More than once in my articles, I have mentioned that we are in the “EFIS” period. In 2000, it was GPS. MFD came a few years later. EFIS entered GA in 2004 with the G1000 OEM options and in the aftermarket with the G500 in 2009. It’s exploded in the last few years, especially with solid-state options designed and certified to replace your standard, vacuum horizon, always a good idea when IFR is planned. Until now, if your standard vacuum horizon was also the sensor for your legacy autopilot, replacing it with a solid-state, ADAHRS electronic option was not available but replacing your suspect, mechanical vacuum autopilot AI with a modern EFIS unit is now possible on some legacy autopilot models. The Dynon D10A ($2,200) was the first solid-state AI upgrade to reach certification and, consistent with Dynon’s experimental/light-sport pricing, it was very affordable. Garmin followed in 2016 with the G5 ($2,150) for AI and DG/HSI ($3,000) and has essentially set the standard, competing hard on price with Dynon and for features with Aspen in the PFD category. I don’t think the G5 AI would have been priced where it is if Dynon was not also a player. This shows that competition is a good thing! We won’t talk about Aspen here — we will focus on the new GI 275 electronic flight instruments. But first, let’s briefly visit the features of the Garmin G5 and the Dynon D10A to establish a baseline and then highlight the new benefits found in the latest electronic flight instruments from Garmin.
Dynon D10A and Garmin G5 common features
Both the D10A and G5 offer primary attitude and allow you to replace your existing vacuum horizon, but the instruments also show you airspeed, altitude, turn rate, slip/skid, barometric setting, GPS track, and a few other features in a supplemental role. The information is there in front of you, but the original instruments must remain. Dynon gives you an up/down timer, G-meter, and volts. Garmin adds vertical speed reference and shows selected altitude. The D10A DG/HSI is not included in the STC so replacing your vacuum DG/HSI is not a Dynon option. The Garmin G5 DG/HSI is certified to replace your existing unit, which opens the door to removing your vacuum pump and associated plumbing and creates the ADAHRS foundation for the GFC 500 autopilot. While the G5’s were introduced in 2016, it is safe to say the majority have been installed in the last 18 months during the big avionics “push” of 2019 (thanks to ADS-B), so if you just upgraded to G5’s, you may have been less than excited to see the announcement of their new GI 275 series. As I stated before, Garmin is moving fast on technology. The good news is that Garmin will be there to support the G5’s for a long time.
GI 275 flight instrument or multi-function instrument
Garmin’s marketing calls the GI 275 both a flight instrument and a multi-function instrument. Both are true and that’s the primary difference between the GI 275 and the G5. The G5’s role is limited to a primary AI with secondary advisory or a DG or HSI when interfaced to Garmin’s GAD 29B nav data interface. The GI 275 does more. The GI 275 can be a primary attitude indicator, a CDI, an HSI, a primary engine management unit, and a multi-function indicator with a shopping list of functions. The configuration is different than the G5. Unlike the G5, the GI 275 fits a standard instrument hole and stays within the confines of the standard 3 1/8-inch instrument hole as opposed to the G5’s bezel that extends beyond and sometimes requires a little panel work especially to those plastic overlays. The GI 275 is touchscreen (with dual concentric knobs) and has built-in Wi-Fi and Bluetooth and interfaces to the Garmin Pilot app for database “concierge” and for downloading engine data. A backup battery is available as an option for all units but is required when the GI 275 is used as a primary or backup AI or ADI. There are three hardware versions of the GI 275: the GI 275 basic, GI 275 ADAHRS, and the GI 275 ADAHRS+AP. Let’s take a look at each version of the GI 275 and estimated price.
GI 275 basic This is the basic hardware version of the GI 275 with no ADAHRS or autopilot interface. The GI 275 basic can be a CDI or an engine management system.
The 275 CDI can replace most mechanical CDIs and accepts nav data from two GPSs or VOR/ILS-based nav receivers. Switching between the nav sources is built in and this simplifies installation if you want to use the 275 for more than one nav source. GI 275 primary engine management — EIS with GEA 24 Estimated street price: $3,995* The GI 275 with GEA 24 engine indication system becomes a dedicated primary engine management system in a 3 1/8- inch configuration. Twins can use two GI 275s. Note that the GEA 24 is certified for Class I and II aircraft. Revolutions per minute, oil temperature and pressure, and manifold pressure (if installed) are required, but a full package of sensors can be added including CHT/EGT, TIT, fuel quantity, and volt/amps. Many of your existing probes and sensors may be compatible. *Plus sensor package for $1,000 (four cylinder) to $1,400 (six cylinder) and installation. GI 275 as a basic MFD As you will see below, the GI 275 can serve multiple roles but using the GI 275 basic unit, it can be configured as an MFD. In this role, using the internal VFR GPS and an antenna connection, it provides mapping and map data including terrain from its internal database and a broad list of information from external devices including weather (ADS-B, Sirius XM, or Stormscope) and traffic (ADS-B or TCAS), and can display radar altimeter if so equipped. As you will see below, adding the ADAHRS allows the GI 275 to serve as both an MFD and backup ADI, which seems to me to be a better use of panel space and budget. There is an upgraded EIS, the GEA 110 that is required for Class III aircraft that must be installed by a Garmin dealer.
GI 275 ADAHRS Add an ADAHRS and battery backup and you have the GI 275 ADAHRS version. This version serves as a primary attitude indicator ($3,995) providing primary attitude, airspeed, and altimeter. Add the optional GMU 11 magnetometer and the unit becomes an ADI ($4,295) providing additional heading as a primary or backup ADI in Class I or II aircraft. Versions for Class III/IV aircraft are available, but all are Garmin dealer install only. When installed as a primary attitude indicator only, the original AI, airspeed, and altimeter must be maintained but most pilots installing the GI 275 will install a second unit as a combination MFD/ ADI or HSI/ADI and eliminate the need for mechanical backups. A VFR GPS is installed in the unit and requires either the optional panel top antenna or a GPS position interface into the unit to provide backup ground track in the event of a failure of the magnetometer. You can add synthetic vision to the AI or ADI. GI 275 HSI Unlike the G5, which can only interface to digital GPS navigators or nav/coms (VOR/ILS). The GI 275 ADAHRS in HSI configuration will communicate with most digital or analog nav sources and it does not require an adapter (like the GAD 29B for the G5). The GI 275 with GMU 11 magnetometer ($4,295) gives you an advanced HSI/EHSI with the option of a map underlay. In this configuration, you can display data on the moving map as well as lateral and vertical deviation, but you can also configure the HSI on an MFD/standby ADI. In this configuration, the backup unit will automatically revert to the ADI page in the event of an issue with the primary ADI. Wow! All non-EIS GI 275’s rely on optional databases to provide navigation, mapping, and alerting functions. Updates are done either through a USB connection, from another Garmin LRU like a G500, GPS 175, etc. , or wirelessly through Garmin Pilot. Base map and terrain database updates happen automatically without any prompting or acknowledgement from the pilot!
GI 275 EIS Note that the GI 275 basic as a CDI/MFD (with or without EIS) is an over-the-counter item. You can buy it from a Garmin dealer or online and take it to you local shop.
GI 275 ADAHRS+AP AP stands for autopilot so this version of the GI 275 does everything above and adds an autopilot interface. While the G5 and the GI-275 AI both can serve the Garmin GFC 500 autopilot as position sensor, the G5 HSI (with GAD 29B) only interfaces to digital nav sources for lateral and vertical deviation. The GI 275 goes way beyond the G5 in both phases! First, the GI 275 ADAHRS+AP, in addition to driving the GFC 500, can replace the existing vacuum attitude indicator in many legacy “position-based” autopilots. A good example is the BendixKing KFC series autopilots, that uses the KI 256 AI/flight director. These are still good “true” IFR autopilots, but the weakness has often been the mechanical/vacuum KI 256. The GI 275 replaces it and gives these autopilots and now, many legacy autopilots dependent on a mechanical AI, solid, ADAHRS control. Many Cessna and Piper legacy autopilots are listed as compatible. Secondly, the G5 was limited to interfacing to modern, digital nav sources only. If you have a BendixKing KX 155 for example. It would not interface to the HSI and therefore would not track a course or ILS. The GI 275 will interface with the KX 155 and most legacy, analog nav sources. The GI 275 ADAHRS with GMU 11 magnetometer (for heading) with the AP interface is $5,295 list, so probably about $4,700 street price.
Typical GI 275 panel OK, we start with your standard six-pack. Remove the mechanical AI and HSI, airspeed, and altimeter. Now, what we need is a GI 275 as primary ADI with ADAHRS/GMU and backup battery and either GPS antenna or external GPS interface. Add the AP function if you have a compatible position-based autopilot and want to upgrade it to ADAHRS control. If you stop here, you’ll need to retain your existing AI, airspeed, and altimeter as backup or consider a second GI 275 (also with ADAHRS/GMU and battery) to the right of the primary to serve as backup ADI and as a multi-function instrument providing mapping, terrain, and weather and traffic. In this configuration, the backup ADI will revert (kick in) if the primary fails. Add the GI 275 ADAHRS+AP with GMU 11 to replace your existing mechanical HSI and why not go all the way and put your primary engine management on the left of the primary ADI by adding the GI 275 basic with GEA 24 engine indication system interface and necessary probes and sending units?
Here are the Numbers* … (List less Installation)
GI 275 ADAHRS + AP with GMU 11 (as Primary ADI) $5,295
GI 275 ADAHRS with GMU 11 (as Back-up ADI/MFD) $4,295
GI-275 ADAHRS + AP with GMU 11 (as HSI) $5.295
GI 275 Basic with GEA 24 EIS $3,995
*SVT, OAT and Databases are extra
Installation
If you follow my articles, you know that I frequently quote street price on equipment and actual estimated labor costs based on my experience of how many hours a task takes and based on the current hourly install rates. I try to talk in “real” numbers! Simply stated, I currently don’t have a handle on what it takes to do the GI 275, but we have some guidelines. I have seen install quotes on the Dual G5s (AI and HSI) in the $8.800- $9,400 range. This would put labor in the 36 to 44-hour range. Removing an existing mechanical HSI like the KCS-55A would put you on the high side. The GI 275 ADI and HSI should be about the same. A second GI 275 as backup ADI/MFD adds about 16 -20 hours and the GI 275 EIS would be typical of a primary engine management unit in the 35- to 40-hour range. Add it up and we have an estimated 96 hours or $9,600 labor at the current $100 per hour rate putting the above Garmin GI 275 panel at $30,000 installed plus database/SVT pricing.
Conclusion
When I started writing this, my intention was to discuss both the GI 275 and the new uAvionix AV-30C option. We’ll have to discuss the uAvionix option next month. There’s just too much here with the GI 275! What Garmin has done here is give you a way to have a lot of information in front of you without installing a G500 or similar big screen PFD/MFD. There are compromises and some savings. In “True IFR Panel” in the April issue, I estimated a dual screen G500 TXi (with separate EIS panel) at about $41,000 installed and you don’t have the expense of a new panel with the GI 275’s. At the same time, Garmin has found a way to interface this new technology with legacy technology as in the autopilot and legacy analog avionics interfaces. Since the budget for updating a legacy aircraft avionics panel often requires a mix of old and new, this can’t be a bad thing. Any way you look at it, here’s Garmin with some amazing new technology for the general aviation aircraft owner — again!
Thanks for Reading!