Perhaps no single industry has benefited more from advancements in computation, analytics, and optimization than the airline industry. Operations Research (OR) is now ubiquitous in the way airlines develop their schedules, price their itineraries, manage their fleet, route their aircraft, and schedule their crew. These problems, among others, are well-known to industry practitioners and academics alike and arise within the context of the planning environment which takes place well in advance of the date of departure. One salient feature of the planning environment is that decisions are made in a frictionless environment that do not consider perturbations to an existing schedule. Airline operations are rife with disruptions caused by factors such as convective weather, aircraft failure, air traffic control restrictions, network effects, among other irregularities. Substantially less work in the OR community has been examined within the context of the real-time operational environment. While problems in the planning and operational environments are similar from a mathematical perspective, the complexity of the operational environment is exacerbated by two factors. First, decisions need to be made in as close to real-time as possible. Unlike the planning phase, decision-makers do not have hours of time to return a decision. Secondly, there are a host of operational considerations in which complex rules mandated by regulatory agencies like the Federal Administration Association (FAA), airline requirements, or union rules. Such restrictions often make finding even a feasible set of re-scheduling decisions an arduous task, let alone the global optimum. The goals and objectives of this thesis are found in Chapter 1. Chapter 2 provides an overview airline operations and the current practices of disruption management employed at most airlines. Both the causes and the costs associated with irregular operations are surveyed. The role of airline Operations Control Center (OCC) is discussed in which serves as the real-time decision making environment that is important to understand for the body of this work. Chapter 3 introduces an optimization-based approach to solve the Airline Integrated Recovery (AIR) problem that simultaneously solves re-scheduling decisions for the operating schedule, aircraft routings, crew assignments, and passenger itineraries. The methodology is validated by using real-world industrial data from a U.S. hub-and-spoke regional carrier and we show how the incumbent approach can dominate the incumbent sequential approach in way that is amenable to the operational constraints imposed by a decision-making environment. Computational effort is central to the efficacy of any algorithm present in a real-time decision making environment such as an OCC. The latter two chapters illustrate various methods that are shown to expedite more traditional large-scale optimization methods that are applicable a wide family of optimization problems, including the AIR problem. Chapter 4 shows how delayed constraint generation and column generation may be used simultaneously through use of alternate polyhedra that verify whether or not a given cut that has been generated from a subset of variables remains globally valid. While Benders' decomposition is a well-known algorithm to solve problems exhibiting a block structure, one possible drawback is slow convergence. Expediting Benders' decomposition has been explored in the literature through model reformulation, improving bounds, and cut selection strategies, but little has been studied how to strengthen a standard cut. Chapter 5 examines four methods for the convergence may be accelerated through an affine transformation into the interior of the feasible set, generating a split cut induced by a standard Benders' inequality, sequential lifting, and superadditive lifting over a relaxation of a multi-row system. It is shown that the first two methods yield the most promising results within the context of an AIR model.

<p>This report describes how an aircraft creates and flies its User Preferred Trajectory from take-off to landing, based on the objectives and constraints the aircraft is subjected to from a technological and operational viewpoint.</p><p>A basic description of commercial aircraft operation is given, with an emphasis on identifying the different stakeholders (Air Navigation Service Providers, Airline Operation Center, Pilot/Aircraft, Airport and Civil Aviation Authority). A general description of Instrument Flight Rules operations is also given, together with an explanation of the capabilities of modern flight management systems.</p><p>The objectives and constraints of the trajectory building process from an aircraft and air traffic management viewpoint are described in Chapter 4. Those are instrumental in understanding how the user preferred trajectory is built. The initial and detail route planning process is then described.</p><p>The initial route planning is performed long before the flight and usually by the airline operating center, while detail flight planning, including take-off, runway and departure procedure is performed later by the crew. This process is re-performed minutes before take-off, and usually iterated during the flight when the details of approach and landing are communicated to the aircraft crew.</p><p>The implementation of this user preferred trajectory is explained in terms of the options that the pilots have in the aircraft avionics to perform the mission. The implementation explained in this report is based on the avionics suite of a Boeing 737NG aircraft equipped with the most advanced flight management systems.</p><p>An implementation of a user preferred trajectory, where the aircraft crew is able to best fulfill their objectives is composed of an idle or near idle descent from the cruise altitude. This type of descent, called an advanced continuous descent approach has been implemented by some air navigation service providers, airlines and airports, based on advanced technology that will be further described in this paper. Those procedures are called Green Approaches.</p><p>In the last part of this report, the benefits of flying Green Approach procedures are analyzed by means of aircraft simulations. The analysis describes in detail the lateral and vertical trajectories of the Green Approaches at Stockholm’s Arlanda Airport and Brisbane Airport (Australia), together with the calculated advantages in term of fuel consumption, noise and gas emissions.</p>

The Normal Operations Safety Survey (NOSS) is an observational methodology to collect safety data during normal Air Traffic Control (ATC) operations. It aims to inform organizations about safety matters by using trained ATC staff to take a structured look at everyday operations. By monitoring normal operations through the use of direct over-the-shoulder observations, it is believed that safety deficiencies can be identified in a proactive manner prior to the occurrence of accidents or incidents. NOSS was developed as a collaborative effort between the International Civil Aviation Organization, ATC providers, controller representatives, government regulators, and academics to fill a gap in available ATC safety information. System designers consider three basic assumptions: the technology needed to achieve the system production goals, the training necessary for people to operate the technology, and the regulations that dictate system behavior. These assumptions represent the expected performance. When systems are deployed, however, particularly in realms as complex as ATC, they do not perform quite as designed. NOSS aims to capture the operational drift that invariably occurs upon system deployment. NOSS captures how the ATC system operates in reality, as opposed to how it was intended to operate. NOSS is premised on the Threat and Error Management (TEM) framework. TEM frames human performance in complex and dynamic settings from an operational perspective by simultaneously focusing on the environment and how operators respond to that environment. TEM posits that threats and errors are a part of everyday operations in ATC and must be managed in order to maintain safety margins. This dissertation describes NOSS and its contributions to ATC safety management systems. It addresses the validity and reliability of NOSS data and presents case studies from field trials conducted by a number of ATC providers. / text

Generally, the thesis relates modern technological developments in air traffic and air traffic control services to their legal regulation. It discusses the possible ways in which the liability of air tratfic control agencies could be regulated internationally. [...]

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Interruptions in time-critical, dynamic, and collaborative environments, such as air traffic control (ATC), can provide valuable, task-relevant information. However, they also negatively impact task performance by distracting the operator from on-going tasks and consuming attention resources. This thesis develops and assesses a tool to assist radar air traffic controllers in managing interruptions. Field observations and interviews with air traffic controllers were utilized to develop an understanding of how interruptions occur in real ATC environments, and to identify where opportunities exist to use technology to support the interruption management process. It was identified that operators in these environments could better manage the effects of interruptions if there were indications to one operator of the availability of a collaborator and the urgency of an interruption from a collaborator. Present communication systems do not facilitate the awareness of these functionalities. An initial prototype for providing these functionalities in operational ATC displays was designed. Feedback on the prototypes was solicited through Participatory Design (PD) sessions with air traffic controllers. Based on the refinement of these prototypes, the Working Awareness Interruption Tool (WAIT) was developed to support more efficient and appropriate interruption timing in the context of complex, real-time, distributed, human operator interactions. Variations of the tool demonstrated several ways of showing the availability of the controller to be interrupted (either through manual settings or automatic detection) as well as incorporating a means of conveying the urgency level of the interruption. In order to examine the utility of the tool and to assess the importance and validity of its features, an experiment was conducted in a laboratory-based setting. The results of the experiment show the potential of this tool in an environment representative of air traffic control tasks and communication. Although the sample size was limited, the WAIT facilitated improved performance on both objective measures and self-reported measures, and reduced the distraction effects of interruptions from other operators. These improvements occurred without affecting perceptions of the effectiveness of communications. Questionnaire and interview results showed that participants appear to prefer an automated setting of availability to be shown to other collaborators. Identifying two examples of key features supporting interruption management (communicating availability and urgency) in air traffic control is one of the key contributions of this work. The work also makes a contribution by demonstrating that providing a tool incorporating these features can improve performance in an environment representative of ATC, albeit with naïve participants. Finally, the research makes a contribution by presenting the challenges associated with evaluating interruption management tools that require collaboration between operators in a system.

Workload and complexity measures are, as of today, often imprecise and subjective. Currently, two commonly used workload and complexity measuring formulas are Monitor Alert Parameter and the “Bars”, both using the same measurement variables; amount of aircraft and time. This study creates formulas for quantifying ATC complexity. The study is done in an approach environment and is developed and tested on Stockholm TMA by the creation of 20 traffic scenarios. Ten air traffic controllers working in Stockholm TMA studied the complexity of the scenarios individually and ranked the scenarios in reference to each other. Five controllers evaluated scenario A1-A10. These scenarios were used as references when creating the formulas. The other half of the scenarios, B1-B10, ranked by another five controllers, was used as validation scenarios. Factors relevant to an approach environment were identified, and the data from the scenarios were extracted according to the identified factors. Moreover, a regression analysis was made with the ambition to reveal appropriate weights for each variable. At the first regression, called formula #1, some parameter values were identical. Also, some parameter weights became negative in the regression analysis. The basic requirements were not met and consequently, additional regressions were done; eventually forming formula #2. Formula #2 showed stable values and plausible parameter weights. When compared to a workload measuring model of today, formula #2 showed better performance. Despite the small amount of data samples, we were able to prove a genuine relation between three, of each other independent, variables and the traffic complexity.

Our intended topic is a general discussion of the basic elements of liability related to airline accidents to which fully automated cockpits have constituted an associated contributory factor. In addition we addressed the liability of air carriers arising from injuries or death caused to passengers traveling on international flights. For this purpose, we reviewed the Warsaw System and the different international instruments that constitute it. We also reviewed principles of common law applicable to aircraft manufacturers and the "Free Flight" as an example of the growing automation environment, which is a general benefit to commercial aviation but also a likely contributory cause for accidents in particular cases. In the last part we briefly discuss a personal view regarding the interplay between manufacturers and airlines under the 1999 Montreal Convention, which is an international treaty unifying the desegregated Warsaw System into one single instrument that is expected to enter into force in a few years.