Embraer EMB145 Operation Manual page 90

VERSION 20.7
The EICAS 20.7 features implemented in the software are described
below:
Autopilot:
 Autopilot disengagement without aural warning Correction: It was
verified that under certain circumstances the autopilot can
disengage without aural warning. It occurs when autopilot is
engaged and TCS button pressed. If any pitch trim switch is
commanded while the TCS is being released the autopilot
disengages with no aural warning. The same situation can occurs
when deploying/retracting speed brake simultaneously to TCS
releasing, due to the automatic pitch trim command during speed
brake actuation.
 Symbol Generator Reversion Correction: It was verified an
abnormal behavior in the Automatic Flight Control System when a
Symbol Generator reversion occurs on the pilot side. In this case
the Autopilot reverts to basic mode and automatically couples to
the co-pilot Flight Director as expected. If a vertical mode is
selected to either climbing or descending following the Symbol
Generator reversion, the Autopilot will not hold the pre-selected
altitude although the Flight Director bars indicate level off and the
PFD shows the correct mode transition from the selected vertical
mode to ASEL mode and from ASEL mode to ALT HOLD mode.
 CAT II operation at Providence Airport: Automatic Flight Control
System changes were required in order to allow CAT II operation at
Providence Airport, which has a RA Minimums of 80 ft. The current
RA Minimums interval does not include 80 ft. Therefore, the 80 ft
RA Minimums was included in the CAT II logic to allow proper
operation in this airport.
 Roll Oscillation Solution at high altitudes: Yaw Damper control law
was modified in order to minimize the roll oscillation observed at
high altitudes when autopilot is engaged. This modification is
enabled only in the 135 family airplane (EMB-135ER, EMB-135LR
and EMB-135BJ) via IM-600 new parameter called RUDDER BIAS.
REVISION 41
AIRPLANE
OPERATIONS
MANUAL
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GENERAL
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