What type of perception occurs during the Pitch-Up Illusion?

The Pitch-Up Illusion is primarily attributed to linear acceleration. This illusion occurs when an aircraft experiences a rapid ascent, often leading the pilot to perceive that the aircraft is climbing more than it actually is. This misperception is largely due to the effects of linear acceleration on the vestibular system, which contributes to our sense of orientation and motion in space. In such cases, the sensation experienced can create an impression of a nose-up attitude, even if the aircraft’s actual pitch is not as pronounced.

The basis for the sensation is rooted in how linear acceleration affects the body's internal references for directional cueing; as the airplane accelerates, the body interprets this acceleration as an upward motion hence leading to the pitch-up illusion. While other types of perception related to yaw, adverse yaw, or constant speed descent are important aspects of aircraft handling and motion, they do not specifically pertain to the misleading sensations associated with a rapid increase in altitude that defines the Pitch-Up Illusion.