Cockpits Get Smarty

The Evolution of the Glass Panel

General aviation has been begging for something truly revolutionary for decades. Though a series of sidling advances have seen manufacturing revolve—in circles that is—from its robust wartime days, little evolution has occurred in the way we fly. The airframes we construct today remain markedly unchanged. Rigid sheet metal flivvers, tubular frames, and crafts of wood, fabric and composite construction are still pervasive.

A look from the inside out perhaps tells a different story. Significant evolutions have arrived in the cockpit, in the ways we navigate and communicate. Though it’s reasonable to posit we still aviate like it was 1863. That’s when French writer and naval officer Guillaume Joseph Gabriel de La Landelle coined the word aviation, from the Latin avis expressing bird-like qualities. In those very early days, navigation and communication were absent the flying vernacular. Flight was rigid, and aviation was done by the seat of one’s pants.

Classic Cub Panel
The classic Cub panel, a precursor to the six-pack.

While in the age of “steam gauges,” instruments relied on classical physics and coarse (vs. discreet) sensors to quantify relevant aviation data in the airspace environment. Their measures gave latent, relative indications of: wind, ground and vessel movement; time and distance travelled; and propeller revolutions as an expression power and efficiency. The basic instrument panel comprised a set of commonly round dials and, adjunctly if at all, a two-way radio and position transponder. Steam gauges served for decades until the dials’ limitations were foiled by the digital age.

Thankfully modern cockpits strived, at their very least, to bring to bear all three maxims—aviate, navigate and communicate. The fundamental change at hand was arithmetical precision with which power, speed, space and time could be governed. This all happened abruptly at the turn of the century that was Y2K (an alarm expunged in its own hype). The successor was GPS. In this new era, flight specifics were plotted digitally, accurately and nearly instantaneously.

Round dial gauges of the then common analog six-pack transformed to a new silicon standard with GPS at its core. The change started in general aviation with the handheld navigator. Quickly, a preponderance of silicon-based tools, portable devices, found their way into the cockpit. This justly led to their panel mounting, freeing the hands and cockpit of clutter—albeit busying the fingertips.

GPSMAP 496, SL40, GTX 327 stack
Going from “steam gauges” to “glass panel” started with the panel mounting of a handheld GPS.

In step with the May 2000 demilitarization of GPS technology, and freeing impediments on its accuracy, analog gauges began exiting the cockpit. Much like digital television and flat screens did away with the picture tube, so went the round dials of the instrument panel. The “glass panel” cockpit, a perhaps more seductive term than flat screen avionics, became pervasive. Glass panel innovations took their lead from military cockpits and the personal computer. Digital displays emerged and the analog six-pack was cast aside.

Dynon D100 EFIS / D10 EIS, GTX 330, SL40, GPSMAP 396
Glass panel / flat screen avionics brought silicon to the cockpit.

The glass panel would change flying forever. Celebrated at the outset of this transformation was the Dynon EFIS-D100, a first among many EFIS (Electronic Flight Information System) offerings, giving pilots a glimpse of the future. Crystals snuffed out cathodes, dials turned to tapes, and LED arrays replaced needles. Every detail, and then some, of the six-pack panel cozied its way onto illuminated flat screens.

The mid-stream standard glass cockpit, a panel-mounted multifunction handheld device.

As Dynon Avionics continued to innovate, with Pocket Panels and touch screens, a run of popularity endured. Currently, the producer-dynamo has evolved all its strengths into the SkyView HDX, an extensive glass panel device that encompasses just about every cockpit function. Likewise, Garmin arduously moved its portable and mountable GPSMAP x96 series of similar functionality to the present G3X integrated flight deck.

Analogous to Moore’s law—a size to capabilities equation—screen sizes increased and functionality multiplied with each successive release. Cockpit devices thrived on integration, faster speeds, and touch screen advances. The driving elements behind the modern glass panel revolution were enhanced silicon and innovative software.

Garmin G3X
A single touch screen display encompasses all the basics and then some, necessary for flight.

Other vendors followed in form, some leading in their own unique ways. A software approach from Airbox Aerospace Limited, a U.K. based firm, was to “present only the vital information.” In doing so, Airbox created a navigation technology combined with its Aware airspace warning system. Though still in the portable genre, the system took full advantage of the country’s National Air Traffic Services. A combo flight planning, inflight and approach GPS-based unit provided pilots with a moving map over ICAO charts plus alerts of impending airspace infringement. Its alert feature was, in principle, similar to what ADS-B strived to do in the U.S.

By comparison, TruTrak Flight Systems with its EFIS device (now proffering under the BendixKing brand) took perhaps too literal an approach by choosing to focus on “flyability and ease of operation.” Analog dials, thought to be best by the company’s creator, were merely represented in digital form on a new lightweight, flat square screen. One might say it was a six-pack served like a boxed wine, flyable if familiar.

Simultaneously others in the experimental realm, GRT Avionics for instance, subscribed to an “all-in-one” format delivering integration, rich features, and flexible operation with their line of displays. GRT’s EFIS offerings landed agreeably with experimental aircraft builders giving buyers a wide selection of displays, packages and options.

Openness is a trend in information systems development, one which encourages third party collaboration. On a platform of open avionics emerged NextGen Avionics with its antithetical “dumb is the new smart” motto and “highly modular” as its theme. Their flight deck display systems encouraged the integration of remote mounted input/output devices while the glass box was but a facade to present the data.

Meanwhile, Mid-Continent Instruments devised its SAM and FLEX. The latter being a custom function designable display, essentially an open drawing board in a standard two-inch round package. Today FLEX is not alone as uAvionix, Garmin and Aspen have fielded multi-function devices that follow the circular cutout route. SAM, for Standby Attitude Module, was launched with the TruTrak simplicity approach yet aimed purposely at the certified market. It required a rectangular cutout, presenting just the vitals in a familiar analog fashion.

Garmin G3X, GTN 625, G5
An all-on digital affront eliminates analog gauges, adds redundancy and an autopilot.

In addition to the six-pack, radios and transponders went the way of glass and digital. The upgrade path was enunciated by NextGen, referring now to the Next Generation Air Transportation System (not the avionics manufacturer). As with anything FAA, NextGen ushered in another acronym—at last count 6,000 plus—the aforementioned ADS-B. With the “S” standing for surveillance, make no mistake it is more about surveillance than alerting, as was Airbox. Today’s transponders, supporting Extended Squitter on the 1090 MHz frequency and broader bandwidth on 978 MHz, signify digital communications are now all “In” by federally mandated ADS-B “Out.”

Broadened communications introduced by ADS-B also meant greater amounts of data sent to the cockpit. This data arrived as an in-cockpit visual of course, and while timely, informative and indispensable, it introduced obstacles of its own. Primarily, an over-dependency, i.e. fixation, on the glass panel translates to less time spent on the actual see-and-avoid (eyes outside the cockpit) axiom. This is particularly relevant in general aviation whether flying visual, under instrument rules, or at night. Looking for possible incursions, be they weather, terrain, objects, or the sort, still remains a responsibility of the pilot, with or without the supplemental data of a digital cockpit. The sanctimonious sequence of aviate, navigate, communicate is beset by clouds even with the glass panel.

The Virtual Pilot

The modern panel essentially strives to replace the windscreen, like it or not. Flying by the seat of one’s pants, perhaps now uncomfortably numb, has been removed from the pilot’s arsenal (arse pun intended). The once popular notions of cockpit situational awareness and relying on instinct, both acquired by experience, have actually started their devolution into a virtual affair.

For the early Grasshoppers, all flying was by feel. Flight instruments of any consequence were neither supplied nor required. A compass and a fuel gauge, a tachometer and an oil pressure indicator were their only luxuries beyond an ingrained love for flying. – Operation Grasshopper by Dario Politella

Flat screen technology is really about integration, whether panel-mounted or handheld, via iPad, Gamin aera and their likeness, or dedicated displays such as Garmin G3X and Dynon SkyView. Today’s cockpit is a multi-vendor system with various devices aggregating data and depending on software to drive them. As features grow complexity grows, emphasizing the trouble with the virtual world. Will there ever be enough automation, and is reliability ever a sure thing?

Apple iPad, Garmin GTR200, GTX335
A panel-mounted iPad offers carry-in and carry-out capability with easy device management.

While it remains a critical maxim: aviate, navigate and communicate does not cover the pilot’s entire playbook. There’s now a ton of feedback pertaining to the monitoring and controlling of a flight. As a surveillance technology, the virtual cockpit only serves as a barking watchman. Sophisticated glass panels combine autopilots and scads of system data, presenting all in broad detail. The virtual cockpit offers scenarios never before considered, often blurring priorities. While it’s still up to the pilot to fly the plane, an abundance of data brings with it a profusion of additional decision making possibility, and perhaps diffused awareness.

Garmin aera, G5, JPI 350, Trig
Going digital yet keeping it simple with cockpit glass: Garmin aera / G5, JPI 350 engine monitor, and Trig compact radio / transponder.

Avionics development and acquisition was strong prior to 2020, driven largely by ADS-B regulation. Stepping back though, progress has been quite significant. A few decades ago pilots were navigating with maps on compass headings and only just beginning to make copious use of GPS.

At their fingertips, pilots now find a wealth of data… weather, terrain, charts, obstacles, scenarios, tables and procedures to name a few. All are sitting on top of what seems so ordinary, a moving map. It’s a daft reminder of the old school windscreen.

While the integration that we’ve achieved is impressive, consider the scads of data and their instantaneous inquiry onto the glass panel. Notations and calculations, books and binders, and all the distractions from the essential windscreen have been digitized. Everything is there at the touch of button. This alone is an enormous achievement in aircraft development. But what about the pilot?

Now absorbed in the virtual screen before them, pilots still yearn for more. Adding to the flying space of aviate, navigate and communicate are additional audio sources, namely the cell phone and music. Crowded and overstimulated, pilots are simultaneously presented with possible outcomes in both the real and virtual environment.

As the virtual cockpit is upon us, what next? By definition a birdbrain lacks capacity for, say, the finite amount of data we process on preflight alone. A human brain attacks this with a presumptive checklist, but the bird flies without one. It is precisely a bird’s freedom of movement that we wish to replicate. With them such freedom is innate. However, we lack their unique skeleton, airframe dynamics, and instinctive flying ability. We therefore must endeavor to invent the ultimate machine. Only in doing so can we achieve the same freedom.

From There to Here

We celebrate the today’s digital cockpit and its byte-sized impact. The glass cockpit was originally pioneered during the 1970s and 80s in NASA’s 737 flying laboratory at Langley Research Center. Heavies began incorporating them in the ‘90s as airframes outlasted powerplants, systems and avionics. Everything from freighters to cabin class aircraft were ripe for upgrade. Avionics replacement has led the retrofit march ever since.

Restoration, modernization and refurbishment gave aging aircraft new purpose and glass panel upgrades were at the forefront. They were more than merely a fresh coat of paint serving a more youthful appearance, or new wheels and a plush interior impressing that like-new, cozier feel. The satisfaction of an updated instrument panel is in fact more cerebral. A glass panel appropriation redefines our ability to fly and to be free from analog limitations, mechanical constraints, and environments prescribed in convention.

Benefits of the glass panel seem obvious, though selecting a system perhaps more subjective. With glass one achieves redundancy and enhanced backup capability. Solid state electrics imply reliability, speed and precision. Less weight and lower power demands mean fuel savings, conceivably extra payload too. Maintenance costs may be reduced, though software subscriptions enter the fray. Flying is theoretically easier and focus on the aviate function is abundantly enhanced. Adopting the glass cockpit, costs aside, operators have reverently brandished the phenomenon.

The glass cockpit eliminates the six-pack, replacing it with more.

Even the purist wishing to keeping an aircraft authentic has succumbed to some degree of glass, if only for purely practical or singularly subjective reasons. As a showcase of sophistication, and a paradox as to why, the Cub offers an example. Flying with the basics: a tachometer, airspeed indicator, compass, altimeter and engine oil/pressure meter, in a clear skies is wholly sufficient for this type of aircraft. Moreover, it’s properly flown by the seat of one’s pants.

However, every justification seems warranted when modernizing the Cub’s panel and flying one with glass merely crosses the line of paradox. Now common in our vernacular, the glass panel makes flying a Cub simply more extraordinary. Truth is, the Cub had already attained such praise well before the glass panel arrived.

Keeping it real for the aviator purist. The original Cub panel offered power, speed, direction and altitude without all the fuss.

Relevant information supplemented by a wealth of it, all at the press of a finger, that’s the plus of a well-appointed instrument panel. These days there’s no shortage of ingenuity to bring the glass panel to life. But the horizon is forever, as is a pilot’s longing for more. Let’s see where airframe design takes us in the next century. Virtually anything is possible. Let’s keep it real, and safe, for flying’s sake because after all, aviation takes place outside the windscreen.

This article was published in the November 2022 issue of Avionics News. Click here to download the article PDF.

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