Which flight phase is especially prone to somatogravic illusion and why?

• A. Takeoff and rapid acceleration, because forward acceleration can mimic a nose-up attitude.
• B. Cruising at steady altitude in clear weather.
• C. Descent with constant airspeed.
• D. Approach with flaps extended.

Answer: (A)

Somatogravic illusion is a vestibular misperception where linear acceleration is interpreted as a change in pitch. During takeoff and rapid forward acceleration, the strong forward push is sensed by the otolith organs as a nose-up attitude, even though the aircraft may be level. In conditions with limited visual cues, this misperception can lead the pilot to make improper pitch adjustments because the brain thinks the nose is higher than it actually is. That’s why this flight phase is especially prone. In steady cruising, a descent with constant airspeed, or an approach with flaps, there isn’t the same strong forward acceleration driving the illusion, so the tendency to misinterpret attitude is much smaller.