Accession Number:

ADA422207

Title:

Insertion Loss of the HGU-84/P Rotary-Wing Helmet System with Oregon Aero Earcup Replacement Products

Descriptive Note:

Final rept.

Corporate Author:

ARMY AEROMEDICAL RESEARCH LAB FORT RUCKER AL

Report Date:

2004-02-01

Pagination or Media Count:

279.0

Abstract:

The sound attenuation of the H6U-84P Rotary-Wing Helmet System with Oregon Aero earcup replacement products was evaluated in accordance with ANSI S12.42-1995 R1999 Microphone-in-Real-Ear procedures. The differences in insertion losses between the various helmet modifications were generally quite small and unlikely to have an effect on operational considerations, especially if double hearing protection in the form of earplugs, the Communications Earplug CEP, or Attenuating Custom Communications Earphone System for Aircrew ACCES for Aircrew is employed. The insertion loss of the helmet with the Oregon Aero HushKit earcup replacement foam was significantly poorer than the standard helmet system. Insertion losses with the SoftSeal replacement earcup seal with HushKit and the SoftSealHushKit Combo soft replacement earcup were statistically significantly greater than the standard helmet configuration at some frequencies, although the differences were marginal at the low frequencies at which rotary-wing noise hazards are the greatest. Caution is urged when considering the use of the SoftSeal or SoftSealHushKit Combo since, at the time of this writing, neither of these earcup replacement products has been evaluated for helmet retention or blunt impact protection in case of an aircraft mishap.

Subject Categories:

  • Helicopters
  • Acoustics
  • Protective Equipment

Distribution Statement:

APPROVED FOR PUBLIC RELEASE