Vision and Hearing
This domain tests the eye and ear as flight instruments: visual fields and night vision, dark adaptation, visual illusions, and noise-induced hearing loss and equalisation.
Vision
- Rods: dim-light and peripheral vision, no colour, contain rhodopsin; full dark adaptation takes about 30 minutes and cannot be rushed.
- Cones: concentrated in the fovea, provide colour and high acuity in daylight.
- At night, scan 5–10° off-centre so the image falls on rod-rich retina; staring directly at a dim object makes it disappear.
- Empty-field myopia and night myopia blur distant objects in featureless darkness; hypoxia, smoke and fatigue worsen vision.
Hearing
- Sound passes the outer ear, tympanic membrane and ossicles to the cochlea; the Eustachian tube equalises middle-ear pressure.
- Noise-induced hearing loss is cumulative; about 85 dB over 8 hours is a common occupational limit, with shorter limits at higher levels.
- Hearing protection and early equalisation protect both hearing and spatial awareness.
Worked example
On a dark final approach the runway lights seem to move. The pilot should look slightly off the lights and use peripheral vision; direct foveal fixation uses cones that are poor in dim light. If the lights appear to drift, autokinesis is possible and instrument cross-check is required.
Traps that cost marks
- Believing dark adaptation can be accelerated by staring or bright displays.
- Using foveal vision for dim targets.
- Ignoring ear pain on descent instead of equalising early.
- Assuming hearing loss is harmless; it also removes cues for engine and warning sounds.