Horizon HX EFIS

Horizon HX EFIS

The HX is a no-compromise EFIS with a compact 6.5” or 8.4” screen. It is built around a high speed processor that typically operates at 20% capacity while providing a 30-mile synthetic vision view. Interfacing is extensive to support dual redundancy for AHRS and radios. The size allows two screens to be located in front of the pilot, even in compact cockpits. The HX is the ideal solution for the pilot that wants the comfort provided by redundancy, and who depends on this equipment to fulfill his missions.

Starting at only $3,800

6.5″ Horizon HX single display package

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No Interpretation Required

IFR and VFR flight is intuitive. While on the approach, you see the runway on the screen. You feel the cross-wind and sense your height above ground before you look at the altimeter. The high-speed processor means the screen is fluid and the terrain is detailed and realistic. Way-points appear as 3-D balloons. Traffic and obstacles are unmistakable and appear as naturally as they would out the window. You find yourself navigating more by the PFD screen than you do the moving map.

Full interfacing to IFR GPS navigators, such as the G430/G650 is always available via the optional ARINC 429 interface.


Here the PFD shows the way-point on the horizon.  The flight path marker shows the airplane in a slight descent (below the horizon water-line), tracking just the the right of the way point. The flight director has been set at a 1000 fpm decent to 1600 feet and is commanding the pilot to pitch down (nestle the yellow chevron within the magenta) and make a very slight right roll to achieve the descent and a 10 degree heading.  Winds are a left cross-wind at 12 mph.

Ten split-screen combinations are included, combining two or three views into one screen of the PFD, map and HSI, and engine monitoring. Information is clearly presented, making it practical to fly with a single screen and rarely touch a button. For dual screen installations the split-screens provide a single-screen reversionary mode suitable for IFR flight.

Dual-Screen Optimized

Dual screens were never an after-thought. The HX was designed to function together, providing more information, interfacing and redundancy. Illustrated below are two screens configured for takeoff. We like displaying the EGT time history for takeoff. It allows for differentiating between engine problems affecting a single cylinder and those affecting the entire engine–potentially valuable data for making critical decisions!

Below are two HXs as they are configured after initial climb-out. The map now replaces the engine page, and the engine strip is shown on one of the screens. Either screen could show the engine strip. The PFD has the terrain mode turned on. Choosing the screen is one button push away.

VFR Friendly

Often the days we fly do not require constant monitoring of the airplanes attitude. Airspeed, altimeter and a map are all we need, with the PFD attitude to back us up if conditions change. We love those days and so does the HX! That is why we allow you to show airspeed and altimeter tapes on your moving map.

 Obstacle Alerting

The greatest value of obstacle alerting occurs when you find yourself forced to fly under an overcast in less than desirable visibility. At times like this, it must be effortless to understand such threats. That is why we show your threats on the PFD and not just the map. We show you the threat in the exact place you will be looking–the PFD. They appear in the same location out the window as they appear on the screen. Simple, and potentially life saving.

Sectionals, Airport Diagrams, En-route Charts, Approach Plates, and more…

Sectionals, Airport Diagrams, En-route Charts, Approach Plates, and more can be displayed with the airplane position geo-referenced on them. Sectionals and en-route charts are displayed with HX generated airspace, obstacles, flight plans and traffic overlaid, so that alerting is not lost. Data for these functions is provided by Seattle Avionics. The HX also includes a PDF viewer which allows you to display free approach plates, airport diagrams and other data provided by the FAA. (Geo-referencing is not provided).

The Source of the Attitude

The integrity of an EFIS is dependent on the integrity of the attitude data that drives it. GRT Avionics has always lead the way with the only AHRS in the industry that can operate without airspeed or GPS aiding. Read more about the latest generation of AHRS here.

Comprehensive Engine Monitoring

Having produced the EIS engine monitor for over 20 years, we’ve accumulated a great deal of personal and customer engine monitoring experience. From this came such exclusive features as the exhaust gas temperature (EGT) time history. A simple graph of the last two minutes of all EGTs, our engine monitoring system makes it effortless to distinguish between engine problems affecting one cylinder, or the entire engine. This distinction could be essential when making decisions in response to engine problems, especially at critical times such as initial climb out. We find it so useful that we never takeoff without it displayed, and we recommend you don’t either.

CHT time history also proves useful by making the trend obvious. This is especially useful in high-performance airplanes, such as RV’s, Lancairs, and all pushers, where engine cooling can require some pilot technique to manage. It leaves no doubt which way temperatures are headed.

Finally, we love the specific fuel consumption display. Its measure of engine efficiency that confirms when you have leaned properly, and tells you when you need to lean again.

Engine Data with a Bonus

Engine data is provided to the HX via the Engine Information System (EIS). The EIS is a complete instrument with a display and user-interface. Models are available for practically every engine, from 2-strokes, 4-strokes, turboprops and turbines-we have instrumented it. The EIS may be remotely mounted, just like any data collection device, but it can also be mounted in the instrument panel as a primary or backup display of engine data. In tandem seating airplanes it can be used as an instrument for the rear seat. Engine limits can be set in the EIS and can be used to drive its own warning light, even when remotely mounted.

Simple Operation

Dual rotary knobs and 5 lighted softkeys make up the pilot interface. All are high tactile force, which is optimal for operation in turbulence. The bezel includes a hand rest that further enhances ease of use when things get rough. Primary knob functions are heading selection and baroset. Pressing any softkey brings up secondary knob functions and softkey labels. Simple, effective and efficient.

Turbulence Optimized

When on the ground or in calm air, practically any pilot interface will work. Introduce turbulence and the story changes. To operate an EFIS in such conditions, the pilot must be able to position his fingers on the control (knob or button) without activating it. Activation of the control can then take place with assurance the intended operation will be performed. This is why the HX does not have a joystick type control. It has high-tactile force knobs and buttons and a ledge above the buttons to steady your hand. It’s proven, and it works.

Generous Connectivity Options

The HX includes 8 serial ports in and out (one configurable as RS422), dual ARINC 429 in, ARINC 429 out (optional), and dual USB ports. Multiple display units are coupled via Ethernet. Analog interfaces include 8 analog inputs and 8 discrete outputs. We have the interfaces for your needs now and into the future.

Real Redundancy

Redundancy will not be compromised in panel designed around the HX. The extensive interfacing and processing power of the HX allows dual inputs for attitude/air data, while still accommodating dual GPS and nav/com into every display unit. Automatic cross-checking is provided, and rarely must data sources be divided among display units. Each device is wired directly to each display unit, creating a simple, robust connection for ultimate redundancy. Data buses are not used for communication between various devices, as these introduce the opportunity for a single point failure. Even dual data buses are subject to possible data overloading or other common mode faults that can simultaneously fail both buses (as has been experienced by one of our competitors).

Autopilot Ready

The HX includes full autopilot functionality. Just add GRT servos and you are on your way to a fully automated cockpit. Like all GRT EFIS systems, it can also control an external stand-alone autopilot. Even without servos, all autopilot functions are available to drive the flight director, giving you a single cue to follow to control attitude and navigation, greatly improving accuracy while reducing workload. Read more here.

Already own an autopilot? Just wire it to the HX, and the system will couple it to all your navigation sources.

Heads-Up Display Capable

A heads up display can now be part your your GRT Avionics equipped airplane for as little as $300. Our pursuit of heads up display technology has led to support for the Hudly automotive after-market heads up display. Graphics optimizations in the GRT remote app, combined with the impressive readability and value of the Hudly have resulted in the first practical heads up display for experimental and general aviation (certified) airplanes.

  • Aircraft mounted heads-up display
  • Sunlight Readable Color Symbology
  • Primary Flight Data
  • Flight Director and HSI Guidance
  • Lateral/Vertical Deviation for Approach
  • Stall warning and all other features of GRT Remote app

PFD Video with Overlay

The HX supports forward looking low-light or infrared cameras. Controls are provided to scale and align the video with the EFIS orientation. This allows the EFIS to draw outlines around runways and way-points, and also show the flight path marker correctly against the image from the camera. Video can also be displayed without an overlay, as might be desired for other camera views.

Angle-of-Attack (AOA) Sensing/Stall Warning

The GRT Avionics AOA function drives on-screen AOA symbology that shows too fast/too slow/optimal approach speeds, as well as stall warning. In addition, an audio output is providing an approaching stall warning annunciation (a pulsating tone that varies with proximity to the stall warning angle) and a solid tone indicating stall is imminent.

Sensing is via a two-port 45 degree pitot tube, such as those commonly available from a variety of manufacturers, or using a probe fashioned by the builder. This method has no moving parts, and allows the use of heated pitot tubes that preserve the stall warning function even in the presence of icing.

The GRT Avionics AOA function drives on-screen AOA symbology that shows too fast/too slow/optimal approach speeds, as well as stall warning.

In addition, an audio output is provided on the Horizon HX display unit. This audio provides an approaching stall warning annunciation (a pulsating tone that varies with proximity to the stall warning angle) and a solid tone indicating stall is imminent.

Audio Alerting System

Voice alerts are provided for critical engine and flight conditions, as well as altitude call outs. System changes, such as autopilot disconnect and way-point passage, are also annunciated. Angle-of-attack audio utilizes an attention-getting beeping tone that increases in urgency as your approach stall. You can even use your own audio recordings for your alerts.

Control Radios and Flight Plans with Your Android Phone or Tablet…

Install an optional Bluetooth dongle and connect with your Android phone or tablet using our GRT REMOTE App for Android. Fully control your connected radios, create & edit active flight plans, and view the flight instruments all on your Android tablet or phone–perfect for the backseat co-pilot. The radio tuning portion of the app offers so much information, you may not want to tune them without it!

Free Database and Software Updates

Navigation database updates are provided free for all US territory. Software updates are also free. All GRT equipment includes bootloaders, allowing them to be updated via USB without removing them from the airplane.

We support that!

We have always supported the spirit of experimental aircraft by providing the builder with as many options as possible. This is why we provide free HX software support for the following equipment:

  • ADS-B (Traffic and Weather) including Radenna Skyradar, Dual XGPS170, iLevil
  • Multiple GPS Receivers (all types)
  • Garmin 400/500/600/700 Series Panel Mount GPS/Nav/Comm
  • RS-232 radios such as SL30/SL40
  • XM Satellite Weather
  • CO Guardian
  • TIS Traffic datalink (GTX330, Trig TT21/TT22)
  • Zaon Traffic
  • BF Goodrich WX-500 Stormscope
  • Vertical Power (All Models)
  • Tru-Track Autopilot
  • Trio Autopilot
  • TCAS systems

(If there is a device that you do not see on this list and you would like the HX to interface with it, drop us a line! We are always willing to consider new devices, and thanks to the extensive interfacing and powerful processor within the HX, future growth is built-in!)

Chose your screen size

The HX is available in 6.5” and 8.4” screens, with the 8.4” being the most popular. Both feature the sunlight-readable LED backlit screens. The compact design allows two 6.5” screens to be stacked in the typical panel, such as an RV. The 8.4” screens can be mounted side-by-side in front of the pilot. The HX also works great alone, or with with another HX, HXr or Mini.

Easy Upgrade Path from Older Horizon Systems

The HX shares the same wiring as our Horizon HXr systems, and is 100% compatible with the Horizon HS and WS systems. User settings can be backed up and transferred from legacy equipment into a new HX, making upgrading even easier.

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