Glass panel question
 

What is your opinion of a glass panel with a primary EFIS and a backup EFIS, but without an air speed indicator or altimeter for backup, or for that matter, any analog round gauge at all? In other words, do you think it is safe to have a panel without a simple old direct reading ASI for backup?

Ron

How pilot types here???

I suppose the simplest way would be to use a backup EFIS that has internal battery backup power, and preferably from a different manufacturer than the primary. I'm having trouble thinking of a down side to that, if you don't consider EMP a big issue.

I didn't search but I'm betting this has been discussed many times before.

Like all things aviation "it depends."

What is your mission? How much hard IFR will you be doing? Do you trust the system you're installing? Battery backup? Planning on night flight?

For me personally, I wanted all the above. G3X with battry back up, Dynon D6 for back up as well. YMMV. No "steam" dials anywhere on the panel.

If you wanted a third backup, most of the handheld GPS units have some varient of a "six pack" they'll display if all else fails.

My first panel had a D100 w/ backup battery. Next to that I installed an airspeed indicator and altimeter. For backup nave purposes I had a Garmin 496 in the panel.

Later, when I upgraded the panel with a 10" SkyView I pulled out the steam gauges and never looked back. However, the 496 is still in there and I have a Dynon D1 Pocket Panel.

Keep in mind, if you install steam gauges that use the same static and pitot system as your EFIS, then you really don't have redundancy as a problem with either of those two lines would impact both the EFIS and Steam gauge.

To get true redundancy you need to install a second pitot system and either a second static system or a way to open the one you have.

You need a backup
 

If you fly 'hard' IFR, you need a backup. The questions becomes what type of backup are you comfortable with. Paul Dye described a very robust electrical architecture, so he has backup electrical capability. If you add an independent backup EFIS with its own backup battery, you probably have it all covered. I fly professionally behind such a system.

For my airplane, I added a round ASI and altimeter, because if things go bad, I want to look at a round guage and not have to think about how to get power to my electronics. I also don't intend to fly more than occasional IFR in the RV, (other than time under the hood to remain current).

DD

I think you will find that many serious IFR efis panels now use a second brand efis as a back-up instead of steam. Most are using the Tru-Trak Gemini or Dydnon D-6. I like the D-6 with an internal back-up battery since it does not require a GPS input from another source. The Tru-Trak does. My D-6 will be completely independant.

For actual IFR you "should" have 3 separate attitude sources from at least 2 different manufacturers. Two of them "should" be connected to the Pitot/Static sources for airspeed and altitude. The different manufacturer is in case one manufacturer has a bug in their software that affects all their products.

Now, these can be all glass as long as the glass is not supsceptible to electrical failure. I have a Dynon Skyview, a Dynon D6 and a Garmnin AERA as my 3 attitude sources. All of them with 2hr+ of battery backup. No Steam guages in my panel.

I also agree with the post about at least an alternate static source for real IFR, but that is no different for glass as it is for steam.

BTW You can no longer buy some new production aircraft (like the Cessna TTx seen below as an example) with steam gauges of any kind. Even their backup is glass.



My 2 cents.
:cool:

One more thing to consider... A Second Alternator...on my Flying RV-7A I have 2-G3X displays that have a TCW battery backup, I have a Dynon D10A as my standby EFIS (with internal battery backup)... Because I never intended to have a vacuum system, I installed a second alternator on my vacuum pump pad. My RV is IFR certified with WAAS GPS only, no VOR/ILS, etc... With 2 alternators and 2 battery backups, and the main battery, my confidence level is high that if my systems become problematic (whether VFR or IFR) I can land my RV safely.

Good luck with your decision.

Victor

About 5 minutes after you posted this, Stein sent a progress pic of my panel. D6 as back up.