Backup AI for dual Aspens (non-MAX)

GoDores

GoDores

Filing Flight Plan
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GoDores
I just had my vacuum AI fail in flight. It’s the only vacuum driven instrument I have left and I’d like to get rid of the vacuum system.

I currently have dual Aspen 1000 PFD/MFD with the backup batteries. They are the older non-MAX versions for which the STC requires a backup AI. I don’t have any original steam gauges except the vacuum AI and an electric TC that drives the autopilot, which will stay.

The plan was to install an AV-30C with a field approval, or if that wouldn’t work, a G5. Avionics shop says field approval won’t work for the AV-30C because the STC is only for single engine airplanes, and the G5 won’t work because it’s only approved as a primary and not a backup AI. But they say I could use a GI275, which is about double the cost.

Is this accurate? If not, can anyone point me to actual FAA paperwork that would show my shop that one of the more reasonably priced options would be legal? It seems crazy that in the event the Aspens failed the FAA would rather I have a vacuum-driven AI than a G5 with airspeed and altitude information and a battery backup, but I recognize this may be the case unless I can prove otherwise.

Edit: plane is a PA-30.
 
I believe the G5 was originally intended for the experimental - amateur built market. It's application in a certificated airplane is limited. The G5 cannot replace either the airspeed indicator nor the altimeter - you have to keep your original two instruments in place if you install a G5 to replace the original AI.

The GI 275 does not have that restriction; it can replace the gyro and the AS and altimeter.

Does the Aspen STC require a backup for the AI only? Or does it have to back up your airspeed and altimeter as well?
 
Hmmm so STCs continue to catch up on the digital world- why not an RCA26 for the time being? I think that can be used as primary


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Dual Aspens can back each other up for airspeed and altitude. I don't have any AS/altitude indicators in my cockpit except for the Aspens. (So if I were to lose both Aspens, I would have no airspeed or altitude indications, which is one reason I want to replace the mechanical AI with an electric unit that displays airspeed, altitude, and heading.)

The RCA26 appears to have no more functionality than a vacuum AI but at the price of a G5. Don't really see any benefit there.

I can and have flown in hard IMC with only a single G5 for an attitude indicator, and that was perfectly legal. But somehow it becomes illegal to use that same G5 as a backup AI to two other certified glass attitude displays, each with its own battery backup. (But if I buy the $4k electric AI instead of the $2300 electric AI, it goes back to being legal again.)
 
GoDores said:
it goes back to being legal again.)
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FWIW: Why not contact the Aspen STC holder and inquire on a possible G5 option. They're the ones that could issue you an EO to the STC and possibly use one of your lower cost options.
 
The G5 ADI has no AP pickoffs so it cannot be used to drive your Century-based autopilot.

The GI275 should do what you're looking for. As far as I know it's the only way to eliminate the vacuum-powered ADI (and, for that matter, potentially the entire vacuum system.)
 
I have same setup as you. Information given to you is correct. I installed an RC Allen 2610 - very, very easy install. Works great. Got rid of vacuum system. This is in a Mooney M20J. Buy the one with the new yaw indicator, install in turn coordinator location.
 
I have an Aspen PFD and just had the vacuum system removed completely with the installation of the RC Allen 2610-3. That is your best bet. $2795.00 from Spruce.
 
Having to put this on the back burner for a little bit. It’s looking like I need to OH both engines :(
 
GoDores said:
Having to put this on the back burner for a little bit. It’s looking like I need to OH both engines :(
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So sorry to hear that. It is a pity that we original Aspen owners have to deal with the backup AI STC idiocy. I just kept my vacuum system and AI that connects to my autocontrol 3b piper autopilot on my Archer, but was hoping that AV30c would be the savior in the future for both vacuum removal and autopilot connectivity. I’ll just have to stay tuned for this option to become viable when/if I need it.
 
bnt83 said:
I would fix the vacuum one and be done...
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This makes sense to me. The dual Aspens already provide some redundancy, so that the main practical concern is that the Aspens somehow both fail. One way that can happen is an electric power failure, which would not affect the vacuum AI.

OTOH, if you've got two batteries and two alternators, like a Cirrus, then there's not much concern that a failure of just one component will take out all of your AI needs, and getting rid of the vacuum makes good sense in that case.
 
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I did contact both Aspen and uAvionix and both told me in writing they believed an AV-30C would meet the Aspen STC requirements for backup attitude information in my installation. Right after that is when the shop doing the annual found lots of ferrous metal in both oil screens, so obviously that will have to be addressed first, but at least that allows some time to sort out the legalities.

I don't see myself putting new vacuum pumps and an AI in. Plan A will be to try and make it work with an AV-30C per the responses I got from Aspen and uAvionix. Plan B would be the same thing with a G5, and plan C is the GI275.
 
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