GNC 255

Part Number: 010-01025-50
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List price quoted is MSRP and actual price is determined by the dealer. Price is shown without installation cost, additional parts may be required. For more complete pricing information, including installation cost, please contact an authorized Garmin aviation dealer.


Add Powerful Nav/Comm Capabilities to Your Panel

  • 10 W or 16 W Comm and 200 channel Nav with VOR/localizer and glideslope receiver
  • Automatically displays tuned frequency's navaid or airport identifier
  • Automatically decodes Morse signals so you don't have to
  • Advanced standby monitoring means you'll never miss an ATC call while listening to ATIS
  • Bright sunlight-readable display
  • As compact as it is capable, the GNC 255 can bring powerful Nav/Comm capabilities to virtually any cockpit. Not only does the GNC 255 meet the basic needs of most pilots – including adhering to new airspace requirements in Europe – it also features a number of advanced features that save you time and effort. It also contains an internal VOR/LOC converter and 40-channel glideslope receiver.

    Choose Your Installation

    GNC 255

    The GNC 255 is available in 2 versions to fit your needs. Each version comes with 25 kHz frequency channel spacing and 8.33 kHz channel spacing to meet the impending Single European Sky mandate that all aircraft in Europe will need to operate with by 2018. The GNC 255 is available with either 10 W or 16 W of transmitter output, letting you find the right balance of power and price. It includes a 2-place intercom that’s ideal for 2-seat aircraft; no additional hardware is required to communicate with your passenger. It also contains an internal VOR/LOC converter and a 40 channel glidescope receiver. Plus, remote frequency flip-flop capability can help in demanding operating environments like helicopters, letting pilots keep their hands on the controls.

    Reduce Your Workload

    In addition to traditional Nav/Comm features, the GNC 255 incorporates a number of functions that can save you time and effort. Provide the GNC 255 with an airport or navaid identifier and it will automatically find all available frequencies (and vice versa) thanks to a built-in, updateable database. With a compatible GPS input, the device will find the nearest airport to your location and easily access its weather, center and FSS frequencies. You'll have the confidence to know you're talking to the right controller every time. The Nav/Comm's database technology also allows you to quickly pull up your most frequently or most recently used frequencies. The device even automatically decodes a station’s Morse code to provide a positive identification – no aural decoding required.

    The GNC 255 will provide distance, time and speed when installed with a compatible GPS source like our GTN or GNS series avionics. All information is displayed on a bright sunlight-readable display so you can quickly read it all at a glance. And when paired with a G500, G500H, G600 or G3X flight display, it allows for the display of VOR and ILS indications on the PFD and can follow autopilot commands. Alternatively, you can use an HSI or CDI like our MD200-306, which has been specifically designed to work with the GNC 255.

    Listen to 2 Frequencies with 1 Comm

    With the standby frequency-monitoring feature in the GNC 255, you won’t have to worry about missing an ATC call or other critical transmission. The GNC 255 allows you to listen to ATIS without leaving your assigned ATC channel. Swapping your active and standby frequencies is done with a single touch of a button. Pressing and holding frequency transfer key will automatically set the emergency frequency as your active radio. You can use the built-in timer to assist with approaches, holds and other assigned maneuvers.

    Need night vision?

    For pilots flying patrol aircraft or helicopters while using night vision goggles (NVGs) to aid visual surveillance, the GNC 255 series NAV/COMM radios are available in versions that offer NVG-compatible displays. Featuring readouts and lighting designed to suppress light waves in the red to near-infrared (NIR) spectrum, these radios screen out distracting light interference for NVG operations – while providing crisp, vivid display readability under all lighting conditions, from nighttime to bright daylight.


Worldwide Nav and Comm Database
Enter the navaid or airport identifier to find the frequency (or frequencies) associated with that location. Uses GPS input (from compatible systems, sold separately) to determine locations for each of the 25 nearest VORs, airports, Flight Service Stations, ATC facilities, WX stations, etc.

Navigation Radio Features

  • Built-in VOR/Localizer converter
  • Database lookup of frequencies using navaid ID
  • VOR receiver displays to/from and radial
  • Digitally decoded OBS setting
  • Sunlight readable full alphanumeric display
  • Automatic display of station ID by decoding Morse code
  • Interfaces with most CDI (w/resolver), HSI, and autopilot systems

Comm Radio Features

  • Flight Service Stations, ATC facilities, WX stations, etc.
  • Active and standby flip-flop frequencies
  • One-touch 121.5 emergency channel tuning
  • Comm frequency monitor function (listens to standby while monitoring the active)
  • Recall of frequency from database by facility name and type
  • Database reverse lookup of frequencies providing station ID andfrequency use (TWR, ATIS, etc.)
  • Volume control bar graph display
  • Alphanumeric display of frequency types (ATIS, GRND, TWR, etc.)
  • High-visibility alphanumeric LCD display
  • Transmit status indicator
  • Backlit keypad controls
  • Automatic and manual, pilot-selectable display intensity control
  • Built-in, two-place voice activated intercom
  • Frequency memory and recall
  • Stores/recalls 15 user defined frequencies
  • Stores/recalls previous 20 frequencies used
  • Squelch test function
  • Stuck mic time-out
  • 12 W audio amplifier



Communication channels: 760 with 25 kHz spacing; 2280 channels with 8.33 kHz spacing
Frequency range: 118.000 to 136.992 MHz (with 8.33 kHz spacing
Transmit power: 10 or 16 W (optional)
Input voltage range: 9 to 33 VDC
Operating temperature range: -20 to +55 C
Certifications: TSO C169a (transmitting and receiving), TSO C128a (stuck mic)


Dimensions: 1.65”H x 6.25”W x 10.4”D (4.19 x 15.88 x 26.42 cm)
Weight: 3.02 lbs (1.37 kg) unit only; 3.46 lbs (1.57 kg) with mounting rack
Depth: 11.23 inches (28.52 cm) behind panel, including mounting rack and connectors

In the Box

  • GNC 255
  • Installation kit
  • Manual


DEVICE Com Nav 8.33kHz Transmit Power
GNC 255A X X X 10W
GNC 255B X X X 16W