Noise-induced hearing impairments in Iranian airlines pilots: risk factors and occupational comparisons

After vision, hearing is the most important sensory mechanism for obtaining essential and critical information during flight operations. Pilots are at risk of hearing loss due to exposure to excessive noise which usually causes permanent and incurable hearing damage. This study investigated the hearing status of Iranian pilots and explored the relationship between the severity of their impairment, age, work experience and flight hours.

In this cross-sectional study, eligible pilots were selected. Demographic information, job characteristics, flight hours and auditory complaints were collected. Subsequently, the pilots underwent hearing tests (Pure tone Audiometry) and the hearing threshold was measured at different frequencies.

the study involved 100 pilots (57 fixed-wing pilots and 43 helicopter pilots) with the mean age of 47.77 ± 7.53 years (28-64 years). The average and standard deviation of work experience in all the studied subjects was equal to 24.84 ± 8.44 years. 55 pilots had no auditory impairments, while 45 were diagnosed with some form of hearing impairment. The findings indicate that older age, longer work experience, and more flight hours are significantly associated with greater hearing impairments. Individuals with any level of hearing impairment (slight to mild) had higher age, more work experience, and flight hours compared to those with normal hearing. Helicopter pilots exhibited higher hearing loss severity across frequencies compared to fixed-wing pilots, with statistically significant differences at 2000 Hz for the left ear and 1000, 2000, and 3000 Hz for the right ear. The comparison between the two ears showed that the hearing threshold in any of the flight devices (fixed wing or helicopter), in any of the investigated frequencies, has no significant difference between the left and right ears.

Exposure to loud noise during flights can significantly impact the hearing of pilots. The severity of hearing loss in helicopter pilots is higher across all frequencies compared to fixed-wing pilots. Increased age, work experience, and flight hours are significantly associated with higher severity of hearing loss in both ears. Regular auditory assessments for pilots, especially helicopter pilots, are essential for early detection and monitoring of noise-induced hearing loss.