Helmet-Mounted Displays: - USAARL - The - U.S. Army

Acoustical Performance 227
Figure 8.5. Speech intelligibility verses speech level
in UH-60 noise for three devices.
hearing-impaired aviators wearing CEP or ANR were compared with the
95% confidence interval for the normal aviator wearing the SPH-4 helmet
are shown in Figure 8.6. Only 1% of the hearing impaired aviators were in
the 95% confidence interval while wearing the SPH-4, as compared to 65%
while wearing the CEP helmet and 40% while wearing the ANR helmet.
Operational Assessment
One of the most critical requirements of systems development is to
define the worth and acceptability of the system to the user group. User
acceptance testing should be performed by the user in the environment or,
at a minimum, a high fidelity simulation of the environment. Personal
equipment such as communications and hearing protective devices must be
assessed during as many user conditions as possible and in as many
climatic and environmental conditions as practical (Staton, Mozo, and
Murphy, 1997; Mozo and Murphy, 1997a).
A study (Mozo and Murphy, 1997a) comparing the CEP and the HGU-
84 using Navy and Marine Corp aviators assigned at Quantico, Virginia,
was accomplished over a 4-month period. A preference questionnaire was