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Electric AI backup options


M016576

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I’m in the process of trying to get rid of the vacuum system in my Mooney.  I’ve got a two tube Aspen with external battery...
what are the best (and, separately, the most affordable) options for a 14V backup AI? 



I have a two tube Aspen without the extended battery. I have the L-3 ESI-500. You can use it as a basic AI, add a magnetometer, Nav capability and/or synthetic vision.

Some guys are getting approval for the G5 to be used as the backup.

4606b4d0008e5a8ac1afa8c7dac60b40.jpg


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5 hours ago, LANCECASPER said:

There are some people installing Glass and taking out MidContinent Lifesaver Electric AI's. I got mine with battery backup for less than $1000.

Now we’re talking- I think that’s what I’m looking for- something like that- thanks!

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With the external battery you do not need a airspeed or altitude indicator which makes the lifesaver gyro a good option. Make sure you get the version with a battery backup.  I’d go for the G5 w/gad29b for the future AP support and the backup nav cdi (if you have Garmin stuff). The legal way, and only 2.5k more is the L3 500. 

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Just now, MIm20c said:

With the external battery you do not need a airspeed or altitude indicator which makes the lifesaver gyro a good option. Make sure you get the version with a battery backup.  I’d go for the G5 w/gad29b for the future AP support and the backup nav cdi (if you have Garmin stuff). The legal way, and only 2.5k more is the L3 500. 

I’m an anti-Garmin kind of guy... I’m avidyne equipped.  

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The life safer is a great unit . However , I like the lightweight and low depth attributes of AHRS based AIs

Mooney panels tend to sag and there is not a lot of space between the firewall and the panel. 

Options are G5, SAI-300 and the L3 ESI-500 

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1 hour ago, OR75 said:

The life safer is a great unit . However , I like the lightweight and low depth attributes of AHRS based AIs

Mooney panels tend to sag and there is not a lot of space between the firewall and the panel. 

Options are G5, SAI-300 and the L3 ESI-500 

That’s fine, and I agree.... but I’ve already got TWO individual AHRS, with TWO independent units, on TWO seperate displays with TWO individual battery backups.. the second being an extended life battery (good for 2.5 hours).  So I’ve already got two AHRS based AI’s and that doesn’t count my Stratux driven ipad.

I just need to satisfy the FAA requirement for a certified backup, which apparently the second Aspen unit with battery backup will do for airspeed and altitude, but doesn’t fit the bill for attitude.  

I know this may bring some contraversy, but I view this instrument as a tertiary display... if it gets down to me having to fly on this display... it’s a SERIOUSLY bad day. I have no doubt that in these circumstances, an electric, Gyro driven AI will get me where in need to go: missed to VMC to a suitable alternate.

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11 hours ago, OR75 said:

The life safer is a great unit . However , I like the lightweight and low depth attributes of AHRS based AIs

Mooney panels tend to sag and there is not a lot of space between the firewall and the panel. 

Options are G5, SAI-300 and the L3 ESI-500 

I am going with the Sandia Quattro 340. With a wiring harness of two wires, a pitot, and a static connection it was simple and fairly quick to get installed. With the exception of heading information, it is all I need. Under $3000 from Aircraft Spruce and weighs 0.51 lbs.

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17 hours ago, M016576 said:

That’s fine, and I agree.... but I’ve already got TWO individual AHRS, with TWO independent units, on TWO seperate displays with TWO individual battery backups.. the second being an extended life battery (good for 2.5 hours).  So I’ve already got two AHRS based AI’s and that doesn’t count my Stratux driven ipad.

I just need to satisfy the FAA requirement for a certified backup, which apparently the second Aspen unit with battery backup will do for airspeed and altitude, but doesn’t fit the bill for attitude.  

I know this may bring some contraversy, but I view this instrument as a tertiary display... if it gets down to me having to fly on this display... it’s a SERIOUSLY bad day. I have no doubt that in these circumstances, an electric, Gyro driven AI will get me where in need to go: missed to VMC to a suitable alternate.

Personally I'd take your backup attitude a little more seriously because your two AHRS aren't entirely independent. What I am referring too is that a failure of your pitot heat in icing will bring down both AHRS entirely; showing nothing for attitude, airspeed or altimeter making that backup attitude instrument more important. I went with the ESI-500 for my panel so that I also have backup nav functionality as well as IAS, Alt & VS, but an electric gyro with it own backup battery should do the job for you Ok. 

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6 hours ago, kortopates said:

Personally I'd take your backup attitude a little more seriously because your two AHRS aren't entirely independent. What I am referring too is that a failure of your pitot heat in icing will bring down both AHRS entirely; showing nothing for attitude, airspeed or altimeter making that backup attitude instrument more important. I went with the ESI-500 for my panel so that I also have backup nav functionality as well as IAS, Alt & VS, but an electric gyro with it own backup battery should do the job for you Ok. 

I am ashamed to have been initially incredulous of this post - I would have thought surely there's a pitot-static independent mode with degraded backup AI function for my Aspen pfd. Nope.  Below is a  video of flying over the north Atlantic with dual Aspens that illustrates the problem as more than theoretical - see around  9-10min mark.  The L3 ESI-500 certainly is the Cadillac glass backup option.  The Sandia Quattro looks like a good budget alternative.  The Dynon D10A is slightly cheaper still, but the graphics look dated and clunky.  Some are installing the even more economical Garmin G5 as backup, although it's not STC'd as such, and the basis to do so without field approval remains fuzzy. It will probably be my choice if a regulatory path sorts out in the next year. At least the G5 doesn't go blank if the airspeed fails!   I was hoping for more glass backup choices soon, but I've heard of none on the horizon.

On another note, I wonder about backup battery life, replacement interval, and replacement cost as considerations for a glass backup AI.  With no vac in an alternator failure, a glass backup is only as good as its lithium battery, which loses capacity over time. The Sandia has a 2 hour battery. The Garmin G5 has a low cost 4 hour battery that is fairly cheap - excellent.   I haven't seen battery capacity info for the L3 or Dynon.

 

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I am ashamed to have been initially incredulous of this post - I would have thought surely there's a pitot-static independent mode with degraded backup AI function for my Aspen pfd. Nope.  Below is a  video of flying over the north Atlantic with dual Aspens that illustrates the problem as more than theoretical - see around  9-10min mark.  The L3 ESI-500 certainly is the Cadillac glass backup option.  The Sandia Quattro looks like a good budget alternative.  The Dynon D10A is slightly cheaper still, but the graphics look dated and clunky.  Some are installing the even more economical Garmin G5 as backup, although it's not STC'd as such, and the basis to do so without field approval remains fuzzy. It will probably be my choice if a regulatory path sorts out in the next year. At least the G5 doesn't go blank if the airspeed fails!   I was hoping for more glass backup choices soon, but I've heard of none on the horizon.
On another note, I wonder about backup battery life, replacement interval, and replacement cost as considerations for a glass backup AI.  With no vac in an alternator failure, a glass backup is only as good as its lithium battery, which loses capacity over time. The Sandia has a 2 hour battery. The Garmin G5 has a low cost 4 hour battery that is fairly cheap - excellent.   I haven't seen battery capacity info for the L3 or Dynon.
 


I saw this video when it was first posted. Matt is the 19 year who circled the globe in a Bonanza.

The “failure” of the Aspen was due to pitot icing in clear air. Once they heated the pitot, it came back.

But this video proves the point that if you have a glass cockpit, you better know the failure modes of the equipment and what your backup strategy is. The G500 is power dependent. If you don’t have a secondary alternator/battery, you will be limited to your battery capacity. The Aspen has a battery backup, but is dependent on a functional pitot static system which is another limiting factor in our planes.

I opted for the L-3 ESI-500 because it could provide the degraded AI which the G-5 can’t (or isn’t certified to do) and the ability to support a Nav source.

One of the advantages of plane ownership is you get to decide how to stack the cards in your favor. Back in the early days of my ownership, have a Precise Flight standby Vacuum was the cat’s meow. Amazing how far removed we are from those days.


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I was at a sensor conference a couple of years ago and there were severa venders of AHRS modules. A few were selling very high end modules that cost well over 10k each. All of them suffered some form of out degradation unless they had some form of speed input, otherwise they were affected by acceleration. Some vendors were using a gps input for speed, others were using a pressure sensor. A few had flight simulators set up so they could show what happened when the speed input was turned off. 

Edited by N601RX
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1 hour ago, Marauder said:


I opted for the L-3 ESI-500 because it could provide the degraded AI which the G-5 can’t (or isn’t certified to do) and the ability to support a Nav source.

One of the advantages of plane ownership is you get to decide how to stack the cards in your favor.

 

Apparently someone at Garmin claims that the G5 AI performs quite well even when stripped of both airspeed and GPS inputs:

https://www.beechtalk.com/forums/viewtopic.php?f=21&t=134783&start=30

The NAV display for the L-3 does seem like serious value added though over the other options.  I wish it were a bit cheaper.

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On 12/27/2017 at 12:38 PM, kortopates said:

Personally I'd take your backup attitude a little more seriously because your two AHRS aren't entirely independent. What I am referring too is that a failure of your pitot heat in icing will bring down both AHRS entirely; showing nothing for attitude, airspeed or altimeter making that backup attitude instrument more important. I went with the ESI-500 for my panel so that I also have backup nav functionality as well as IAS, Alt & VS, but an electric gyro with it own backup battery should do the job for you Ok. 

That’s valid, and I hadn’t considered the single point of failure for the two aspen displays.  Thanks!

I think I’ll still opt for the electric standby Gyro with backup battery- again, just because I’m confident in my steam driven flying capabilities due to recurrent, continuous training during my “day job” (which has a steam driven AI/HSI), and the goal of the backup is (or would be) to get me out of IMC, to a safe, VFR type divert- which is in my acceptable risk profile when flying the mooney.  I don’t think a third digital AHRS backup Gyro/unit /pfd would change my risk tolerance.

tertiary options in the event that I’m shooting an approach, my pitot tube ices up, my pitot heat fails (or I forget to turn it on), would be the electric Gyro, with the option for altitude/airspeed on both my panel mounted GPS (ifd440) and also my iPad with Synthetic vision.  Not optimal, but could get the job done I need them to do in a very very stressful (and hopefully very unlikely) pinch.

Edited by M016576
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