Noise Attenuation Performance of the Lightning II Generation II Helmet When Worn in Combination with the Joint Service Aircrew Mask (JSAM)-Joint Strike Fighter (JSF).

摘要

Noise attenuation measurements were conducted by the AFRL on the Lightning II Generation II (Gen II) Helmet Mounted Display (HMD) when worn in combination with the Joint Service Aircrew Mask (JSAM)-Joint Strike Fighter (JSF) at WPAFB in October 2012. ANSI S12.6 and S12.42 were used to measure the passive attenuation and active insertion loss performance respectively. The objective of this study was to determine if the JSAM-JSF hood would meet the noise attenuation performance requirement. When comparing the total noise attenuation of the Gen II HMD with and without the JSAM-JSF, a degradation of 3 dB or more was found in multiple frequencies with the addition of the hood. This degradation was due to the large reduction of active insertion loss. The addition of communication earplugs worn in combination with both the helmet and the hood provided more passive attenuation. Still degradation was found at the lower frequencies (125 and 250 Hz).