This document describes a practical system for a user to determine observer-to-aircraft distances. These observer-to-aircraft distances can be either closest point of approach (CPA) distances during field measurements or overhead distances during acoustic certification tests. The system uses a digital camera to record an image of the subject aircraft. A method of using commercial software to obtain the distance from such an image is presented. Potential issues which may affect accuracy are discussed.
This SAE Aerospace Information Report (AIR) summarizes prior empirical findings (AIAA 2018-3991; Chati, 2018) to recommend a modified baseline fuel flow rate model for jet-powered commercial aircraft during taxi operations on the airport surface that better reflects operational values. Existing standard modeling approaches are found to significantly overestimate the taxi fuel flow rate; therefore, a modified multiplicative factor is recommended to be applied to these existing approaches to make them more accurate. Results from the analysis of operational flight data are reported, which form the basis for the modeling enhancements being recommended.
The scope of this ARP embraces the description of a configuration for a ground-plane microphone installation that may be used to determine sound pressure levels equivalent to those which would have been measured in an acoustic freefield at the microphone location. The one-third - octave-band center-frequency range over which equivalent freefield sound pressure levels may be obtained is from as low as 50 Hz to at least as high as 10,000 Hz. The specific application of the measurement technique described in this ARP is the determination of the equivalent freefield sound pressure levels of the noise produced by propeller-driven light aircraft, in flight, for sound incidence angles within 30 degrees of the normal to the ground. For larger angles to the normal, additional adjustments may be necessary which are outside the scope of this ARP.
The scope of this ARP embraces the description of a configuration for a ground-plane microphone installation that may be used to determine sound pressure levels equivalent to those which would have been measured in an acoustic freefield at the microphone location. The one-third - octave-band center-frequency range over which equivalent freefield sound pressure levels may be obtained is from as low as 50 Hz to at least as high as 10,000 Hz. The specific application of the measurement technique described in this ARP is the determination of the equivalent freefield sound pressure levels of the noise produced by propeller-driven light aircraft, in flight, for sound incidence angles within 30 degrees of the normal to the ground. For larger angles to the normal, additional adjustments may be necessary which are outside the scope of this ARP.
Recommendations presented in this document are intended primarily for the acquisition of far-field acoustical data. The test engine is to be appropriately configured and operated so that the acoustical signals generated are consistent with the specific objectives of the test. The principal output of the data reduction system is one-third octave band sound pressure levels. However, broader or narrower bandwidth analysis of the recorded data may also be accomplished when appropriate. Although not specifically intended to apply to special purpose engine noise testing (for example, tests involving unique instrumentation or procedures to identify specific noise sources), some of the practices described herein may be appropriate for such testing. Specification of reference conditions is outside the scope of this document although procedures to adjust data to a reference condition are described in 7.2.4.
Satisfactory measurements of noise in personnel-occupied rotorcraft cabins may require test techniques different from those prescribed for other types of aircraft (ARP1323) because rotorcraft operate under significantly different flight conditions. Recommendations of this ARP apply to the recording of acoustical data on magnetic tape and the subsequent processing and analysis of the recorded data.
Recommendations presented in this document are intended primarily for the acquisition of far-field noise data. The test engine is to be appropriately configured and operated so that the sound pressure levels obtained are consistent with the specific objectives of the test. The principal output of the data reduction system is one-third octave band sound pressure levels. However, when appropriate, data may be recorded for purposes of broader or narrower bandwidth analysis.
Satisfactory measurements of noise in personnel-occupied rotorcraft cabins may require test techniques different from those prescribed for other types of aircraft (ARP1323) because rotorcraft operate under significantly different flight conditions. Recommendations of this ARP apply to the recording of acoustical data on magnetic tape and the subsequent processing and analysis of the recorded data.
This document describes methods for calculating the attenuation of sound due to line-of-sight blockage or shielding from non-level terrain. This method applies to sound propagating from an airplane to locations on the ground during ground roll, climbout after liftoff, and landing operations. AIR1845 and AIR5662 provides guidance for modeling aircraft noise at airports with flat terrain. In reality, many airports are surrounded by non-level terrain that may result in attenuation (or shielding) of sound at some receptors. This noise blockage can be accounted for with the line-of-sight blockage calculation, based on the difference in propagation path length between the direct path and propagation path over the top of terrain feature. The purpose of this aircraft information report is to provide a method that accounts for the attenuation due to line-of-sight blockage of aircraft noise by terrain features.
This SAE Aerospace Recommended Practice (ARP) provides engineering methods that can be applied to monitoring aircraft noise and operations in the vicinity of airports using either attended or unattended monitoring systems, as well as methods for validation of measurement results from permanent systems. Part 1 provides guidance on the components, installation and administration of permanent systems and guidance on analysis of data collected from temporary monitoring of aircraft noise. A separate document, Part 2, describes both system screening tests and detailed test methods for validating the data reported by permanently installed systems. This document is intended as a guide toward standard practice and is subject to change with experience and technical advances. Potential users include: airport proprietors, airport neighbors, federal, state and local government agencies, equipment vendors and other public bodies and officials.
This SAE Aerospace Recommended Practice (ARP) provides engineering methods that can be applied to monitoring aircraft noise and operations in the vicinity of airports using either attended or unattended monitoring systems, as well as methods for validation of measurement results from permanent systems. Part 1 provides guidance on the components, installation and administration of permanent systems and guidance on analysis of data collected from temporary monitoring of aircraft noise. A separate document, Part 2, describes both system screening tests and detailed test methods for validating the data reported by permanently installed systems. This document is intended as a guide toward standard practice and is subject to change with experience and technical advances.
This SAE Aerospace Recommended Practice (ARP) provides engineering methods that can be applied to monitoring aircraft noise and operations in the vicinity of airports using either attended or unattended monitoring systems, as well as methods for validation of measurement results from permanent systems. Part 1 provides guidance on the components, installation and administration of permanent systems and guidance on analysis of data collected from temporary monitoring of aircraft noise. Part 2, this part, describes both system screening tests and detailed test methods for validating the data reported by permanently installed systems. This document is intended as a guide toward standard practice and is subject to change with experience and technical advances.
This SAE Aerospace Recommended Practice (ARP) provides engineering methods that can be applied to monitoring aircraft noise and operations in the vicinity of airports using either attended or unattended monitoring systems, as well as methods for validation of measurement results from permanent systems. Part 1 provides guidance on the components, installation and administration of permanent systems and guidance on analysis of data collected from temporary monitoring of aircraft noise. Part 2, this part, describes both system screening tests and detailed test methods for validating the data reported by permanently installed systems. This document is intended as a guide toward standard practice and is subject to change with experience and technical advances. Potential users include: airport proprietors, airport neighbors, federal, state and local government agencies, equipment vendors and other public bodies and officials.