Engineering Commons^™

Nurturing Systems Thinking: Developing A Framework Based On The Human Factors Analysis And Classification System (Hfacs) To Improve Systems Development Processes, Arjun Vijayanarayanan

Doctoral Dissertations and Master's Theses

Large systems engineering projects have an astonishingly high failure rate. The reasons hypothesized for such a high failure rate include the neglect of nonsalient system elements such as social and human or organizational aspects of systems. Social and human factors have long been known to be critical elements of systems that are frequently ignored (e.g., Goguen, 1994). Systems engineering processes can benefit and be improved by effective utilization of a framework that helps developers expand their attention and efforts beyond the salient aspects of the system and the development process. In the aviation field, the Human Factors Analysis and Classification …

The Effect Of Shift Turnover Strategy And Time Pressure On Aviation Maintenance Technician Performance, William R. Warren

Doctoral Dissertations and Master's Theses

Aviation maintenance technicians (AMTs) provide the technical and applied knowledge required to maintain airworthiness in aircraft. In commercial aviation, maintenance tasks are performed across multiple shifts. When AMTs share a maintenance task between shifts, the shift turnover strategy used may determine if information is effectively transferred between AMTs. Ineffective shift turnover strategies are a contributing factor in many aviation accidents and incidents. Additionally, time constraints on certain maintenance tasks may cause AMTs to commit error when performing a task. The present study examined the effect of shift turnover strategy (face-to-face or written) and time pressure on error capture, accuracy, and …

Ultimate Compression After Impact Load Prediction In Graphite/Epoxy Coupons Using Neural Network And Multivariate Statistical Analyses, Alexandre David Grégoire

Doctoral Dissertations and Master's Theses

The goal of this research was to accurately predict the ultimate compressive load of impact damaged graphite/epoxy coupons using a Kohonen self-organizing map (SOM) neural network and multivariate statistical regression analysis (MSRA). An optimized use of these data treatment tools allowed the generation of a simple, physically understandable equation that predicts the ultimate failure load of an impacted damaged coupon based uniquely on the acoustic emissions it emits at low proof loads. Acoustic emission (AE) data were collected using two 150 kHz resonant transducers which detected and recorded the AE activity given off during compression to failure of thirty-four impacted …

Effects Of Online Training On Aircrew Monitoring Behaviors: A Field Study, Brian A. Potter

Doctoral Dissertations and Master's Theses

Data from aircraft accidents and line observation studies indicate that inadequate pilot monitoring is a growing safety concern. In the cockpit environment, pilots who fail to properly manage their workload commit more monitoring errors. Given the lack of training and educational programs available to pilots which emphasize improving their monitoring skills, more research is needed to assess the usefulness of types of training that can be used to improve pilots' monitoring. This research project sets out to determine if the potential exists to enhance pilots' monitoring skills through online training. For this study, 40 military helicopter pilots (participants) were divided …

Analysis Of Airport Security Screening Checkpoints Using Queuing Networks And Discrete Event Simulation: A Theoretical And Empirical Approach, Stephen Louis Dorton

Doctoral Dissertations and Master's Theses

This study utilized discrete event simulation (DES) and queuing networks to investigate the effects of baggage volume and alarm rate at the Security Screening Checkpoint (SSCP) of a small origin and destination airport. A Jackson queuing network was considered for a theoretical assessment to SSCP performance. A DES model using Arena version 12 was utilized for an empirical approach. Data was collected from both literature and by manual collection methods. Manual data was collected during the peak operating time of 6am-7am local time at the airport being modeled. The simulation model was verified and validated qualitatively and quantitatively by statistical …

Preliminary Design Of An Asteroid Hopping Mission, Michael D. Scheppa

Doctoral Dissertations and Master's Theses

In 2010, NASA announced that its new vision is to support private space launch operations. It is anticipated that this new direction will create the need for new and innovative ideas that push the current boundaries of space exploration and contain the promise of substantial gain, both in research and capital.

The purpose of the study is to plan and estimate the feasibility of a mission to visit a number of near Earth asteroids (NEAs). The mission would take place before the end of the 21st century, and would only use commercially available technology. Throughout the mission design process, while …

Pilot Perception Of Light Emitting Diodes Versus Incandescent Elevated Runway Guard Lights, Hilary Stevens

Doctoral Dissertations and Master's Theses

Pilots must understand and be aware of the purpose of each airport sign, light and marking, for there are numerous. The Federal Aviation Administration (FAA) is planning on replacing the current incandescent lighting with far more economical LED airport lighting. In preparation for this change, two experiments were conducted for this thesis. Experiment 1 attempted to determine what pilots know about the meaning of the signs, markings and lights on the taxiways and runways through a questionnaire that was developed with the FAA. Experiment 2 evaluated pilot perception of LED lighting compared to current incandescent elevated runway guard lights.

The …

Acoustic Emission Fatigue Crack Monitoring Of A Simulated Aircraft Fuselage Structure, Jeremy James Lucas

Doctoral Dissertations and Master's Theses

The purpose of this research was to replicate the fatigue cracking that occurs in aircraft placed under loads from cyclical compression and decompression. As a fatigue crack grows, it releases energy in the form of acoustic emissions. These emissions are transmitted through the structure in waves, which can be recorded using acoustic emission (AE) transducers. This research employed a pressure vessel constructed out of aluminum and placed under cyclical loads at 1 Hz in order to simulate the loads placed on an aircraft fuselage in flight. The AE signals were recorded by four resonant AE transducers. These were placed on …

A Comparison Of Algorithms That Estimate The Effectiveness Of Commercial Airline Boarding Strategies, Dalila Giraldo

Doctoral Dissertations and Master's Theses

The number of passengers carried by commercial aircraft has increased dramatically over the past 50 years, closely in-step with advances in aircraft design. This makes unloading and loading an aircraft, called turn-around time, critical to the success of the airport, the aircraft and the airlines. A number of mathematical algorithms have been developed over the years that purport to determine the most efficient boarding strategy for passengers by decreasing turn time. This thesis evaluated the boarding strategies most often used by the airlines and algorithms used to predict boarding efficiency. The models used were obtained from the literature and from …

Formation Feedback Control Of Uav Flight, Stephen Stegall

Doctoral Dissertations and Master's Theses

This thesis is a study of formation control with autonomous unmanned aerial vehicles using the formation as feedback. There is also an investigation of formation methods presenting insight into different algorithms for formations. A rigid formation is achieved using a proportional-derivative virtual structure with a formation feedback controller. There is an emphasis on stick controlled aerodynamics. The rigid formation is verified by a simulation of a longitudinal model. Formation control ideas are presented for rigid formations.

Moral Development In Pilot Populations, Erica Anne Diels

Doctoral Dissertations and Master's Theses

Ethical issues are becoming more commonplace in society today and while most industries are taking steps to improve poor ethical decisions through ethics education, aviation is lagging behind in both understanding of ethical issues inherent to the industry and ethics education. In this study three groups of pilots (students, instructors, and faculty) at Embry-Riddle Aeronautical University are examined in an effort to determine moral development level in terms of P score on the Defining Issues Test 2 (DIT2) and two domain specific additional questions. It was hypothesized that differences would be found between the groups and that the moral development …

The Effect Of Display Design On Pilot Performance In Controlled Flight Into Terrain Scenarios, Jeremy Charles Smith

Doctoral Dissertations and Master's Theses

New technologies are being developed to prevent the continuing problem of Controlled Flight into Terrain (CFIT) accidents. One such technology, the Synthetic Vision System, seems to hold the solution. While it is readily adapted to the commercial aviation instrument environment, it may not be intuitive enough for the General Aviation private pilot with minimal instrument training. This experiment attempted to examine how pilots of every experience level use and interpret the depiction of synthetic terrain to recognize and avoid potential CFIT situations. The outcome of CFIT was measured against pilot experience and display condition.

A New Guidance System For Aircraft Based On Gps, Mukul Mishra

Doctoral Dissertations and Master's Theses

The navigation displays commonly used in aircraft (Course Deviation Indicators), provide only the offset from desired track, leaving the pilot to figure out steering correction necessary to get back on track. This correction, determined by trial and error, adds to the workload, especially in windy conditions. The feasibility of using a new algorithm for providing guidance to the pilots for improved interception and tracking is examined in this thesis. The proposed system employs GPS to calculate the offset from the track as well as the instantaneous ground speed vector, to provide steering information. Thus, precise tracking is possible in real …

Controlling Lead Exposure During The Process Of Cleaning Aviation Spark Plugs, Curtis E. Beers

Doctoral Dissertations and Master's Theses

This study examines the process of removing lead bromide from aircraft spark plugs and the health hazards associated with the present method of cleaning the lead bromide accumulation from aviation spark plugs. Aviation maintenance technicians can be inadvertently exposed to lead while cleaning the lead bromide accumulation from the spark plug electrode during scheduled engine maintenance.

This study explores controlling the lead bromide particulate matter after it is removed from the spark plug electrode. Various control methods and/or procedural changes that may be employed to control the spread of lead bromide dust throughout the shop environment and the prevention of …

Aviation Safety And Security: A Call For Educating The Flying Public, Mariann Elizabeth Abbonizio

Doctoral Dissertations and Master's Theses

Aviation safety and security: A call for educating the flying public, is an account and testimonial to the problem of the lack of aviation safety and security knowledge by the flying public in the National Airspace System (NAS). It discusses the confusion over both new (post 9-11-01) and old (pre 9-11-01) security regulations as well as basic passenger safety recommendations and advice that could possibly save hundreds of lives. It will discuss the need for a public education campaign regarding aviation safety and security for the American flying public, and point to past public educational campaigns in different realms as …

Analysis Of The Aboriculture Industry Safety Culture From The Standpoint Of Injures, Illnesses, Employee Response, And Industry Standards, Joshua T. Mcclenahan

Doctoral Dissertations and Master's Theses

The author researched 215 recorded injuries and illnesses to all field employees between January 1, 1991 and July 1, 2002 at an arboricultural company in California. Detailed interviews were conducted with each of the 38 field employees to determine employee perceptions of safety training, management, communication, and personal discomfort to provide a clearer picture of the company safety program. This information was correlated with the tree worker claims and industry standards to determine the effectiveness of the safety program based on employee discomforts and claim related descriptive statistics. The claims' tabulations show that back strains are the most prominent injuries …