Spatial disorientation & illusions

Without an outside horizon, your balance organs and your eyes lie to you. The defence is one rule: trust the instruments, not your senses.

Vestibular illusions (the inner-ear balance organs):

• The leans (most common): a false sense of bank after a slow, unnoticed roll.
• Coriolis illusion: a head movement during a turn gives a violent tumbling feeling.
• Graveyard spiral: a steady turn comes to feel level, so easing back only tightens the spiral.
• Somatogravic illusion: forward acceleration feels like a nose-up pitch, tempting you to push down.

Visual illusions (the eyes):

• False horizon: sloping cloud or ground mistaken for the real horizon.
• Black-hole approach: a featureless night approach feels too high, so you fly low.
• Runway width/slope: a narrow or up-sloping runway feels too high; a wide or down-sloping one feels too low.
• Autokinesis: a single fixed light in the dark seems to move.

Trap: acting on what your body feels. In cloud or on a black night the sensations are convincing and wrong, so fly the instruments.

Note: TC AIM AIR 3.7 names the false horizon and the steady-turn recovery illusion, and says to trust your flight instruments. The fuller illusion taxonomy (the leans, Coriolis, somatogravic, graveyard spiral, black-hole, runway width/slope, autokinesis) is grounded in the FAA Pilot's Handbook (FAA-H-8083-25), a free public-domain text; the model is universal.

Practice