There are tons of illusions pilots can experience which lead to spatial disorientation. The ultimate fix? To know about them, how and why they occur, when they occur, and how to recover from these tendencies
First up is The Leans. The leans occur when a quick correction of a banked attitude happens to slowly. The sensory in your inner ear send your brain the sensation of banking in the opposite direction. However the disoriented will just over bank in the wrong direction possibly rolling the aircraft.
Coriolis Illusion The Coriolis Illusion Is caused by making a quick head movement during a constant rate turn that has ceased stimulating the inner ear. The most common occurrence of this is. A pilot making a timed 180 degree turn for one minute, dropping a pen, approach plate etc. Thus stirring up the fluid in the inner ear, when the pilot comes back up he will feel as though he is straight and level, although his instruments show he is still turning. It is best to avoid abrubt head movements while under IFR.
Graveyard Spin The pilot recovering from a spin that was stopped the fluid in the inner ear can create the illusion that he or she has entered a spin in the other direction although they just re-enter the orignal spin
Graveyard Spiral While turning you notice you have lost altitude. Your sensory systems makes you feel as though you are in level flight so you pitch back. Although you are actually in a turn, the abrupt pitching back tightens the turn and you loose more altitude and increase the loss of altitude, the process then repeats itself.
Somatogravic Illusion This is caused usually during take-off. The rapid acceleration pushes the pilot back in his or her seat, giving them the sensation of a nose up attitude to correct the pilot noses the plane over towards the earth. NOTE: A rapid deceleration has the opposite effect.
Inversion Illusion A quick change from a climb to level flight makes the pilot feel as though he or she is tumbling backwards. The natural tendency is to nose the aircraft over, which actually intensifies the illusion.
Elevator Illusion On a turbulent day and updraft could cause extreme vertical acceleration the pilot then proceeds to nose over the aircraft, this illusion also has the opposite effect with downdrafts. Although intense this illusion presents the least of troubles, considering it usually happens at higher altitudes.
False Horizon A false horizon can be caused by city lights, clouds, stars, darkness. It causes the pilot to believe that it is the horizon. The pilot then places the aircraft in this dangerous attitude.
Autokinesis at night, when a light is stared at for a long period of time it begins to “move” While flying at night pilots should not stare at stationary lights for long periods of time to avoid this sensation
For more info on illusions in flight Check out Chapter 8 Section 1 Part 5 of your AIM