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6.4
AUTOPILOT OPERATION
NOTE: Refer to the AFM for specific instructions
regarding emergency procedures.
The autopilot operates flight control surface servos
to provide automatic flight control. Pitch and roll com-
mands are provided to the servos, based on the active
flight director modes. The autopilot uses pitch and roll
rates to stabilize the aircraft attitude during upsets and
flight director maneuvers. Flight director commands are
rate- and attitude-limited, combined with pitch and roll
damper control, and sent to the pitch and roll servo mo-
tors.
Pitch autotrim provides trim commands to the pitch
trim servo to relieve any sustained effort required by the
pitch servo. The pitch servo measures the output effort
(torque) and provides this signal to the pitch trim servo.
The pitch trim servo commands the motor to reduce the
average pitch servo effort.
When the autopilot is not engaged, the pitch trim ser-
vo may be used to provide manual electric trim (MET).
This allows the aircraft to be trimmed using a control
wheel switch rather than the trim wheel. Manual trim
commands are generated only when both halves of the AP
TRIM Switch are operated simultaneously. Trim speeds
are scheduled with airspeed to provide more consistent
response.
Servo motor control limits the maximum servo speed
and torque. The servo mounts are equipped with slip-
clutches allowing the servos to be overridden in case of
an emergency.
190-00567-01 Rev. A
Garmin G1000 Cockpit Reference Guide for the Columbia 350/400
Engaging the Autopilot
NOTE: Autopilot engagement/disengagement is
not equivalent to servo engagement/disengage-
ment. Use the CWS Button to disengage the
pitch and roll servos while the autopilot remains
active.
When the AP Key is pressed, the autopilot and flight
director (if not already engaged) are activated. Engagement
is indicated by a green 'AP' annunciation in the center of
the AFCS Status Box. The flight director engages in Pitch
and Roll Hold modes when initially activated.
Autopilot Engaged
Figure 6-25 Autopilot Engaged
Control Wheel Steering
During autopilot operation, the aircraft may be hand-
flown without disengaging the autopilot. Pressing and
holding the CWS Button disengages the pitch and roll
servos from the flight control surfaces and allows the
aircraft to be hand-flown. At the same time, the flight
director is synchronized to the aircraft attitude during the
maneuver. The 'AP' annunciation is temporarily replaced
by 'CWS' in white for the duration of CWS maneuvers.
In most scenarios, releasing the CWS Button reengages
the autopilot with a new reference. Refer to the flight
director modes section for CWS behavior in each mode.
Control Wheel Steering
Figure 6-26 CWS Annunciation
SECTION 6 – AUTOMATIC
FLIGHT CONTROL
6-21
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