U.S. Army CH-47D cargo helicopter crewmembers are exposed to high leve
ls of noise on a routine basis, yet must accomplish demanding missions
that rely heavily on clear communication, This study looked at the au
ditory influences affecting communication by 17 crewmembers of a CH-47
D Army Reserve unit, Results revealed (1) noise levels that exceed tho
se of other Army rotary-winged aircraft, (2) different exposure levels
for aviators and crewchiefs, (3) an overall preference for hearing ''
critical or diagnostic'' aircraft sounds rather than wearing double he
aring protection, (4) complaints of postflight tinnitus or muffled hea
ring, (5) helmet discomfort among the majority of crewmembers, (6) a h
igh incidence of hearing loss, (7) difficulties in adjusting radio vol
ume controls for aviators, and (8) the effects of eyeglasses or protec
tive masks on hearing and communications.