More like a dog to gently nudge the pilot if he is relying on a system that isn't working. Most issues I've read about happened when the systems either weren't engaged properly or automatically disengaged because their operating parameters weren't met anymore, suddenly forcing the pilots to take control.
Example Air France 447, where (presumably) the airspeed sensors where blocked by ice, which lead to the autopilot to disengage. There is also the theory that the pilots then made some of their mistakes based on the belief that the avionics would stop them from bringing the plane in an unsafe state and didn't realize that the system wasn't able to do so with missing information. (I hope I'm presenting this correctly, but that's what I remember reading afterwards)
There is also the training aspect: if a system takes care of something 99,9% of the time, the pilot is less experienced in the 0,1% where it doesn't. There is a reason the safest airline pilots often fly way smaller aircraft as a hobby and get some instinct for manual flying there.
I think the main problem with aircraft is lack of redundancy. They still count on the ability of letting the pilots control the aircraft (e.g. .1% of the time as you mentioned), I think they should just try to go all the way as much as possible. For example, if they had 4 redundant pilot tubes on different places and other redundant methods to measure altitude and airspeed the AP would never have disengaged. For a large plane those sensors are basically free, and it's very easy to tell whether they're working correctly by cross-verification/calibration (i.e. maintenance/reliability is easy) -- they just don't go all the way because they're still on the paradigm that "well if a couple pilot tubes and/or other systems fail we can just hand it to the pilot".
>> I think the main problem with aircraft is lack of redundancy. They still count on the ability of letting the pilots control the aircraft (e.g. .1% of the time as you mentioned), I think they should just try to go all the way as much as possible.
I'm not an airliner pilot, but I have the impression almost everyone is always grossly underestimating how often a human pilot is still required to safely fly a commercial airliner. Yes, the autopilot may be able to handle 99% of the flights without intervention, or even 99.9% of the flights, but simple math shows that that means there are still tens if not hundreds of thousands of flights every day where the pilot needs to take action, and that any individual pilot will get into a situation where the autopilot will fail to handle a situation probably once or twice a year. Likely a lot more often.
Large parts of the world have weather conditions, diversions, or airports with spotty or unreliable ground systems by the way, in those areas the need for a human pilot will be several times higher than once every hundred flights. There's ample examples of plane crashes that were caused by automated systems, rather than pilot error (I don't remember the exact location and date, but I know that e.g. not very long ago a plane crashed because the ILS beacon at the airport was malfunctioning). In other cases the level of automation enabled lousy pilots with bad training to fly the airplane (case in point: the Air Asiana crash at SFO), which IMO is not 'pilot error' because these people should not have been flying the plane in the first place.
All this makes me think the solution to improve airliner safety even further is not more automation, but better pilot training.
As for autonomous driving, besides AI assisted highway cruising, I don't believe in the concept at all, and my bet is that in 25 years we've realized that we've been wasting most of the time trying to build fully autonomous vehicles. Limiting the possibilities of driver error seems like a much better investment (e.g. automatic cruise control, automatic emergency braking, etc).
Modern aircraft have excellent redundancy. Commercial aircraft already typically have 3 Pitot* tubes and 3 static ports. They need unobstructed airflow and are placed accordingly. In this kind of aircraft they do cross-verify each other as well, but if they all are reading different values, there's not much to be done. Conditions were such on AF447 that they all experienced some amount of icing until the aircraft descended enough. I don't see how having one more pitot tube is the proper response.
Well clearly having altitude/velocity readings is critical to autopilot function, so some kind of redundancy should be put in place. Not necessarily specifically more pilot tubes, but some kind of solution, like heating/deicing the tubes inlets, better placing them, etc -- guaranteeing in some way the chances that all measurements are unavailable is astronomically low.
"For example, if they had 4 redundant pilot tubes on different places and other redundant methods to measure altitude and airspeed the AP would never have disengaged."
There's a lot to be said for that. The pilots didn't know their altitude and airspeed either. They thought they were overspeeding when they were stalling.
Some military aircraft, mostly the stealth ones with terrible aerodynamic stability, need that sensor data to stay in the air at all. If they lose the sensor data or the stability control system, the only option is to eject. So they tend to go in for more sensor redundancy. There's certainly no reason that large transport aircraft can't have more sources of basic attitude/altitude/airspeed info.
That sounds like a UI issue. Like, it shouldn't be too hard to put a blinkenlight on the control that indicates it's under autopilot control (or the absence indicates it isn't).
There was also a stall warning that shutoff when the pilot pulled up because it no longer had reliable info, the pilot assumed pulling up was somehow stopping a stall
Wasn't there also the problem with other pilot pushing down in panic, rudder being so enclosed that nobody noticed, and the fact that plane averaged the two inputs?
There is no basically in an aircraft accident. If you wish to make such a statement, please explain what actually happened in this flight (icing of the pitot tubes, deactivation of normal flight control law for the fly-by-wire system, flight at night over the ocean and over a storm, stall under the specifications for the stall warning system). It's respectful for the crew.
There's an old joke about a pilot lost in a deep fog who shouts out the window "Where am I?", hears in response "You're in an airplane!", and immediately realizes that he is over the Microsoft tech support building, because no one else could be so accurate and so useless at the same time.
That's what you're doing here. Saying "the copilots crashed it" teaches us nothing; we need to know why they crashed it, what cues they misunderstood and what skills they lacked, so we can keep it from happening again.
Example Air France 447, where (presumably) the airspeed sensors where blocked by ice, which lead to the autopilot to disengage. There is also the theory that the pilots then made some of their mistakes based on the belief that the avionics would stop them from bringing the plane in an unsafe state and didn't realize that the system wasn't able to do so with missing information. (I hope I'm presenting this correctly, but that's what I remember reading afterwards)
There is also the training aspect: if a system takes care of something 99,9% of the time, the pilot is less experienced in the 0,1% where it doesn't. There is a reason the safest airline pilots often fly way smaller aircraft as a hobby and get some instinct for manual flying there.