All glass -vs- backup instruments

[stu517]

looks like a good start. i would hope that you would give yourself some backup instruments (Attitude, Altimeter, Airspeed). I have flown behind a number of the newer EFIS's both certified and experimental - they all have issues and the manual backup is well worth the $$. good luck

[lostpilot28]

Originally Posted by stu517

looks like a good start. i would hope that you would give yourself some backup instruments (Attitude, Altimeter, Airspeed). I have flown behind a number of the newer EFIS's both certified and experimental - they all have issues and the manual backup is well worth the $$. good luck

Hi Stu,
No mechanical backups! This is what it will be, except maybe the addition of an IFR GPS. Each EFIS can act independantly from the other, or in a Master/Slave config so you have synchronized data. If one unit goes down, the other takes over. It's a beautiful setup, really, and I'm not inclined to move backward in technology with my panel (unless I have to!).

[pierre smith]

Originally Posted by lostpilot28

Hi Stu,
No mechanical backups! .......... It's a beautiful setup, really, and I'm not inclined to move backward in technology with my panel (unless I have to!).

....will not have any round gauges on Mr. Blanchard's -7 we're helping build. Only dual Dynons with the new terrain and synthetic vision/autopilot combo.

Each is considered a redundancy for the other and have internal backup batteries in case you lose alternator/battery power.

Makes for a really neat install.

Regards,

[SteinAir]

Sonny - Nice panel!
Pierre - you guys should also end up with a nice panel.

Quick question for both of you....are you both considering these setups to be used for IFR/IMC flight/approaches, etc?

This truly isn't anything other than to settle my personal curiosity, but do both of you feel comfortable using MGL and/or Dynon screens (or any mfgr for that matter) as the only equipment in the panel as suitable for IFR or IMC flight with no "2nd system"? Basically what I'm asking is that would both of you go barreling off into the overcast or clouds with a singular system?

Just curious.

Cheers,
Stein

[pierre smith]

Originally Posted by SteinAir

Sonny - Nice panel!
............., but do both of you feel comfortable using MGL and/or Dynon screens (or any mfgr for that matter) as the only equipment in the panel as suitable for IFR or IMC flight with no "2nd system"? Basically what I'm asking is that would both of you go barreling off into the overcast or clouds with a singular system?

Just curious.

Cheers,
Stein

Stein, when I consider how often we used to fly a Cherokee or Cessna xxx into soup and do approaches with a vacuum system and the only redundant instrument was an electric turn and bank Yes, with dual Dynons/GRT/AFS/Oddysey,etc, I would be very comfortable after I fly with a buddy as safety pilot. I mean, two full panels, dual engine monitors, each capable of standalone ops, regardless of alternator failure.

Regards,

[Ironflight]

I think that what Stein was asking was really about "unlike redundancy". While I am a proponent of thinking outside the box on what we really need in our panels, and I am quite comfortable without "traditional" instruments as backups, I do want to protect from any single point failure. In the old days, the electric T&B protected us from a vacuum failure for instance> But if you have two of the same electronic things, are you fully protected? What happens if there is a software failure? A bug takes them both down, and you have nothing. This has happened more than once in certified and military systems. I solve this in my airplane by having a separate autopilot design from my EFIS. In Louise's -6, we have an ADI Pilot II as backup to the dual Dynon's. I personally wouldn't be comfortable with a single-source panel, because bug-free software does not yet exist. The truth is that the hardware you have installed in an EFIS airplane is actually quite unlikley to fail. Your biggest potential for trouble is the software, or an electrical fault.

Unlike redundancy is your friend!

Paul

[SteinAir]

Originally Posted by pierre smith

Stein, when I consider how often we used to fly a Cherokee or Cessna xxx into soup and do approaches with a vacuum system and the only redundant instrument was an electric turn and bank Yes, with dual Dynons/GRT/AFS/Oddysey,etc, I would be very comfortable after I fly with a buddy as safety pilot. I mean, two full panels, dual engine monitors, each capable of standalone ops, regardless of alternator failure.

Regards,

That was my point exactly. If you only have two identical EFISes in your panel (and nothing else, not even a handheld GPS)...when one is leaning left and one is leaning right - which one is correct?

Paul eluded to this, but obviously the heavy iron requires a "non like" system as a backup. Different technology, different sensors, etc..

You could have 10 EFISes, but if they all rely on pitot/static or gps or other singular external aiding to keep the attitude display correct, it does you little good to have all identical systems if they can be brought down by one bug, pitot/static, gps, or whatever.

Anyway, don't want to start a war here - just making sure people are really thinking this through. I'm pretty sure the EFIS mfgrs would never openly market their systems as a sole source of primary and simultaneous backup for IFR/IMC flight....and if they did they obviously haven't talked to their lawyers!

Cheers,
Stein

[Radomir]

But Stein.. let's review the facts.. 90% of RVs seem to be equipped for IFR (some for "light IFR")... yet... of those... what.. maybe 2-3% (tops!) ever see a whif of cloud.. seems like most of that small percentage seems to be backed up "ok"

My biggest concern is to have redundant shade for the sun in case the cheapo walmart one pops off the canopy and doesn't wanna stay there

ok.. couldn't resist.... sorry

[N941WR]

I agree with Radomir about the cheep-o K-mart shade. I hate it when it falls on my head!

As for duel, indipendent but identical systems, hitting the same bug at the same time, in the same plane...

IMHO, that is very unlikely, possible, but unlikely. Even when dealing with the poorly written business systems I've managed, it was very rare that two "identical" systems whould hit the same error at the same time.

Granted, the same inputs should cause the software to react exactly the same every time. This is true, but when the inputs are created from an aircraft flying through space, it is unlikely two units sitting side-by-side, running off their own internal clocks, would hit the same bug(s) at the same time in a well tested application.

[Ironflight]

Originally Posted by Radomir

But Stein.. let's review the facts.. 90% of RVs seem to be equipped for IFR (some for "light IFR")... yet... of those... what.. maybe 2-3% (tops!) ever see a whif of cloud.. seems like most of that small percentage seems to be backed up "ok"

well, you're right Rad - the vast majority of flying I do in my well-equipped IFR bird is VFR - I rarely have to file for a number of reasons, but it is nice to know that if I DO have to file, I can do it with a significant amount of risk reduction already in place.

I am a lousy gambler - I have no tolerance whatsoever for losing, so I simply don't play anything but a sure bet. And that's just with money - when it's my own little pink body, I make sure that everything is way stacked in my favor.

You're right that the likelihood of having a failure on the one day that a person decides to file IFR in their airplane is small. However, the severity of consequences if it id happen are very high. I like to analyze risk on a two-dimensional scale, with severity of consequences on one axis, and likelihood of occurrence on the other. I can live with points close to the origin - low probability and low consequences. It is when you start getting out to the high end of "bad consequences" that I personally get nervous.

All just food for thought. I happily flew IFR with little to no redundancy decades ago because we didn't have any options. Today, we have very cost-effective options for dissimilar redundancy with digital systems. Many manufacturers stuff talks and plays well with other systems from other companies, so it is not hard to put together a system with fault tolerance and great capability.

Paul