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EFIS failures

G

gfb

Well Known Member
Thinking through my panel and wondering... has anyone here experiences a failure on a two-screen same system EFIS where both screens had an issue?

Trying to figure out how much I really need a 2nd-vendor EFIS backup.
 
EFIS failure

Yes

...both screens on a popular system went wonky at the same time but plane was vfr at the time. Afterwards a separate simple attitude indicator with airspeed and headings installed as a backup.
 
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Yes

Yes and thankfully the backup Airspeed and Altimeter steam gauges didn't crash too. I learned my lesson.
cj
 
grubbat said:
Yes and thankfully the backup Airspeed and Altimeter steam gauges didn't crash too. I learned my lesson.
cj
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Yes and exactly as above. Steam gages or an efis of different manufacturer can save your bacon.
 
I see the op is building a RV-9a. If the plane is intended for VFR only, I would be quite comfortable with just 1 or 2 same manufacturer EFIS and zero backup instruments. The 9 really is that easy to fly... in vfr conditions. A failure of all instruments in our 9 would be little more than a minor annoyance in vfr conditions.
Having personally experienced an EFIS roll inverted on takeoff just 50 feet agl in IMC, I designed my panel so that steam backups are part of my normally used instrumentation and converting to them is not a major issue.
I am guessing by the question, the op plans on IMC.
 
Could somebody explain this

This thread really surprised me.:eek: I'm no avionics guy, and I've been trying to see if I could swing a GRT HXr and also either GRT's mini X or mini AP, and make my plane IF &R. Based on this thread, could one of you knowledgeable guys out there explain why this would be?

Thanx Much
 
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
 
Mugabe seen it happen on a Garmin G900X, so it can happen. As others have said, a VFR flight is no big deal, but IFR can change things. Having some kind of independent backup is always a good idea, but not required.
 
Pros and cons of mixing EFIS suppliers.

FORANE said:
Yes, it has occurred.
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Any supporting information about the brand of EFIS, failure mode and resolution would be helpful.

"Steam gages or an efis of different manufacturer can save your bacon".

Unless you fully understand the failure mode of the 'single manufacturer' EFIS system, you can not necessarily conclude that an EFIS from an alternate manufacturer would have 'saved your bacon'.

There are many ways for a 'two EFIS' system to fail where the blame for failure lies elsewhere. For example a common power supply between the two screens. When designing a two screen system, extra diligence is required to mitigate failures. I would consider a dual bus system to be a prerequisite together with a second power source, either battery or alternator.

There are numerous advantages to designing an integrated system that are lost when components are mixed from different suppliers. For example, only one EFIS in a mixed system can control an autopilot from the same vendor. Consider also the cost of adding a third party autopilot and a second ADAHRS. You need to be aware that you may potentially be compounding your potential failure modes.

I would conclude that the advantages of an integrated system from one manufacturer outweigh the disadvantages of mixing suppliers and creating a less integrated system. Also consider the workload/cost of keeping software and mapping upgrades current.
 
I would go with the EFIS of your choice and add something like the Dynon D1 or D2 PocketPanel and handheld GPS.

The advantage with this setup is that the PocketPanel does not tie into your pitot or static system and has an internal battery backup. The handheld GPS will let you navigate and will also have an internal battery and even XM weather, if you want.

Those two items will let you keep the airplane upright and find a place to land. You could even toss in a handheld radio, if you wanted
 
An Ilevil and a Nexus running Naviatior can give you fully independent PFD, mapping, and weather. Everything but engine stuff.
 
EFIS Back up

In my case I have a Skyview as my main system and use a Garmin 796 with a GDL-39 3D which give me a second source for attitude,airspeed(GS) & altitude (GPS)..
I always make sure the 796 is working properly and is set to the AI prior to take off IFR.

I flew with the 796 only and it is working really well.

Bruno
 
YellowJacket RV9 said:
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
Click to expand...

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
 
RV7A Flyer said:
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
Click to expand...

Good points for sure. There is probably much more common code out there than I realize.

I also agree that non-software issues are probably more likely to take out multiple EFIS's at once, making the manufacturer irrelevant. This makes either steam gauges or completely independent (battery powered) systems like a Stratus 2 or ilevil with an ipad seem like the best bets for true redundancy.

Chris
 
GRT

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)
 
donaziza said:
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)
Click to expand...

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.:(
 
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rleffler said:
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.
Click to expand...

Bob,

I don't think he was saying it won't fail. THEY ALL DO under some (probably unknown to us) scenario.

What all the major vendors have is some history of failures. I suspect that they all have pretty good reliability when operating within a certain set of parameters.

I suspect that the comment was a reflection that there have been more failures reported to them that were POWER related than anything else.

So, if I am in a plane with a DYNON D10A with battery backup or a GRT MINI with battery backup or MGL little one (???I am not familiar) then I personally feel a little better as it is hard to know the REAL reliability of some of the power setups on some the planes.

In my personal plane, I have multiple busses but also THREE different batteries that can keep electrons flowing.

James
 
donaziza said:
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.:(
Click to expand...

Don,

I would say don't over think this.

Look at what various people have and ask about their failure modes and experiences. Understand how your setup would/could fail and how you would deal with it. If you "design in" failure mitigation then you are probably going to be just fine.

There are lots of thinks that COULD go wrong on the dark, dreary night in the clouds over the mountains. Assess what is "likely" to go wrong and what is your "out".

You are probably much better off than you think. Just think about what planes and systems we like a few years ago. :)

James
 
Scratching my head

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.
 
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+1 for Jerry's post.
And don't forget it's not just money you need to invest. You also need to regularly invest your time in practice, so if the day comes that you need those backups, you actually know how to use them.
 
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.
 
Good question David. Redundancy should be built into an IFR airplane. If it is planned out well there is no reason to not have your EFIS control your autopilot.

My GRT system is set up so my main EFIS normally controls the a/p, but one of my Mini standby's can also. Same servos, differnt controllers.

Others choose completely seperate a/p, some with attitude displays for redundancy. These systems work very well with all the major EFIS systems also.

Just plan accordingly when designing your system if having an autopilot available to you in an abnormal situation is critical to you.
 
Separate Autopilot

David-aviator said:
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.
Click to expand...

While most EFIS manufacturers now sell integrated auto pilots, most of them can still work with the "external" AP units such as Trutrak. In my RV-8, I use a Trutrak Vizion 385 (Upgraded from Digiflight II VSGV that I originally installed) that integrates very nicely with my GRT Horizon EFIS. In the event of EFIS failure, I can drive the Trutrak straight from my GNS430W, or it can operate completely independently of outside data sources in wing leveler and altitude hold mode. My panel also has full steam gauge back up including an electric AI.

Skylor
RV-8
 
RV8iator said:
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.
Click to expand...

This has certainly discussed many times in the past and a personal preference. When I was building and going over the same Q&A, and contemplating two different EIFS, there was a full glass plane with complete electrical meltdown that crashed. So, I do have redundant EIFS & AHAR (GRT of course) but also my back up is steam gauges that with the exception of the ADI, none of it require power.
My A/P can also be driven by itself, GRT or 430W but if I do have the complete electrical meltdown, it wouldn?t matter how the A/P is controlled. The stick and my arm would be the only thing controlling it.
 
Finley Atherton said:
Do you have any details?

Fin
9A Australia
Click to expand...

No, unfortunately I don't and this is from about 8 or maybe 9 years ago during my building and selection process and don?t know how to research it to find it. If my memory serves me right, it was in California
 
ECO as a backup autopilot?

I have a single Trutrak APIV EFIS that controls the autopilot in my 6A. It flys enroute and coupled approaches beautifully. For backup attitude I have a Trutrak PFD and an iLevil ADSB which adds an attitude indicator to my IFly GPS. There are backup batteries in case of electrical failure. I get XM weather on my garmin 560. My biggest worry is losing the autopilot during IMC if the EFIS failed. I've been thinking how nice it would be to have an ECO autopilot as a backup for the primary autopilot. I realize that it could get interesting if you somehow had both autopilots on and fighting for control. Has anyone done it? John
 
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