Validation of Aircraft Noise Prediction Models at Low Levels of Exposure


Book Description

Aircraft noise measurements were made at Denver International Airport for a period of four weeks. Detailed operational information was provided by airline operators which enabled noise levels to be predicted using the FAA's Integrated Noise Model. Several thrust prediction techniques were evaluated. Measured sound exposure levels for departure operations were found to be 4 to 10 dB higher than predicted, depending on the thrust prediction technique employed. Differences between measured and predicted levels are shown to be related to atmospheric conditions present at the aircraft altitude. Page, Juliet A. and Hobbs, Christopher M. and Plotkin, Kenneth J. and Stusnick, Eric and Shepherd, Kevin P. (Technical Monitor) Langley Research Center NAS1-20103; RTOP 538-03-15-01







Validation of Aircraft Noise Models at Lower Levels of Exposure


Book Description

Noise levels around airports and airbases in the United States arc computed via the FAA's Integrated Noise Model (INM) or the Air Force's NOISEMAP (NMAP) program. These models were originally developed for use in the vicinity of airports, at distances which encompass a day night average sound level in decibels (Ldn) of 65 dB or higher. There is increasing interest in aircraft noise at larger distances from the airport. including en-route noise. To evaluate the applicability of INM and NMAP at larger distances, a measurement program was conducted at a major air carrier airport with monitoring sites located in areas exposed to an Ldn of 55 dB and higher. Automated Radar Terminal System (ARTS) radar tracking data were obtained to provide actual flight parameters and positive identification of aircraft. Flight operations were grouped according to aircraft type. stage length, straight versus curved flight tracks, and arrival versus departure. Sound exposure levels (SEL) were computed at monitoring locations, using the INM, and compared with measured values. While individual overflight SEL data was characterized by a high variance, analysis performed on an energy-averaging basis indicates that INM and similar models can be applied to regions exposed to an Ldn of 55 dB with no loss of reliability. Page, Juliet A. and Plotkin, Kenneth J. and Carey, Jeffrey N. and Bradley, Kevin A. Langley Research Center AIRCRAFT NOISE; NOISE INTENSITY; NOISE REDUCTION; FLIGHT CHARACTERISTICS; RADAR TRACKING; POSITION (LOCATION); FLIGHT OPERATIONS; SOUND PROPAGATION; NOISE PREDICTION (AIRCRAFT); AEROACOUSTICS; AUTOMATED RADAR TERMINAL SYSTEM; RELIABILITY; AIRPORTS; APPLICATIONS PROGRAMS (COMPUTERS); EXPOSURE...







Validation of Aircraft Noise Exposure Prediction Procedure


Book Description

The NOISEMAP predictive procedure is used to describe the noise environment around airbases and thereby aid airbase planners to prevent community encroachment limiting the effectiveness of the installation. This report delineates the results of measurements made over one to three week periods at four Air Force airbases to acquire the data needed to validate and/or modify the noise predictive algorithms in NOISEMAP for takeoff, landing, traffic pattern, and ground runup operations. In general, the algorithms currently used in NOISEMAP provided predictions that agreed well with measured data. It was found the obtaining accurate data on aircraft operational procedures (engine power settings, airspeeds, and flight paths) was essential.













Aircraft Noise


Book Description

Aircraft noise has adverse impacts on passengers, airport staff and people living near airports, it thus limits the capacity of regional and international airports throughout the world. Reducing perceived noise of aircraft involves reduction of noise at source, along the propagation path and at the receiver. Effective noise control demands highly skilled and knowledgeable engineers. This book is for them. It shows you how accurate and reliable information about aircraft noise levels can be gained by calculations using appropriate generation and propagation models, or by measurements with effective monitoring systems. It also explains how to allow for atmospheric conditions, natural and artificial topography as well as detailing necessary measurement techniques.




Analysis of Measured Environmental Noise Levels: An Assessment of the Effects of Airbase Operational Model Variables on Predicted Noise Exposure Levels


Book Description

This report presents an exhaustive study of measured noise data collected over a three week period at McChord AFB. The NOISECHECK methodology for comparing noise predictions to measured noise data was used in an effort to quantify the complicating factors relevant to airbase environmental noise prediction. These factors are dominated by parameters of the aircraft operations model. The operational model parameters are segregated and their effects on noise level predictions discussed, using the Probability of Consistency as a measure of their overall impact. It was found that noise generation was very sensitive to relatively small changes in power setting. The operational model of aircraft altitude and track location produced the most significant effects on predicted noise levels. The level of detail analysis attained allowed further assessment of the problems of noise generation and propagation modeling. The detailed NOISECHECK Sound Exposure Level analysis was automated using a database management system, which greatly reduced the effort required to conduct the repeated analyses required for this study. The retrieval and comparison of NOISEMAP noise level predictions were also automated. An accurate approach to estimating the operational parameters needed to model variable aircraft operations was developed and partially validated.