A complete reference for the Garmin GFC 500 autopilot and the GMC 507 mode controller in your 182Q. Tap any tab to switch between the visual controller, button-by-button reference, real flight scenarios, and quick reference.
What you're working with
A two-axis autopilot with yaw damper, mode controller, and direct integration with your Garmin glass panel.
The GFC 500 is the autopilot itself — three servos under the panel and behind the firewall (roll, pitch, pitch-trim), plus an optional yaw-damper servo. You'll never see those. What you interact with is the GMC 507 mode controller — the panel of buttons and a knob to the right of your G3X.
The autopilot has two independent axes:
Lateral (left/right) — controls where the airplane is pointing or tracking
You can run them in different modes simultaneously. For example: NAV laterally (following the GPS course) + ALT vertically (holding altitude). That's a cruise configuration. Or HDG laterally + VS vertically for a heading-and-vertical-speed climb to altitude.
The three rules
Rule 1
The autopilot is a tool, not a co-pilot. It flies what you tell it to fly. If you set the wrong altitude bug, it climbs to the wrong altitude. If you press NAV without a flight plan loaded, it does nothing useful. You are always the pilot in command.
Rule 2
Trim before you engage. The autopilot expects a stable, trimmed airplane. If you engage it while you're holding back-pressure or wing-low, it inherits that imbalance and fights to correct. Always trim first.
Rule 3
Know how to turn it off — instantly. The red AP DISC button on the yoke is your immediate kill switch. Press it any time the airplane is doing something you don't understand or didn't expect. Disconnect first, troubleshoot second.
Lateral modes (left-right)
ROL
Roll hold — default when you engage AP. Wings level. Use when you just want it to stop flying for a minute.
HDG
Heading mode — follows the heading bug on your PFD. You spin the bug, airplane turns.
TRK
Track mode — same as HDG but for ground track. Compensates for wind drift automatically.
NAV
Navigation — follows the magenta GPS course from the GTN. Sequences waypoints automatically.
APR
Approach mode — couples to a loaded approach (GPS, VOR, or ILS). Lateral + vertical guidance to minimums.
BC
Back course — flies the back course of a localizer. Niche but available.
Vertical modes (up-down)
PIT
Pitch hold — default when you engage AP. Holds whatever pitch attitude you had at engagement.
ALT
Altitude hold — holds current altitude. The most-used vertical mode.
VS
Vertical speed — climbs or descends at a fixed feet-per-minute rate set with the V/S knob.
IAS
Airspeed hold — climbs or descends to maintain a target airspeed. Best for climbs (engine can't overspeed).
VNV
VNAV — vertical navigation using altitudes set in the GTN flight plan. Advanced.
GS
Glideslope — captured automatically during APR mode. Flies you down the approach.
The GMC 507
A clean illustration of your mode controller. Tap any button to jump to its detailed reference.
GMC 507 · Autopilot Mode Controller
— Top row —
— Middle row —
— Bottom row —
Layout is representative. Your actual GMC 507 button arrangement may vary slightly. Refer to your airplane.
The yoke disconnect
One critical control isn't on the GMC 507 — it's on the pilot's yoke. The AP DISC button (red) instantly disconnects the autopilot. Press it any time. It also silences pitch-trim warnings.
Memorize the location
The red AP DISC button is on the pilot's yoke, usually on the left horn. Find it by feel before every flight. You should be able to press it without looking, in turbulence, with eyes closed. This is muscle memory you build deliberately.
Every button, explained
Tap any button on the controller (previous tab) to jump here. Each entry includes what it does, when to press it, and what to expect.
Real-flight scenarios
Common situations and exactly what to press. Each scenario builds from the previous — start at #1 if new.
Quick reference
In-flight cheat sheet. The stuff you'll glance at while doing it for real.
Pre-engagement checklist
TRIM
Airplane trimmed for hands-off flight
BUGS
Altitude bug set, heading bug set, baro set
SOURCE
HSI source correct (GPS or VLOC as needed)
MODE
Know what mode you want before engaging
ALT
Above 800 AGL minimum (Garmin spec)
Standard cruise engagement
STEP 1
Set altitude bug to cruise altitude
STEP 2
Press AP (engages with ROL + PIT defaults)
STEP 3
Press ALT (holds current altitude)
STEP 4
Press NAV or HDG (whichever lateral mode you want)
STEP 5
Press YD (yaw damper on)
STEP 6
Verify green annunciators on PFD
Annunciator decoder
GREEN
Captured — actively flying this mode
WHITE
Armed — waiting to intercept or trigger
YELLOW
Caution — mode degraded or limit approaching
FLASHING
Action required from pilot
If something feels wrong
1.
Press AP DISC (red on yoke) — disconnect immediately
2.
Hand-fly the airplane to stable wings-level
3.
Identify what mode you were in
4.
Re-engage with correct mode if appropriate
5.
If still wrong, leave it off, hand-fly the rest
Hard limits — when NOT to use AP
BELOW
800 AGL on departure (Garmin minimum)
PATTERN
Traffic pattern — hand-fly always
FINAL
Below minimums on an approach — you fly the landing
TRIM
When airplane is grossly out of trim
CLIMBING
In a stall buffet or near stall warning
FOCUS
When you can't monitor it — don't engage and walk away mentally
Memory items — emergency
CONFUSED
Press AP DISC on yoke. Fly the airplane.
DISORIENTED
Press LVL — blue button. Wings level, recover.
RUNAWAY TRIM
AP DISC, then hold electric trim disconnect, then manual trim
UNUSUAL ATTITUDE
LVL button — let it recover, then disconnect and hand-fly