The ERJ-170 airplane will use fly-by-wire (FBW) technology as a
means of sending command and control signals to the control surface
actuators of the rudder, rudder trim, elevator, spoilers, horizontal
stabilizer, and auto speedbrake. The ailerons will be controlled by a
traditional cable linkage to the hydraulic actuators.
The ERJ-170 FBW flight control systems provide two modes of
operation, direct and normal. Direct mode provides an analog link
between pilot commands and control surfaces. In direct mode, flight
control transducers send signals to Actuator Control Electronics units
(ACE). The ACE sends analog command and control signals to the Power
Control Units (PCU), which move the control surface actuators of the
rudder, rudder trim, elevator, spoilers, horizontal stabilizer, and
auto speedbrake.
In normal mode, the rudder, elevator and spoiler command-to-surface
gain schedules are tailored to particular flight conditions to provide
improved control characteristics. These gains are calculated digitally
in the Flight Control Module (FCM) and supplement the direct mode
commands provided by the ACEs.