocations of authority and responsibility in aircraft merging and spacing operations during arrival. The methodologies described and demonstrated in this thesis can be used by designers of concept of operations to both analyze and synthesize allocations of authority and responsibility. Further, the results of the case study can inform the design of similar concepts of operations.
Applying a model-based observer to quantitatively assess spatial disorientation and loss of energy state awareness

(Georgia Institute of Technology, 2015-04-27) Bozan, Anil Emilio

This thesis demonstrates how a model-based observer can be applied to estimate the reference pilot expectation that can be achieved with any instrument scanning behavior and established models of vestibular inputs. The MBO, developed by the Georgia Tech Cognitive Engineering Center, is applied here in both simple maneuvers examining spatial disorientation and full Air Traffic Control concepts of operations examining loss of energy state awareness. The computational experiments presented in this thesis examine how different effects (i.e., instrument scan pattern, accuracy of pilot perception of flight display information, and awareness of control surface deflections) can prevent or mitigate the susceptibility to spatial disorientation and loss of energy state awareness, thus setting requirements for intervention and countermeasure designs in terms of the scanning behavior they must foster.
Conflict resolution in a decentralized air traffic concept of operation

(Georgia Institute of Technology, 2015-01-09) Genton, Antoine

The current air traffic concept of operations relies on a centralized process in which ground controllers are responsible for determining conflict-free trajectories. However, with new technologies such as ADS-B and GPS, aircraft could directly interact together to resolve their own conflicts in a decentralized manner. The challenge is to guarantee aircraft separation while converging to reasonably fair resolutions for all aircraft. The difficulty is that aircraft have only limited information about how the other aircraft evaluate the cost of conflict resolutions. Thus, this thesis proposes to frame decentralized conflict resolution using game theory. A collaborative decentralized conflict resolution is developed as a sequential bargaining process between the different aircraft. The goal of each aircraft is to minimize the cost associated with the conflict resolution. However, each aircraft doesn’t know the cost function and performance constraints of the other involved aircraft. In the sequential bargaining process developed, aircraft propose at each step personal trajectories to the other aircraft, corresponding to trajectories they would be ready to fly. Then they compute response trajectories, corresponding to trajectories they would have to fly to avoid the conflict if the personal trajectories were flown. If some response trajectories are cheaper than the offered personal trajectories, an agreement is reached; otherwise compromises have to be made by the aircraft by offering more expensive personal trajectories at the next step. Several pairwise conflict experiments, corresponding to different conflict geometries, were conducted to explore different ways of handling performance constraints and different ways of searching trajectories in the resolution space. Ultimately, the algorithm was demonstrated in a large scale simulation with more than a thousand aircraft flying over the Indianapolis Center, incurring more than five hundred conflicts. The traffic sets were taken from real ETMS data over five hours, to represent ‘real’ conditions. 93% of the conflicts were successfully solved by the bargaining process.
Testing the effects of violating component axioms in validation of complex aircraft systems

(Georgia Institute of Technology, 2014-12-08) Kansal, Aparna

This thesis focuses on estimating faults in complex large-scale integrated aircraft systems, especially where they interact with, and control, the aircraft dynamics. A general assumption considered in the reliability of such systems is that any component level fault will be monitored, detected and corrected by some fault management capability. However, a reliance on fault management assumes not only that it can detect and manage all faults, but also that it can do so in sufficient time to recover from any deviation in the aircraft dynamics and flight path. Testing for system-level effects is important to ensure better reliability of aircraft systems. However, with existing methods for validation of complex aircraft systems, it is difficult and impractical to set up a finite test suite to enable testing and integration of all the components of a complex system. The difficulty lies in the cost of modelling every aspect of every component given the large number of test cases required for sufficient coverage. Just having a good simulator, or increasing the number of test cases is not sufficient; it is also important to know which simulation runs to conduct. For this purpose, the thesis proposes simulating faults in the system through the violation of “axiomatic conditions” of the system components, which are conditions on the functioning of these components introduced during their development. The thesis studies the effect, on the aircraft dynamics, of simulating such faults when reference models of the components representing their key functions are integrated.
Developing a computational model of the pilot's best possible expectation of aircraft state given vestibular and visual cues

(Georgia Institute of Technology, 2014-12-05) Onur, Can

Loss of Control (LOC) accidents are a major threat for aviation, and contribute the highest risk for fatalities in all aviation accidents. The major contributor to LOC accidents is pilot spatial disorientation (SD), which accounts for roughly 32% of all LOC accidents. A pilot experiences SD during flight when the pilot's expectation of the aircraft's state deviates from reality. This deviation results from a number of underlying mechanisms, such as distraction, failure to monitor flight instruments, and vestibular illusions. Previous researchers have developed computational models to understand those mechanisms. However, these models are limited in scope as they do not model the pilot's knowledge of the aircraft dynamics. This research proposes a novel model to predict the best-possible-pilot-expectation of the aircraft state given vestibular and visual cues. The proposed model uses a Model-Based Observer (MBO) as the infrastructure needed to establish an “expert pilot”. Expert pilots are known to form an internal model of the operated system through training and experience, which allows the expert to generate better internal expectations of the system states. Pilots' internal expectations are enhanced by the presence of information fed through the pilots̕ sensory systems. Thus, the proposed model integrates pilot's knowledge of the system dynamics (i.e. an aircraft model) with a continuous vestibular sensory model and a discrete visual-sampling sensory model. The computational model serves to investigate the underlying mechanisms of SD during flight and provide a quantitative analysis tool to support flight deck and countermeasure designs.
Developing a training program for the traffic alert and collision avoidance system in context

(Georgia Institute of Technology, 2013-03-26) Fleming, Elizabeth Scott

The Traffic alert and Collision Avoidance System (TCAS) is an aircraft collision avoidance system designed to prevent mid-air collisions. During an advisory, danger is imminent, and TCAS is assumed to have better, more up-to-date information than the ground operated air traffic control (ATC) facility. Following a TCAS RA is generally the safe course of action during an advisory. However, pilot compliance with RAs is surprisingly low. Results from a TCAS monitoring study show pilots are not complying with many TCAS advisories. As revealed by pilot-submitted Aviation Safety Reporting System (ASRS) reports, this noncompliance could be attributed, in part, to pilot confusion to TCAS operation as well as misunderstandings of the appropriate response to a TCAS issued advisory. This thesis details the development and evaluation of a TCAS training program intended to improve pilots' understanding of TCAS use for collision avoidance in a range of traffic situations. The training program integrated Demonstration Based and Event Based Training techniques. Its efficacy was analyzed in an integrated ATC-cockpit simulator study in which eighteen commercial airline pilots were asked to complete the TCAS training program and afterwards experienced twelve experimental traffic events. The trained pilots' performance was compared to the performance of 16 baseline pilots who did not receive the modified training. Overall, the training program did have a significant impact on the pilots' behavior and response to TCAS advisories. The measure Time Pilots First Achieved Compliance decreased with the trained pilots, as did the measure Autopilot Disconnect Time After RA Initiation. Trained pilots exhibited less aggressive performance in response to a TCAS RA (including a decrease in the measures Altitude Deviation Over Duration Of RA, Average Vertical Rate Difference, Maximum Vertical Rate Difference, and Maximum Vertical Rate). The measure Percent Compliance did not significantly vary between trained and baseline pilots, although trained pilots had a more consistent response in the traffic event with conflicting ATC guidance. Finally, on the post-experiment questionnaires, pilots commented on their increase in understanding of TCAS as well as an increase in their trust in the advisory system. Results of this research inform TCAS training objectives provided by the FAA as well as the design of TCAS training. Additionally, conclusions extend more broadly to improved training techniques for other similar complex, time-critical situations.
An evaluation of interval management (IM) using task analysis and work domain analysis

(Georgia Institute of Technology, 2013-01-04) Swieringa, Kurt A.

Work Domain Analysis (WDA) and task analysis are methods that can be used to develop complex systems that support human operators. Task analysis can be used to describe the nominal tasks of many complex safety critical systems which are also highly proceduralized. However, complex systems may require human operators to have a greater understanding of the system's dynamics than can be obtained from procedures derived from a task analysis. This is particularly true when off-nominal events occur, for which there is no procedure. By concentrating on the constraints in the work domain instead of tasks, work domain analysis can complement task analysis by supporting operators during off-nominal events that do not have any predescribed procedures. The goal of this study was to use WDA and two forms of task analysis to derive interface and procedure modifications for a new aviation concept called interval management. Interval management is a new concept whose goal is to increase runway throughput by enabling aircraft to achieve a precise interval behind a lead aircraft. This study used data from a human-in-the-loop study conducted at NASA Langley Research Center to develop a Hierarchical Task Analysis (HTA), Control Task Analysis (CTA), and WDA. The HTA was used to describe a nominal set or procedures, the CTA was used to describe strategies pilots could use to make decisions regarding the IM operation, and the WDA was used to determine representations and procedures that could convey complete and accurate knowledge of interval management to the flightcrew.
Improving pilot understanding of TCAS through the traffic situation display

(Georgia Institute of Technology, 2013-01-02) Cleveland, William Peter

The goal of this thesis is to improve pilot understanding of the Traffic alert and Collision Avoidance System (TCAS) by changing the Traffic Situation Display (TSD). This is supported by two objectives. The first objective is to create an integrated, realistic air traffic environment. This serves as an experimental platform for testing and evaluating future TCAS TSDs. The simulator environment includes a desktop flight simulator, background air traffic simulator, and intruder aircraft. The intruder aircraft uses seven dimensional waypoints to robustly follow trajectories and cause specific resolution advisories. Second, the relative benefits of, and potential concerns with, new TCAS TSDs are explored using a structured, iterative design process with subject matter ex- perts (SMEs). Incremental changes to the TSD were implemented into the simulator environment. SMEs evaluated the displays and potential points of confusion were identified. Several display features are discussed and implemented for future evaluations. These include boundary lines of TCAS variables depicted on the TSD and on a vertical situation display, speed lines which vary with the TCAS estimate of time to closest point of approach, and a prediction of the safe altitude target during a resolution advisory. Scenarios which may be confusing or misleading are discussed. These scenarios may be ameliorated or exacerbated by display features. This information is useful to guide both design and certification or operational approval and is a starting place for future TCAS experiments.