Future Flight

Next-generation airplanes may be trivially easy to fly. But are we being sold a bill of goods?


Tucked away in labs around the country, engineers are hard at work designing the next steps in a plan that would revolutionize transportation. The goal is one any aviation buff would admire: Substantially shift personal transportation between cities from being based on personal automobiles on highways to small aircraft.

The Small Aircraft Transportation System ties together the work of other NASA and industry programs that have aimed to improve the powerplants, weather capabilities and navigation complexities of small aircraft. The visionary goal is lofty – to create a way to reduce the cost of a new jet to a point comparable to a high-end luxury vehicle in order to reduce average door-to-door travel times between cities by half in 10 years and two-thirds in 25 years. Furthermore, this innovation would have to be done at a cost comparable to building and maintaining interstate highways.

Achieving such a revolution in air travel requires groundbreaking innovation in aircraft hardware and computer software. Most of all, it requires a massive shift in public perception about the safety and economic viability of light plane travel.

The vision has two ideal eventualities. One is that substantially more people learn to fly and buy airplanes, reducing some of the airline congestion inherent in the hub-and-spoke system. The other is that enterprising companies set up fleets of air taxis – light six-seat jets flown by professional pilots that ferry people as an on-demand charter service at roughly the cost of a current coach airline fare.

The project also will have substantial impact on general aviation, regardless of whether the lofty vision comes to full fruition or not.

The developmental programs focus on jets for several reasons. They are more reliable than piston engines and small, advanced jet engines carry the promise of being quieter. In addition, jets allow for more speed, which is really the whole purpose of the exercise anyway.

However, jets also have a major shortcoming. The lag between applying power and getting increased performance is shrinking, but still threatens to challenge pilots making the initial transition from propeller airplanes, just as it does now.

The reliability of other systems remains something of a crap shoot. While the instrument panel will shift to computer screen displays, the sensors and probes that generate the data displayed there will still be subject to failure. In addition, the increased complexity of the airplane introduces more systems into the mix.

The current generation of SATS simulators use computers driven by Windows operating systems. The current prototypes include two, one that displays flight information and one used for navigation, weather and systems status.

Windows, however, crashes with a frequency alarming to pilots, so at least three computers would be desirable. Using custom software to drive the computers may be more stable, but runs counter to the philosophy of using mass production to reduce costs.

When the computers are working, they create redundancy unheard of in light aircraft today. If one computer or screen fails, another can take its place. Because the screens can be tailored to display whatever information the pilot wants, partial panel operations would be a thing of the past – unless the equipment driving the displays fails.

Electrical failure, however, would be a bit more problematic without dedicated backup batteries. Imagine trying to land an airplane whose instrumentation consisted of three blank computer screens and a single power lever. It can be done, but it represents the kind of challenge that keeps many people away from flight training already. Up the ante with higher approach speeds and the questions mount.

Advances in navigation, driven by GPS moving maps, are forecast to advance rapidly. Navigation remains the area where the development programs may impact the greatest number of pilots in the shortest time. Moving map displays can be upgraded to include terrain, collision avoidance and weather information, and already this technology is beginning to trickle into the cockpits of mainstream aircraft.

Advances such as touch-screen flight planning will help. And what would you give for automatic autopilot operation that analyzes your flight plan, selects the best altitude (given the airplanes performance, weather, traffic and length of trip), and then flies it? Add to that datalinks that automatically negotiate your flight plan with other aircraft and ATC, allowing you to fly direct to your destination without doing anything other than touching your destination on a map.

This operational simplicity is considered a key element of attracting enough new users – Can you even call them pilots anymore? – to make the system cost-effective.

But dependent as it is on GPS, the system can be criticized for ignoring what to this point has been a fundamental of aviation: redundancy. The loss of position data due to the loss of satellites, military intervention or weather eliminates the aircrafts knowledge of terrain, position, traffic and destination. Without secondary navigation equipment on board, the operator will be reduced to basic pilotage – a skill that may atrophy when everything is working.

Information processing
Advanced airplanes will have datalinks that continuously update the weather, traffic, flight plan and position. They will get their own clearances, plan their routes and fly them. The pilot settles firmly into the role of systems monitor – more so even than a driver on a rural interstate with the cruise control set.

Designers may want to take a page from the lessons learned by early interstate highway engineers. Highways were initially designed to be as flat and straight as possible. Then people began falling asleep at the wheel – with predictable results. Rural interstates are now designed with gentle curves and hills even when terrain does not require it.

Information will likely be presented on three computer screens. One will be for flight information and contain information on attitude, heading, vertical speed, power and airspeed. It will also contain a graphical representation of intended flight path, using concentric boxes to illustrate the programmed route.

The second computer screen will contain navigation information, including flight plan, weather, and traffic. The current experimental prototypes also include pages for systems monitoring, but such information will likely be hidden unless the computers detect an anomaly. Designers may opt for a third screen to display systems information full time.

Comfort and Safety
Ralph Naders landmark book, Unsafe at Any Speed, influenced car design by putting safety into the minds of consumers. But just as Nader influenced automobile design, some say Cirrus and Lancair have already influenced aircraft design.

Crashworthy seats, crumple zones and diverting/absorbing energy before it gets to the human bodies will take on new relevance. Such designs will necessarily include cleaner interiors that most people will think of as more car-like. That carries with it the promise of easing the transition into the cockpit by people who are not now pilots.

It also helps advance the development of a more standard design that would make transitioning from one type of airplane to another easier, much like stepping up to a rental car counter and getting the keys without having to take a driving test.

One of the biggest factors influencing the long-term success at attracting more people is weather detection. Datalinks will provide information from ground-based radars and weather stations, but thats not likely to be enough.

Accurately detecting icing conditions will be crucial, as will development of anti-ice capabilities. Then theres instrument approaches. Flying fully-coupled approaches right down to the runway every time may make sense in the distant future, but for now reliability and accuracy remain sticking points.

Safety will definitely be enhanced by the ability to use the on-board computing power to turn the data pilots now get into information they can use. Coded METARs, nearby ATIS, Flight Watch and National Weather Service would be rolled into the computers brain, and out would come a graphic illustration of poor visibilities, thunderstorms, icing, turbulence and other threats.

The pilots judgment, then, could be based on the big picture, rather than the subjective weightings most pilots now use to assess their chances of completing the trip.

While improved weather detection will help, flying an approach in bumpy air will still be uncomfortable to many people used to riding in a car.

The light wing loading found on small planes increases the bumpiness, especially close to the ground. Increasing the wing loading smoothes out the ride, but the tradeoff is higher approach speeds. Automated cockpits and improved wing design may be able to improve the ride in the long term, but in the short term people will either have to accept riding in what one acquaintance calls a puke bucket or opt for high approach speeds that mean more of a risk of losing control on the runway or overrunning it.

Meeting the cost projections NASA envisions demands high economies of scale and a new certification approach by FAA. The emphasis on expanding aviations appeal through reducing costs begs a comparison to automobiles.

In the early days of car travel, most people thought driving would remain a hobby for the technically minded and a tool/play toy for the rich. Sound familiar? Even into the 1960s and 1970s, cars were full of hard surfaces and sharp edges and more design effort was placed on looks and manufacturing concerns than on safety. Sound even more familiar?

Still, over the years automobiles have evolved to the point where most drivers can get into an unfamiliar car and operate it passably well within at most a few minutes – this despite differences in manufacturer, design, performance, control placement and displays. Getting aircraft to that point is another goal of the SATS program.

Moreover, cars are built for a cost of roughly $7 per pound of empty weight. That number can vary somewhat depending on options, performance and other concerns, but works as a fleetwide average. Specialty cars such as the Dodge Viper may go for as much as $14 a pound. Aircraft, on the other hand, cost more than $90 per pound to build – sometimes far more.

The SATS goal is to get the cost of aircraft down to $30 to $40 per pound or less. Put in current terms, that would be the same as reducing the cost of a new Mooney Eagle 2 from more than $360,000 to less than $90,000 or a Piper Archer from $190,000 to just over $50,000. That comparison is not quite fair, however, because the aircraft SATS envisions would be faster, safer and easier to operate.

Those savings would come from cheaper and lighter engines, instrumentation displayed on computer screens such as those found in laptops, new manufacturing techniques, and overhead spread over thousands of airplanes rather than a few dozen.

What It Might Do
The advanced light aircraft transportation system would revolutionize air travel and change what it means to be a pilot. That, of course, is a double-edged sword.

Some people note road rage incidents and poor driving habits and wonder if they want people like that flying over their neighborhood. In addition, the capabilities of the new generation of aircraft will leave out a large number of people who couldnt afford to move into the new airplanes, even if they are cheaper.

Since traffic avoidance will be based on datalinks rather than systems such as TCAS, airplanes that are not equipped with the datalink wont show up unless the FAA routes radar positions and transponder information through the datalink as well. Even so, this represents a layer of complexity that wont help keep costs down.

In an odd sort of way, the development could help ease the shortage of flight instructors on several levels. First, the nature of the vision is such that airline growth will slow somewhat. Second, it creates a new career path that will not only attract more potential workers, but move flight instruction a step further from the right seat of an airliner.

If companies develop fleets of on-demand air taxis around the country, airlines will find pilots who fly those kinds of routes to be much better candidates for employment than someone building flight time in the right seat of a trainer doing touch-and-goes. This is doubly true if the fleets of airplanes are jets and primary trainers remain prop planes.

There could conceivably become two classes of pilots: those who have the archaic flying skills and those who know only the sophisticated, super-reliable aerial limousines.

What It Cant Do
There are several areas where serious questions remain. While reliance on enhanced navigation and autopilots will help prevent many of the accidents that result from controlled flight into terrain or loss of control due to flying in IMC, at some point the human operating the airplane has to be able to cope with the demands of flying. Where that should be remains a point of contention.

Two of the most common causes of accidents stem from loss of control on the runway and fuel exhaustion.

The runway accidents fall into many categories, but usually are the result of trying to land too fast or take off too slow. Because the new generation of light planes are not intended to have autoland capabilities, the pilot will still need to transition to the landing environment in a high-performance jet.

Stiff crosswinds, gusty conditions and missed approaches would still be facts of life. For most pilots, those three maneuvers generate the most sweat and are the most antagonistic to the feel-good flight environment most of the traveling public demands.

Fuel exhaustion is a tougher nut to crack. More accurate fuel gauges would be a start, but could be applied without such a sweeping revolution. The human nature that insists on trying to shave some time off an important trip suggests that some pilots will always run out of fuel. Perhaps the only solution is to program the autopilot to assess how much fuel is left and automatically divert to the nearest airport before the airplane runs out of gas. Even that may be a clumsy solution, however, because it would have to take into account the possibility of missed approaches and unexpected winds.

Then theres the problem of weight management. Airplanes typically are not designed to carry full fuel, full seats and full baggage compartments simultaneously. However, loading a car involves stuffing into it what you want to carry, slamming the door and driving off. Flying commercially means stuffing as big a bag as possible into the overhead compartment, slamming the door and walking back 23 rows to your seat. If these are the kinds of travelers targeted to become pilots, a substantial shift in mindset has to occur.

With the SATS program completing only the first year of a planned five-year program, its not surprising it has raised as many questions as it has answered. NASA plans to spend nearly $70 million on the effort. Combined with other efforts, developing advanced airplanes and a system in which to fly them has already consumed $180 million in tax money and an unknown amount of R&D money by companies working to develop the hardware and software needed to make the dream come true.

Change in any industry takes time, but changes in aviation seem to move at glacial speeds. The cost involved with developing the technology, certifying it and then producing it may price potential users out of the market for many years.

The research may show the original goal was too lofty, but may spin off enough new technology and ideas to make the present system work better – change through evolution rather than revolution.

But the industry may also respond with a level of innovation and enthusiasm unheard of since the airlines discovered the pressurized jet. The market success of the Cirrus SR20, hailed as a precursor of the revolution to come, shows there is a pent-up demand for real innovation. The interest surrounding plans for light jets by Eclipse Aviation and Safire Aircraft shows that current pilots are interested in higher performance at reduced costs.

Whether the products meet the design objectives that now seem fantastic has a large impact on whether that market demand is real or wishful thinking. But the success of these programs will have a huge impact on future aircraft operations, airspace congestion and safety of flight.


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