The following list represents the different types of SD illusions that are implemented in the DFS today:
Jet-upset illusion (Somatogravic pitch-up)
On takeoff the inertial force from the forward acceleration combines with the force of gravity to create a resultant gravito-inertial force directed down and aft. The pilot, perceiving down to be in the direction of the resultant gravitoinertial force, feels in an excessively nose-high attitude and is tempted to push the stick forward to correct the illusory nose-high attitude.
The coriolis illusion occurs when a pilot has been in a turn long enough for the fluid in the ear canal to move at the same speed as the canal. A movement of the head in a different plane, such as looking at something in a different part of the flight deck, may set the fluid moving and create the illusion of turning or accelerating on an entirely different axis. This action causes the pilot to think the aircraft is doing a maneuver that it is not. The disoriented pilot may maneuver the aircraft into a dangerous attitude in an attempt to correct the aircraft´s perseived attitude.
is any attitude the airplane is in that is not what the pilot perceives it to be in. This could be a very mild deviation of the perceived attitude or it could be a major deviation.
In either case the airplane needs to be righted back to the desired attitude.
The pilot must be taught to resist the optical illusion he or she sees outside the airplane or “feels” in their head. They must be taught to understand their own physiological limits and rely on their aircraft instruments.
In fast-moving aircraft, the G-excess illusion can occur as a result of the moderate amount of G force pulled in a penetration turn or procedure turn, for example. If the pilot has to look down and to the side to select a new radio frequency or to pick up a dropped pencil while in a turn, he or she should experience an uncomman-ded tilt in both pitch and roll planes due to the G-excess illusion.
The G-excess has been suspect in several mishaps involving fighter/attack aircraft making 2 to 5.5 G turns at low altitudes in conditions of essentially good visibility. For some reason, the aircraft were overbanked while the pilots were looking out of the cockpit for an adversary, wingman, or some other object, and as a result descended into the terrain.
Post rotatory illusion
A normal reaction of the eyes in reaction to the body being rotated in a swing. The eyeballs respond by constantly moving in a cyclical direction.