Thesis (Ph.D.) -- University of Texas at Arlington, 2008.

No description available.

This study examines the main problems associated with passenger survival and evacuation in survivable aircraft fire situations under current regulatory safety requirements and assesses current and alternative strategies to combat cabin fire, and assist evacuation, with a view to identifying a best alternative strategy. The technical and management findings associated with a research programme which was conducted into passenger smoke hood protection are then described. The survival/evacuation/pathology aspects associated with 10 selected accidents to public transport aircraft which involved fire are reviewed at the outset of this study in order to set forth the attendant problems of survival in such situations. The pathology and toxicological findings associated with these accidents are then discussed. The assembled information is then analysed with a view towards identifying the key problems inherent in survival and evacuation from aircraft fires, including those which stem from survivable in-flight fires. The current regulatory requirements and associated strategies relating to occupant survival/evacuation are then critically reviewed against the key problems identified. A review of alternative strategies is then conducted and an assessment made of technical potential, related cost-benefit data, problems still to be resolved and possible timescales for implementation. A'best-strategy'is then selected. The potential benefits of this strategy are then set forth in terms of its relevance to the survival/evacuation problems identified, associated cost-effectiveness, potential synergy with existing, and possible future, requirements and implementation timescale. A review of data on aircraft fires is then conducted, including that associated with the thermochemical characteristics of such combustion atmospheres and related effects on animals and humans. Using this data, the approach used to develop a set of acceptance criteria for aircraft passenger smoke hood designs is described. In addition, the way in which a challenge combustion atmosphere model was developed, and against which filter-type smoke hoods could be tested, is described. The organisation and implementation of a research programme to evaluate the performance capability of a range of breathable-gas and filter-type smoke hoods is then described in terms of the technical and management aspects, and the results set forth- Finally, the results of the study are analysed from both a technical and management perspective and appropriate conclusions and recommendations presented.

Aviation represents a complex socio-technical system in which a strong emphasis is placed upon safe operation. Advances in this area have traditionally been reactive following particular incidents or accidents. As the traditional accident causes (predominantly technical engineering factors) have become better understood, the need for proactive solutions to counteract the increasing proportion of human performance related accidents has grown. This thesis proposes and utilises case-study research methodology to examine the reasons behind Australia's good record for airline safety. At the time of writing, no lives have been lost in an Australian jet passenger aircraft accident. The methodology is designed to advance the application of systemic safety investigation in order to avoid the traditional "primary-cause focussed safety investigations" which are generally used following accidents. Having established the safety record for commercial jet RPT (regular public transport) operations to be above average, a number of factors which may have an effect on that record are reviewed. The analysis is divided into three main sections, namely the human, operational and natural environments. Evidence used comes from a variety of sources so as to ensure validity. Data collection methods included primary data obtained through expert witness interviews and attitude surveys of 2,600 Australian and British flight crew and air traffic controllers. Secondary data came from extensive literature reviews which have attempted to bring together existing micro-level research work in a systems context. Initial conclusions point to the existence of a number of natural environment factors which are perceived to have a major effect on flight safety. However, deeper examination has suggested that there are a number of cultural factors within the human and operational environments which exist at professional, corporate, industry and national levels. These have contributed to the quality and quantity of risk countermeasures which have been instrumental in creating the good safety record. This thesis explores the importance of these influences and how they may be changing in the current and future aviation environment.

Thermal anti-icing systems are commonly used to protect aircraft leading edges from a potentially hazardous build-up of ice. Such systems have proven reliable in service and are relatively cheap and efficient. Typically, hot air is tapped from the engine compressor and ducted (via a regulation and control system) to the surface to be protected. Ideally an optimisation process should be employed at the design stage in order to ensure adequate anti-icing capability with minimal use of engine bleed air, since the latter represents a performance penalty. Following submission by the author of an MSc thesis concerning thermal modelling of a hot air anti-icing system for a civil turbofan intake (Wade 67 ), it became clear that extension of the studies was necessary to enable systematic accounting of the factors which limit ice accretion. An experimental programme was therefore carried out to investigate primarily: various exhaust geometries (through which spent anti-icing air is emitted to join the main engine inlet airflow and provide heating of the downstream surface; various cowl internal configurations on a full-scale model section of a large civil turbofan Nose Cowl. The internal geometry affects the effectiveness of the cowl lipskin heating, and the spent anti-icing exhaust air limits the quantity of unevaporated water which runs back along the intake acoustic surface downstream of the directly heated area and freezes. The Computational Fluid Dynamics package PACE (Prediction of Aerodynamics and Combustor Emissions) was used to model the internal, freestream and exhaust airf lows to determine the program's potential and usefulness for predictive purposes in this type of application. PACE is capable of modelling two or three dimensional, recirculating or non-recirculating flows for simple rectangular or polar geometry. It encompasses a suite of sub-programs to generate meshes and to create and solve the set of coupled linear equations representing the fluid flow. Various parameters, including heat transfer coefficients, were predicted in two regions: downstream of the exhaust plane to model the mixing of the spent anti-icing air and the freestream main engine inlet flow; inside and outside the Nose Cowl highlight area to predict skin temperature distributions for the three internal geometry configurations tested. This thesis describes the experimental work and compares the results with the Computational Fluid Dynamics predictions. Agreement was generally found to be good, and it was concluded that PACE may provide a useful modelling (design) tool, albeit with some reservations.

Modem control methods have often been advocated by academics as able to solve fairly complex control engineering design problems in the aircraft industry. However, evidence suggests that practicei s still gearedt owardsu sing classicalt echniques,e ven on the most modem fighter aircraft which are open-loop unstable. This thesis stems from a need to understand the reasons for this. Modem methods are examined in order to determine their strengths and weaknesses when applied to industrial problems. As a representative situation, a modem control method, eigenstructure assignment, is examined. One objective of the research described in the thesis is to improve the application oriented aspects of the methodology of eigenstructure assignment. The purpose of this is that every facet of the method can then be explained in terminology that is familiar to the aircraft control engineer. Furthermore, the theory is developed such that it is compatible with easily understandable controller structures and control design strategies, to provide a control system with good performance and robustness characteristics. The design of a robust controller for a civil aircraft model developed by the GARTEUR (Group for Aeronautical Research and Technology in Europe) demonstrates the utility of eigenstructure assignment and culminates in suggestions as to when and where the method has its greatest strengths and weaknesses.

When we consider regional differences in air safety, a call for regional solutions is needed. This research probes the current situation in Taiwan and part of Asia from a regional perspective, aiming to better understand safety management in this region. Data was drawn from an extensive survey involving both airline pilots and aviation authority officers. The research investigated respondents' perceptions in airline safety management, and examined at their opinions about the role of aviation regulatory authorities and language disadvantages when exchanging safety information. The results demonstrated that there were key differences between the Captains and the First Officers surveyed in many aspects of airline safety management. The First Officers were more eager to have a blame-free and information-shared culture in current bureaucratic systems than were the Captains. Most pilots expected airline top management and aviation regulatory authorities to take more information responsibility for circulating safety related messages and information. It is believed that a confidential incident reporting system is one of the most appropriate tools for improving safety. It would be sensitive enough to provide early identification and warning for rooting out underlying causal factors, and allow constant tracking of hazards and evaluation of risks they involve. Hence, the second part of the thesis discusses the feasibility of establishing a national-level confidential incident reporting system in Taiwan from the viewpoints of the airline pilots and the air traffic controllers. The survey showed that there was great expectation for the introduction of a national- level confidential reporting system. However, there was need to undertake a high profile promotional period within the aviation community, followed by a two-year trial period. This would help to motivate potential reporters, eliminate their fear of punitive action, and enable consensus and support to be sought from the airlines. Initially, it is advised to begin with the participant of flight crew and air traffic controllers only. At the end of the trial period, an evaluation of the system achievements was recommended. After two years of successful operation the system might be extended to include maintenance personnel, cabin crews and other relevant parties.

A review of techniques for stability and response investigations is presented and the averaging technique of Beecham- Titchener-Simpson is applied to the lateral equations of. motion for two combat aircraft. The analytic technique predicts oscillation amplitudes and frequencies accurately, for non-linear aerodynamic characteristics with respect to sideslip or roll rate. However, limitations of the method are apparent when non-linearities in roll rate and sideslip are treated simultaneously. Rates of growth to limit cycle oscillations are predicted by the averaging method and two formulations for a local damping factor are compared with simulation results. Results from extensive wind tunnel tests on a High Incidence Research Model (HIRM) are presented along with estimates of dynamic stability derivatives and polynomial fits to the wind tunnel data. The lateral stability and response of the HIRM at high angles of attack, is investigated using the analytic techniques described earlier, as well as simulations. Six degree of freedom eigenvalue results for the HIRM are shown. An investigation into the effects of cross-coupling derivatives and different forms of roll rate data, using non-linear and linearised simulations, concludes the thesis.

A study has been conducted into the design of civil aircraft seats which are forward-facing and use the lap-belt method of restraint. Within these terms of reference, the response of the seat restraint occupant system (SROS) to impact loading has been analysed using physical (dynamic testing) and analytical (computer simulation) modelling techniques. With the increasing use of fibre-reinforced polymer composites in aircraft for weight efficiency, and the consequent appearance of composite seats, attention must be given to the crash performance of these structures. Composite structures are characterised by brittle failure with low impact energy absorption, in comparison to the collapse of metal structures which may exhibit plastic deformation prior to failure. However, using the developing technology of composite sub-structures with high specific energy absorption capability, seat structures have been modified to incorporate composite load-limiting elements. The redesign process involved the compatibility of energy absorber loads with occupant dynamics to minimise injury potential, together with the alleviation of forces in the structural load path to reduce damage and preclude failure of the seat, floor track, and other components. Shortcomings of existing seat designs were assessed, and the dynamics of lap-belted occupants analysed, including secondary head impact with the forward seat structure. The computer' model created was validated against the results of dynamic tests, and then used in a parametric study of occupant dynamics. Conclusions and recommendations include guidlines relating to the future design of both metal and composite seats.

Thesis (Master of Military Studies)-Marine Corps Command and Staff College, 2008. / Title from title page of PDF document (viewed on: Jan 5, 2010). Includes bibliographical references.