Rant about EFIS

The following is presented as an opinionated rant.

Your homework is to read, absorb, ruminate and present your own ideas.

I invite respectful disagreement and well-reasoned discussion. Keep the knee-jerk responses under control, if you please.

Though this rant mentions one particular manufacturer, it is NOT, repeat NOT, as in NOT, NO WAY, NO HOW intended as an attack upon that manufacturer. In fact, one of that manufacturer's products happens to be one of my favorites at the moment. So I AM NOT ATTACKING THAT MANUFACTUER, m'kay? They are only mentioned in order to get the reader to think critically about the topic. So DON'T GIVE ME GRIEF FOR MENTIONING THEM. Please.

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As an instrument pilot who has flown real-deal ILS approaches down to minimums in the snow, in a single, I will NOT trust my tender pink butt to some gee-whiz non-certificated glass gadget in that situation without a stone-simple backup in place. I'll trust EFIS as far as I'll trust vacuum gyros, but no further.

I've seen stuff from builders about going all-glass, with no "steam gauges" at all. Even if I never flew IFR, I'd never rely 100 percent on an EFIS.

I don't care how "capable" the technology might be...I've seen what the deal is with my own eyes (meaning sitting in a cockpit in hard IMC only a few hundred feet off the ground and traveling at 100+ knots) and felt the pucker factor with my very own precious sphincter, and having the backup is worth every penny, no matter what the cost. When you are an instrument pilot, you will eventually have a telling experience: You will be looking at an instrument, mechanical or electronic, and realize that your very life depends on it functioning correctly. The more backups you have, the better.

Don't forget that EFISes are not unlike the computer you're using to read this thread. (THE PREVIOUS SENTENCE HAS BEEN EDITED TO REMOVE A FACTUAL ERROR ABOUT EFIS OPERATING SYSTEMS.) Has your computer ever locked up? How would you like that to happen in hard IMC? LOOK AT YOUR COMPUTER RIGHT NOW, AND DECIDE WHETHER YOU WOULD TRUST YOUR LIFE TO IT, RIGHT THIS SECOND. NO ARGUMENTS, NO PREVARICATION, NO JUSTIFICATION..... DECIDE !!!!NOW!!!!

(In the interests of fair disclosure, I use a Mac with its UNIX-founded OS, and though it's never let me down I'm not at all sure I'd trust it to get me home no matter what.)

I'm not slamming the EFIS manufacturers here...as far as I'm concerned, all of them are the same for now, because I'm years away from choosing. (THE PREVIOUS SENTENCE HAS BEEN EDITED FOR CONTEXT.) When it comes to making the actual choice of which way to go, there will be more information available and I'll decide based on that information.

In the hard, real world of instrument flight, capability is irrelevant. Reliability is everything. When you fly hard IFR, you are by definition trusting your life to technology. You need to decide, before you get in the cockpit, how far you're willing to go with that trust.

I am only willing to go as far as replacing one major system (vacuum). So, for me, the minimum for-real IFR panel would include at least one EFIS, plus a traditional mechanical/static-based airspeed, altimeter, VSI and TC. (This is Checkoway's panel, BTW....the moment I saw how he did his airplane, I knew I'd like the guy.) Should the EFIS go teats-up, it's exactly the same scenario as vacuum failure in a traditional airplane. This is something that's not pretty, but I've trained for it. A second EFIS (the dual Blue Mountain EFIS Lite G3 scenario) would be really, REALLY great...better than a certificated vacuum system for sure!

However, for VFR-only flight, I'll gladly give up a bunch of that stuff. I don't need a VSI or TC to fly VFR. So to start with, just install an EFIS, airspeed and altimeter. Or in an extreme sense, go Piper Cub-simple and delete the EFIS. Plan for the full deal and install it later.

You are invited to discuss, compare and contrast.

There will be a quiz next Friday.

I think before you rant about what operating system an company uses you should check with them and see what operating system that they use I think you will find that Blue Mountain does not use the Windows operating system.

I agree with most of the original poster's points. However a couple of comments/questions.

Re: BMA is Windows based
Are you sure? I've only played with the BMA stuff at shows, but as an experienced embedded systems software engineer - I didn't see anything that led me to suspect Win CE in this device. I say this as someone who's written a fair amount of the Mac OS code and has shipped a bunch of products based on Win CE/embedded XP (ugly), QNX (not bad), VxWorks (ugly), custom OS (a bunch of work), and linux (pretty spiffy).

Re: Steam gauge backups
I agree with this philosophy. I suspect it is likely there are still important bugs that remain to be found in the Dynon or BMA products. I have steam gauge backups for my Dynon (but no attitude backup unless you count an AP or TC), but I'm not about to say my RV is IFR ready. When I do decide to take my RV IFR, I'll need a real attitude backup. My current plan is to decommission some steam guages once I have comfort in the Dynon's performance, at that point I'll install a BMA sport and make my D10 serve as backup.

It seems especially risky when I see folks installing two units from the same vendor with one serving as the backup for the other. As somone who writes a lot of this sort of software, I'd place fair odds on a software failure. If you put two identical units into your plane, each faced with (nearly) identical inputs you are running a chance of exposing a software bug simultaneously in both units. Too much risk for me - it is worth thinking carefully about this.

Kevin

My bad about the OS. I don't know where I got the idea that BM is Windows-based from.

The original post has been edited to remove this error.

The basic argument remains the same regardless.

Certified EFIS

You seem to be discussing uncertified EFIS systems. How do your opinions change when discussing certified EFIS systems? (Although it is interesting to note that current Garmin installations in Cessna and Avidyne installations in Cirrus retain an electro-mechanical backup ADI.)

TDT

This rant sounds a bit like someone who has only flown factory built aircraft commenting on home builts.

My -9 will be a day / night VFR ship and I will use the Dynon units for both the flight and engine instruments. My flight instrument backups will be a standard airspeed, altimeter, wet compass, and slip ball. The backup for the engine instrument will be the big loud noise coming from out front. If the Dynon unit goes Tango Uniform and my engine is still making lots of noise, I will land and fix the Dynon. If the Dynon is working and my engine goes Tango Uniform, I?ll land a bit sooner than in the first scenario and fix the engine and hopefully not the plane.

I?m not seeing a real problem with the duel instrument thing for a VFR ship. IFR is something entirely different and I would have more redundancy built in.

The long and short of is, pick your risks and compensate accordingly. Some people trust electronic gauges and some people trust steam gauges.

Build and outfit your craft according to what you know and believe in. After all, isn?t that why each of us is building OUR own plane?

adouglas said:

(In the interests of fair disclosure, I use a Mac with its UNIX-founded OS, and though it's never let me down I'm not at all sure I'd trust it to get me home no matter what.)

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In the interest of fair disclosure nothing will get you home "no matter what". I'd bet your odds of getting home safely are higher with hitchhiking than in single pilot, single engine IFR.

adouglas said:

In the hard, real world of instrument flight, capability is irrelevant. Reliability is everything. When you fly hard IFR, you are by definition trusting your life to technology. You need to decide, before you get in the cockpit, how far you're willing to go with that trust.

Click to expand...

It depends on how you define capability. Much research has been done on HITS and the new OZ stuff that shows that pilots flying with new technology maintain measurably better control of the aircraft (simulator) using HITS/OZ than they do with Gyro/Needles/Static. I suspect that scared pilots (pucker factor) have more accidents than those who are in better control of the situation.

Another way to say this is: when flying on a working mechanical system or working EFIS your odds of making it to your destination safely are enhanced with an EFIS. But this is all hard to quantify.

adouglas said:

I've seen stuff from builders about going all-glass, with no "steam gauges" at all. Even if I never flew IFR, I'd never rely 100 percent on an EFIS.

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Are there really people out there who are sticking a lone dynon in their bird and wanting to fly hard IFR with it? If there are people doing this, I to question their sanity. Are they trying to do partial panel with a GPS and whiskey compass? A sole EFIS box has a lot of functionality tied up in one failure.

When you say 'an' EFIS do you mean having a panel with one EFIS and no attitude backup?
Do you mean 'an' EFIS and a second identical EFIS backup?
Do you mean 'an' EFIS with mechanical attitude backup?
Do you mean 'an' EFIS with a second EFIS made by a different manufacturer?

Most everyone would agree that flying IFR with the first panel would be high risk but doable (thats what I got my instrument in). I ranked these four based on my percieved risk (since I don't have MTBF data). I strongly agree with kevinh that EFIS backups from the same MFG have a single point failure mode in the software and thus aren't as redundant. Since I think the chance of a software bug is greater than the chance of the EFIS hardware dying I would not consider a dual BMA or the dual GRT AHRS. A dual GRT (single ahrs) with a dynon backup would look nice though

Chuck:

FYI In my 400hrs of RV time I've had a gyro go and an ASI and no electronics failures. The ASI failure was tricky.

Train to identify EFIS failures

chuck said:

I strongly agree with kevinh that EFIS backups from the same MFG have a single point failure mode in the software and thus aren't as redundant.

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Ok here's another issue to remember: What happens when one of the two units fails? Imagine you're in IMC and the two EFIS attitude indicators start giving different attitude readings. How do you determine which one to believe? It's certainly a risky situation. When you use two EFIS systems from different manufaturers, you reduce the probability that *both* units will fail simultaneously, but at the same time you increase the probability that at least one of the units will fail (because they have different failure modes). This is similar to the single vs twin failure probability analysis.

So what's my point? This is obvious, I'm sure, but just remember that having backup isn't the end-all be-all, that you need to train how to identify failures and deal with them.

Alex

Real-Deal IMC and EFIS

adouglas said:

As an instrument pilot who has flown real-deal ILS approaches down to minimums in the snow, in a single, I will NOT trust my tender pink butt to some gee-whiz non-certificated glass gadget in that situation without a stone-simple backup in place. I'll trust EFIS as far as I'll trust vacuum gyros, but no further.

Click to expand...

Great thread, and agree with the well thought out responses about backing up EFIS equipment.

EFIS and Gyros may not be the weak link in single pilot, single engine IMC. No disrespect meant, but flying single pilot freight in light twins many years ago, I had my share of Pucker. I understand your "real-deal ILS" and "trust my tender pink butt" comment. (Although the "pink butt" word picture is ).

Sounds like you won?t do IFR with gee-whiz EFIS. You have to be comfortable. However, the integration of data in these EFIS displays can improve situational awareness and safety. Some not only have attitude, they have all flight info, power and Nav data in one display. Also they have the potential to be more reliable than mechanical gyros and vacuum pumps could ever be. When was that last time your TV failed? Obvious to most, EFIS requires independent back-up, mechanical or independent electronics as Kevin stated below.

I agree new GA EFIS equip is not mature. Airline and corporate ops have flown "glass" for 20 years plus. Granted the redundancy, tolerance, technology and fault monitoring is still beyond any experimental EFIS equipment. Limited fault monitoring may be the weakest aspect of experimental EFIS. The big stuff cross checks and reports on its health. Maintenance replaces units before they fail. I can?t think of any significant problem in 13 years. Mechanical gyros, even on airliners were never this reliable. Even with all the sophistication, Jets have a small stand-by gyro, which are small mechanical electric units. Now even the new jet standby gyros are going to solid-state.

Dry vacuum equipment in GA aircraft has accrued a dismal reliability record, and the ability of GA pilots to deal with vacuum failure and fly partial panel (needle ball and airspeed) in ?real-deal? IMC is even worse. I'll save the "There I was at 10,000 feet" story, but I have had two vacuum failures. One was in IMC giving dual instruction.

Once you experience EFIS, you won?t want to go back. The down side is you loose your scan. The good part is you don't need to scan, because all the info is there. EFIS equip can improve safety, but the weak link in GA flying, again no offense, is the pilot not the equipment. Practice under the hood with a qualified safety pilot, often, with the min instrumentation you plan on using when you EFIS or vacuum pump fails. With just a little turbulence the TC wiggles a lot on a RV. A guy with traditional vacuum instruments is no safer than an EFIS equipped RV, if they can?t fly with min the back-up gyro, usually just a turn coordinator.

Cheers George

This is a good one.

Good topic. Now I am not qualified to put my opinion in on the home grown EFIS, never used 'em. But I can tell you I have about 6000 hours flying commercial EFIS and have never ever had one in-flight hic-up. The stand-by ADI is about the size of a gum ball and my eyes aren't what they used to be. Hope I don't have to stare at that thing "down the pipe" in 200-1/2. I have about 4000 hours in a Saab 340 and I have another 2000 in a Boeing 737-700 and the only time I have ever even seen one show any signs of fault was after a power interruption. But that was always on the ground switching from aircraft power to ground power. I do still fly 73's with the old steam driven stuff and don't really see a problem with them except that parts for them are getting harder and harder to get. Situational awareness is 100 times better with glass. Procedure turns and holding patterns are depicted so, in theory, it should be hard to screw them up.
Sorry so jumbled, I'm in a hurry and wanted to put in my 1 cent. The other penny was used for taxes.

EFIS and backup

I'm a private pilot (comm, CFI) with no commercial experience. We've flown a lot of real single engine IFR with approaches to minimums over 30 years. Like some other guys, I've had two vacuum failures. Luckily both were in VFR conditions. We practice partial panel, for which I prefer a turn needle - just old fashioned and used to that, I guess. For my RV-8, under construction, I have a Dynon EFIS D10 and a TC for backup (the Tru Trak also gives a "gyro stab." hdg rererence). Also have a Garmin 296 GPS. Another friend with 5000+ hours and I have experimented and find we can fly the pseudo panel on the 296 very well under the hood; it's a great potential back up and absolutely independent of aircraft systems/antennae. I hope the MTBF for a unit like the Dynon is much better than a dry vacuum system but that's not hard data. We've all had software glitches. The Spaceship One pilot sure liked the Dynon! Anyway, I feel better about my RV-8 panel, in an electric airplane with two alternators, than any other I've been lucky enough to fly. The best might be a second simple AI, all electronic, such as the Stratromaster Smart Single AI. Has anybody had actual experience with that unit or the Dynon? This is a great thread - thanks.

Bill,
For a backup ADI, also keep an eye on TruTrak because they're going to introduce their own ADI that will also include a slip ball plus heading window.
They're going to introduce it at Sun n Fun for a little over $1000.

Scroll to the bottom of the page at: http://www.chiefaircraft.com/cgi-bi...serve&item=/Avionics/MfgSZ/TruTrak.html#pilot

I want to see more info about it, but it may be a good backup to consider.

Back up

Thanks Vern. Missed Sun n Fun but will go to OSH and hope to see it there. My pace as a builder is so slow the time's no prob. Bill