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drozovs

Member
Hello,

I am writing to find out if anyone knows if a back up (i.e. small) indicator exists that depicts the following:

1. Attitude (AHRS derived)
2. KIAS
3. Baro Alt
AND
4. Engine info

The closest I have found has been the MGL Extreme Mini EFIS. I am trying to create a very clean G3X/GTN750 setup but I want one more layer of redundancy... its an exercise of sorts :)

Thanks in advance!

-David
 
What engine info do you consider essential?

If you are just trying to get the airplane down after a major EFIS failure, and the engine is running fine, you might only need an oil pressure light from a dedicated switch - Lycomings that are running fine will probably keep running fine, and you'll be able to set power by ear pretty quickly after flying yours awhile.

If you just want RPM, you can get a very simple gauge for that.

If you feel the need for full-up data on everything, you're looking at a GRT EIS 4000, or a D-100 (or 180) from Dynon, or some other engine monitor like you described from MGL. With many people upgrading to full-scale EFIS's, it is easy to find used simple units around for a good price - but sharing probes with the big unit is not simple.

Personally, I'll ferry a Lycoming with just an oil pressure switch/light if I need to, for a short flight, and it has a good history. Your comfort level might vary.

Paul
 
Thanks Paul!

I was hoping to emulate the data from the G3X touch though that may be a tall order. Ive seen the GRT though I will have to take a look at the D-100. I also like the idea of a oil indicator! Many thanks again and happy new year!

V/R

David
 
interesting thoughts on minimal (redundant) instrumentation

Wondering what the oil pressure light will tell you, or allow you do do preemptively, that the sound of the engine slowing and seizing wouldn't... What options do you have if the light says the oil pressure is critically low that the engine won't already force on you a few seconds later? Sincere question; never faced this and don't want to!
 
Its a good point Bill. For me, and I didnt think this through in my reply, I always verify on a second indication. I really want full back up on a second instrument but the -8s panel gets cramped with the 10" G3X. The 7" makes it a lot cleaner though you get a smaller symbology window. This is going to keep me thinking :)
 
To have a "backup" or "redundant" engine monitor, you need two sets of sensors. Most sensors are powered by the engine monitor, and can't be split to two displays as double the power will cause the reading to be wrong on both displays. On sensors that can be connected two places, you actually have LESS redundancy with two engine monitors, you have twice the opportunity for one of them to fail and mess with the sensor wire and make the remaining display read wrong.

Of course, in the end, some of the most problematic things on an airplane tend to be the various engine sensors. A man with two oil pressure gauges has no idea whatsoever his oil pressure is!

Systems like Dynon's SkyView take the very reliable engine monitoring box and allow it to be displayed on more than one screen, even if one screen fails. That's probably the most redundancy you'll find in small GA aircraft for engine data. As has been said, if you really lose you engine monitor, what about that prevents you from getting down safely? You're not going to be continuing your flight normally with a failure of all your primary flight instruments anyway.
 
Agreed... I'm less worried about the sensors than I am about the box that displays it... not Garmin, Dynon, or any other manufacturer perse, just probability-wise the number of things in a "box" that can shut it down are much higher than the single thread voltage of the wire... Again, I am WAY before this step but then again, the whole purpose of this build for me is to implement every bit of human factors knowledge I have learned to a sort-of best practices type airplane :)
 
Bill Boyd said:
Wondering what the oil pressure light will tell you, or allow you do do preemptively, that the sound of the engine slowing and seizing wouldn't... What options do you have if the light says the oil pressure is critically low that the engine won't already force on you a few seconds later? Sincere question; never faced this and don't want to!
Click to expand...

Good question Bill. I can tell you that I once had an oil cooler line break and dump all of the oil in the engine overboard - but it went DOWN under the belly, so the first indication I had was the oil P light coming on. I then looked at the oil pressure gauge and saw it at zero. The engine was running great, but I pulled the power back, picked out a local airfield and turned excessive altitude into the energy I needed to make the field. Engine was still running fine as I rolled out and onto the ramp, where I shut down - probably seven minutes elapsed from the light coming on and shutdown. Visual inspection inside the engine showed no damage, and it did indeed run fine for another thousands hours.

So that's a single datapoint - but I doubt the engine is going to seize the moment you lose oil pressure, and in fact, it can give you plenty of heads-up warning to find a safe place to land.

Paul
 
You could pull MP in tandem and a second RPM, Op, and OT sensor. Not too bad, its the cyl/egt that would be a hassle. Skip them? The new MGL discovery lite is self contained and way more capable than the extreme.
 
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