Some excerpts taken from the book:
Gyroscopic Instruments
CHAPTER 4
ARTIFICIAL HORIZON
Artificial Horizon is the DR navigational reference for the pitch and roll attitudes of the aircraft (fig. 4.1). In the human body, this instrument corresponds to the semi- circular neurological canals, which control the up- right (or normal) posture of the body.
An aircraft flight attitude is normal if the nose and the wings
4.1.3 Acceleration Error.
The acceleration error of the Artificial Horizon is represented in the vorticity equation (2.5) by the term . It depends on the y- component of the Coriolis torque and, therefore, it produces a gyro drift similar to the one of the DGI apparent wander (see section 2.2.3). This drift, however, is noticeable only in the pressure models because the pendulous unit (fig. 4.3) amplifies it when the aircraft accelerates or decelerates. Since the electrical models dispense with the pendulous erection unit system, the acceleration error does not affect them.
4.1.4 Turning Error.
The Artificial Horizon drift known as the turning error is