Interesting stuff

Flying made easy
David H Freedman

03/01/2001
MIT’s Technology Review

56
Copyright © 2001 Bell & Howell Information and Learning Company. All rights reserved. Copyright Massachusetts Institute of Technology Alumni Association Mar 2001

IT AIN’T THE JETSONS. BUT NASA AND FRIENDS HAVE A PLAN FOR REDUCING AIRLINE AND HIGHWAY CONGESTION: FLY
YOURSELF TO A COMMUNITY “SMARTPORT” IN AN IDIOT-- PROOF MINI-SUPERPLANE.

I recently traveled from outside Boston to Groton, CT–a popular in these parts, thanks to a nearby casino–and then on to Cape Cod, before returning home. It’s about a five-hour drive, if the traffic isn’t too bad. I did it in a little over two hours, by flying. Not a commercial flight; just driving to Boston’s Logan Airport, checking in a boarding takes two hours. I flew myself in a rented Cessna, for a total cost of $160–a cost I could have split up to four ways if I had gone with friends. Besides being quick and relatively cheap, the trip afforded stunning panoramas of explosively colored fall foliage and ragged shoreline inaccessible from the earthbound perspective of a car or through the plastic peephole of a 747.
That’s the good news about flying a small plane. Here’s the bad news: before the flight, I had to pore over charts and airport directories, compile lists of radio navigation aids, digest a long weather briefing, and calculate wind correction angles and fuel consumption figures. Throughout the flight I had to engage in streams of aviationspeak (“Cessna one-eight-hotel, report left base following Warrior, confirm you have traffic in sight, winds three-three-zero at nine”) and actively monitor eight gauges.

To land, I had to adjust carburetor heat, lower wing flaps, and turn the plane askew to compensate for crosswind, among other tasks, all while remembering that an omission or error could have been fatal-- the sort of error that plays a role in a third of the 700-odd non-commercial aircraft deaths that occur each year. And this was in clear skies; flying in clouds brings a quantum jump in complexity.

No wonder a mere 26,000 people or so earn pilot’s licenses each year, compared to some four million who get driver’s licenses. And this despite the fact that our increasingly mobile population is choking on clogged roadways and an often near-gridlocked commercial airline system–while the runways at some 4,500 small public airports mostly sit empty.

But this picture could change dramatically over the next decade if ambitious programs jointly undertaken by NASA, the Federal Aviation Administration, small-aircraft manufacturers and university researchers remain on track. The general goal of these programs: making small aircraft as easy and safe to operate as cars–maybe even easier and safer–and almost as inexpensive.

At the heart of this nascent transformation are new systems, components and designs aimed not so much at commercial airliners and corporate jets, the traditional beneficiaries of advances in aviation technology, but at some of the smallest and least costly aircraft made. Able to do everything from avoiding other aircraft to correcting for wind and assisting landing, these technologies are so heavily computerized and user-friendly that the cockpit in a leading-edge small plane is looking less like the console of a steam locomotive and more like the interior of a luxury sports sedan modified for Web surfing. What’s more, these systems are being built to take advantage of new weather radars, position sensors and airtraffic monitors that can convert the humblest of community airports into hightech “smartports” able to automatically accommodate a stream of planes. The eventual result: even relatively unskilled pilots will be able to home in on runways, even in bad weather, with negligible chance of things going wrong. Sums up Keith McCrea, air service and policy coordinator for the Virginia Department of Aviation, “These improvements will make flying so intuitive that any dummy will be able to do it, and without a lot of training.”

Flying for Dummies

It’s been a long time coming. Drive over to the nearest small airport–it’s almost certainly less than a half hour away–and peek in a window of any of the four- or six-- seat aircraft parked on the ramp. Chances are you’ll be looking at a control panel dominated by a dozen or so needle-- and-numbered-dial gauges, making it mostly indistinguishable from a panel that came off an aircraft assembly line in the 1950s. In flight, an experienced pilot can glance at the dancing needles in these gauges and immediately infer the plane’s altitude, heading, speed, rate of turn, rate of climb and “attitude”–its angle with respect to all three axes–as well as the aircraft’s rough location in relation to navigational radio stations. To a novice, however, translating the gauge readings into an understanding of the flight situation is an opportunity for serious math anxiety. “How many people enjoy doing math calculations in their heads?” asks Dean Vogel, vice president of research and development for Cirrus Design, an aircraft maker in Duluth, MN. “How many like doing them in their heads when they know that if they get the wrong answer they’re going to kill their wife and kids?”

Vogel poses this gruesome question because he thinks he has the answer–at least a big part of it. In 1999, Cirrus started turning out a four-seat plane called the SR20. For a pilot used to the traditional small-aircraft panel, the SR20’s console is jolting in its simplicity. Gone is the dizzying array of gauges and needles. In their place: a 26-centimeter video display fed by Global Positioning System (GPS) data that provides a literal picture of the terrain beneath the aircraft, with airport, flight route and weather information superimposed on it. “You let a computer gather the information you need and integrate it,” says Vogel, “and then it presents the information to the pilot in a form that the brain understands intuitively.”

And that’s not the half of it. The SR20 display is the precursor of a more comprehensive set of pictorial tools being advanced under a multimillion-dollar program called Highway in the Sky that is funded chiefly by NASA, in concert with the aviation industry. A display developed under this program will be fed by GPS satellites and an onboard geographic database containing information on everything from terrain to dangerously tall antennas and airport traffic patterns. After a pilot push-buttons her way through a series of intuitive menus to program in the destination airport, the system will compare the aircraft’s position to the intended flight path throughout the journey, calculating the direction in which the plane must fly to stay on course. But here’s the impressive part: enlisting a graphics processor, the system will display the correct flight path as a series of hoops, lines or brackets superimposed on a 3-D-- like simulated view of the airspace and terrain in front of the plane.

Flying with a Highway in the Sky display thus becomes largely a matter of lining up the crosshairs in the screen’s center with the hoops or lines–a task the average 12-year-old could accomplish with one hand while working a Game Boy with the other. “I could take someone with no training and in five minutes have him flying a plane all the way through a landing,” says John Hansman, an MIT aeronautics researcher involved in developing pilot control interfaces. That isn’t much of an exaggeration. Technicians at NASA’s Langley, VA, facilities brag that one day they grabbed a secretary who’d never sat in a small plane and got her to fly a "Highway"equipped aircraft around a traffic pattern. And, since I happen to be the proud owner of my very own 12-year-old, I challenged Hansman to demonstrate with my son, Alex (see “The Five-Minute Pilot,” p. 62).

Some of the first production copies of these displays are likely to come out of AvroTec, of Portland, OR. AvroTec’s new panel is going through a painstaking FAA certification process. However, it is expected to be standard equipment later this year on four-seat planes made by Lancair, of nearby Bend, OR, while also available in a “retrofit” version for older aircraft. At an expected cost of $35,000, the system is pricey, but not prohibitively so, since conventional panels run about the same. AvroTec president Mary Nolan points out that the system will lower the bar even on some of the most challenging flight situations. “A computer is perfect at calculating minute changes to a course and projecting those changes out into a flight path” she says. “That frees the pilot to do the kinds of things that the human brain is suited to, which is assimilating information and executing judgment.”

Nolan offers as an example a pilot taking off from inside a cloud-shrouded canyon–an extremely hazardous scenario often encountered in the Rocky Mountains. Once off the ground and in the clouds, the pilot would normally have to estimate his location with respect to the canyon walls on a printed chart while watching gauge needles to make sure he stayed on course. With the new technology, the pilot would simply follow the hoops or dashed lines on the display. Because the system synthesizes its image from GPS data and onboard terrain databases–not the view from the cockpit–it works just as well in poor visibility. What’s more, it would be programmed to account for the aircraft’s performance capabilities-along with air density, temperature and wind data–allowing it to calculate the safest way out of the canyon. The pilot could check the projected path before takeoff, and if it passed too close to the canyon walls, he could scrub the flight and wait for better conditions.

The National Aviation Road Map

Highway in the Sky emerged from the Advanced General Aviation Transports Experiment, a consortium of 70 organizations that includes aviation industry manufacturers, universities and the FAA. Since its 1994 inception, the effort has been spearheaded by NASA, under director Dan Goldin’s stated aim to establish a 91 national general aviation road map to enable doorstep-to-destination travel at four times highway speeds to virtually all of the nation’s suburban, rural and remote communities." Though the original consortium effort is fading into the background, it has passed the mission on to several spinoffs, of which “Highway” is one. Another is the Small Aircraft Transportation System, a five-year, $69 million program that kicked off last year. Technically, the program is an umbrella effort that embraces Highway in the Sky and other small-aircraft technology efforts. In practice, it is focused on the other side of the equation: the airport and air traffic control infrastructure necessary to support high-tech small aircraft. After all, a fancy display system will be no better than the data it crunches; providing that data is the Small Aircraft Transportation Systems mission.

Currently, flying through low-visibility conditions requires maintaining radio contact with ground-based air traffic control stations. These outposts track aircraft via radar, enabling controllers to issue verbal instructions that keep pilots on course–and out of each other’s way. When approaching an airport through clouds, the pilot of a small aircraft tries to stay in the ordered pattern and zero in on the runway by repeatedly centering a needie tuned to a series of radio beacons. Every year, confused pilots fatally lose control of their aircraft. In theory, it would be far easier to track your approach on a GPS-driven display, available for $400 in handheld versions specially designed for pilots. But the standard GPS signal can be off by tens of meters–an error range that can all too easily place an approaching aircraft in a position to crash.

Part of the Small Aircraft Transportation System mission is to change all that, by providing displays with “differential” GPS signals corrected to an accuracy of as little as one meter. There are several schemes for achieving this goal, but the most significant for small aircraft is the Wide Area Augmentation System. The idea is to equip special ground stations with GPS receivers. By monitoring location information derived from the standard GPS signal and comparing that to the precisely known position of the station, it’s possible to calculate the moment-to-- moment error in the transmission caused by interference. The ground station then beams the corrected information to a satellite, which relays an updated, farmore-accurate signal to onboard GPS displays. Much of the system is already in place in the United States, though it will likely take a few years to work out reliability issues and achieve FAA certification for small-aircraft landing approaches.

When it does go into practice, and especially when combined with forthcoming display technologies, the Wide Area Augmentation System promises to make it far easier to touch down at airports that currently rely on instrument landing-system aids (which require pilots to align aircraft with runways by following ground-based directional signals) for poor-visibility approaches. The real benefit for small planes, though, is that the vast majority of local airports that could never justify the $1 million-plus cost of installing an instrument landing system at one end of a single runway should be able to certify both ends of every runway for poor-visibility landings for free. (Aircraft can land from either end of a runway, depending on wind direction; so authorization of poor-visibility landing from both approaches requires two systems.)

In fact, the savings for most small airports will be substantially more than $1 million. The low angles and gentle descents of instrument landing-system approaches force airports to purchase-- or at least acquire easements over-large tracts of land leading up to a runway. But the greater accuracy and coverage of Wide Area Augmentation System technology enable steeper approaches, allowing the airport to minimize, or even forego, these runway protection zones. “The most important aspect of [the Small Aircraft Transportation System] is that it extends instrument landing capabilities to virtually every runway, end to end, in the nation,” says McCrea, who for the next three years will be overseeing the first statewide test of the system.

In addition to providing the ability to stay on track through poor-visibility approaches into almost any runway, the Small Aircraft Transportation System also seeks to eliminate much of the need for conventional air traffic control procedures for separating planes. In their place will be a “self-separation” or “free flight” system (see “The Digital Sky,” p. 50), in which each aircraft broadcasts its GPS-determined location to every other plane within 250 kilometers; a Highway in the Sky display can then adjust a plane’s flight path to keep it out of everyone else’s way, eliminating the need for a manned control tower at smaller airports.

Over time, as more airports install increasingly precise and affordable weather radar, the Small Aircraft Transportation System initiative will also add technologies that provide pilots with “micro-- weather” data about an airport, including warnings of dangerous runway turbulence created by the wingtips of larger aircraft landing ahead of them. By punching through a few menus on a cockpit display, pilots will even be able to schedule fuel and maintenance services while still aloft, signal the airport rental car agency to have a vehicle waiting, or make a reservation at a nearby hotel if an unscheduled layover is in the cards. In this way, aviation authorities hope to turn thousands of community airports into “smartports,” in most cases without large expenditures.

Did Anyone Say “Skycar”?

What will it cost to fly all this technology? Less than it costs to operate a midrange BMW, according to the Small Aircraft Transportation System goals. That’s not cheap, of course, but it’s about half of what it costs to fly a slower, less reliable, far more difficult-to-operate plane today. What’s more, Highway in the Sky systems and other easy-to-use technologies are expected to save at least 40 percent of the roughly $5,000 cost of getting a basic license today-and a like percentage on the nearly $5,000 more needed to obtain a rating for low-visibility flying.

Indeed, the emerging panorama of aviation advances raises the tantalizing possibility that planes could fly themselves, without requiring a trained pilot on board. Hansman, for one, sees that as a literal no-brainer. “With Highway in the Sky, a human pilot just acts as a meat servo,” he says. “An autopilot could do it just as easily.” In fact, autopilots are fairly standard equipment on most aircraft today–it’s just that pilots usually have to hand-program the course and altitude information. What’s more, because today’s small-aircraft autopilots lack the topnotch reliability and precision needed to faithfully execute the stream of minute, rapid attitude corrections usually made in the critical seconds before touchdown, the FAA won’t certify them for landings.

All that may be changing, however. Cirrus’s Vogel contends that the eventual availability of “fly-by-wire” systems-- that is, setups in which a computer oversees all aspects of a plane’s controls–will provide the refinement needed to enable auto-landing. “It’s going to be a while before we see planes where you just punch in your destination and sit back-maybe decades,” Vogel admits. Still, he insists, that day is coming.

In the meantime, small planes should be able to at least provide backup piloting in the case of a serious mistake or other emergency, notes Dan Schwinn, president of Avidyne, a Lincoln, MA, avionics manufacturer also working on Highway in the Sky systems. “In cars you have traction control and antilock brakes, which prevent driver errors or get you out of trouble if you make one,” he explains. “In airplanes you could have controls that prevent the pilot from overbanking at slow speed, or that flip you back over if you’re inverted by severe turbulence.”

How far will the quest for high-performance, easy-to-own-and-operate personal aircraft take us? Perhaps as far as the Skycar, an outrageously ambitious machine under development by Moller International in Davis, CA. The Skycar, which currently exists only as a prototype-in-progress, looks something like a cross between a race car and a tiny jet fighter. On takeoff, the blast of air from four large “power pods,” which contain counter-rotating Wankel engines attached to turbine blades, is directed downward by louvers, theoretically allowing the Skycar to lift straight up-no runway necessary.

After reaching a safe height, the power-pod louvers slide back up, accelerating the vehicle straight ahead to around 500 kilometers per hour. The pilot has a pair of joysticks–one for vertical motion, the other for direction–but in essence these only serve to signal the pilot’s intentions. The actual control is handled by 26 computers that assess the aircraft’s position and attitude and monitor 72 components as often as 100 times a second. What’s more, the Skycar is narrow enough to be driven down the road on its three wheels; it even fits in a two-car garage. Projected cost in volume production: less than $100,000. Moller has already taken deposits on early production versions, expected to go for about $1 million each, but buyers will have to stand in line behind the US. Army, which is gaga over the machine. “We just hope the U.S. Army is the first army in the world to get these capabilities,” says Colonel Larry Harman, vice director of the Combat Service Support Battle Laboratory in Ft. Lee, VA.

Okay, so it’s a little early to start marking off the backyard landing strip. But any dramatic improvement in the safety, ease of operation or cost of small planes will translate into a jump in the number of private pilots-which will help justify the investment necessary to bring on yet more improvements. In this way, we may soon find ourselves in a golden era of personal aviation, in which hopping into the family aircraft to eat at a restaurant 500 kilometers away will seem less adventurous than a 50-kilometer automobile jaunt did a century ago.