Once, while flying a small aircraft at night and in clouds—which meant that I had no visual reference outside the plane—I became convinced that I was in a steep climb. I recognized this intense feeling as a sensory illusion resulting from spatial disorientation. 

During flight training, pilots are taught not to believe or act on the perceptions of the physical senses. They learn to trust instead the information presented by the aircraft’s instruments about the plane’s position and attitude (i.e., how it is oriented in relation to the earth). So that’s what I did when the aircraft suddenly appeared to pitch up steeply. The instruments confirmed that the plane was nearly straight and level, and I trusted that. 

Cloudy, rainy conditions continued during the next two hours, and the impulse to respond to false sensory information persisted. My vigilance in monitoring the flight instruments and my resistance to believing the bodily senses had to remain unwavering. Persistence in responding only to what was true—to what the flight instruments reported—enabled me to avert what could otherwise have been a disastrous outcome.