Yes and thankfully the backup Airspeed and Altimeter steam gauges didn't crash too. I learned my lesson.
cj
Any supporting information about the brand of EFIS, failure mode and resolution would be helpful.Yes, it has occurred.
EFIS units from the same manufacturer may have similar or identical software on them. At the very least, there are probably some subroutines (parts of programs) common to both, to save programming time and expense. This means that if there is an error in one of these common modules, it can affect both units at the same time.
An obvious example would be a Y2K-type bug that caused software to go crazy at a certain time. Any number of tiny bugs could cause a system issue, and if it happens to be in a common piece of code, it could crash both units at once.
With 2 units from different companies, odds are much better that they will not share the same software bug.
Chris
For an early seminal piece of work in this field, see http://sunnyday.mit.edu/papers/nver-tse.pdf
A lot of interesting work has been done here...the odds may not be as improved as you think they are. Aside from common methods for designing software and coding it, many times software contains either libraries purchased from a 3rd party vendor or code which comes from "standardized" references such as Numerical Recipes or The Art of Computer Programming. If two separate teams used the same source material, the independence would be significantly lessened (and those sources have errors in them...ask me how I know this).
For an early seminal piece of work in this field, see http://sunnyday.mit.edu/papers/nver-tse.pdf
For what its worth, I talked to a GRT tech rep about this today. He said they don't use any outside vendors for for software or code. He said they only use their own. He read all these threads while we were on the phone. He felt the most likely way for all EFIS units to fail at once wasn't software, but rather power supply sources. And if that happens, their mini's have a backup battery.
I "think" Dynon's small backup EFIS's also have a backup battery.
(Don't know anything about Garmins, and their backups)
As a software professional for thirty years and the only thing I can tell you is that if a programmer states his code can't fail, then run as fast as you can the other way.
There are going to be bugs in all code, that's just a fact of life. The question then is how many bugs, what are the side effects, and is there a chain of events that could cause catastrophic failure?
I'm not bashing GRT or any other EFIS vendor. In my opinion, the simplest method to mitigate the risk is to have a small unit from a different vendor than you main EFIS vendor as a backup and/or tie breaker if you are planning on flying in IMC.
I recently had a AHARS die. I have two installed. Fortunately, it was VFR and wasn't a big deal. I could easily see from looking out the window, which one was correct. However, if I was in IMC it would have been a different story. I have a pair of AFS 4500s and a TruTrak Gemini. A quick glance at the Gemini and it becomes very apparent to which EFIS to trust.
I recently had a AHARS die. I have two installed. Fortunately, it was VFR and wasn't a big deal. I could easily see from looking out the window, which one was correct. However, if I was in IMC it would have been a different story. I have a pair of AFS 4500s and a TruTrak Gemini. A quick glance at the Gemini and it becomes very apparent to which EFIS to trust.
Hi Bob, Thanks for the feedback above. Regarding your AHARS problem, GRT has a "dual AHARS" for their big HXr EFIS. And then if you get their small mini AP, that one also has its own AHARS. So now there's 3, ie, a tie breaker. But regarding the rest of your info, I don't know what to think. I thought I had this all sown up on what to get, now I'm not so sure anymore.
It is worth considering having an auto pilot completely separate from EFIS.
If the auto pilot source platform is EFIS it is useless with EFIS failure.
I've been reading this thread and from the OP I thought the worry was what if your EFIS system/s failed and how you would safely aviate back to mother earth.
The many statements from folks about using handheld's, and iPads as an IFR backup has me baffled.
If you are going to be flying IFR it's my opinion that you need a real backup system that you can fly IFR with and bet your life on. I have two backups with seperate power for each. That gives me 3 ADHRS so I have a tiebreaker. Like Bob stated above, he had one fail and was OK since he was VMC, but if he had been IMC how would he have decided which one to believe.
How many threads have we read in the past about iPads overheating, crashing, locking up, no GPS, whatever... I recall a lot.
For VFR it's one thing. There is no such thing as soft IFR. I worry about putting all your faith to protect you, your loved ones and your airplane in an inexpensive system that was never intended to be such.
The opening poster was wondering what you would do if it all just quit. In today's world of EFIS's they are all mature with probably millions of flight hours of actual use on the software. Even though the odds are extremely slim, Murphy is alive and well and if your day is getting so lousy that it's going to quit, you should have a safe backup to get you back down safely. I'll say this,,
An iPad is better than nothing.
This obviously is just my opinion on the matter. But it is a serious subject that needs to be discussed. It's your life your betting on.
complete electrical meltdown
Do you have any details?
Fin
9A Australia