Originally Posted by upperdeck
Garmin guys, can you expand on this statement?
"independent and dissimilar flight instrument"
Thanks for asking this question. It is an important one.
When we developed the original product goals and features, high on the list was a requirement that the unit be the most robust and trusted backup instrument on the market for customers using any brand of EFIS system, including Garmin G3X and G3X Touch.
To accomplish this, we knew we needed to maintain a high level of independence and dissimilarity in both the hardware and software design such that a common mode fault in either hardware or software that could simultaneously affect both the G3X system and the backup instrument be extremely
improbable, if not impossible.
We started by choosing brand new attitude sensors. We have great sensors in the GSU 25 ADAHRS and would have liked to re-use those, but to have the best assurance that no common mode fault of these sensors could possibly jeopardize the display of attitude information (however remote!), new sensors were chosen, incorporated, and tested.
On the software side we started with a brand new simplified Garmin operating system that isn't common with the one used in the G3X displays (which is quite large, complex, and capable in comparison).
We kept out many features common to EFIS systems like internal database loading/use (and thus synthetic vision) and Bluetooth to keep from having to re-use or re-develop large bodies of code that are used in the G3X displays. Not only is the G5 display rather compact in comparison to the big displays and thus not the best place to attempt to show synthetic vision, but we didn't want a backup instrument with over a million lines of code! We even developed a new graphics library that operates very differently than the one used in the G3X displays.
Even the backlight is handled in a dissimilar manner. Instead of following an aircraft lighting bus that might be common to the large displays, the G5 uses either photocell backlighting control or manual (your choice).
All of these features in combination with built-in independent WAAS GPS receiver, airspeed, and altitude sensors means you can install this instrument with confidence in any aircraft regardless of the brand of EFIS system you are using.