This 1,200-word piece is not intended to be a manifesto of advocacy for autonomous aircraft. Its purpose is to explain what autonomous control systems in general do, and—at a very perfunctory level—how they do it. It is not a blueprint for how to build one. But if nothing else, it shows that that real people like me actually have considered these things, and have figured out ways to do them successfully.
What does “autonomous” mean?
“Autonomous” is a hot buzz-word in aviation, these days. While often reviled, it’s widely misunderstood, and even misused—as in the case of one of my favorite oxymorons: “semi-autonomous.” In the most basic sense, autonomous means “in charge.” That does NOT mean “not subject to rules.” (There’s a difference between autonomy and anarchy.) But autonomous does mean possessing full authority to operate within the rules—authority that cannot be usurped by any external authority, at any time. No little “I’ve got it” button; no remotely-piloted operations. A true autonomous aircraft has no cockpit; no displays, buttons, knobs, or levers; no flight controls. And of course, no pilots.
How do autonomous control systems work?
Despite all of the pious talk about go/no-go decisions, in the real world, each flight that any of us makes is a continuous string of decisions that amount to this:
- Continue with the plan, OR
- Modify the plan
Someone—or something—has to make those decisions, in real-time. Pilots do that. Autonomous control systems do that, too. “Autopilots” do NOT make decisions—they just do what their pilots tell them to do. These two respective defining characteristics are mutually exclusive. If you’re going to build an autonomous aircraft control system, autonomy has to be baked-in from the very beginning. You cannot add it in, later.
Machine decision-making already is mature, everyday technology. It is successfully employed in applications that are far more complex than flying an aircraft. But let’s consider machine decision-making in an aviating context.
I hope that every pilot among the readership can agree that the highest priority should be the safety of the aircraft and its contents (people and things).
- Axiom number 1: Safety is the highest priority of an autonomous aircraft control system.
Next, I suspect that we all can agree that getting from point A to point B also is of great importance.
- Axiom number 2: Successful completion of the flight at its intended destination is the second-highest priority of an autonomous flight control system.
How do pilots do this? They utilize available resources to mitigate (overcome) any impediments that can prevent them from safely getting from point A to point B.
An autonomous control system does it the same way.
What are “resources?” Generally, abilities and/or things that endow abilities. The aircraft can climb and descend; it can turn, and vary its speed. It may have a surplus of fuel on board, etc.
What are “impediments?” Generally, rules, performance limitations, and circumstances, that interfere with our objectives; they can pop up at any time. Examples: restricted airspace; the aircraft’s service ceiling; a thunderstorm directly ahead; unanticipated winds; an engine failure; runway closures; medical emergencies.
What does “mitigate” mean? Take action that prevents an impediment from thwarting our mission. Examples: fly around the thunderstorm; stop for extra fuel, etc.
- Axiom number 3: Autonomous flight control systems utilize available resources, to mitigate impediments that could jeopardize the safe completion of a flight.
Human pilots don’t train for every conceivable combination of circumstances; machines don’t need to be programmed for that, either. Impediments to the Plan are ad hoc; mitigations are ad hoc.
System architecture: I’m going to surprise many, by eschewing the “diversity = innovation and progress” model, in favor of a “consistency = reliability and safety” model. A properly-designed system architecture will permit every vehicle–from an S-LSA to a Boeing 747–to employ the exact same code base, so that the behaviors of every vehicle will be predictable and reliable. Thus, any autonomous aircraft control system designed by YARS would be a classic Expert System. No “Machine Learning.” Unfortunately, space constraints prevent me from including a detailed treatment of this, here and now. Perhaps in a follow-up guest blog…
Questions and doubts
“It’ll never work. Flying an airplane is too complicated for a machine to do it.” Have you seen this video?
What if it breaks? The aviation industry already builds–and relies upon–“can’t fail” computer technology, in straight-forward everyday fly-by-wire control systems. That same level of reliability (contrast with redundancy) would have to be a characteristic of any certificated autonomous aircraft control system, whether hooked up to an FBW or to a good old control-cables-and-servos aircraft.
Separation anxiety: The objective of Air Traffic Control is separation, so let’s not conflate that end with some specific means. It is both stunning and demoralizing to realize that the FAA’s multi-billion-dollar “Next Generation” air traffic control system still relies upon voice communications conducted on simplex open-frequency VHF channels–the mother of all party lines. The FAA already has admitted that ADS-B is insufficient even to handle just the “surveillance” part of the ATC task, in a sky filled with literally millions of drones, large and small. Future traffic separation will be both automated and distributed. In other words, aircraft will “work it out” with other aircraft that present an airspace-occupation conflict. But voice recognition and synthesis already is everyday technology–isn’t it, Alexa? So, if an autonomous aircraft control system had to communicate with classic ATC via good old simplex VHF, it could.
Why would you build an autonomous aircraft control system–or not?
“Not everything that CAN be done, SHOULD be done.”
Why would anyone design, certify, and build an autonomous aircraft control system, which–by definition–would eliminate the cockpit and the flight crew from an aircraft?
Three reasons immediately come to mind:
- Increased safety. Pilot error is the leading cause of aircraft accidents. Eliminate the pilots; eliminate their learning curves and their errors; improve safety. MCAS fiasco. Kobe Bryant tragedy.
- Lower cost. No direct expenses or training costs for flight crews.
- Increased access to aviation. Autonomous aircraft would democratize aviation. You wouldn’t need to be–or to hire–a pilot, in order to fly.
Why would anyone NOT design, certify, and build an autonomous aircraft control system, which–by definition–would eliminate the cockpit and the flight crew from an aircraft?
- Regulatory hurdles. Thomas Edison’s electric light bulb didn’t meet the regulatory requirements for candle-wax purity.
- Labor objections and resistance. Don’t take away my job! And fanning the flames of these next two:
- General-public anxiety. Everything from Chicken Little to SkyNet.
- Passenger anxiety. Two things will quickly mitigate this: successful cargo service, and low seat prices.
Mama, don’t take my Kodachrome away
From my cold dead hands! The advent of autonomous aircraft will NOT result in the prohibition of our beloved hand-flown aircraft–any more than the advent of automatic transmissions resulted in the prohibition of stick shifts and clutch pedals. And I wouldn’t want it to. I enjoy abusing an airplane, just as much as the next guy/gal does. Most of all, I still treasure training new pilots. It’s the most fun that I still can have with my clothes on.
Tom Yarsley is a retired international-award-winning design engineer, who spent 45 years on the bleeding edge of commercial and military technology, in aerospace, marine, environmental, entertainment, and telecommunications applications. His specialties include business-process-automation, and radiation-hardened mission-critical autonomous control systems. He is a multi-thousand-hour pilot and flight instructor, whose greatest joy is giving primary instruction to aspiring aviators. Yars has been described as having “a face that’s perfect for radio.” A volunteer at his high school alma mater for 54 years, he still can be caught behind a microphone at local sporting events.