PILOT’S GUIDE The Brains Behind Beauty What Makes Glass Cockpits So Smart?

By Gary Picou

oday’s are marvels of , integration, Tapplication and innovation. They bring safety and conve- nience to the pilot in new ways, while maintaining a consistent structure that is recognizable to any pilot with a few hours under his belt. This entire slick human inter- face, which often looks like a Microsoft flight simulator, didn’t just happen. All of this technology has taken years of work, study, research and development. So, what happens behind the panel — from design to signals in space — that allows pilots to fly behind a glass panel?

What Is This Thing Called? The first use of EFIS for civil rendering crisp pictures in a wide Let’s define some terms to aviation was in the 757 viewing angle, in bright sunlight or help us understand the avionics and 767 in 1978. Boeing began in the dark of night. Any glass is environment pilots find them- development of the 757 and relegated to a non-glare cover on selves moving toward. certification of the electronic the front — the CRT has gone the • Glass Cockpit: This term cockpit. In general aviation, the way of the 8-track and betamax. conjures up an image of fragil- Beechcraft Starship was the • Steam Gauges: This is a ity, but it is really a throwback to early adopter for electronics descriptive term for the elec- the first generation of electronic instrumentation, with 27 CRT tromechanical instrumentation. flight displays, or EFIS (electronic displays that mimicked the elec- These are the mechanical instru- flight instrumentation system). tromechanical instrumentation, ments dating back to Elmer These were cathode ray tube which was introduced in 1988. Sperry and Jimmy Doolittle that (CRT) systems that started as a Today’s “glass cockpits” are have been both the reliable stan- way to concentrate the vital data actually a collection of flat-panel, dard and have caused disaster or while mimicking the conventional liquid crystal displays (LCD) heartache when they are misin- instrumentation. with the latest in technology for terpreted or fail.

- 38 - • EHSI: The most basic of of tomorrow. Air Data glass cockpit instruments is the The pretty picture you see is The airspeed and electronic horizontal situation only as good as the information steam gauge instruments that indicator (EHSI). This takes a that feeds it, and this is where rely on pitot and static pressure conventional HSI and replaces science and technology have have been replaced with an air the wiggly needles with an elec- had the greatest impact. These data system that relies on the tronic display that can portray screens are populated with preci- same pitot and static pressure. navigation information in a vari- sion data from an array of sen- Physics is physics, after all. ety of formats, from mimicking a sors in, on and remote. However, improvements have card and course devia- been made with a shift away tion indictor to a full moving map Gyros from a mechanical bellows type with weather and anything in Gyroscopic instruments rep- of pressure instrument to an elec- between. resent the area in which today’s tronic pressure sensor with more • MFD: The multi-function glass cockpits have improved the precision and reliability. display (MFD) is the screen that most over steam gauges. The Computational power allows gives the background and sup- reliability of attitude and heading the components of the air mass, porting information about a flight, systems has improved 100-fold such as absolute pressure, pitot an and the surround- over vacuum instruments. ram pressure and temperature, ings. Here is where the maps are The reason for improvements to be converted into useable — the weather presentation, be in accuracy and reliability is information in real-time. The E6B it from the satellite datalink, radar today’s micromachining electron- will take its place next to the slide or Stormscope. ics. Older instruments were only rule and sextant. (We will leave • PFD: The primary flight slightly better than Elmer Sperry’s the debate about using machines display (PFD) is where all the spinning iron gyros — bigger to do important tasks without critical, need-to-know-now infor- mass meant more stability, but having a basic understanding of mation lives — such as attitude, was harder to keep spinning. the fundamentals to the fourth- heading, airspeed and altitude Today’s micromachines are small- grade teachers who deal with — that must be in front of the er, have few moving parts, and long division versus calculators.) pilot at all times. are highly reliable under the most • IFD: The integrated flight severe environmental conditions. Data Concentrators display (IFD) has it all in a com- Glass cockpits typically use an In any given airplane, there are posite of all the flight information, attitude heading reference system a slew of signals available, and navigational and situational infor- (AHRS), which is a collection of these have to be input into the mation combined into a single accelerometers and micro-gyros glass cockpit’s “brain” and sorted display. This is where the industry that provide the same information out with regards to the nature is headed with “highway-in-the- as the artificial horizon, directional of the information, the relative sky” (HITS) displays. gyro and turn coordinator: “Which importance and the update rate. way is up, which way are we For instance, the information What’s Behind the Panel? going?” from the attitude sensor is very The picture you see is only the The new generation of atti- important and dynamic, chang- very surface of the system. It is tude and heading sensors (call- ing in a matter of fractions of a the end result of all the develop- ing them gyros is like saying second, and therefore, has to ment, engineering and certifica- a Cessna Mustang is a “flying be updated and presented to tion efforts that take years and machine”) is a remarkable source the pilot almost instantly. On the millions of dollars to complete. of accurate data with high-speed other hand, the weather, while Today’s glass panels are much digital outputs. These systems important, doesn’t have to be more than a computer simulation have more in common with the updated as often because it of the instruments of yesterday. airbag sensor, which responds doesn’t change as often and is They leverage every advance within microseconds, than the not a part of the pilot’s moment- in technology, from Apollo moon directional gyro of old, which had to-moment scan. landings to the cell phone/HDTV to be reset from time to time. Continued on following page…

- 39 - GLASS COCKPIT useful without the addition of to flying into weather for airplane Continued from page 39 pan-accurate position indication. fatalities. Elements like traffic and ter- We’ve become so spoiled by the rain are somewhere in between. sub-meter accuracy of our ubiq- Mode S These decisions are designed uitous GPS that we lose sight Where does a transponder into the glass cockpit by the of the technological wizardry fit into a glass cockpit? Usually, engineers and vetted by certi- inside. the transponder only rides along fication. But the data will vary Consider the GPS. This unit, for the benefit of ATC, and only depending on the type of infor- which is somewhere between helps the pilot by keeping him out mation and the source. a pack of cards and a credit of trouble with the FAA. But the If you have a clean sheet of card in size, will receive signals Mode S transponder is different paper and all of the systems from nearly 11,000 miles away because it can contribute some come from a single source, you — signals so small they can’t important information to the pretty can have one data-transfer for- be detected without the aid of pictures on the display. mat. This sounds like a good sophisticated filters. These sig- Today, traffic information ser- idea, but in actuality the real nals — from three, six or more vice (TIS) is uploaded from the work often makes a single format individual satellites at any one FAA stations to the , where impractical. time (two dozen in all) — must it is presented on the display. In the free market, “Company be heard and understood. Then, A” may make up 90 percent of the precious timestamp is fed TIS the cockpit, but “Company B” into more filtering, and micro- The traffic information system, comes up with a better mouse- second delays teased out of the or TIS, was designed as a low- trap — or lightning detector. arithmetic. cost alternative to the TCAS I The consumer demands the Finally, the GPS will evaluate and TCAS II collision avoidance “Company B” system be integrat- these time differences and com- systems. By using the information ed into “A’s” glass cockpit, but pute a position relative to those available on the ATC radar sites the data format is different. So, satellites and convert that to a and up-linking it to the airplane “Company A” will make accom- position relative to an arbitrary over the Mode S data link, pilots modation in the glass cockpit planet model, then it will cal- can have a near real-time pre- suite. culate a latitude and longitude sentation of the traffic situation That’s just one example. based on a look-up table — and around them on their MFD. Imagine if there were four or five do all this three times each sec- The beauty of TIS is, all of the different formats required, which ond without error. computational power resides with occurs frequently with retrofit the FAA’s ground system — they avionics — such as if you want Terrain ship you the picture, reducing the to update your airplane to add a The GPS is capable of deter- hardware cost for the consumer. moving map, but not the heading mining an aircraft’s position to The bad news is, the future of TIS system, which is a 20-year-old within a few feet. The database is uncertain. Economics and poli- HSI with analog outputs. available to the GPS may con- tics may mean TIS service is not Data concentrators may not tain the distance and heading able to realize the capability TIS be a separate box and may just for the airports, navaids or promises. be some circuits of processors McDonald’s. But it also can con- Automatic dependent surveil- inside the main avionics suite, tain a database of the surface lance–broadcast (ADS-B) is but they are still there and a features of the planet, including another traffic avoidance system valuable part of the glass-cockpit man-made protuberances that that will provide a situational dis- experience, acting like a bunch present a hazard to . play of nearby threats and can be of UN translators to convert one Now, that’s smart. a replacement for the TIS. format to another and feed it to When that information is ADS-B doesn’t need any the central processors. made available in the MFD, or ground system and works even overlaid on the PFD, it can because each aircraft will broad- GPS be a lifesaver. Controlled flight cast its position in space. Every That pretty map would not be into terrain (CFIT) is second only other ADS-B airplane within range

- 40 - of the transponder signal will sented in the order of importance drifts out of established limits, the “hear” the location and plot it on and intelligently keep some tra- glass cockpit will inform the pilot the MFD. ditional attributes, such as active immediately, or at least in some and standby frequencies, and con- timely manner relative to the Weather ventional names, like NAV 1. But severity of the condition. For all of the hazards lurking in the radios themselves are some- Full authority digital engine the sky, nothing kills more avia- where else, leaving the valuable controls (FADEC) represent tors than weather. It could even real estate for information impor- a complete fusion of technol- be said that weather radar was tant to the pilot. That’s smart. ogy with the traditional aviation the first “glass cockpit” when dim demand for simple, reliable green spots were first shown to engine operation, and will inevita- pilots as indications of deadly The autopilot has two important bly make flying safer and easier. storms. inputs for the glass cockpit: mode Today, airborne weather radar, indications and selector controls. Pretty Colors more sophisticated and accu- Traditionally, in steam-gauge Those pretty colors showing up rate, is but one way to paint pre- , the mode indication on the glass-cockpit displays are cipitation and other hazards on was close to the , far more than an artistic interpre- a screen. Besides radar, which square in the pilot’s field of vision. tation — they are the smart result needs a complicated antenna and It is important to know what the of years of research by govern- room, there are systems autopilot is up to, after all. ment and industry into human like the Stormscope that detect On the PFD, many glass-cock- factors. How a picture is pre- lightning dangers and can paint pit autopilots will have graphic sented is as important as what is the location of discharges on the pointers showing the selected shown — if a pilot doesn’t under- screen. modes, the selected altitude and/ stand it, it is useless or even haz- In addition, there are several or vertical speed. On the MFD, ardous or misleading, which can ways to upload weather depic- there will be indications for the present a worse situation. The tions from service providers to selected heading and course, use of red, green, blue and brown present the same sort of an over- course deviation trend indicators, may seem intuitive, but it needs all weather picture from ground- and plotted course along the map. to be applied with consistency. based radar, satellite images and To learn more about mak- METAR data. These can be com- Engine Gauges ing a smart glass-cockpit dis- bined as well, providing a compre- A wise person once said the play, or any aspect of a fully hensive look at what is happening ’s job was to keep pilots integrated cockpit, download in the atmosphere around the cool, because they really sweat GAMA Publication 12 from www. airplane — and between you and when it stops. If the engine is gama.aero. This free publica- your destination. working within nominal limits, we tion, “Recommended Practices don’t care what those numbers and Guidelines for an Integrated Radios are; yet, it is critical the engine Cockpit/Flightdeck in a 14 CFR Nearly a half century ago, operating parameters are avail- Part 23 Certificated Airplane,” has Narco Avionics introduced a able to the pilot at all times and a wealth of interesting information general aviation radio that was they are monitored in case they valuable for homebuilders, avion- mounted in the center of the get out of kilter. ics installers and aircraft owners instrument panel. Called the One of the more important who want to upgrade their panels. Mark II, it was 6.25 inches wide. aspects of the glass cockpit is the It takes the guesswork and sub- Today’s avionics by Narco, addition of sophisticated engine jectivity out of cockpit planning Garmin and Honeywell often are instrumentation. These electronic because it is based on extensive 6.25 inches wide, or “mark width.” “brains” watch the engine sensors research and experience. With a glass cockpit, there is no continually and with more accu- reason to have mark-width radios racy than their human counterpart. Shiny Buttons and Knobs on the instrument panel. However, they don’t bother the Intelligent design meets artistic In a glass-panel environment, flight crew unless something is interpretation in the careful place- the controls of the radios are pre- going off kilter. When something Continued on following page…

- 41 - GLASS COCKPIT Continued from page 41 ment of the buttons, knobs and human-input devices the pilot uses to manipulate the glass cockpit. These controls — and there are many of them — need to make logical sense to a major- ity of pilots, which is no small feat. Their arrangement is the sub- ject of much research. Where we find differences is between manufacturers. Each manufac- turer has a design philosophy they believe in and have been able to certify. This is also an area where human factors meet brand loyalty. Because you like “Company A’s” human interface, you may want to stick with that company through upgrades even though your hangar-mate prefers “Company B.”

Synthetic Vision Beyond the glass panel is something called synthetic vision: “We won’t need no stinking win- dows because the electronics will gather all of the information around the airplane, sense all of the threats and show us the way to fly to the destination on a display mounted in front of our eyes.” This is not some Buck Rogers fantasy — synthetic vision is real and in use today. It’s a similar application as the first glass cockpits of 30 years ago, as commercial aircraft are perfecting the system for general aviation. There are many technological- ly advanced integrated cockpits on the market, and more are on the way as new companies are springing up with innovations to keep the industry fresh and growing. ■

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