For the love of “steam gauges”

“But what I don’t understand,” said Lisa, her face earnest and serious, “is where the steam that runs these things comes from.”

It was one of those speed bump moments that sometimes happens in conversations.

We’d been talking avionics, which is a fancy word for instruments that go in airplanes. Increasingly, over the last few years, most modern avionics are computer screens called “glass” or “glass cockpits” in the flying world; while the older traditional round-dial flight instruments are now universally called “steam gauges.”

I have no idea where the label “steam gauge” came from, but I suspect it started out as a slur perpetrated by glass cockpit salesmen that eventually went mainstream—losing its negative connotation in favor of a nostalgic fondness. But Lisa, a razor-sharp scientist by education and profession, tends to take things literally, and assumed it was a functional label. I could almost see her doing a mental inventory of her new plane, confused about where the water tank for the steam gauges could possibly be hiding, and how often she should refill it.

Of course, old-school flight instruments do not, in fact, run on steam. They run on either air pressure or electricity, depending on the model and type of instrument. I suppose that if the label “steam gauge” wasn’t a conspiracy of the glass cockpit crowd, maybe the term came about because, for some, all those wonderful round gauges reminded them more of the cab of an old-fashioned steam engine than that of a modern flying machine.

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But I’m here to defend the airplane steam gauge, because in reality, it’s anything but old fashioned. Rather, the steam gauge is a modern marvel. Now, if you’re a lover of high-res color moving screens, just hear me out, because a traditional flight instrument is an absolute miracle of graphical presentation that you might not have appreciated, one unrivalled in human history, and not deserving the lowly title that it’s now saddled with.

Think about it. A true steam gauge, on a boiler in a basement in a Third World country somewhere, is nothing more than a single needle that tells you how close the steam tank is to blowing its lid. Aircraft steam gauges, on the other hand, can tell us how our planes are orientated within a three-dimensional environment; if we are on course or off; and can even guide us to fog-shrouded runways—keeping us correctly lined up on the runway while descending safely through space without hitting anything on the ground.

Try that with a steam gauge out of a Union Pacific Big Boy 4-8-8-4 locomotive.

And there’s more. Not only do aircraft steam gauges display an amazing range of data, they do so in a way that allows for a six-second scan, literally taking six seconds to take in all the various instruments to assure that all is well with the flight. How is that even possible? Because aircraft-quality steam gauges are actually carefully engineered hieroglyphic interfaces.

Now wait a minute, you say. Aren’t hieroglyphics those funky symbols in the Pharos’s tomb? The ones no one can read?! Well, yes and no. It’s true that the meaning of some ancient hieroglyphics is lost to time, giving the word hieroglypha quasi-enigmatic connotation, but in its purest form, a hieroglyphic system of writing uses symbols to form words and concepts. In other words, picture writing. And we all know that a picture tells a thousand words, making it the fastest way to communicate a lot of data. After all, we humans are visual creatures.

Here, let me give you an example of another great steam gauge, one that pre-dates the world of aviation, to illustrate what I’m talking about. If you were born before 1972, you were probably raised with the granddaddy of all hieroglyphic instruments: The wrist watch. A traditional wrist watch (not the pilot type with all sorts of unnecessary dials to make us look smarter than we are) has one dial and two hands. A scale on the dial shows half the day, twelve hours. Overlaid on that scale is a second scale that shows sixty minutes. One of the two hands of the watch indicates where we are in hours during the day by pointing to the hour scale, and the other hand indicates how far through that hour we are by pointing to the minute scale. A fancy model ups the ante with a third hand for tracking seconds.

It sounds mind-numbingly complex when laid out in words, but in action it brilliantly does what the best graphical interfaces do: It paints a picture. Quickly. Once you learn its language, you can “read” it without thought. At a mere glance, you “know” what time it is. On the other hand, if you look at a digital watch that says 3:59 p.m., you have to think.

And thinking takes time. Who has time for that?

Especially in an airplane.

That’s one of the things I love about airplane steam gauges. The instruments collectivity paint a picture of my airplane in the sky. Without needing to think about it, I know, as if I were glancing at my watch, that all is well—or that something isn’t right. That’s a pretty sophisticated interface. One that, like the wrist watch, thrives best on simplicity.

Airplane steam gauges keep it simple. They are visual Haiku.

Of course, glass instruments have graphics, too, but there’s no Haiku to be found there. It’s more like an epic poem. They display a ton of information, and for me anyway, that’s part of their problem. I have a hard time seeing the trees for the forest, or the forest for the trees. All that brilliant color and fancy graphics just doesn’t click in my brain the way a good set of steam gauges do. But maybe that’s just my age. For digital natives, I’m sure it’s different.

Another thing I like about steam gauges, and this would hardly be a reason for choosing them, is that I think they look better on the ground. Yeah, I know that’s not where they matter, but when walking around the ramp, poking my nose up against the windows to look into various cockpits, steam gauges give a parked airplane a business-like look. Sure, the tires are flat on that old Cherokee chained to the cracked and weed-infested far end of the ramp. Yeah, its paint is worn, fading, and peeling; and there’s a bird’s nest in the engine cowl—but the cockpit is alive with possibilities. Compare that to the shiny new Cirrus over by the fuel pump. Powered off, its blank cockpit looks like an abandoned black and white television set in the back of the Salvation Army store. Glass makes planes seem dead on the ground.

In a similar fashion, I like climbing into a cockpit that looks ready to go before my finger strokes the master switch.

But neither my fondness for the steam gauge as a concept, nor my joy in sliding into a cockpit that looks ready to go, had any bearing on my recent decisionto remove the several pieces of glass we had installed and replace them with (horrors!) steam gauges.

Nope. It was completely pragmatic. Our plane, Tessie, is a flying greenhouse. She has glass (the kind you look through, not the modern instrument kind) in front. Glass to the right. Glass to the left. Glass above. Glass behind. It’s a lovely bubble of view. It also doesn’t have even an inch of shade. Nor does our panel have a sun shade, or room for one.

The result? Glare. Epic glare. The only time I can read a glass panel display is when the plane is in the hangar. Oh. Right. I can’t read it there either, because the plane isn’t running. This was never a problem with the steam gauges of old. They have glass faces, but something about the material used in them resists glare, while something about the material used in modern glass cockpit displays seems to attract glare the way a magnet attracts iron filings.

So I’m not a luddite. And while I’m an aficionado of the classics, that had no bearing on my decision. I just want to be able to read the story my airplane is telling me. And for this plane, for this pilot, steam gauges are the only way to go

Now, if you’ll excuse me, I’ve got to go refill the water tank.

 

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