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Originally Posted by rpads1 My thought was more like, the car does not go on autocruise on its own, default is disabled and one has to explictly enable. |
Sure, but bear in mind these days cars have a lot of automated system that are always activated. Some you can switch off, some you can not or only partially.
ABS as a very simple one, and under certain (ice) condition it might well be preferred to have it switched off. You also never know if it will work when needed. In most cases it does of course, but occasionally these systems will fail and you might never notice until you brake on a slippery road.
Think about all these electronic limited slip differentials, electronic stability systems, all are always switched on. The car and handling were designed with everything switched on permanently. Some you might be able to disconnect, many of these system you can not or only partly disable.
Somebody, the design team, has decided for you what the performance of a car is going to be and how that will be achieved. And that includes some permanent electronic trickery these days.
Plenty of functions on an modern aircraft are automated. They hum away doing their thing quietly with nobody ever knowing. Some of it you switch on deliberately (e.g. an auto throttle, auto pilot, navigations systems). Some are on by default, e.g. by design.
In case of the 737 MAX the discussion is about whether the pilots should have known there was this MCAS device that was permanently switched on. (but only does it’s trick under very specific conditions). And there was a routine, non normal checklist that would disable it without the pilots knowing it. Because if this thing runs amok, it manifests itself as a runaway auto-trim (which it is). Disabling the auto trim correctly disables the auto trim system and the MCAS.
Whether Boeing should have told/instructed/trained pilots on the actual presence of MCAS is something currently hotly debated in aviation circles. We will just have to wait till the regulator (FAA) passes judgement.
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Originally Posted by rpads1 If use is over-riding the auto mode should it not let him over-ride and have preference over the controls. I do understand manual still means a lot of electronics is involved but at-least the input to the electronics is human and not an automated input driven by a sensor that could malfunction. |
You have heard of glass cockpits, no doubt. All main instruments you use to fly and all main indicators and annunciators are all on digital displays. Guess what all that information on what the plane is doing (altitude, vertical speed, airspeed, ground speed, drift, slip, attitude etc) are all derived from countless sensors and computers. So even flying manual these days, all your instrumentation is driven by banks of computers, systems, sensor etc.
If the input is wrong (in this case an incorrect AoA) it does not matter whether the autopilot is flying or the pilot as such. Because initially they will start to respond (to the faulty signal) in an identical way.
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Originally Posted by rpads1 Also whatever the level of automation involved, I think unless you know the exact logic it follows it would be very difficult to quickly grasp (in a panic situation) what is going on and how to circumvent it .
Do note, all my observations are theoretical and I have absolutely no exposure to the aeronautical electronics technology. |
This is a very relevant point when it comes to automation in general. Aviation, process automation, but for instance also driverless cars.
Slightly off topic, rarely spoken of, but the biggest challenge in driverless cars is actually this automation-human interface in case things go wrong. At the best of times it takes an average person some time to respond to an emergency. If you were head down reading your iPad and suddenly the computer yells at you to look up and take control it will take considerable time.You have no situational awareness. You are startled, you need to look up, look around, figure what is wrong, decide what action to take and execute.
People are very poor at this sort of thing. Say you are driving at 72 km/h, which is 20 m/s, this could easily take 2-4 seconds, that means the car has already driven 40 to 80 meters before any action starts happening.
Pilots, well, at least commercial pilots are selected to be much better at this sort of stuff than the average person. Also, they get trained in all sorts of scenario. The have all kinds of routines and procedures drilled into them, memory items, checklist etc. As mentioned before take off and landing are the most crucial phases of a flight (most accidents happen during these two flight regimes). But it is a relatively short space of time, they will be very focussed and concentrated. So if anything goes wrong whether they fly manually or have engaged the autopilot the response time is minimal and they will have / should have excellent situational awareness. For instance, on a Boeing doing an autoland the pilot flying will have one hand on the yoke and one hand on the throttles. The autopilot (lots of computers) has actual control of the plane and it moves the yoke and throttle accordingly. The pilot’s hand follow though to what the computer is telling the controls to do. It enhances his situational awareness. If he needs or wants to take manual control, he pushes a little button on the yoke under his thumb and he disconnects the autopilot and takes manual control. Very little lag/response time.
(not sure how this works on an Airbus, the side stick doesn’t move, not sure about the the throttles.)
Once you are in cruise things tend to relax a little more. Also, if anything does go wrong, usually you have a little more time to figure out what it is.
Say for arguments sake that in the case of the Lion air crash, the crew really messed up. If they had just followed the procedure and handled as if it was a runaway auto trim, that would have been the end of it.
If you are in charge, what would your recommendations be narrowed down to three simple options:
- Train/instruct pilots better and more?
- Automate less, because obviously one crew could not deal with it
- Automate more, in order to exclude human error in this manner
It is probably fair to say that all three will improve the chance of this never happening again. Neither of them will be able to provide a 100% safeguard. Most likely the more automation option gives a better improvement over the first two.
These things are hugely complex, but less automation is not necessarily the best solution.
Jeroen