UMA Instruments

Analog gauges still have a place in the digital era.


This story is about a company that makes aircraft gauges, but bear with me a bit while I set the scene.

My Searey’s instrument panel is caught in a time warp, somewhere between steam gauges and glass cockpit. When I completed the kit back in 2003—”finished” is not the operative word for an airplane I built myself—it had a six-pack of flight instruments more than adequate for VFR flight. A few years later, I replaced those six gauges with a Dynon D10A EFIS, which did everything they did, and more. A year after that, I added a big GPS and, more recently, an even bigger GPS (an iFly 740).

Original 2003 “steam-gauge” instrument panel (awaiting the transponder).

That gave me a hybrid, poor man’s glass cockpit, with the two digital displays for flight info and residual round gauges for engine and fuel, plus 2-inch gauges for airspeed and altitude in case the electrical system goes pfffft, which it did two years ago when the voltage regulator died a long way from any place I wanted to land. Electrical failure stays in the back of your mind forever, by the way.

The new UMA 2-inch tachometer with colors and lighted dial.

The glass displays give me more than enough information to navigate and fly—except that I almost never look at the EFIS’s airspeed display. It’s just numbers. I want to know about how much airspeed I have without doing math, especially when landing. Digits are great for other purposes, such as headings and altitude and elapsed time, but for landings, I’m an analog pilot.

So, when my Searey’s original 2-inch round tachometer went berserk recently, I had to decide whether I was analog or digital for engine rpm. After mulling it over a bit, the answer came back: analog. Let’s leave well enough alone in an airplane intended for fun flying.

OK, I figured, a tach is a tach, right? So I went online to my favorite big-name aircraft-stuff retailer—you’d recognize the name—and quickly found a lighted tach with a colorful dial, coded especially to match my turbocharged Rotax 914. It has white numbers on a black dial, with colored bands to indicate the 914’s speed ranges of red for 0-1800 rpm (too slow), green for 1800-5500 (just right), yellow for 5500-5800 (for five minutes), and a bright red line at 5800. Those colors looked gorgeous on my computer monitor.

Hey, and it was a UMA tach—cool! I had several other UMA gauges, and they had always worked reliably and were, as far as I could tell, perfectly accurate (unlike a few other gauges I’d had). And they’re made in America, too.

I entered my credit card number. Expiration date. Security code. Done. Gotta love computers!

Whoops. Not done. A few days later, an email arrived from the big-name retailer, saying that installing a dial light made it a special order. Colors were special order, too. I’d have to contact the manufacturer.

Wha-a-at? It says right there on the website…

Oh, well. There was no good in arguing with an email message. I phoned the number for UMA.

2018 panel with new UMA tachometer in the center upper row and airspeed indicator closest to the two glass displays. The iFly 740 GPS shows a synthetic view of the runway above a sectional-chart moving map.

The Analog World

A woman answered—surprising in this age of Siri, Alexa, and robot phone systems. I was actually a bit shocked. And unprepared; I was already on speakerphone with the keypad displayed, ready to press 1 to place an order.

Sharon, the public face of UMA, talks with customers, takes orders, troubleshoots, and much more.

She said she was Sharon. How could she help me? It seemed almost as though we were old friends. Or she was a friend’s mom. I sputtered out about my big-name retailer order as best I could, and right away she was explaining in clear but technical language what needed to be done.

The lighting and colors were extra features because most customers didn’t need them.

I heard keys clicking, and in a few seconds she said, “I’ve just checked your [big-name retailer] order and our own records. You’ve paid for the tach, but we haven’t shipped it yet. So it’ll be easy to open the case and silk-screen the dial and install the electroluminescent light. And there’ll be two more wires for the lighting power.”

Wow! I was feeling better already.

It was about then I noticed that UMA was located not too far from my home. Hmm…Could I pick up the tach at the factory? That seemed like it might be quicker than waiting for delivery, and the gasoline wouldn’t cost much more than shipping.

“Of course,” Sharon said. “Let me just check with Marie to see when she’ll have it finished. Is it all right if I put you on hold for a minute?”

A portion of the machine shop, with Valeriy preparing to turn an altimeter part. A CNC machine is in the background.

Well! This was getting a little strange. I hadn’t expected any of this…humanity. It’s an instrument factory! They make precision instruments. Should there really be a Marie who is going to install electroluminescent lighting in my tachometer? It hadn’t occurred to me to wonder.

Sharon was back in less than a minute. “Marie says it will be ready on Thursday.” (It was then Tuesday afternoon.) “But maybe Friday would be safer, just to be sure nobody’s child gets sick or anything like that. Or you can pick it up any time after that, of course.”

“Friday,” I managed to say. “Yes. Sure, Friday will be great. Uh, what time would be best?”

“Oh, any time at all. We’re open ’til five. Just whenever you get here.”

It was like talking with somebody’s mom.

But not just anybody’s mom. “Remember,” Sharon said, “for electroluminescent lighting you’ll need an inverter to power it: 120 volts output, AC.” She was knowledgeable, too.

I said I had an inverter…

“Well, we make them, but almost any will probably do. Just bring yours along, and Sefik will check it and let you know whether it will work.”

Sefik, eh? This is really getting interesting.

She said, “There’ll be an extra charge for the options. Fifty dollars. You can pay when you get here.”

“Um, do you suppose it would be all right it I looked around a bit while I’m there? I’ve never been in an instrument factory before.”

“Sure,” Sharon said. “We love to show customers around. There’s even an invitation in our catalog. Happens all the time.”

I was beginning to believe her.

Ammeter shunts after soldering.

Small Town America

On Friday I drove up into the Shenandoah Valley, to the very small town of Dayton, Virginia, surrounded by lush, rolling farmland and close to the James Madison University campus in Harrisonburg. The UMA building is on Main Street. It looked just like the picture on their website—unassuming and businesslike, and with a neat little two-person bench beside the door.

The door opens right into a practical room, a lobby with a couple of large tables and a photocopy machine, and several doorways leading to other parts of the building. Through one doorway a woman sat between a sturdy desk and a computer table. Sharon, of course.

She had my tach right there on her desk. I opened the box—and it was, in fact, gorgeous! The colored bands were crisp and bright against the matte black face and the white numerals.

“Did you bring your inverter?” she said. “Let’s take it back for Sefik to check and be sure it will work.”

Just then, a young woman about 30 came out of another office. Sharon said, “Nadia, this is the gentleman who wanted to look around.”

Nadia shook my hand and said she was the owner’s daughter, and of course she’d be delighted to show me around.

And now you know why I asked you to bear with me, back at the beginning.

The main assembly room, where everything comes together.

What UMA Does

UMA makes precision gauges, not digital displays. And as I learned that afternoon, it makes nearly every part that goes into those gauges: gears, bellows, pointers, dials, cases—everything.

I asked Nadia what UMA stands for.

“UMA no longer stands for anything,” she said. “We just go by UMA,” and she said it like the letters’ names, You Em Ayy. (There are periods in the company name above the front door and on her business card, but nowhere else that I know of. I had been calling it You-Ma.)

Bellows for altimeters during the assembly process.

She said that about 75% of their business nowadays is for aircraft instruments, but in the very beginning, back in 1936, UMA stood for United Medical Apparatuses, and one of its early products was a sphygmo-oscillometer, a complement to the device commonly used to measure blood pressure (a sphygmomanometer). UMA’s sphygmo-oscillometer—an updated version is still in production—measures blood flow with precision, and that ability has saved many diabetics’ limbs from amputation by proving that blood circulation was sufficient.

With WW-II and America’s sudden need for warplanes and the myriad gauges they required, UMA became United Medical and Aircraft. In 1974 three Grumman engineers bought the company and, seeking a better environment for their children, moved it from New York City to the Shenandoah Valley of Virginia. One family didn’t take to small-town life and soon went back to the city. The other two carried on together until Nadia’s father, Awad Da’Mes, bought his partner’s share. He is in his 80s now but still comes in to work, although Nadia is the operations manager and takes care of the day-to-day activities. As I learned that afternoon, she knows how to do almost every job the company has.

A mounted bellows with hairspring.

Work in Progress

Nadia led me down the hallway, past her office and back into the first of several work rooms that were larger the farther back we went. The type of work done in them ranges from mainly mental in front to small-part assembly in the middle, and on to huge, heavy machine tools at the back.

At first I was confused, partly because I had assumed without thinking that everything would be sterile and spartan, an assembly line operated by colorless, robot-like workers performing the same mindless tasks over and over again. But I had assumed all wrong—just as I had when I first dialed the UMA phone number earlier in the week. Everything was different from what I had imagined. And one result was that it took me a while to get oriented to how gauges are created and how the 25 employees interact with each other.

Soldering tachometer circuit boards.

Part of my confusion came because people don’t stay at one workstation all the time. The parts and gauges come to them, but they also move with the gauges, as well as conferring with each other. Each person, I eventually saw, is self regulating—a real craftsman and an integral part of the overall process, rather than a simple cog in an impersonal machine.

When we arrived at the very back of the building, I was beginning to figure it out. The process starts at the back, where raw materials and the few parts that UMA doesn’t make itself arrive, and are stored until needed.

Tavon preparing to silkscreen dials.

Next (moving toward the front) is the machine shop, the largest room in the building. There are heavy-duty metal lathes, drill presses, power saws, and two giant CNC machines that convert chunks of aluminum and brass into instrument parts. Several highly skilled machinists work there, making parts ranging from rugged ammeter shunts to the most delicate brass gears, some only 2 or 3 millimeters in diameter.

Those completed parts are moved into the main assembly room, where several different workers fit them together and solder circuit boards.

Assembling a pointer. The hammer will be used to seat the pointer on the tiny brass bushing.

In the next room, toward the front of the building, workers paint cases, silkscreen dials and pointers, assemble mechanical parts, and so on. This is where parts become gauges. Eventually the assembled gauges are tested and calibrated.

This is also where the medical instruments are built. They are self contained in rugged metal cases with hinged lids and heavy-duty leads and hoses. They can be used equally safely in sterile hospital operating rooms and in the field where no electrical power is available and conditions aren’t inherently sanitary. They don’t look anything like aircraft gauges, but inside many of the parts are the same.

Christina testing an airspeed indicator.

While Nadia was describing the various types of assembly activities, a woman passed by, carrying a tray of gauges. “I built your tach,” she said as she ducked through a doorway. That was Marie—and I was so tickled to see that she was, indeed, a real person.

Engineering and R&D

Adjacent to the assembly rooms is engineering, with easy access for workers to discuss any problems and ensure that assembly goes well and instruments work properly. One of the engineers is Sefik, who checked my inverter and pronounced it “OK, good.”

Engineering is also where research and development happens. Brian, the other engineer, was excited about a new 2-inch precision altimeter that he was developing. His prototype had two concentric pointers, each with its own numbered scale, to indicate feet and thousands of feet. The gear train in that little gauge looked exquisite, with tiny, tiny gears and shafts, and jeweled bearings.

Calibrating a 1-inch diameter oxygen sensor.

Lest you assume that’s not a big deal, just try to find one for a price you like. My favorite big-name retailer lists only one, made in Germany, for $993.

Several companies make non-precision 2-inch altimeters—UMA made the one in my Searey. But the tip of the single pointer in my non-precision gauge moves only about 1 millimeter (just over 1/32 inch) for a 100-foot change in altitude. That’s barely perceptible in the best of conditions and rather disquieting in turbulence or at night.

Brian’s prototype precision 2-inch altimeter, on the other hand, should be just as useful as—and more intuitive than—the traditional 31/8-inch four-pointer gauges that almost all pilots learned to fly with until about 10 years ago, while taking up only half the space in an instrument panel. (Half? Yes. Round gauges have square bezels, so for area, square a side instead of multiplying it by pi.)

R&D: Brian showing off a 2-inch precision altimeter prototype.

Keep in mind that this is a mechanical gauge—no electricity needed. It doesn’t duplicate a digital altimeter; it’s an entirely different animal. It (plus a mechanical airspeed indicator) will make an airplane not merely legal to fly if the glass panel dies, but practical to do so—the same if there’s no glass panel installed at all.

An ultrasound wattmeter, ready for testing.


The quality control department is connected to the assembly room, too—although it’s somewhat misleading to think of UMA’s quality control as a separate entity because inspection and quality control are integral parts of each stage in building any gauge or instrument. Everyone checks their own work against established criteria, and someone else double-checks before the gauge can be moved to the next stage or department.

After a product is finished, it goes to the shipping department. But calling it “shipping” is convenient shorthand. This is where orders are filled by collecting the items as they become ready, placards and labels are attached to them, gauges and other parts are boxed individually, and items are checked off on a customer’s order.

Before the boxes are packed for shipping, yet another quality control check occurs—and then it is rechecked and verified by a supervisor. Finally, the order is weighed and labeled. When all that is complete, the order is ready for pickup by FedEx or UPS for delivery to the customer.

Engineering: Sefik, who checked my inverter.

Family Business

UMA is a family business. The company is owned and operated by the Da’Mes family, and the workers all seem to relate to the company and each other as they would to a biological family. It impressed me as a very schmoozy place, yet one where everyone is sharply focused on producing excellent instruments.

The CEO and president of the company is Nadia’s father, Awad Da’Mes, a brilliant and genial man. He came to the USA from Palestine as a young engineer, attended grad school, and then went to work for Grumman, where he met the other two original owners of UMA.

Nadia and her father, Awad Da’Mes, with an early sphygmo-oscillometer on the desk.

Nadia grew up in the business. She worked there after school and in summers and whenever she happened to be around, even when she wasn’t working officially. She can do most of the manufacturing operations, including painting and silk-screening, and she understands the intricacies of the other work, even if she isn’t as expert as some of the specialists.

She majored in biology, and after college worked in a lab for a while. But she said it felt like she was in a cage. Now that she is the operations manager at UMA, she finds all aspects of her work fulfilling. She says she enjoys working with customers and loves listening to them brag about the airplanes they have built.

The Future of Gauges in the Digital Age

One of the most obvious things about UMA is that they make gauges by hand. It’s labor-intensive. There’s not a pick-and-place robot in the building.

Can that method of manufacturing be competitive in this era of mechanized manufacturing? Apparently, it can. Nadia says that their sales have increased steadily during the glass-cockpit era. About 75% of UMA’s business is custom work that by nature requires humans.

Nadia (left) and Marie, who said, “I made your tach.”

Despite the labor-intensive production, UMA’s prices are competitive. Take my tachometer as an example: The big-name retailer sells about 13 different 2-inch round analog tachometers for Rotax four-stroke engines, five of them made by UMA. Prices range from about $75 to $300, with UMA’s basic model listed at $140. (It’s hard to make useful comparisons from a catalog because types of specifications vary by manufacturer and there’s little indication of quality.)

So, my cost seems very reasonable: $250 for a custom-made 2-inch precision tachometer with electroluminescent lighting and a brightly colored dial. Not to mention a free tour of the factory—and meeting the person who built my tach!

Analog Digital Glass Gauge

It seems to me that the issue here is not so much analog versus digital because a glass panel can display analog information just as well as digital. That’s mainly a matter of personal preference. For the same reason, it isn’t gauge versus glass, either. It’s more like gauge and glass because they’re complementary.

But as far as flight safety is concerned, it’s essentially electrical and mechanical. Electrical instrumentation, whether presented by a pointer on a dial or a glass computer display, can be extraordinarily powerful and helpful to a pilot. But it also has many different failure points, any one of which can suddenly make the screens go dark. That’s when mechanical gauges really shine.

So, aircraft need mechanical displays of critical flight information—airspeed and altitude at the very least. (Whether they should also have mechanical backups for other instruments may be more complicated.)

Precision 2-inch altimeter prototypes. The smallest gear visible is about 3 millimeters in diameter and is made in the UMA machine shop.

UMA’s customers also include restorers of older aircraft who want the gauges to be as close as possible to the originals—or at least to resemble the originals closely enough that the aircraft appears to be completely original, even if they are more effective. UMA’s custom, hands-on construction is able to meet those needs. And it’s only a phone call away.

I asked Nadia what UMA’s biggest problem is, expecting she’d say something about competition from cheap foreign labor. Her answer surprised me. Even though the company is located close to a large state university and in an area with several major industries, she says they have trouble finding skilled workers, especially machinists and mechanical and electrical assemblers. Fortunately, they have been able to recruit several local residents who grew up in countries where technical education is more highly valued than it is today in the USA.

My biggest problem, on the other hand, is waiting for that 2-inch precision altimeter to go into production. I’ve already ordered one to replace the non-precision gauge in my Searey. And when it is ready, I’ll probably drive up to Dayton, Virginia, and thank its builders personally.


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