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Aircraft noise is one of the most controversial environmental concerns in the aviation industry, partly due to the difficulty in harmonizing countries' regulation regarding this issue. The purpose of this thesis is to analyze the ways in which aircraft noise is regulated at the national and international levels, and to compare the legislative responses to aircraft noise issues in Europe and North America. Each of the four main chapters of the thesis takes into consideration a different aspect of the problem. The first chapter describes the objective and subjective ways of measuring aircraft noise. This process is necessary in order to allow the legislation to meet its purpose, namely, to protect the environment, the sources of the aircraft noise, and the effects of the aircraft noise on people. The second chapter describes the evolution of aircraft noise issues at the national levels in the US and throughout the EU, respectively, as well as at the international level, such as at the ICAO. The third chapter analyses the EU Regulation 925/1999, which created tension between the EU and the US due to its alleged discriminatory nature. This thesis examines the arguments of both sides. Finally, the fourth chapter analyses the noise certification standards developed by ICAO, namely the "balanced approach".

Thesis (M.T.P.) -- University of Adelaide, Dept. of Architecture, 1976.

The aim of this research work was to develop an Acoustic Emission (AE) source location method suitable for Structural Health Monitoring (SHM) of composite aircraft structures. Therefore useful key signal features and sensor configurations were identified and the proposed method was validated using both artificially generated AE as well as actual AE resulting from damage. Acoustic Emission is a phenomenon where waves are generated in stressed materials. These waves travel through the material and can be detected with suitable sensors on the surface of the structure. These stress waves are attributed to propagating damage inside the material and can be monitored while the structure is in service. This makes AE very suitable for SHM, in particular for aircraft structures. In recent years composite materials such as carbon fibre reinforced epoxy (CFRP) are increasingly being used for primary and secondary structures in aircraft. The anisotropic layup of CFRP can lead to different failure mechanisms such as delamination, matrix cracking or fibre breakage which affects the remaining life time of the structure to different extents. Accurate damage location is important for SHM systems to avoid further inspections and allows for a maintenance scheme which considers the severity of the damage, due to damage type, extent and location. This thesis presents a novel source location method which uses a small triangular AE sensor array. The method determines the origin of an AE wave by a combination of time of arrival and modal analysis. The small footprint of the array allows for a fast and easy installation in hard-to-reach areas. The possibility to locate damage outside and at a relatively far distance from the array could potentially reduce the overall number of sensors needed to monitor a structure. Important wave characteristics and wave propagation in particular in CFRP were investigated using AE simulated by an artificial source and actual damage in composite specimens.

published_or_final_version / Environmental Management / Master / Master of Science in Environmental Management

The focus of this thesis is to develop and evaluate a cutback noise minimization process - also known as dynamic cutback optimization - that considers engine spool down during thrust cutback and is consistent with ICAO and FAR Part 36 noise certification procedures. Simplified methods for flyover EPNL prediction used by propulsion designers assume instantaneous thrust reduction and do not take into account the spooling down of the engine during the cutback procedure. The thesis investigates if there is an additional noise benefit that can be gained by modeling the engine spool down behavior. This in turn would improve the margin between predicted EPNL and Stage 4 noise regulations. Modeling dynamic cutback also impacts engine design during the preliminary and detailed design stages. Reduced noise levels due to cutback may be traded for lower engine fan diameter, which in turn reduces weight, fuel burn, and cost.

published_or_final_version / abstract / toc / Geography / Master / Master of Geographic Information System

published_or_final_version / Environmental Management / Master / Master of Science in Environmental Management

Thesis (MTech (Environmental Health))--Cape Peninsula University of Technology, 2006 / Airport operations have become a major source of concern due to aircraft nOIse, particularly in areas close to airports and aircraft flight tracks. Public opposition to aircraft noise is a threat to the continued growth of civil aviation in South Africa. This study investigated the psychological effects of aircraft noise on residents and school activities at a neighbourhood close to the airport, particularly the area located under the flight tracks or adjacent to the landing and departure pattern of aircraft. Bishop Lavis was chosen as the experimental area and Kensington, about 17km away from the airport, was chosen as a control area. Questionnaires coupled with oral interviews and observations were used to gather information. The findings are focused on annoyance and disturbance. The study revealed that noise exposure caused annoyance, activity disturbance and some mild effects on school results, when compared with the control area. Disturbances were experienced in some activities that need concentration. Aircraft noise also caused communication interference, sleep deprivation and affected the teaching process. The community at the experimental area indicated some non-acoustical effects, such as fear of aircraft crashing over their homes but they indicated no willingness to leave the area. As such, it becomes essential when locating and designing airports to optimise flight paths in a way to reduce noise exposure to nearby communities. Recommendations for mitigation of noise exposure are proposed, which include operational procedure, banning chapter I and 2 aircraft, restricting night flights, proper land use planning and enforcing international environmental regulations.

Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Physics, 1980. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND SCIENCE. / Bibliography: leaves 346-350. / by David Herbert Munro. / Ph.D.