 An abrupt change from climb to straight-and-level flight can stimulate the otolith organs enough to create the illusion of tumbling backwards, or inversion illusion.The disoriented pilot may push the aircraft abruptly into a nose-low attitude, possibly intensifying this illusion.The head-up illusion involves a sudden forward linear acceleration during level flight where the pilot perceives the illusion that the nose of the aircraft is pitching up.