S-TEC-style autopilot

A panel-mount autopilot like the S-TEC unit in X-Plane 12's 172: six mode keys under a tan LCD that shows RDY, the engaged modes and the selected vertical speed, plus a VS knob. You can fly the simulator's autopilot from the iPad the way you would the real unit.

Modeled on: S-TEC-style autopilot (the one in X-Plane 12's Cessna 172), tan LCD mode display
Category: Autopilots
Size: 2 × 1 cells
Version: 1.0 · 2026-10-19
Plan: Pro
Simulators: MSFS 2020 · MSFS 2024 · X-Plane 11 · X-Plane 12

Features

Tan LCD with RDY standing at the left, and the legend of each engaged mode (HDG, NAV, APR, REV, ALT, VS) shown above its key
GS appears next to APR once the glideslope is captured
In VS mode, the selected vertical speed in hundreds of feet a minute, with a + or - sign and seven-segment digits
TRIM cue with an up or down arrow when the vertical speed is more than 300 fpm off what the autopilot is trying to hold (the selected VS, or zero in ALT)
No separate AP key: the first mode key you press engages the autopilot in that mode, and pressing the engaged lateral mode key again disengages it
VS x 100 knob with DN / UP arrows printed around it
Legends show only while the autopilot is engaged
At night the faceplate, keys and knob take the red flood light, while the LCD keeps its own color, dimmed
Thin 2 x 1 unit: you can stack it with another thin module in one 2 x 1 slot or put it in a rack

On the iPad

Tap HDG, NAV, APR or REV: with the autopilot off, it engages the autopilot in that mode; with it on, it selects that mode; tap the engaged lateral mode again to disengage the autopilot
Tap ALT or VS to select altitude hold or vertical speed mode (engages the autopilot first if it's off)
Turn the VS knob by dragging around it: one detent per step (100 fpm), ten steps at a time when you turn it fast; left is down, right is up

Keys and controllers

Map any of these to a key, a game controller's button or axis, or a MIDI knob (how):

Autopilot AP
Autopilot FD
Autopilot YD
Autopilot HDG
Autopilot NAV
Autopilot APR
Autopilot BC
Autopilot ALT
Autopilot VS
Autopilot FLC
Autopilot LVL
Autopilot UP / DN +
Autopilot UP / DN -
Altitude +
Altitude -
Altitude sync

Simulator data

What the Hub reads from the simulator for this instrument, and what the instrument sends back. Names are the simulators' own: MSFS SimVars and events, X-Plane datarefs and commands.

Reads

Value	MSFS	X-Plane
Autopilot modes, one bit each (ApBit: ap, fd, yd, hdg, nav, apr, bc, alt, vs, flc, lvl, gs, vnv) (bitfield)	`AUTOPILOT MASTER (bool)AUTOPILOT FLIGHT DIRECTOR ACTIVE (bool)AUTOPILOT YAW DAMPER (bool)AUTOPILOT HEADING LOCK (bool)AUTOPILOT NAV1 LOCK (bool)AUTOPILOT APPROACH HOLD (bool)AUTOPILOT BACKCOURSE HOLD (bool)AUTOPILOT ALTITUDE LOCK (bool)AUTOPILOT VERTICAL HOLD (bool)AUTOPILOT FLIGHT LEVEL CHANGE (bool)AUTOPILOT WING LEVELER (bool)AUTOPILOT GLIDESLOPE HOLD (bool)`	`sim/cockpit2/autopilot/servos_onsim/cockpit2/autopilot/flight_director_modesim/cockpit2/switches/yaw_damper_onsim/cockpit2/autopilot/heading_statussim/cockpit2/autopilot/nav_statussim/cockpit2/autopilot/approach_statussim/cockpit2/autopilot/backcourse_statussim/cockpit2/autopilot/altitude_hold_statussim/cockpit2/autopilot/vvi_statussim/cockpit2/autopilot/speed_statussim/cockpit2/autopilot/roll_statussim/cockpit2/autopilot/glideslope_status`
Autopilot vertical speed target (fpm)	`AUTOPILOT VERTICAL HOLD VAR (feet per minute)`	`sim/cockpit2/autopilot/vvi_dial_fpm`
Vertical speed (fpm)	`VERTICAL SPEED (feet per minute)`	`sim/cockpit2/gauges/indicators/vvi_fpm_pilot`

Sends

When you…	MSFS	X-Plane
Mode keys, with the ApBit of the mode (REV sends bc). With the autopilot off, it first sends apKey for ap and then the mode; tapping the engaged lateral mode sends apKey for ap (disengage)	`AP_MASTERTOGGLE_FLIGHT_DIRECTORYAW_DAMPER_TOGGLEAP_PANEL_HEADING_HOLDAP_NAV1_HOLDAP_APR_HOLDAP_BC_HOLDAP_ALT_HOLDAP_PANEL_VS_HOLDFLIGHT_LEVEL_CHANGEAP_WING_LEVELER`	`sim/autopilot/servos_togglesim/autopilot/fdir_togglesim/systems/yaw_damper_togglesim/autopilot/headingsim/autopilot/NAVsim/autopilot/approachsim/autopilot/back_coursesim/autopilot/altitude_holdsim/autopilot/vertical_speedsim/autopilot/level_changesim/autopilot/wing_leveler`
Turning the VS knob (steps, x10 when turned fast)	`AP_VS_VAR_SET_ENGLISHAP_SPD_VAR_SETAP_PITCH_REF_INC_UPAP_PITCH_REF_INC_DN`	`sim/cockpit2/autopilot/vvi_dial_fpmsim/cockpit2/autopilot/airspeed_dial_kts_machsim/autopilot/nose_upsim/autopilot/nose_down`