Some kind of 'safe return to (air)port' can probably be implemented without too many changes on the ground - it's basically the same as radio failure: start squawking no radio/emergency, send a few CPDLC messages to the same effect, and then line up and land at the most convenient runway and approach expecting ATC to keep stuff out of your way.
Navigation following GPS failure is going to be a reasonably big open question, but I don't think it's insurmountable, especially with a decent number of NDBs and ILSs available.(edit: Better detection of GPS spoofing and sanity/integrity checking of GPS data is essential, regardless of whether automation increases or not. Differential GPS amongst multiple receivers is I think near impossible to spoof without essentially fake satellites, and you accurately know aircraft orientation as a bonus)
Eventually, I would expect to see a system akin to cab signalling/moving block signalling as used on railways. Instead of just giving you vectors or instructions, ATC gives you blocks of airspace and times you can occupy them, with protections that mean it's impossible to clear two aircraft to be in (nearly) the same airspace at (nearly) the same time. Essentially how NATS is handled but you can slice-and-dice it much more tightly if it's automated. Once you have that, it will be much easier to automate normal flight.
The big long-term question is IMHO whether full-authority one-pilot operation is even acceptable due to e.g. Germanwings: it doesn't matter how many redundant computers, IRSs, and radios you have if the pilot can start pulling breakers to force direct law. I think you're going to find that the avionics bays (plural) are sealed in-flight, and the computer will be effectively 'captain' (whether the pilot is flying or not) unless it decides the flight is unsalvageable or it has lost too much capability.
Long term, I think you might see remote control from a ground situation room as the mechanism to deal with severe emergencies or an in-flight upset, instead of pilots on board. There's enough bandwidth to get multiple good video streams and a lot of instrumentation, and you can have ~5 people involved instead of 1-2.
Last edited by Someone Somewhere; 9th April 2025 at 01:36.