Page 164 - PPL-engelsk 2025

Human Performance

Remember that vision, if you get just a brief glimpse of a horizon line, will

correct a person's erroneous perception of their position in space (spatial

disorientation).

A rotation of a certain magnitude (over 3 degrees per second) is required

before the canal registers the movement.

Only if we can use our vision to determine our position

can we use the signals from the semicircular canals!!

2.5.5.1 Spatial disorientation

As described earlier, there are many ways to experience false perceptions of

orientation relative to the environment.

When our perception of orientation does not match reality, we experience

spatial disorientation.

This is particularly problematic for VFR pilots in IMC (Instrument Meteorological

Conditions). Studies show that if a pilot without instrument training loses visual

reference to the horizon, they typically lose control of the aircraft within 3

minutes. Stress and anxiety further reduce this time.

Examples of spatial disorientation:

- Graveyard spin

- Cross-coupling illusion

- The leans

- Pitch-up/down illusions

- Distance misjudgment
- White-out conditions

- Slanted cloud layers

- Lack of situational awareness

Flight Theory PPL(A)(UL)/LAPL Henning Andersen, Midtjysk Flyveskole© 2025 164