Noise attenuation of helmets and headsets used by Finnish air force pilots

Abstract

The noise attenuation properties of aviation helmets and headsets are generally given only in commercial brochures, and attenuation comparisons between different types of helmets and headsets are seldom shown. Therefore a comparative study was carried out. Four military fighter helmets and two headset types were studied against pink noise in an anechoic chamber. In addition, the active noise reduction (ANR) system of one helmet and the deterioration effect of the noise attenuation of an Alpha aviation helmet in combination with sunglasses and a cushion cloth were studied. When the A-weighted noise attenuation values were compared, the noise attenuation value was 31 dB for the Silenta Super earmuffs, 27 dB for the Ampliguard earmuffs, 25 dB for the Alpha helmet with ANR, 22 dB for the Alpha helmet, 21 dB for the FFV 113B helmet, 16 dB (unadjusted) for the ACS helmet, and 10 dB for the ZSH-5 helmet. The sunglasses reduced the noise attenuation by 4 dB, and the cushion cloth only by 1–2 dB. ANR improved noise attenuation by 3–19 dB in the 63–250 Hz frequency range. We concluded that noise attenuation of greater than 20 dB is needed because modern fighters and helicopters often have a noise level higher than 100 dB in the cockpit. Therefore, the noise attenuation properties of aviation helmets should not be forgotten in helmet and headset design.