Are you confused about the TXi, NXi, and Xi versions of the Garmin EFIS displays and GPS navigators? These are the updated versions of their previous incarnations. From a pilot’s perspective they work much the same way the earlier versions did. So how are they different?
First, they have improved (faster) processing power (dual processors), more memory, and improved screens with higher resolution, wide angle views, and better colors. These changes mean faster operations, and they allow new features to be added. Since these are hardware changes it means you can’t just update the software of your old unit. Some dealers will exchange your unit for these upgraded devices at a modest price when compared to a new unit. They plug into the same panel slot, and the configuration card in the tray sets up the replacement unit.
In a major update of the G1000 NXi about two years ago (the NXi was originally offered in 2017) processor and screen improvements were made and new features added, such as Safe Taxi, Terminal Traffic, and Surface Watch (explained on Garmin videos). Memory increased from 64 MB to 16 GB, which is huge. The original GFC700 autopilot used in the system was also improved with Stability Control and Envelope Protection. The PFD screen now has an MFD map with the current flight leg inside the HSI for better situational awareness, as shown in Figure 1. There are other features as well that you can find listed on their websites.
Figure 1. The new MFD map inside the HSI of the G1000 NXi, one of several new features on these devices. Others include Safe Taxi, Terminal Traffic, and Surface Watch.
With the GTN 750 Xi announced in January this year, the units are lighter and draw less current, and the Home button was moved down to the D-> button. They too got processor and screen upgrades. Charts and databases are stored internally, as they are on the G1000 NXi. Exciting new features were recently added to the Xi’s, as described later.
How about the TXi versions of their PFD and MFD flight displays? They too got dual processors and screen updates, and they can now display Engine Indication System (EIS) data. On the new G500/600 units (10.6-in landscape display units) there is no physical dividing bar between the left and right half of the screen. This allows for some choice of where to put vertical dividing lines on the screen between different displays (60:40 splits). In Figure 2 the screen has been set up with MFD, PFD, and EIS sections, but you could display only one or two items on the screen.
Figure 2. The 10.6-inch landscape version of the G500 TXi (GDU 1060), with no physical division between the left and right half. This gives a lot of flexibility in what features to display and how much screen space to use. Here the splits are 40:40:20.
The seven-inch portrait units (GDU 700P) can be configured in several ways to display an EIS, PFD, or MFD. In Figure 3 the unit is set up for engine instruments (left) and as a PFD (right). From a display perspective, these units offer similar options as the earlier EFIS options from Garmin, but now with EIS displays added.
Figure 3. The seven-inch portrait TXi display set up on the left as an engine monitor (EIS) and on the right as a PFD.
Two features have recently been added to Xi and TXi units that use this added performance: glide rings and Smart Glide. Glide rings have been a part of the Chelton EFIS units for 20 years and ForeFlight has had glide rings for some time, so pilots are likely to be familiar with them. Their addition to the GTN 750 Xi, G500/600 TXi and G3X Touch is welcome.
The glide ring is an irregular line around your present position that shows how far you can glide at best glide speed, given terrain and existing wind conditions. The units are first setup for your best glide speed, glide ratio, and other parameters. On the Nearest Airport page those inside the glide ring have a green check mark next to them.
Smart Glide is a new feature in Garmin’s Autonomi suite of options that include Autoland, Enhanced Stability Protection, Emergency Descent Mode, Smart Rudder Bias and now this Smart Glide (available by software update Aug 2021). Figure 4 shows the glide ring on a GTN 750 Xi display when Smart Glide is activated (with a separate switch or holding the D-> button for two seconds). Weather, terrain, runway length, and wind figure in the near instantaneous selection of an airport and alternates selected for landing. The area outside the ring is visually subdued on the map. This display is also on the G500/600 TXi.
Figure 4. The GTN 750 Xi screen when you select Smart Glide to help in an emergency landing. Pushing the yellow Glide button displays navigation and runway information for the selected airport.
Your flight plan is replaced by a leg to the chosen airport; that leg is also shown on the G500/600 TXi MFD. With air data supplied by a Garmin TXi and a Garmin digital autopilot this system will couple the leg to your autopilot and fly you close (two nm) to the airport (both lateral and vertical) so you can perform the landing.
Press the yellow Glide button (on either the Xi or G500/600 TXi) to bring up information pertinent to this emergency landing. Runway information is shown, frequencies are sent to standby, altitudes are shown, and the new flight leg is shown on a highlighted section of the map. These features are shown on a Garmin slide (Figure 5) from a Webinar on the subject. This is not Autoland, but it is a major time saver and valuable assistant in an emergency.
Figure 5. Smart Glide information shown when the Glide button is selected in Figure 4. Runway and altitude information is shown, with buttons to Squawk 7700 and or to select another alternate within the glide ring. (Slide from Garmin Webinar).
The equipment requirements in addition to the GTN 750 Xi for Smart Glide are varied, and you should consult your avionics shop for details. It’s possible to have Smart Glide with a GI 275 rather than a Garmin EFIS, for example. Later this year the G5 should provide the required Air Data, and in 2022 it’s expected that this capability will be available on the G500/600 (not the TXi version) but again paired with the GTN 750 Xi. Smart Glide comes to the G3X in Q4 2021.
Dr. Thomassen has a PhD from Stanford and had a career in teaching (MIT, Stanford, UC Berkeley) and research in fusion energy (National Labs at Los Alamos and Livermore). He has been flying for 63 years, has the Wright Brothers Master Pilot Award, and is a current CFII.
