GTX 330ES-style transponder
The GTX 330 with extended squitter: the same green-LCD Mode S transponder with the code, mode and FUNC pages, with ES shown on its display. In the app it's the second model of the GTX 330.
- Modeled on
- Garmin GTX 330ES-style Mode S transponder with ADS-B Out
- Category
- Radios and panels
- Size
- 2 × 1 cells
- Version
- 1.0 · 2026-10-19
- Plan
- Pro
- Simulators
- MSFS 2020 · MSFS 2024 · X-Plane 11 · X-Plane 12
Variants
GTX 330v1.0
Without the ES indication
Picker: MODEL > GTX 330
GTX 330ES (ADS-B Out)v1.0
ES shown at the top of the display
Picker: MODEL > GTX 330ES (ADS-B Out)
Features
- ES annunciation on the LCD
- Mode, R while replying, IDENT, and the large code
- FUNC pages: PRESSURE ALT with trend, FLIGHT TIME, ALT MONITOR (tone 200 ft off), OAT, DALT, COUNT UP, COUNT DOWN, CONTRAST, DISPLAY
- VFR key toggles the VFR code and the previous code
- GND on the ground with the automatic ground mode
- Display dark without avionics power; dimmed at night
On the iPad
- Same as the GTX 330: IDENT, VFR, the mode keys, the 0-7 code keys, FUNC, CRSR, START STOP, CLR, 8 / 9 for contrast and backlight
Settings
- Model: GTX 330 or GTX 330ES (picker variant)
- App Settings: VFR code and automatic ground mode
Keys and controllers
Map any of these to a key, a game controller's button or axis, or a MIDI knob (how):
- Transponder IDENT
- Transponder STBY
- Transponder ALT
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 |
|---|---|---|
| Transponder mode: 0 off, 1 standby, 2 test, 3 on, 4 altitude (enum) | TRANSPONDER STATE:1 (number) | sim/cockpit2/radios/actuators/transponder_mode |
| Transponder code as its four digits (e.g. 1200) (code) | TRANSPONDER CODE:1 (number) | sim/cockpit2/radios/actuators/transponder_code |
| Transponder identing (1/0) (bool) | TRANSPONDER IDENT:1 (bool) | sim/cockpit2/radios/indicators/transponder_id |
| Pressure altitude (ft) | PRESSURE ALTITUDE (feet) | sim/flightmodel2/position/pressure_altitude |
| Indicated altitude (ft) | INDICATED ALTITUDE (feet) | sim/cockpit2/gauges/indicators/altitude_ft_pilot |
| Outside air temperature (degC) | AMBIENT TEMPERATURE (celsius) | sim/cockpit2/temperature/outside_air_temp_degc |
| On the ground (1/0) (bool) | SIM ON GROUND (bool) | sim/flightmodel/failures/onground_any |
Sends
| When you… | MSFS | X-Plane |
|---|---|---|
| IDENT | XPNDR_IDENT_ON | sim/transponder/transponder_ident |
| OFF (0), STBY (1), ON (3), ALT (4) | SimVar write: TRANSPONDER STATE:1 | sim/cockpit2/radios/actuators/transponder_mode |
| Fourth digit typed, or VFR | XPNDR_SET | sim/cockpit2/radios/actuators/transponder_code |
Add-on aircraft with their own systems may use other variables; the Hub reads the standard ones.
Changes
The instrument's version counts what its faces share (the case, the mechanism, the data, the sounds); a face's own version counts that face alone.
- 1.0 2026-10-19
- First numbered version.
