Accession Number : AD0718098

Title :   Six Indices for Predicting Speech Interference Within Aircraft,

Descriptive Note : Final technical 1 Oct 68-6 Jul 70,

Corporate Author : SCHOOL OF AEROSPACE MEDICINE BROOKS AFB TEX

Personal Author(s) : Gasaway,Donald C.

Report Date : DEC 1970

Pagination or Media Count : 35

Abstract : Acoustic noise within aircraft during flight often causes some degree of interference with aural communication. Several methods have been used over the years to identify and predict degrees of speech interference. Six of these methods are discussed: four involve octave-band averaging; two use frequency weighting. The assessment is based on application of each of the six indices to noise levels measured within the cockpits of 191 fixed-wing and 58 rotary-wing aircraft, grouped into 11 categories by engine type. Equivalent speech interference levels obtained from the use of each of the six indices are provided for the acoustic spectra developed for the 11 classes of vehicles. The operational considerations which influence speech interference values are described. Noise attenuation provided by headset devices commonly used by Air Force aircrew members is shown for different groups of noise spectra. Criteria are given for evaluating protected and unprotected exposures to noise that compromise communications. (Author)

Descriptors :   (*SPEECH, INTERFERENCE), (*VOICE COMMUNICATIONS, INTELLIGIBILITY), (*AIRCRAFT NOISE, AUDITORY PERCEPTION), AVIATION MEDICINE, MATHEMATICAL PREDICTION, ATTENUATION

Subject Categories : Acoustics
      Voice Communications

Distribution Statement : APPROVED FOR PUBLIC RELEASE