Low-altitude overflights of fighters and the risk of hearing loss.
OBJECTIVE
Much data are available on noise properties which cause hearing loss. There are not, however, reports on the effects of low-altitude overflight noise on the permanent threshold shift (PTS).


METHODS
Low-altitude overflight noise generated by the Finnish Air Force's jet fighters and an advanced jet trainer was measured with flight distances varying from 50-310 m from the measurement point. The aircraft were always subsonic, velocities being usually 0.9 Mach or less. The measurements were undertaken because of two claims for the compensation of hearing loss caused by overflights of jet fighters on cross-country training missions.


RESULTS
Peak noise levels (LCpeak) varied from 109-150 dB depending on aircraft type and the use of afterburner. The 1-s single A-weighted exposure levels (ASEL) during these overflights were 95-135 dB which correspond to daily (8 h) exposure levels of 50-90 dB.


CONCLUSIONS
According to these results and the principles of noise evaluation, there should be no risk of permanent hearing loss when the distance to an overflying jet fighter is more than 200 m. However, we have received two claims, and the audiometric analyses of two subjects who had suffered hearing loss in one ear in Finland during the 1990s may indicate that there is very likely a connection between the incidents and the hearing losses.
Finnish Air Force Headquarters, Tikkakoski.
P
P
Kuronen
R
R
Pääkkönen
S
S
Savolainen
D000054:Acceleration; D000401:Aircraft; D000531:Altitude; D001299:Audiometry; D001305:Auditory Fatigue; D004781:Environmental Exposure / Q000009:adverse effects* / Q000032:analysis*; D016057:Evoked Potentials, Auditory, Brain Stem; D005260:Female; D005387:Finland; D006317:Hearing Loss, Noise-Induced / Q000175:diagnosis / Q000209:etiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D008889:Military Personnel; D009624:Noise, Transportation / Q000009:adverse effects*; D012307:Risk Factors; D013067:Speech Perception; D013997:Time Factors