From a very naïve perspective, why isn’t air traffic control a solved problem?
Would love to be educated here, but it seems like there are just not that many moving pieces per airport (<10,000) and all of them are tagged with transponders, etc. And a human in the loop with respect to coordination might be the biggest source of risk.
This all seems like queuing theory and collision avoidance, which are very well done by computers.
Worked in this area for a couple of years. We have automated collision avoidance systems and have for years. But things can go off nominal fast and you don't want passenger aircraft making drastic maneuvers that fast. Because conditions can change so fast, queueing theory isn't that useful either. It's useful for more strategic as opposed to tactical air traffic control, what we call air traffic flow management. There's been a ton of research in this area for decades, for example at the National Center of Excellence in Aviation Operations Research (NEXTOR) and at NASA's Aviation Systems division. I could say a lot more offline about why, in my humble opinion, progress has been unbelievably slow, but the short answer is that it's government plus modern day academia operating in an environment where funding is low and risk tolerance is lower.
I'd suggest looking at Admiral Cloudberg's recent analysis of the Jan. 2025 airliner/military helicopter collision in Washington DC. It's a study in the difficulties of air traffic control in the 21st century and the reality of transponder usage, complicated by an overwhelmed airport and legislative indifference. Transponders aren't universally used, technology and people aren't perfect.
This one is long; I suggest reading the first chapter, then skipping to chapter 7 for the important parts of the story.
Weather conditions, ground/runway conditions, obstructions, mechanical issues. There are tons of edge cases with huge consequences for error. Same reason self driving is not a solved problem, but with dramatically less tolerance for error.
But it feels like planes have a huge advantage in that they all have trackers constantly broadcasting their location to one another. Almost like they are working as a team compared to FSD systems which are limited to a small range of self collected info from vision/lidar.
Not that it can ever be fully automated but it seems like much easier problem to solve.
Doesn’t meaningfully change the answer. There are still tons of edge cases with catastrophic failure modes. The transponder won’t tell you about the alligator on the runway, a vehicle where it shouldn’t be, unexpected braking action, a mechanical problem, or a plane not doing what it was cleared to do. Tracking the planes is the easy part.
The reasons we haven't automated air traffic control are similar to the reasons why we still have pilots in the cockpit even though we technically don't need to some of the time.
The thing is... not everything you need to track, not even all airplanes, will have transponders.
Sometimes the transponders will be faulty, sometimes you have to direct a broken aircraft safely to the ground with no transponder available.
And sometimes you are doing ATC for a zone that does not, in fact, require transponders (those are required only for the strictest controlled zones, not in general)
My impression is that it's at least partially down to how brittle a fully automated system could be. You want as much of a "manual" backup as possible, and that only be achieved by doing things manually all the time to keep up practice. With the current system, even with enormous degradation (massive power outages, cyberattack, software flaw, etc.) it's possible to get planes out of the sky without much risk. If a fully automated system fails, it's an enormous disaster.
The other problem is that the "worse is better" arrangement where ~everything is done via voice over radio makes automation difficult. Voice is simple, universal, and enormously flexible, but hard for computers to handle systematically. Some two-way protocol and associated pilot UI would be useful... but then you have to decide on that protocol and UI, every manufacturer has to implement it, every airline has to buy it, and every pilot has to be trained. Unless it's very, very clear what the optimal solution is and that the benefit outweighs the cost, that sort of coordination is difficult.
(And remember, the ultimate result of such a change would be a rigid system that is difficult to change, more fragile, and does not save much money relative to the total cost of the airline industry.)
It's not only a dangerous assumption, it's simply incorrect. Transponders on aircraft are not required in most of the US, including around Class D towered airports unless operating within a designated Mode C veil or at/above 10,000 feet MSL.
Consider the ratio of air traffic controllers to the number of people moving through the airport. It's not a huge cost. There's often far more staff moving bags.
It was a problem at very rural airports, and now some people man those remotely.
Would love to be educated here, but it seems like there are just not that many moving pieces per airport (<10,000) and all of them are tagged with transponders, etc. And a human in the loop with respect to coordination might be the biggest source of risk.
This all seems like queuing theory and collision avoidance, which are very well done by computers.