Ditch vacuum system?

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MPB

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MPB
Hi folks,

If I've got an AV30 as an attitude indicator and add either a G5 or GI275 as an HSI - can I ditch my vacuum system? Can you mix and match like that?
 
I’m interested in the answer as well. I guess it would depend if the AV30 is considered your primary attitude gyro, and if it is suitable to be a primary.

IFR, right?
 
MPB said:
If I've got an AV30 as an attitude indicator and add either a G5 or GI275 as an HSI - can I ditch my vacuum system? Can you mix and match like that?
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Which one would end up being your primary attitude indicator? That's the one for which you'll need to consult its install manual, for it will tell you what backup instruments are needed.

Side note: Between the G5 and GI-275, the GI-275 has a much nicer display with higher resolution, better clarity and more brightness. I've flown with both, and the GI-275 would be my choice despite the higher price.

- Martin
 
I also have flown with both, personally I prefer the G5 because to me it is easier for me to use and see, more like a PFD.
Maybe I am influenced by my avionics shop who thinks the G5 is not as cluttered even though I know they are the same size overall.
Then my buddy who is a 26000 hr captain recently said to me he is going with 2-G5 in his arrow after having a 275 in his old cheerokee and has a 275 now in his arrow as a nav indicator. He thinks the 275 is too cluttered and the thick bezel on both his cheerokee and arrow restrict the view a little, especially if your tall?
I have been flying with 2-G5 since 2018 and no vacuum system, 950 hrs so far. Yea I don't like change...lol
IMG_2651.JPG

Here's picture os my buddys cheerokee, the piper bezel is made different than a cessna and it makes seeing the 275 tougher if your tall. I don't know what kind aircraft the OP has?
IMG_9558.JPG
 
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Assuming we're taking about certified aircraft, the G5 STC requires two G5's to allow removal of the vacuum system. I don't know about the AV-30, but I assume they'd have a similar requirement. They appear to post the stc and install manuals on their site, so the answer is there, it's just going to take a little digging.
 
I wish the G5s had the resolution that the GTN Xi series but I have no complaints. We bought 5 of them prior to the 275 being available and have no regrets or desire to change them. The costs of these was crazy low to put them in with a family A&P with IA doing the work for free and a repair station contracted to the part 91 inspections. If we do have failures repairing them is heaper than the 275 as well.

A agree the 275 is pretty cluttered depending on the options used.
 
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I'm sure some of you are curious about why I asked about mixing the AV30 and either a G5 or GI275 HSI. I've presently got an AV30 attitude indicator with a vacuum DG - happy with the AV30 - it works fine. I've also got an STEC30 that uses the heading bug on my vacuum DG. My plan was to switch to an AV30 DG, but Uavionix does not seem to be moving on getting the autopilot heading bug adaptor for the STEC autopilots going - in the absence of that I'll lose my heading bug if I switched to an AV30. So I'm kind of stuck here as to how to move forward other than pulling the AV30 and switching to Garmin. Driver for this is that the DG is starting to get lazy and done right that'll be around 1000 USD in and out - that's a long way towards an electronic HSI.
 
MPB said:
I'm sure some of you are curious about why I asked about mixing the AV30 and either a G5 or GI275 HSI. I've presently got an AV30 attitude indicator with a vacuum DG - happy with the AV30 - it works fine. I've also got an STEC30 that uses the heading bug on my vacuum DG. My plan was to switch to an AV30 DG, but Uavionix does not seem to be moving on getting the autopilot heading bug adaptor for the STEC autopilots going - in the absence of that I'll lose my heading bug if I switched to an AV30. So I'm kind of stuck here as to how to move forward other than pulling the AV30 and switching to Garmin. Driver for this is that the DG is starting to get lazy and done right that'll be around 1000 USD in and out - that's a long way towards an electronic HSI.
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Considering the lack of functionality the AV30 has as a DG replacement, I don't think anyone is wondering why you'd be going for a unit that actually works.
 
It is very dumb on the part of Uavionix to not support as many legacy autopilots as possible.
The HSI input seemed to be the easiest thing to interface with legacy autopilots. In my case, with my Century 2B, the G5, Aspen, and GI275 no problem. It was the Attitude info interface that was more problematic. Non existent for the G5, but as an add on for the Aspen and GI275, per my understanding. I would have thought that your rate based autopilot would have been a shoe in. Makes me wonder if Uavionix will be slowing down the attitude interface functionality that was promised in future iterations. Despite my Aspen, I’m currently not dumping my vacuum system as my vacuum AI is the least expensive option to continue feeding my autopilot.
 
I read recently that the AV30 HSI doesn’t have glide slope and isn’t suitable for IFR. Were you wanting IFR?

Also, many people are having issues with heading drift on the AV30 DG/HSI and the magnetometer fix isn’t approved yet for certified aircraft.
 
MPB said:
I'm sure some of you are curious about why I asked about mixing the AV30 and either a G5 or GI275 HSI. I've presently got an AV30 attitude indicator with a vacuum DG - happy with the AV30 - it works fine. I've also got an STEC30 that uses the heading bug on my vacuum DG. My plan was to switch to an AV30 DG
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We have two Cessna 172s with the AV30 attitude and heading indicators. Lots of problems with the heading indicators.
 
texasclouds said:
I read recently that the AV30 HSI doesn’t have glide slope and isn’t suitable for IFR. Were you wanting IFR?

Also, many people are having issues with heading drift on the AV30 DG/HSI and the magnetometer fix isn’t approved yet for certified aircraft.
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For starters, the AV30 isn't an HSI even though they imply that it is in their sales literature.

The magnetometer add on helps but can have its own installation quirks too. Personally, from what I've seen I'd avoid the AV30 altogether.
 
Still too much smoke about the HSI functionality for me too. If I could, I’d wait till perfected. On the other hand, I have not heard a negative thing about AI version.
 
With regards to the original question. If you have no instruments that require vacuum, then why keep the system? Your A&P can make a log book entry indicating removal of the vacuum pump and lines due to no instrumentation requiring it.
 
I have the two G5s to replace my vacuum system . When I was looking they were having some problems with the av30. I’m happy with the garmin.
 
The STC will be crystal clear what you need to have in order to remove the vacuum system. For Garmin, you need to install dual G5s to eliminate the vacuum instruments. The AV30C is not set up for use as a CDI, which has implications for IFR use. The G5s can act as a primary CDI for your primary GPS/NAV/LOC unit. I have two G5s, and removed the vacuum system and all the vacuum instruments. Very happy with this arrangement for IFR and integration with a rate-based legacy autopilot. The Aspen E5 was an alternative to two G5s, and similar in cost and capability. The AV-30 units were never in the picture for IFR.
 
Re: AV30 as a DG -- Don't do it. I put two units in my PA28 back in November and ditched the vacuum system. The DG drift issue is very real, and it's excessive. The shop that installed mine said another customer of his is having the same issues. The AI is fine, but the DG is unsafe, IMO. Been going back and forth for months with Uavionix "tech support" and it's "try this, try that." Met one of their sales reps at a recent AOPA fly-in and he acknowledged their DG was still having these issues. I am very close to pulling them out and sending them back for a refund and installing G5s. On the most recent email correspondence, their tech rep said they "will likely sell customers with DG drift issues an external magnetometer at a reduced cost." -- No way am I dumping more $$ into their faulty product. Please learn from my mistake. Don't do it and tell everyone you know-- I certainly am.
 
Jason Kadah said:
Re: AV30 as a DG -- Don't do it. I put two units in my PA28 back in November and ditched the vacuum system. The DG drift issue is very real, and it's excessive. The shop that installed mine said another customer of his is having the same issues. The AI is fine, but the DG is unsafe, IMO. Been going back and forth for months with Uavionix "tech support" and it's "try this, try that." Met one of their sales reps at a recent AOPA fly-in and he acknowledged their DG was still having these issues. I am very close to pulling them out and sending them back for a refund and installing G5s. On the most recent email correspondence, their tech rep said they "will likely sell customers with DG drift issues an external magnetometer at a reduced cost." -- No way am I dumping more $$ into their faulty product. Please learn from my mistake. Don't do it and tell everyone you know-- I certainly am.
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The internal magnetometer is the issue. They should give us av30 owners the external one for free tbh
 
ktup-flyer said:
The internal magnetometer is the issue. They should give us av30 owners the external one for free tbh
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YES they should
My advice - do NOT go with the AV30. Go G5’s or other. Even for VFR
I have AV30 and the DG is almost worthless. Talking to uA and have not been able to get it to remotely maintain correct heading even with all the setting changes etc
 
Hal said:
YES they should
My advice - do NOT go with the AV30. Go G5’s or other. Even for VFR
I have AV30 and the DG is almost worthless. Talking to uA and have not been able to get it to remotely maintain correct heading even with all the setting changes etc
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I just keep mine on HSI mode
 
Didn't they just get the magnetometer certified ?

How much does this thing precess without a magnetometer...just asking ?
 
Some people report minimal precession, some say its it worse than a wore out mechanical that requires adjustment every minute or two.
 
Internal magnetometers are inherently problematic. Garmin requires a GMU 11 remote magnetometer for heading indication on the G5. They will also sell you one for $365.

UA learned the hard way. Tried to do a little too much at too low a price point. Fortunately the fix appears on the way.
 
Doug Reid said:
How much does this thing precess without a magnetometer...just asking ?
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texasclouds said:
Some people report minimal precession, some say its it worse than a wore out mechanical that requires adjustment every minute or two.
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The amount of precession seems like it may be related to what type of aircraft it is installed in and how much the instrument panel vibrates. I have one installed as a DG in an aircraft with a floating instrument panel that shakes a fair amount and the precession is worse than the mechanical gyro it replaced. I’ve seen others installations that aren’t as bad.

The problem I have with the uAvionix is that their product performance is hit or miss. You might install one and it’s fine, but install another and it’s a problem. You don’t have the same discussions with other options on the market.
 
mondtster said:
The amount of precession seems like it may be related to what type of aircraft it is installed in and how much the instrument panel vibrates.
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I would speculate it is related to how much ferrous material and large electrical currents are in proximity to the instrument.

My Decathlon encases the cockpit in a cage of steel tubes. An AV-30 in the DG position would be within 1 inch of the steel instrument panel support bracket. About 3 inches away, the main bus, battery, and alternator lines connect to the ammeter. Those are 8 gauge wires on 60 amp breakers. That's a whole lot of potential magnetic fields. But hey, at least my instrument screws are brass!

Out on the wood spar wing with aluminum ribs ... different story. Gimme that remote magnetometer, please.
 
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Ed Haywood said:
I would speculate it is related to how much ferrous material and large electrical currents are in proximity to the instrument.
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I don't have proof of it but I believe the primary way the AV30 is stabilizing the gyro is via accelerometer, not via an actual magnetometer. The external one should help, but I'm curious to see what people's feedback of the installation and calibration process is. Assuming it is similar to the experimental version, that may just open up a new set of problems.
 
mondtster said:
I don't have proof of it but I believe the primary way the AV30 is stabilizing the gyro is via accelerometer, not via an actual magnetometer. The external one should help, but I'm curious to see what people's feedback of the installation and calibration process is. Assuming it is similar to the experimental version, that may just open up a new set of problems.
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Have there been issues with the experimental magnetometer?
 
Ed Haywood said:
Have there been issues with the experimental magnetometer?
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I haven't read or heard anything one way or the other with it. But I installed one, in an attempt to address the precession issue. I thought the setup was rather convoluted, and I had a hard time finding a spot on the aircraft that met the desired noise requirements. In the end, I disabled it because I ran out of time to deal with trying to get it right.
 
mondtster said:
I don't have proof of it but I believe the primary way the AV30 is stabilizing the gyro is via accelerometer, not via an actual magnetometer. The external one should help
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AFAIK nobody has been able to do heading by accelerometer alone. Even AHARS attitude needs some kind of external reference to periodically reorient itself. UA tried to pull it off with an internal magnetometer. Looks like Faraday beat 'em.
 
Ed Haywood said:
I would speculate it is related to how much ferrous material and large electrical currents are in proximity to the instrument.

My Decathlon encases the cockpit in a cage of steel tubes. An AV-30 in the DG position would be within 1 inch of the steel instrument panel support bracket. About 3 inches away, the main bus, battery, and alternator lines connect to the ammeter. Those are 8 gauge wires on 60 amp breakers. That's a whole lot of potential magnetic fields. But hey, at least my instrument screws are brass!

Out on the wood spar wing with aluminum ribs ... different story. Gimme that remote magnetometer, please.
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Garmin suggests mounting their magnetometer in the outboard section of the wing.
 
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