Study Of The Effect Of Fighter Aircraft Noise On Hearing And Performance Of Pilots And Ground Crew

The noise level in fighter cockpit is rather high. It was measured that the cockpit noise levels of J-6, J-7 and J-8 were 108—110 dB(A) respectively while the maximum noise level of J-8D was as high as 116.3 dB(A), that is far beyond the stipulate limit for cockpit noise 108 dB(A). The noise intensity outside the cockpit is also very high. The engine hatchway noise level of the main types of fighter aircraft in our country ranged from 117 to 130 dB(A), while the maximum engine hatchway noise of J-8D exceeded 140 dB(A). This is far beyond stipulate criteria for protection of hearing home and aboard, that is the noise should not exceed 115 dB(A) for naked ear noise exposure. The main hazard of aircraft noise is that it will induce hearing loss of aircrew and ground crew; by the way, it will influence the performance of aircrew. The aim of this study is to improve the medical support forfighter pilots and ground crew.Hearing of 103 fighter pilots was examined in Air Force sanitarium. In an Air Force unit, hearing of 62 ground crew was examined; hearing of 18 pilots was examined before aircraft noise exposure, 0.5 h, 1.5 h and 15 h after exposure; using correct rate of simulated code as the performance index, the recognition of code was examined in 18 pilots before noise exposure and 40 min after exposure. In the laboratory, recognition performance of 56 Chinese phrases (abbreviations phrases) on information of cockpit display by hearing was tested in 3 conditions as follows: in quiet environment wearing passive anti noise headset; in environment with simulated aircraft noise wearing passive anti noise headset; in environment with simulated aircraft noise wearing active anti noise headset.The result showed that, 50 out of 103 (48.5%) pilots had hearing loss at high frequencies. 16/103 (15.5%) had hearing loss at voice frequencies; 43 out of 62 (69.4%) ground crew had hearing loss at high frequencies; 13/62 (21.0%) had hearing loss at voice frequencies; The V shaped deepening of audiogram in pilots and ground crew is at 6000 Hz. The effect of fighter aircraft noise on temporary hearing threshold shift in pilots is significant: the maximum shift 2 min after exposure was as high as 40 dB(A), the tendency of restoring was found 1.5 h after exposure, a great degree of restoring occurred 15 h after exposure but did not return to normal at most frequencies. The correct rate of code recognition in 18 pilots before noise exposure was 96.8%, and lowered down to 83.2% 40 min after noise exposure, the difference was statistically significant. The results of performance test for recognition of...