Replacing vacuum gyro artificial horizon with electric

[NotarPilot]

I would like to see what opinions are out there about getting rid of my vacuum AI and replacing it with an electrical one. I like the idea of the reliability of an electric AI. I know the argument will be "What if you have a full electrical failure during IMC?" but I fly with an iPad mini, which I can eventually use with as a back up AI once I get that AHRS unit one of these days.

Have any of you gotten rid of your vacuum driven instruments in favor of all electrical? My AI is the only vacuum driven instrument I have in my panel.

[Danb]

I had a rc Allen electric digital in my J model which is great, you can have a battery backup in many electrics in case of power failure. Mine was a backup in case of vacuum failure which came in handy on 2 occasions... Have a great holiday all you mooniacs

[takair]

I'm pretty sure you are required to have it so that you have dissimilar power source. You would need an independent electrical system from your tuen and bank to do as you suggest. You might be better off replacing your T&B with an electric AI, or add one in a spare hole. As bad as vacuum can be, I would still hate to rely on a single string electrical system for my only source of right side up.

[Piloto]

Before you replace your existing vacuum gyro verify is not used by the autopilot. Most GA autopilots use the AI for roll and pitch control. Check on the back of the AI case for any cable with multiple wires coming out. If this is the case your other option is to replace the turn indicator with an electric AI.

 

José 

[Z W]

Get a Dynon D1 or D2.  Keep your vacuum unit.  

 

Done for under $2k and you have not just an electric gyro, which still has a relatively high failure rate, but a solid-state AHRS with no spinning parts.

 

Not certified, but probably safer than a certified electric gyro AI at less than half the cost.

[rbridges]

I gave it a lot of thought, but I think I'm going to go with a Stratus 2.  It has AHRS to serve as a backup.  I may eventually go with some type of electric AI and HI, but I think the Stratus 2 will buy me some time to look around some more.  I've considered the Aspen units, but I'm concerned about cost/support availability over time.  An obsolete Stratus 2 is easier to swallow than an obsolete Aspen.

[Mooneymite]

At this point in the march of technology, going to electrical gyros would be a step backward.

If you want to get rid of your vacuum system, go electronic, not electric.

However, the old vacuum systems, backed up by the electric TC, have a proven track record. Look before you leap. I have an acquaintance who fried both his electric AI and DG with a voltage spike on start-up ($1500 repair).

I think we are in a transitory stage in the certified world. The iPad and low cost accessories have shifted the paradigm.....

You might want to hang on a little longer to see "what's next".

[Jamie]

You might want to hang on a little longer to see "what's next".

 

No kidding. Remember back in '98, when garmin had tablet-like maps? The prices, oy. But that was because it was specialized hardware built for a small market and they were the only game in town.

 

I hope computer driven cars happen in a big way. Know why? Because there's NO way they retrofit the millions of miles of roadways to support them. They'll have to do it autonomously. And that means a combination of tech that'll make WAAS look down right crude by comparison. Just like iPads, the advances we'll take advantage of won't happen because aviation needs them, they'll happen in some other area and embarass the "industry leaders" out of their monopolistic practices.

 

And while I'm on my soapbox...

 

The FAA complains about the safety statistics, and then stands guard on the wall just inside TSO moat surrounding the manufacturer's camp. Let me in! Hey, FAA.... instead of hiding behind all of the certification voodoo, why don't you lead a mini-space race to produce an affordable (and don't just say it, define it... say, $10000) panel that includes the latest and greatest tech, drop all barriers to adoption and bring the entire GA fleet into the 21st century? That'd do a hell of a lot more for safety than hosting WINGs seminars.

 

harumph.

[M20F-1968]

A concern between a vacuum artificial horizon and and electric artificial horizon is that the vacuum unit is able to correct from an unusual attitude more readily and is more stable.  Yes you have a vacuum pump, but that is a plus when everything else is electric.  This is the reason I have the electronic G600, 3" vacuum AI and 2" electric AI.

 

John Breda

[NotarPilot]

Good info. I already have an electric TC that's part of the S-Tec 30. The AI is the only vacuum driven instrument. We have three AC at my work with electric AIs and I don't think we've ever had one fail yet.

[wiguy]

 I wanted some backup & found a slightly used Castleberry electric for $1300 from an avionics shop. Now I have my regular vacuum and the electric. My 'backup' seems better that the main gyro now.

[Jerry 5TJ]

I installed an electric AI as a backup to the M20C's vacuum AI several years ago.    The electric AI is said to be 'non tumbling' and in fact I did test it (No, not in the plane!) by rolling and tumbling the instrument as it spun, powered by its internal battery.  It came back to level each time, I'm happy to report.   But, if I were upgrading the gyros today I would look hard at the solid-state options.

[NotarPilot]

I've been exploring this again recently when I saw how relatively inexpensive an overhauled electric TSO'd attitude indicator is. I also came across a recent change in policy by the FAA making the switch easier but making it a minor alteration. This is great news. After recently having to replace my vacuum pump I think this would be a great upgrade for my panel to improve reliability.  

Here's a link to the article about the policy change.

Replacing a vacuum driven AI with an electrical one.

Edited January 9, 2016 by NotarPilot

[Jerry 5TJ]

And while you're at it, Steve, you can remove the vacuum pump, vacuum regulator, gauge, low/high lights, vacuum filter and all those darn hoses. 

( I'd have done that on the "C" but if I did the PC wing leveler and the step retraction wouldn't work. )    

[Gone]

 

And while you're at it, Steve, you can remove the vacuum pump, vacuum regulator, gauge, low/high lights, vacuum filter and all those darn hoses. 

( I'd have done that on the "C" but if I did the PC wing leveler and the step retraction wouldn't work. )    

Me too.  The only reason I would keep the vacuum pump is to power the retracting step.

[NotarPilot]

I wonder how much weight I could end up saving by removing all of that?

[DXB]

It had been my (perhaps erroneous) understanding that maintaining a vacuum pump system was still cheaper than a electric/electronic AI, mainly due to the very high backup battery replacement costs on all the units certified for this.  Has this changed?

I just had a nearly all new panel with Aspen pfd installed and ended up keeping the vac pump, which now drives nothing other than a backup AI.  It feels silly.  No retractable step on the '68C, The AHRS on the Aspen is backed up by the one in my FS210, and the one in the Stratus 2 in case I lose the whole electrical system.   The vac-driven AI seems a pointless maintenance item in this context, and a heavy one at that.  I would replace if I were convinced it wouldn't cost me more in the long run.   I'm just going to run my current vacuum pump until it croaks and then reassess.  

[Marauder]

It had been my (perhaps erroneous) understanding that maintaining a vacuum pump system was still cheaper than a electric/electronic AI, mainly due to the very high backup battery replacement costs on all the units certified for this.  Has this changed?

I just had a nearly all new panel with Aspen pfd installed and ended up keeping the vac pump, which now drives nothing other than a backup AI.  It feels silly.  No retractable step on the '68C, The AHRS on the Aspen is backed up by the one in my FS210, and the one in the Stratus 2 in case I lose the whole electrical system.   The vac-driven AI seems a pointless maintenance item in this context, and a heavy one at that.  I would replace if I were convinced it wouldn't cost me more in the long run.   I'm just going to run my current vacuum pump until it croaks and then reassess.  

Dev -- the Aspen requires a backup AI as part of the installation. Your options are to remove the vacuum system and mechanical AI and replace it with an electronic version. Or keep the vacuum system. The cost of entry into these electronic AIs is pretty high.

I have not removed my vacuum system and have left the mechanical AI in place. With vacuum pumps running around $700 and and overhaul for an AI running around $500, I will keep the system until and if the electronic versions are much cheaper to acquire.

With a second Aspen in my plane, the mechanical unit becomes less important as a backup.

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[Tom]

Note that the Sandia Quattro has been certified.  Attitude plus altimeter and airspeed.

Spruce has them for $3400 currently. 

Don't forget that a Part 23 re-write may occur that would allow the use of non-STC'd equipment (more on this elsewhere).

I didn't know this before, and not the point of this thread, but it seems as though you can replace your T&B with a second AI per this AC referenced in the Quattro marketing information.
 

Edited January 11, 2016 by Tom

[Guitarmaster]

I gave it a lot of thought, but I think I'm going to go with a Stratus 2.  It has AHRS to serve as a backup.  I may eventually go with some type of electric AI and HI, but I think the Stratus 2 will buy me some time to look around some more.  I've considered the Aspen units, but I'm concerned about cost/support availability over time.  An obsolete Stratus 2 is easier to swallow than an obsolete Aspen.

You can fly an entire approach using just your iPad and the Stratus2. Oddly enough, I can verify this with absolute certainty!

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[gsxrpilot]

 

You can fly an entire approach using just your iPad and the Stratus2. Oddly enough, I can verify this with absolute certainty!

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The next time I'm out for practice approaches, I intend to do this.

[Guitarmaster]

A great point has been brought up here. Aircraft electronics are changing as rapidly now as computers were in the 90's. The price point on many Avionics has dropped very dramatically in just the past couple years. The EDM 900 is a prime example of this.

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[1964-M20E]

 

Me too.  The only reason I would keep the vacuum pump is to power the retracting step.

I've found a place that has electric linear actuators that would work well but the only catch is getting it approved field or otherwise.

 

Engine vacuum may work as well???

Edited January 11, 2016 by 1964-M20E

[carusoam]

Send a message over to TakAir...

Rob, has the linear actuator and FAA paperwork combined experience to make something like that happen.

The auto-lean controls the red knob using a linear actuator.

It would be nice to separate the vacuum pump from the step.

Best regards,

-a-

[Marauder]

Note that the Sandia Quattro has been certified.  Attitude plus altimeter and airspeed.

Spruce has them for $3400 currently. 

Don't forget that a Part 23 re-write may occur that would allow the use of non-STC'd equipment (more on this elsewhere).

I didn't know this before, and not the point of this thread, but it seems as though you can replace your T&B with a second AI per this AC referenced in the Quattro marketing information.

 

I think you are correct about replacing the TC with an AI. Uni fortunately those of us with an STEC AP need the TC in the panel. And replacing it still doesn't eliminate the need for the vacuum version.

I was hoping the new ruling would allow something other than "dual use", but that doesn't look to be the case.

http://www.faa.gov/aircraft/draft_docs/media/PS-ACE-23-08.pdf

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