Accession Number : ADA260689


Title :   In-Flight Evaluation of Noise Levels and Assessment of Active Noise Reduction Systems in the Seahawk S-70B-2 Helicopter


Descriptive Note : Technical rept.


Corporate Author : AERONAUTICAL RESEARCH LABS MELBOURNE (AUSTRALIA)


Personal Author(s) : King, R B ; Foran, D A


Full Text : https://apps.dtic.mil/dtic/tr/fulltext/u2/a260689.pdf


Report Date : Nov 1992


Pagination or Media Count : 46


Abstract : Cabin and at-ear sound spectra in the S-70B-2 at various crew positions and flight conditions were measured in order to determine the noise attenuation properties of the ALPHA helmet and the effectiveness of active noise reduction (ANR) systems developed by the Defence Research Agency-Aerospace Division (formerly the Royal Aerospace Establishment) and the BOSE Corporation. Results show that if newly proposed hearing conservation guidelines are adopted, aircrew wearing the ALPHA helmet would require additional attenuation devices. It is recommended that an ANR system be incorporated into the S-70B-2 as such a system would allow realistic flight duration to be maintained, improve voice communication, and reduce aircrew fatigue.


Descriptors :   *HELICOPTERS , *ACOUSTIC ATTENUATION , *NOISE REDUCTION , FLIGHT TESTING , CORPORATIONS , FLIGHT CREWS , ATTENUATION , AUSTRALIA , VOICE COMMUNICATIONS , DIVISION , FATIGUE(PHYSIOLOGY) , HELMETS , EAR , HEARING , CONSERVATION , NOISE , ACOUSTICS , SOUND , REDUCTION , SPECTRA


Subject Categories : Helicopters
      Acoustics


Distribution Statement : APPROVED FOR PUBLIC RELEASE