In April of this year, a BAE Systems Jetstream research aircraft flew from Preston in Lancashire, England, to Inverness, Scotland and back. This 500-mile (805 km) journey wouldn't be worth noting if it weren't for the small detail that its pilot was not on board, but sitting on the ground in Warton, Lancashire and that the plane did most of the flying itself. Even this alteration of a standard commercial prop plane into an Unmanned Aerial Vehicle (UAV) seems a back page item until you realize that this may herald the biggest revolution in civil aviation since Wilbur Wright won the coin toss at Kitty Hawk in 1903.

The Jetstream flight was conducted as part of the Autonomous Systems Technology Related Airborne Evaluation & Assessment (ASTRAEA) program, which is a UK industry-led consortium aimed at developing unmanned aircraft that can operate routinely in civilian airspace. It’s one of hundreds of UAV projects around the world, but what’s notable about it is how the use of a passenger plane blurs the line between quadcopter-with-a-camera jobs and full-blown airliners.

The UAV revolution

For many people, UAVs came out nowhere. In the popular imagination, they started out as exotic reconnaissance aircraft in the early days of the Afghanistan War that have grown in numbers and sophistication until they’ve turned into experimental combat aircraft taking off from aircraft carriers. In fact, UAVs have come from a number of areas aside from the military. Hobbyists have made their contributions, scientists as well, and, of course, aircraft engineers.

In many ways, UAVs are a bit like computers. First they were rare and then they were everywhere. Whether they’re tiny quadcopters that fly within a few hundred feet of their operator or huge winged affairs piloted via satellite thousands of miles from the joystick, UAVs are taking to the skies in ever-increasing numbers for a a variety of applications.

One obvious area for UAVs to move into is police work. Take away the missiles and hunting for bad guys on a civilian street is very similar to hunting them on the battlefield. The challenges are virtually the same and transferring the technology from one sphere to the other is relatively straightforward. An eye in the sky could be used for general law enforcement, border control, sea lane monitoring, traffic control, crime scene photography, searching for missing persons, and combating drug trafficking.

The FBI has admitted in recent congressional testimony to using UAVs in the US on a number of occasions and some US police departments have been granted permission by the FAA to operate them. In Canada, a UAV is credited with saving a man’s life. However, other locations, such as Seattle, have abandoned plans for their own drones due to the fierce debate over the use of UAVs in law enforcement.

The question isn't just whether drones should be used at all, but also how they should be used. Should they only be used in extraordinary circumstances, such as hostage situations? Should they be used routinely like a CCTV camera on a pole a hundred feet tall? What sort of oversight is needed? How can privacy issues be addressed? When does policing go over the line to surveillance of the public?

Beyond law enforcement, civilian UAVs in the US are almost non-existent. The FAA has only one rule concerning UAVs, which is that they can’t be used. The agency will authorize UAVs on a case by case basis, but has issued less than three hundred permits. Most of these are for law enforcement with the remainder going to university research programs and pilot projects, such as monitoring wildfires. Even then, most UAVs must operate under severe restrictions, such as remaining in sight of the operator at all times and at very low altitude.

Almost limitless applications

Similar restrictions apply in other nations to different degrees, but UAVs with various degrees of autonomy are already being used and the potential for the new technology is already evident. One area is in agriculture, with Japan having used UAVs for seeding and crop dusting for over 20 years. With their small size and ability to fly or hover very close to crops, UAVs can also be used for what is called “precision agriculture.” UAVs, especially when equipped with infrared imagers and other sensors, can be used to monitor livestocks and crops, detect diseases, determine plant ripeness and schedule harvesting. They can also spread poisoned bait for vermin, such as fire ants, mice and rats with minimal environmental impact.

Other areas where UAVs might show applications is in meteorology with swarms of small robot planes taking up the dangerous task of storm chasing as well as being able to take measurements in situations where using conventionally piloted aircraft isn't feasible.

Another job is prospecting with drone aircraft conducting surveys for oil, gas and minerals. It goes without saying that UAVs are excellent platforms for cartography and geophysical and photometric surveying, allowing an aerial perspective that archaeologists, for one, could only dream of a few years ago. They can also be used for data relays or for inspection and maintenance of bridges and other structures.

But the real question is, are UAVs any good at delivering pizzas? At least one company has tried this as part of a promotion, but a restaurant in London did them one better with flying waiters to deliver sushi burgers. These may be novelties, but they illustrate the almost limitless potential of the technology.

The US Army is already using unmanned helicopters for hauling cargo in Afghanistan and it may not be that far off before we see them taking up some of the load at home from trucks. In the meantime, there’s always the UAV as personal assistant and dance partner, which would be doubly impressive if it was mind-controlled.

All of this seems like a technology shooting off in a thousand different directions with every sort of fixed wing or copter imaginable whizzing about in a chaos of invention, but the UAV revolution is much simpler, though with great implications. It’s less a matter of what’s in the UAV than what isn't.

Removing the pilot

Technology often advances in lurches. Computers, for example, were figured out theoretically as far back as the 1830s, but it took the invention of the microchip to send them off and running. Many devices that we take for granted were once clumsy and expensive until plastics made them cheap and easy to manufacture. The same is true of the emerging UAVs. It isn't simply a matter of taking the pilot out of the machine, but also exploiting the tremendous advantages that removal implies.

We tend to think of a pilot as being indispensable for a plane, but in many respects, he’s a liability. A human being takes up space, needs somewhere to sit, air to breathe, the right temperature and pressure, and needs readouts and controls to operate the aircraft. All of these take up space, add weight, and use power.

Worse, humans are rather fragile. Acceleration at five times the force of gravity or “Gs” can render an unprotected pilot unconscious. Even two Gs can cause a blackout if it’s in such a direction that it causes the blood to rush to the head. You can do a lot to prevent this with proper seating and special inflatable trousers to keep the blood from pooling in the feet while making a fast bank, but there are limits and those limits are reflected in the performance of the aircraft.

Now imagine taking the pilot out. There’s no more need for life support, seats, control systems, readouts or even something as simple as a latch that opens from the inside. All that weight and space is saved. This allows the UAV to be much smaller and lighter. A perfect example of this is the hobbyist’s quadcopter. Being remote controlled, it doesn't need to be able to lift the pilot, so it’s possible to make a drone so tiny that it rivals a hummingbird, remain in the air as long as the fuel holds out, and go where it would be impossible or far too dangerous to send a person.

And it’s not just size. For now, engineers are happy if a combat drone like the X-47B can operate as well as a manned aircraft. But what about when they realize that there’s no pilot inside that needs protecting? The UAV of the future will be able to accelerate and turn in a way that would be lethal for a human pilot – and may not even be possible for one on the ground to control without an onboard computer’s aid. It may be that the Top Gun of the 21st century is an artificial intelligence.

From autopilot to UAV

All of this brings us back to the Jetstream test. With all these potential applications and advancements, what does a flight from Lancashire to Scotland and back have that others don’t. Quite simply, it illustrates that the civilian UAV revolution isn't on its way, it’s already here. That’s because what ASTRAEA did with the Jetstream wasn't about fitting it with something radical. Instead, the engineers took the technology that was already in the Jetstream and took it a step further.

When someone mentions “UAV,” it brings to mind images of quadcopters with batteries that last less than an hour or motorcycle-sized helicopters, or maybe military drones like a Predator, which is about the size of conventional plane, but looks like a blind monster. In each case, it seems as if the UAV is playing catch up with where the aerospace industry was decades ago.

In fact, what has really happened is that conventional aircraft have been developing in such a way that the difference between a civilian plane and a UAV is almost a matter of perspective.

Look at the ASTRAEA Jetstream. It is a Jetstream small twin-turboprop airliner. It isn't an airframe that’s been gutted and all the working bits replaced. It is a production Jetstream with some new technology added to it. Some of these included autonomous systems and a very robust communications system that allows a pilot on the ground to not only control the aircraft, but to also keep in touch with air traffic control, yet the key in the Jetstream’s case was its detect and avoid capability, which allowed the Jetstream to detect other aircraft, keep a proper distance and obey flight regulations while doing so. This last bit is vital because UAVs make other pilots nervous.

But what’s the difference between a Jetstream turned into a UAV and a regular one? The answer is: Not a lot. And the same is true of many newer aircraft. If you've flown in a modern, long-haul passenger aircraft you've already ridden in what is almost a UAV.

This isn't a recent development. It goes back to the earliest days of aviation when designers were already trying to automate aircraft. Early planes were a nightmare to fly and required constant, unerring attention on the part of pilots or reacquaintance with the ground would happen very fast.

By the 1930s, pilots had an alternative to wrestling with a joystick every second while staring at the horizon. The first autopilots had been developed using simple feedback mechanisms and gyrocompasses that made the plane fly straight and level and even maintain a course heading for hours on end without human intervention. Today, these systems have become computerized and incredibly sophisticated. While smaller aircraft may be restricted to simple autopilots to control roll or keep them flying level, larger aircraft have autopilot systems that can control takeoff, ascent, cruising, descent, approach, and landing. In the not too distant future, they will even be able to handle rollouts and taxiing.

This isn't surprising because autopilots aren't just a form of mechanical steering. They can control a plane’s throttles, determine its position using GPS, dead reckoning and radio beacons, and balance the plane by automatically pumping fuel from one tank to another. Furthermore, many modern airliners use fly-by-wire systems instead of direct hydraulic linkages. In this set up, the plane’s computers aren't just an adjunct to the pilot, they are an integral part of the controls and, in a sense, the pilot isn’t so much flying the plane as telling the computer what to do. Add in the situational awareness and ability to be directed from the ground that the experimental Jetstream has and you've got a UAV.

The future

So, are we going to be getting on airliners soon that have as big a crew as an elevator’s? That is, none? Probably not. The problem with civilian UAVs is that the robot airplane doesn't exist in a vacuum. It has to deal with other planes and the air traffic system that directs them. The air traffic control system used around the world today was built around pilots, not robots, and its technology and procedures reflect this. A controller can’t talk to a robot. A robot can’t talk back. It can’t respond to spoken instructions. That may seem obvious, but it reflects the fact that air traffic relies very heavily on human judgement and interaction rather than mechanical systems. Furthermore, humans and machines work differently and, for example, landing maneuvers that are best for pilots may not be the best for UAVs.

Another reason why UAVs would have a hard time is that there are a lot of aircraft that don’t use any sort of autopilot. Older and smaller planes may use nothing more sophisticated than the seat of the pilot’s pants and even small airliners of fewer than 20 passengers on short duration flights with two pilots may not have one. If every plane was equipped with GPS, as is planned for the future, and ADS-B tracking technology, then air traffic procedures could be designed so that UAVs and manned aircraft can mix safely. But so long as human piloting dominates and the sort of time delays and need for human judgement is required, UAVs flying over a couple of hundred feet or weighing more than fifty pounds haven’t much of a look in.

Does this mean that civilian UAVs are a regulatory and technological dead end? Hardly. One effect of the increasingly automated plane is that air cabin crews have shrunk remarkably over the past fifty years. At one time, any large airliner would have a pilot, co-pilot, navigator, engineer and radioman. Today, there’s only the pilot and co-pilot and there’s even talk of eliminating the co-pilot. However, pilots don’t make up much of the cost of running an airliner, unions wouldn’t be happy with eliminating them, and the public don’t seem very keen about flying alone with no other company other than an automated drinks cart. So even a plane that can fly itself or under ground supervision may have a human pilot aboard for emergencies and reassurance.

What this means is that civilian UAVs of the airliner variety may be similar to the military’s man-optional aircraft. One trend in military aircraft design is to make combat and transport aircraft that offer the option of accommodating a human pilot, but isn't necessary. The idea is that, for example, a fighter plane might have a pilot onboard when going on a mission, but fly itself when being ferried to a new base. A similar system could be used with civilian aircraft that might have pilots aboard with passengers, but fly themselves when empty or used to carry cargo over water and landing at coastal airports.

Air taxis

Another way in which we might see the UAV move gradually into civilian life is at small airports. Currently, air traffic is a nightmare of centralized air traffic control systems moving fleets of aircraft between hub airports that are stretched to capacity. Aircraft equipped with UAV technology could change this because such craft have the potential to talk directly to one another and operate with a high degree of autonomy instead of waiting for air traffic control instructions.

What this would mean is that as the technology becomes more widespread, air traffic control becomes much simpler and small local airports would be able to do many of the things that only a major one can do today. Imagine a city the size of London, which needs half a dozen major airports to operate, being served by one large airport and a hundred small ones acting like air taxi stands and you get the idea. Indeed, it may be that the first pilotless passenger plane may not be a huge airliner, but a little air taxi that ferries around only a handful of people.

Of course, this sort of a future depends on a lot of technological hurdles being overcome. As was seen in the Jetstream experiment, UAVs have to see and avoid other aircraft. They need to operate with piloted craft, and they need to be supported by an air traffic system that plays to their strengths instead of against their weaknesses. Worse, UAVs need massive amounts of bandwidth, which the military has, but civilian air systems lack.

Finally, there’s the fact that fully autonomous devices aren't completely trustworthy. Even an autonomous machine needs a human for when things go pear shaped. In an emergency, automated systems can do a lot, but sometimes human improvization on the spot is key.

Ultimately, what the world where UAVs are part of everyday life looks like will depend on the decisions we make. Will we have flying robot baristas delivering lattes to our tables? Will we be stepping aboard a crewless airliner as comfortably as we do an automated train? Will we have our own personal assistant following us around like Tinkerbell updating our Twitter accounts throughout the day? Or will we be ever on the lookout for spying drones? Only time will tell, but the technology is moving at such a rate that these are questions we need to start asking ourselves now.

The video below outlines the ASTRAEA program.

Source: ASTRAEA (PDF)