Subjective Evaluation of the Communications Earplug with Flexible Harness (CEP/FH) Among CH-47D Crewmembers.

Abstract : Noise levels in Army rotary-wing aircraft, particularly the CH-47D (Chinook), can reach as high as 115 dBA. Current aviator helmets provide adequate hearing protection. However, speech communication is less than optimum. The Communication Earplug with Flexible Harness (CEP/FH), developed at the United States Army Aeromedical Research Laboratory, may provide an answer to the problem. Seventeen aviators and crewmembers of a U.S. Army Reserve CH-47D unit field tested the CEP/FH and subsequently were queried. Results of the posttrial survey are presented and discussed. When compared with the standard issue SPH-4 series aviator helmet, crewmembers wearing the CEP/FH perceived improved speech clarity and reduced levels of noise. Based on weaknesses relative to the harness and microphone components of the CEP/FH, an advanced prototype of the CEP has evolved. It promises to be more compatible within the CH-47D environment, and more acceptable to crewmembers than the CEP/FH, while providing hearing protection and enhancing speech intelligibility in noise.