AUTOMATIC FLIGHT CONTROL SYSTEM

SECTION 7 AUTOMATIC FLIGHT CONTROL SYSTEM

NOTE: The approved Pilot’s Operating Handbook (POH) always supersedes the information in this Pilot’s Guide.

NOTE: A failure of the primary (#1) GIA 63/63W Integrated Avionics Unit (IAU) results in loss of the flight director. Any IAU failure results in loss of the autopilot and manual electric trim.

NOTE: The GFC 700 is not available for the Cessna 172R.

The GFC 700 is a digital Automatic Flight Control System (AFCS), fully integrated within the G1000 System avionicsarchitecture. TheSystemOverviewsectionprovidesablockdiagramtosupportthissystemdescription. GFC 700 AFCS functionality in the Cessna NAV III aircraft is distributed across the following Line Replaceable Units (LRUs):

• GDU 1044B	Primary Flight Display (PFD)	• GSA 81 AFCS Servos (3)
• GDU 1044B	Multi-Function Display (MFD)	• GSM 85 Servo Mounts (3)

•GIA 63/63W Integrated Avionics Units (2)

The GFC 700 AFCS can be divided into these main operating functions:

•Flight Director (FD) — Flight director operation takes place within the primary (#1) IAU. Flight director commands are displayed on the PFD. The flight director provides:

–Command Bars showing pitch/roll guidance

–Pitch/roll mode selection and processing

–Autopilot communication

•Autopilot (AP) — Autopilot operation occurs within the pitch, roll and pitch trim servo and provides servo monitoring and automatic flight control in response to flight director steering commands, AHRS attitude and rate information, and airspeed.

•Manual Electric Trim (MET) — The pitch trim adapter provides manual electric trim capability when the autopilot is not engaged.

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Garmin G1000 Pilot’s Guide for Cessna Nav III

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AUTOMATIC FLIGHT CONTROL SYSTEM

7.1 AFCS CONTROLS

The following dedicated AFCS keys are located on the bezels of the PFD and MFD:

1	AP Key	Engages/disengages the autopilot
2	HDG Key	Selects/deselects Heading Select Mode
3	NAV Key	Selects/deselects Navigation Mode
4	APR Key	Selects/deselects Approach Mode
5	VS Key	Selects/deselects Vertical Speed Mode
6	FLC Key	Selects/deselects Flight Level Change Mode
7	FD Key	Activates/deactivates the flight director only
		Pressingonceturnsontheflightdirectorinthedefaultpitchandrollmodes. Pressing
		again deactivates the flight director and removes the Command Bars. If the autopilot
		is engaged, the key is disabled.
8	ALT Key	Selects/deselects Altitude Hold Mode
9	VNV Key	Selects/deselects Vertical Path Tracking Mode for Vertical Navigation flight control
10	BC Key	Selects/deselects Backcourse Mode
11	NOSE UP/NOSE	Control the mode reference in Pitch Hold, Vertical Speed, and Flight Level Change
	DN Keys	modes

1	7
2	8
3	9
4	10
5
	11
6

Figure 7-1 Dedicated MFD AFCS Controls

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Garmin G1000 Pilot’s Guide for Cessna Nav III

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AUTOMATIC FLIGHT CONTROL SYSTEM

The following AFCS controls are located in the cockpit separately from the MFD:

AP DISC Switch

(Autopilot Disconnect)

CWS Button

(Control Wheel Steering)

GA Switch (Go Around)

MET Switch

(Manual Electric Trim)

Disengages the autopilot and interrupts pitch trim operation The AP DISC Switch is located on the pilot’s control wheel.

This switch may be used to mute the aural autopilot disconnect alert.

While pressed, allows manual control of the aircraft while the autopilot is engaged and synchronizes the flight director’s Command Bars with the current aircraft pitch (if not in Glideslope Mode) and roll (if in Roll Hold Mode)

Upon release of the CWS Button, the flight director may establish new reference points, depending on the current pitch and roll modes. CWS operation details are discussed in the flight director modes section.

The CWS Button is located on the pilot’s control wheel. Disengages the autopilot and selects flight director Go Around Mode

If an approach procedure is loaded this switch also activates the missed approachwhentheselectednavigationsourceisGPSorwhenthenavigation source is VOR/LOC and a valid frequency has been tuned.

The GA Switch is located on the instrument panel above the throttle. Used to command manual electric trim

This composite switch is split into left and right sides. The left switch is the ARM contact and the right switch controls the DN (forward) and UP (rearward) contacts. The MET ARM Switch can be used to disengage the autopilot and to acknowledge an autopilot disconnect alert and mute the associated aural tone.

Manual trim commands are generated only when both sides of the switch are operated simultaneously. If either side of the switch is active separately for more than three seconds, MET function is disabled and ‘PTRM’ is displayed as the AFCS Status Annunciation on the PFD. The function remains disabled until both sides of the switch are inactivated.

The MET Switch is located on the pilot’s control wheel.

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Garmin G1000 Pilot’s Guide for Cessna Nav III

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