Flight Control; Pitch Axis And Trim; Roll Axis; Yaw Axis - Garmin GI 275 Pilot's Manual

Autopilot

6.2 FLIGHT CONTROL

Pitch and roll commands are provided for control of the servos based on the active Flight
Director modes. Yaw damping is provided by the yaw servo. Servo motor control limits the
maximum servo speed and torque. The servo gearboxes allow the servos to be overridden in
case of an emergency.

PITCH AXIS AND TRIM

The Autopilot pitch axis uses pitch rate to stabilize the aircraft pitch attitude during upsets
and Flight Director maneuvers. Flight Director pitch commands are rate and attitude-limited,
combined with pitch damper control, and sent to the pitch servo motor.
When the Autopilot is engaged, the Automatic Pitch Trim (APT) function commands the
pitch trim actuator to reduce the average pitch servo effort.
When the Autopilot is not engaged, manual trim functionality is available at any time by
using the Trim Switches.

ROLL AXIS

The Autopilot roll axis uses roll rate to stabilize aircraft roll attitude during upsets and
Flight Director maneuvers. The Flight Director roll commands are rate and attitude-limited,
combined with roll damper control, and sent to the roll servo motor.

YAW AXIS

The Autopilot yaw axis uses yaw rate and roll attitude to dampen the aircraft's natural Dutch
roll response. The Yaw Damper uses lateral acceleration to coordinate turns.

6.3 AUTOPILOT OPERATION

COMMAND BARS

Upon activation of a Flight Director, Command Bars are displayed in magenta on the MFI as
a single cue. The Command Bars move vertically to indicate pitch commands and bank left or
right to indicate roll commands.
When the Autopilot is engaged, the magenta Command Bars and the amber Aircraft Symbol
move together in unison.
172
Command Bars
Aircraft Symbol
Single-Cue Command Bars
Garmin GI 275 Pilot's Guide 190-02246-01 Rev. A