COMPARISONS OF VARIABILITY IN AIRCRAFT FLYOVER NOISE MEASUREMENTS

Data from controlled flight testing conducted for 11 aircraft noise certification programs under FAA FAR 25 show typical standard deviations for sets of EPNL and PNL values ranging from 0.8 to 1.4 dB. Much greater variability was found in the noise levels measured near the approach path to runway 21R at Detroit Metropolitan Airport during two ten-day periods of routine operations. EPNL, SEL, and maximum A-level data, classified in jet aircraft groups by number of engines (regardless of type), showed typical standard deviations ranging from 3.8 to 4.9 dB at the different ground measuring points. Correlation of the Detroit noise data with slant distance gave moderately high correlation coefficients, with 95% prediction intervals about the regression lines varying from plus/minus 5/4 to plus/minus 9/5 dB. The regression lines show quite good agreement, particularly in slope, with generalized noise level versus distance curves often used for noise exposure calculations. Correlations between different noise measures were high, as expected. However, prediction intervals about the regression lines were sizable, indicating distinct possibilities for occasional sizable errors in estimating one noise measure from another when analyzing aircraft flyover noise signals.

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  • Corporate Authors:

    Acoustical Society of America

    335 East 45th Street
    New York, NY  USA  10017
  • Authors:
    • BISHOP, D E
  • Publication Date: 1975-12

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Filing Info

  • Accession Number: 00155926
  • Record Type: Publication
  • Source Agency: Massachusetts Institute of Technology
  • Files: TRIS
  • Created Date: Sep 20 1977 12:00AM