Comment by tjlahr | Hacker News Reader

Comment by tjlahr | Hacker News Reader

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I was thinking about this the other day. To me, the future is decreasing the amount of coordination that happens verbally over VHF.

Ignoring takeoff clearances for a moment, my limited understanding is that most traffic in and out of an airport follows a prescribed pattern: You take off, turn to some particular bearing, climb to some particular altitude, contact center on some particular frequency... etc. Listening to VASAviation, it seems like this accounts for > 80% of pilot-controller communication.

It's strange to me that, given the amount of automation in a modern airliner, these instructions aren't transmitted digitally directly to the autopilot. Instead of the controller verbally telling the pilot where to go, it seems feasible that the controller (or some coordinating software) could just digitally tell the plane where to go.

I feel like that's how you dramatically decrease workload on both ends, and then maybe there's more bandwidth to focus on those takeoff clearances (and eventually automate those as well?).

So many other aspects of flight safety have been handed over to the computer to solve, it's curious to me why a critical function like air traffic control still happens verbally over VHF.

There are STAR and SID procedures that are 90% of what you're proposing. A pilot is at the top of descent and is told "Descend via the SID" which takes them to final approach.

As a pilot, I am surprised by how important audio communication is for retention and awareness. Given that my visual senses are (nearly) overwhelmed with information, I think there is a risk that moving ATC from audio to visual would simply saturate the "visual channel" of pilots.

In terms of automating coordination, it's obviously possible but it would take decades to prove its relative safety. (Aviation is extremely safe.) The system would be very fragile, unless you had 24/7 fully staffed backup human ATC, which rather defeats the purpose. Practically speaking too, planes take a long time to build, and the current system allows planes built 80 years ago to fly alongside brand new ones. The cost of abolishing the 'legacy fleet' (i.e. all current passenger aircraft) is pretty high!

Speaking as a pilot for a moment, I think your instincts are correct in theory but hard to actually implement.

In a critical function like control, you don't want to split a pilot's attention. You wouldn't want them to sometimes be monitoring a datalink system, but then also sometimes be listening to the radio for deviations. Even if it's less efficient 70% of the time, you reduce cognitive load by training a pilot to ALWAYS go to the radio for clearance and command.

Of course, there are edge cases these days where pilots use datalink for some clearance delivery before taxi and enroute, but you can see how these phases of flight (before you push back and after the auto pilot is on) are selected for very low competing load. In a live terminal environment, you want a pilot focused in one place for instructions.

Furthermore, you're correct that most pilot-controller communication falls largely within tight set of procedures, but deviations are common enough (weather, traffic, emergencies, hold patterns, taxi route, etc) that you find yourself on the radio regularly to sort it.

Last thing: pilots are allowed to say "unable" if they deem an instruction unsafe. I've personally had to do that many times (most common case for me is trying to comply with a vector instruction under VFR with a cloud in my way). VFR may seem like an edge case that commercial planes don't deal with, but again that's not always true in a terminal environment. Plenty of these planes fly visual approaches all the time. And if ATC is talking directly to the computer and not through the pilot, you lose the opportunity for the pilot to quickly and clearly decline an instruction.

I think this is ultimately true, in a sense, but the challenge is correctly handling all of the edge-cases. It's a challenging problem tantamount to the self-driving car problem.

It happens by humans over VHF because a lot of unpredictable things happen in busy airspace, and it would require a massive investment for machines to automate all of it.

I'm also not sure that people would accept the safety risk of airplanes' autopilots being given automated instructions by ATC over the air. There's a large potential vulnerability and safety risk there. I think there's some potential for automation to replace the role of ATC currently, but I suspect it would still be by transmitting instructions to human pilots, not directly to the autopilot.

Lastly, for such a system to ever be bootstrapped, it would still need to handle all of the planes that didn't have this automation yet; it would still need to support communicating with pilots verbally over VHF. An entirely AI ATC system, that autonomously listens to and responds by voice over VHF seems like a plausible first step though.

>Instead of the controller verbally telling the pilot where to go, it seems feasible that the controller (or some coordinating software) could just digitally tell the plane where to go.

An intermediate step would at least be transmitting those instructions digitally and showing it on a map that the pilot can follow. There have been a number of incidents where pilots misunderstood where they were, and incorrectly followed instructions.

A lot of glass panels these days will do this in the PFD. You get your clearance via datalink from ATC, it loads everything right up, and you just keep the plane in the box or turn the autopilot on once you're in the air.

Of course, this still keeps the pilot in the loop and ideally they will notice if something seems weird.

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