| vfr800 |
12-23-2016 09:01 AM |
Modern redundancy
In a prior RV, we went with a similar approach (though I wasn't IFR trained at the time) & it worked nicely overall. One big 8.4in GRT Hx screen with dual AHRS, plus a Dynon D10a for back up provided dissimilar redundancy. You could select AHARS 1 or 2 for that single screen. Though if that one display failed, now you lost two sources at once.
Nowadays, I think a single big screen (even without dual AHRS), a different brand/software back-up (think G5, GRT mini, Dynon 10a), plus an iPad having a separate source of attitude info (Stratus 2/2S) gives you a tie-breaker and enough redundancy. Many fly with an iPad any ways for multiple reasons, so it's not an added equipment cost for them/me.
Even if some rare emergency destroys all electronics on board, this could provide basic attitude, altitude and ground speed to get down safely. Starting a flight fully charged, the battery life in the Stratus and iPad doesn't require keeping them connected to power except for the longest of XC days (more than 6-8 hours).
More commonly, if one brand/model of primary flight data acts up, it gives you sufficient independent options to compare and decide which to believe.
One downside -- I didn't like how I would lose the display of some desired information when displaying PFD, nav and engine information on the one screen. Specifically, if I remember correctly flap and trim indications come to mind. First world problem, I guess... I had to look over my shoulder to see flaps. Something to consider & assess with your specific model in mind for only one screen.
Just my thoughts with the modern tools readily available to us these days.
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