The uAvionix AV-30-C, the Round-Gauge Glass That Slides Into the Hole Where Your Vacuum Attitude Indicator Used to Spin

The uAvionix AV-30-C is a solid-state cockpit instrument that slides into the standard 3⅛-inch round hole in your panel to replace an aging vacuum-driven attitude indicator or directional gyro. At roughly $2,000 per unit before installation, it lets owners of older aircraft delete the notoriously unreliable vacuum pump without the $15,000-to-$30,000 cost of a full glass panel. It is shipping today in thousands of experimental and certified airplanes.

What Problem Does the AV-30 Solve?

For sixty years, the attitude indicator and directional gyro in a typical light aircraft have depended on an engine-driven vacuum pump spinning mechanical gyroscopes with suction. That pump is one of the least-loved components in the airplane: it fails without warning, often in instrument conditions.

A mechanical gyro works on rigidity in space - spin a mass fast enough and it resists being tilted, so the airplane symbol appears to move around it. It’s elegant, but fragile, power-hungry, and it fails slowly. A dying vacuum gyro doesn’t quit all at once; it winds down. The horizon sags a few degrees, then a few more. In cloud, a pilot can follow that failing gyro into a spiral without ever realizing the instrument went bad.

The AV-30 replaces that spinning mass with solid-state sensors - micro-machined accelerometers and rate sensors, the same family of chips that tell your phone which way it’s pointed. A small processor turns their output into an Attitude and Heading Reference System (AHRS), computing pitch, bank, and heading from motion and gravity rather than from a spinning wheel.

Why Wasn’t This Done Sooner?

The sensor chips have been inexpensive for over a decade. A $500 phone carries better raw sensors than some certified panels. The silicon was never the hard part.

The hard part is trust. Turning noisy little chips into an instrument you’d stake your life on in the clouds takes an enormous amount of software, filtering, and testing. On top of that, getting the Federal Aviation Administration (FAA) to approve it for a certified airplane is a mountain of paperwork. That gap between cheap sensors and a trustworthy, approved instrument is exactly what uAvionix targeted.

What Does the AV-30 Actually Do?

The AV-30 is a chameleon. The same instrument can be configured as either an attitude display or a directional gyro display, and you can switch between the two. Install one in each of your two round holes and you’ve replaced both vacuum instruments with solid-state screens - no suction lines, no filter, no gyro to tumble.

Around the edges of the main display it packs data most round gauges never offered:

• Slip and skid indication
• A G meter
• Airspeed and altitude (with the right inputs)
• Angle of attack, computed - no external probe on the wing
• Bus voltage
• A basic moving-map heading picture in directional-gyro mode

It’s a genuinely dense little instrument.

AV-30-E vs. AV-30-C: What’s the Difference?

There are two versions, and the distinction matters a great deal.

The AV-30-E is the experimental version for home-builts and experimental amateur-built aircraft. It carries less paperwork, a lower price, and unlocks features faster.

The AV-30-C is the certified version - the “C” is for certified. It’s approved to go into a standard-category airplane (a Cessna, Piper, or Bonanza) under a Supplemental Type Certificate (STC), the FAA’s approval saying this specific equipment may be installed in that specific type of aircraft. The certified version costs more and gains features more slowly, because every capability must be proven and signed off before it’s switched on.

How Much Does the AV-30 Cost?

Depending on configuration, expect roughly $2,000 per unit before installation. Compare that to a full glass primary flight display retrofit, which can run $15,000 to $30,000 installed.

The AV-30 is playing a different game entirely. It isn’t trying to be your whole panel - it’s the single instrument you swap when the vacuum pump finally quits and you’re standing at the shop counter deciding what to do.

Who Is the AV-30 For?

There is a large fleet of 40- and 50-year-old singles flying on vacuum systems near the end of their service life. The owner of a $100,000 airplane is not going to spend $30,000 re-paneling it. But $2,000 to delete the pump and gain a modern solid-state display in a hole that already exists? That math works for a lot of people.

That’s the market - not the shiny new Cirrus, but the 1970s-era airplane that a real person owns and flies.

What Are the Downsides?

This is an honest look at a young product in a hard category, and it has had growing pains.

1. It has been through an airworthiness directive. The certified AV-30-C, in its role as an attitude display, was the subject of an FAA airworthiness directive (AD) - a mandatory order, not a suggestion. uAvionix responded with software updates and revised limitations, and a fix path exists. New avionics categories almost always hit early regulatory speed bumps, but if you’re shopping for one, know exactly which software revision you’re getting and exactly what it’s approved to do in your airplane. Read the STC limitations twice.

2. It may be approved only as a secondary instrument. In many certified installations, the AV-30-C is approved as a supplemental or secondary instrument, not automatically as your sole primary attitude source. What it may replace - and what must remain beside it - depends on the approval for your specific airplane. Don’t assume it deletes a backup requirement. Ask the shop and get it in writing.

3. It’s small and dense. Cramming attitude, heading, airspeed, altitude, angle of attack, and a G meter onto a 3-inch round screen means everything is small. Some pilots love the information density; others find it busy, especially in turbulence or with older eyes. Try one in a friend’s panel in flight before you commit.

4. You’re putting more eggs in the electrical basket. A vacuum attitude indicator and the electrical system were two independent power sources: lose vacuum and you kept the electric turn coordinator; lose electrical and you kept vacuum attitude. Going all solid-state and all-electric removes that independence. You must think hard about backup power - what drives your primary attitude if the alternator quits, whether there’s a battery backup in the instrument, and for how long. Redundancy is something you design on purpose, not something you get for free.

Why the Company Behind It Matters

uAvionix didn’t come from the traditional avionics world - it came up through ADS-B (Automatic Dependent Surveillance–Broadcast), the system in which your airplane broadcasts its own GPS position. The company built its name on tailBeacon, a small ADS-B unit that lives inside the tail navigation light.

Their whole philosophy is to put the technology where hardware already lives so nobody has to cut new holes or run new wires. The AV-30 is that philosophy aimed at the instrument panel: find the existing hole and slide the new instrument into it.

Their devices also talk to each other. The AV-30 can pair with the company’s ADS-B gear and a wireless link module to pull traffic and weather onto the display and out to a tablet - a small, connected ecosystem for the owner who can’t afford the big-glass one.

How Does the AV-30 Compare to Competitors?

The round hole is contested territory:

• Garmin sits at the premium end with small primary flight displays that cost more and do more.
• Aspen pioneered glass shaped to fit existing round cutouts.
• Dynon and others dominate the experimental world with full glass at prices certified customers can only envy.

What uAvionix found was the slot nobody else was really serving: the single-instrument, drop-in, sub-$2,000, delete-the-vacuum-pump play for the certified light-airplane owner. Not the whole panel - just the one gauge, at a price a normal owner will actually spend.

The Bigger Picture

The real story isn’t one gauge - it’s the slow retirement of the vacuum pump from the general aviation fleet. That change isn’t coming from glamorous $40,000 glass cockpits. It’s coming from the bottom: a $2,000 instrument that fits a hole that already exists, giving the owner of a 40-year-old airplane a reason to pull the pump and never look back. That’s how technology changes an entire fleet - one affordable retrofit, one tired airplane at a time.

The AV-30 isn’t perfect. It’s young, it’s been through an airworthiness directive, it’s small, and it forces you to think carefully about backup power. But it’s honest engineering aimed at a real problem at a price real people pay.

Key Takeaways

• The uAvionix AV-30-C is a ~$2,000 solid-state instrument that drops into a standard 3⅛-inch panel hole to replace vacuum-driven gyros.
• One unit can be configured as either an attitude indicator or a directional gyro; two units can delete the vacuum pump entirely.
• The -C is certified for standard-category aircraft under an STC; the -E is experimental, cheaper, and gets features faster.
• The AV-30-C was subject to an FAA airworthiness directive and is often approved only as a secondary instrument - read the STC limitations and confirm backup power.
• It undercuts full glass PFD retrofits that cost $15,000–$30,000, targeting owners of older light singles rather than new aircraft.