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Articles 1 - 12 of 12

Full-Text Articles in Engineering

Hybrid Stochastic Models For Remaining Lifetime Prognosis, Steven M. Cox Aug 2004

Hybrid Stochastic Models For Remaining Lifetime Prognosis, Steven M. Cox

Theses and Dissertations

The United States Air Force is developing its next generation aircraft and is seeking to reduce the risk of catastrophic failures, maintenance activities, and the logistics footprint while improving its sortie generation rate through a process called autonomic logistics. Vital to the successful implementation of this process is remaining lifetime prognosis of critical aircraft components. Complicating this problem is the absence of failure time information; however, sensors located on the aircraft are providing degradation measures. This research has provided a method to address at least a portion of this problem by uniting analytical lifetime distribution models with environment and/or degradation …


Extending The Aircraft Availability Model To A Constrained Depot Environment Using Activity-Based Costing And The Theory Of Constraints, Gerardo H. Acosta Voegeli Jun 2004

Extending The Aircraft Availability Model To A Constrained Depot Environment Using Activity-Based Costing And The Theory Of Constraints, Gerardo H. Acosta Voegeli

Theses and Dissertations

The Aircraft Availability Model (AAM) assists managers in the selection of an optimal list of items to repair in order to attain the best aircraft availability rate. The model considers procurement or repair costs for the components as if the costs were unit variable as a price, instead of a repair cost representing a mix of both fixed and variable cost. This research used the AAM in conjunction with Activity Based-Costing (ABC) and The Theory of Constraints (TOC) methodologies to investigate the relationships between price, product mix, Aircraft Availability (AA) and total cost. This approach explicitly recognizes that the Air …


Analysis And Forecasting Of U.S. Navy Operating And Support (O&S) Costs For Rotary Aircraft, Christopher J. Wilkes Mar 2004

Analysis And Forecasting Of U.S. Navy Operating And Support (O&S) Costs For Rotary Aircraft, Christopher J. Wilkes

Theses and Dissertations

This research explores forecasting techniques to estimate the Cost per Flying Hour (CPFH) for Navy rotary aircraft. Three separate forecasting techniques were evaluated to better predict the CPFH for better estimating and budgeting by the U.S. Navy. The process begins by empirically analyzing Operating & Support cost categories for each helicopter. Trends were examined in CPFH. For forecasting purposes, actual CPFH figures were compiled from 1997 to 2003 for the CH-46D, the CH-53D, the MH-53E, the SH-60F, the UH-1N, and the UH-3H helicopters. The forecasting techniques explored were the 3-year moving average, the single exponential smoothing method, and Holt's linear …


Purchasing And Supply Chain Management Costing: An Air Transport Perspective Derived Through Commercial Air Cargo Firms, Kurt Ettrich Mar 2004

Purchasing And Supply Chain Management Costing: An Air Transport Perspective Derived Through Commercial Air Cargo Firms, Kurt Ettrich

Theses and Dissertations

The Air Force has struggled to completely understand the costs associated with its operations. The issue of understanding cost is complex, involving many perspectives, methods and techniques. When examined from a broad standpoint, total supply chain costs can include a firm's costs plus upstream and downstream costs. This perspective takes vendors, suppliers and end customers into consideration. From this broad standpoint, the Air Force does not know its total supply chain cost. Since the Air Force's supply chain is too broad to be a focus of this study, a smaller segment was chosen for a closer look. Specifically, air cargo …


An Analysis Of Coast Guard Hh-65 Engine Reliability: A Comparison Of Malfunctions To Component Removals, Donna L. Cottrell Mar 2004

An Analysis Of Coast Guard Hh-65 Engine Reliability: A Comparison Of Malfunctions To Component Removals, Donna L. Cottrell

Theses and Dissertations

The Coast Guard HH-65 helicopter experienced 31 in-flight loss of power incidents during FY 2003 and 21 during the first two months of FY 2003. Concurrent with this apparent decrease in reliability, the Coast Guard seeks ways to expand the HH- 65’s Airborne Use of Force capabilities as a result of the September 11th, 2001 terrorists’ attacks. This study is an exploratory, empirical analysis of engine and airframe component replacements as related to engine mishaps and reliability in the HH-65. We use contingency table analysis, ordinary least squares regression, and logistic regression to examine the mishap history and component replacement …


Analysis And Forecasting Of Army Operating And Support Cost For Rotary Aircraft, John C. Hawkins Mar 2004

Analysis And Forecasting Of Army Operating And Support Cost For Rotary Aircraft, John C. Hawkins

Theses and Dissertations

This research explores forecasting techniques to estimate the Cost per Flying Hour (CPFH) for Army Helicopters. Specifically, three separate forecasting techniques were evaluated to better predict the CPFH for better estimating and budgeting by the U.S. Army. For forecasting purposes, actual CPFH figures were compiled from 1995 to 2003 for all MACOMs flying the AH-64A, the CH-47D, and the UH-60A helicopters. The number of MACOMs was then reduced to the top three with regard to total CPFH expenditure. The use of a 3-year moving average, the single exponential smoothing method, and Holt's linear method were explored for each helicopter's data. …


A Demand Side Requirements Model To Forecast C-17 Mobility Aircraft Availability, Joseph R. Huscroft Jr. Mar 2004

A Demand Side Requirements Model To Forecast C-17 Mobility Aircraft Availability, Joseph R. Huscroft Jr.

Theses and Dissertations

Current aircraft forecasting methods of the Air Mobility Command (AMC) Directorate of Logistics are reliant on the experience of personnel and lead to after the fact, labor-intensive analysis. These deficiencies led AMC to the development of a Mobility Aircraft Availability Forecasting (MAAF) model. The purpose of the MAAF model is threefold: predict aircraft availability in order to provide the Tanker Airlift Control Center (TACC) with a forecast of aircraft that will be available for AMC mission requirements, provide what if capabilities that analyze the effects of tasking and policy changes, and to provide foresight into problems associated with aircraft availability …


Reusable Space Vehicle Ground Operations Baseline Conceptual Model, Dennis R. Maynard, Patricia Pettit Mar 2004

Reusable Space Vehicle Ground Operations Baseline Conceptual Model, Dennis R. Maynard, Patricia Pettit

Theses and Dissertations

Modeling efforts for future space operation vehicles at the United States Air Force Research Labs Air Vehicles Directorate have been focused towards the in-flight mission. To better serve the research and development effort, a simulation of the ground operations is required allowing for trade-offs within turnaround operations and between the components that drive those procedures. However, before a simulation can be developed a conceptual model must be generated to guide the model building process. This research provides a baseline conceptual model for reusable space vehicles based on the space shuttle as the only operational vehicle of its kind. The model …


Effects Of Duty Schedule Variance And Overtime On The Job Satisfaction And Turnover Intentions Of Usaf F-16 Crew Chiefs, Michael J. Shellhamer Mar 2004

Effects Of Duty Schedule Variance And Overtime On The Job Satisfaction And Turnover Intentions Of Usaf F-16 Crew Chiefs, Michael J. Shellhamer

Theses and Dissertations

This thesis empirically assessed how duty schedule variance and overtime affect the job satisfaction and turnover intentions of USAF F-16 crew chiefs. A survey was completed by 346 active duty USAF F-16 crew chiefs regarding their perceptions of duty schedule variance, overtime, job satisfaction and intent to leave the Air Force. Theory suggests that turnover behavior is a multistage process that involves organizational, individual, and attitudinal components. Using multivariate correlation and regression analyses, plausible evidence was found to support the idea that duty schedule variance and overtime plays a role in USAF F-16 crew chief turnover intentions via job satisfaction. …


Analysis And Forecasting Of Air Force Operating And Support Cost For Rotary Aircraft, Matthew E. Laubacher Mar 2004

Analysis And Forecasting Of Air Force Operating And Support Cost For Rotary Aircraft, Matthew E. Laubacher

Theses and Dissertations

This research explores forecasting techniques to estimate the Cost per Flying Hour (CPFH) for Air Force Helicopters. Specifically, this research evaluates three separate forecasting techniques to predict the CPFH for better estimating and budgeting by the U.S. Air Force. It starts by empirically analyzing the Operating and Support cost by CAIG categories for each helicopter. For forecasting purposes, the actual CPFH figures were compiled from FY96 to FY03 for a total of eight MAJCOMs flying the MH-53J/M, the HH-60G, or the UH-1N helicopters. The research explores the use of a 3-year moving average, the single exponential smoothing method, and Holt's …


Prepositioned Trailers For Aircraft Battle Damage Support, Scott M. Murray Mar 2004

Prepositioned Trailers For Aircraft Battle Damage Support, Scott M. Murray

Theses and Dissertations

Air superiority is essential in today's wartime environment. Aircraft that are damaged and not returned to combat can have a considerable impact on the quest for dominance in the air. To maintain operational effectiveness, an organization must have the capability to quickly repair damaged aircraft. The purpose of an Aircraft Battle Damage Repair (ABDR) program is to rapidly and effectively repair damaged aircraft to fly additional operational sorties and further contribute to wartime objectives. This capability must consist of providing the necessary tools and equipment for the rapid repair of aircraft. When an ABDR team deploys in support of an …


Theoretical Models For Aircraft Availability: Classical Approach To Identification Of Trends, Seasonality, And System Constraints In The Development Of Realized Models, David B. Wall Mar 2004

Theoretical Models For Aircraft Availability: Classical Approach To Identification Of Trends, Seasonality, And System Constraints In The Development Of Realized Models, David B. Wall

Theses and Dissertations

This research provides forecasting models that will enable the AMC Directorate of Logistics analysis section to predict aircraft availability and provide the TACC with a monthly forecast of the number of aircraft that will be available to fulfill AMC mission requirements.