Naked Science Forum

Non Life Sciences => Technology => Topic started by: Geezer on 30/07/2011 00:57:51

Title: Are aircraft "overautomated"?
Post by: Geezer on 30/07/2011 00:57:51
Reading the latest on Air France 447 reminded me of some prophetic statements I heard some time ago. I can't remember who it was that said it now, but their concern was that a lot of automation might result in a situation where the crew is so overwhelmed with data that they forget to fly the aeroplane.
Title: Are aircraft "overautomated"?
Post by: CliffordK on 30/07/2011 03:04:59
I must admit that cockpit photos show a bewildering array of dials and gauges.

Die Hard 2 was about terrorists that captured an airport and apparently changed the elevation readings, and thus none of the planes could land.  That may not be a realistic scenario, but does bring up an risk of having too much automation.

I think for the most part, the automation, sensors, and etc are all good.  I do have to wonder if they are over-sensitive to things like cell phones and computer WIFI, but they can work on better protecting their aircraft electronics.

However, if something goes very very wrong, I would hope there are good pilots on board.

There are many fields where 99% of the procedures are routine.  But, there is that remaining 1% of the time that really needs someone smart at the moment when it is needed.
Title: Are aircraft "overautomated"?
Post by: Geezer on 30/07/2011 04:49:34
Sadly, based on the little that I have read, I suspect that the crew were so bewildered that they didn't believe any of their instrumentation.

It's been suggested that abberations from the airspeed indicators confused the automatic systems. However, if that was the case, it should not have affected the basic attitude and altitude readings that are essential to flying any aircraft, particularly at night.

There could be a great danger in relying too much on automation. Automatic systems can do a wonderful job in all the test scenarios that proved them worthy. However, as soon as you introduce an unanticipated test scenario, they may well collapse.

There is still an enormous difference between artificial intelligence and human intelligence. Automation is a great tool, but it's no substitute for a human when things go "off the map".

 
Title: Are aircraft "overautomated"?
Post by: Don_1 on 01/08/2011 08:44:54
Coming down to Earth somewhat, but still relevant, I recall a company which made power steering units for the auto industry. So confident were they in the automation of their production process, that they began to replace their skilled workers with unskilled workers who they taught to use the machines 'parrot fashion'. The problems soon started to arise, when things went wrong with the production and the company had no skilled workers to identify the problems, let alone put them right.

Automation is all very well, but we still need human skills to keep a check on the machines.
Title: Are aircraft "overautomated"?
Post by: np_complete on 06/08/2011 21:29:56
" I can't remember who it was that said it now, but their concern was that a lot of automation might result in a situation where the crew is so overwhelmed with data that they forget to fly the aeroplane."
I believe the term that you are referring to is "information overload" ;-)

Whilst your question is interesting, one should note that "automation" isn't related to automation - it is related to information acquisition - whether automated or not. In fact, if used correctly, automation can avoid information overload and improve situational awareness of pilots through decision support and/or filtering of incoming data.

Orasanu and Martin wrote an excellent article on the subject: “Errors in Aviation Decision Making: A Factor in Accidents and Incidents” , HESSD, 1999.
Title: Are aircraft "overautomated"?
Post by: Geezer on 06/08/2011 23:21:45
" I can't remember who it was that said it now, but their concern was that a lot of automation might result in a situation where the crew is so overwhelmed with data that they forget to fly the aeroplane."
I believe the term that you are referring to is "information overload" ;-)

Whilst your question is interesting, one should note that "automation" isn't related to automation - it is related to information acquisition - whether automated or not. In fact, if used correctly, automation can avoid information overload and improve situational awareness of pilots through decision support and/or filtering of incoming data.

Orasanu and Martin wrote an excellent article on the subject: “Errors in Aviation Decision Making: A Factor in Accidents and Incidents” , HESSD, 1999.

Actually, I am referring to automation. Modern aircraft are so extensively automated that the crew don't have much oportunity to actually fly the plane. In fact, one of the main problems they face is boredom. Consequently, when things go wrong, and the automation shuts down, their lack of experience can cause problems.
Title: Are aircraft "overautomated"?
Post by: CliffordK on 07/08/2011 07:20:33
One of the problem that has happened to Toyota is that they are now disconnecting the controls from the actuators. 

In every car I've ever owned, there was a cable, wire, or linkage going from the gas pedal to the carburetor or injection pump.

That is no longer the case.

The gas pedal goes to an analog to digital converter to a computer which then sends a signal to the engine to increase or decrease the fuel.  And, it should have something where if you press the brake, it should send a signal to cut the gas.  But, somehow that wasn't working right.  And, something was sending a signal to the engine "wide open accelerator", when in fact it should have been sending "shut down".

On the older vehicles, there was an ignition switch on the dash.  But, the new ones all have it integrated into the steering column.  And, while one may be able to shut off the engine and still steer, I certainly wouldn't want to test it in an emergency situation.

For the first time in my life, I've managed to get a couple of vehicles with automatic transmissions (given to me).  One thing I've noticed is that it is impossible to coast-start the vehicles.  If the engine stalls for whatever reason, one MUST put it in park to get it going again.  I.E.  if one is rolling, one can't pop the clutch, and one must fully stop the vehicle before even restarting with the key.

Anyway, with the small Cessna - type planes, one might have a physical cables connecting from the cockpit controls to the rudder and elevators.  I believe that is done electronically in the newer planes, with the potential for more and more distance between the pilots and the controls.

Here are some notes about the rudder power control unit malfunctioning and causing crashes (presumably).
http://en.wikipedia.org/wiki/Boeing_737_rudder_issues

Of course, you couldn't expand a Cessna into a 747 without some additional electronic control aids.

Ahh... here is what I was looking for.  The "Jackscrew" problem.
http://en.wikipedia.org/wiki/Alaska_Airlines_Flight_261

I suppose my question is whether there is adequate feedback between the cockpit controls and the ailerons and controls.  With the Cessna, if the controls partially fail, it would likely give immediate tactile response to the pilot, although, not necessarily early enough to remedy the problem. 

Here are some more notes about control systems and elevator failures.
http://www.airlinesafety.com/faq/faq10.htm

The last note from that page is particularly distressing as it failed to have a seamless transition from autopilot control to pilot control, nearly causing a crash.

Quote
1985, February 19:   

A B-747 SP, flown by a China Airlines Capt., suffered an engine failure while cruising at 41,000 ft.  The Capt. left it on autopilot too long.  The autopilot tried to maintain that altitude, which was ultimately impossible at that weight, with only 3 engines functioning.  As it approached the stall, because the speed kept decelerating, the Capt. finally disconnected the auto pilot.  He was not prepared, because he had failed to trim in rudder to compensate for the asymmetrical thrust condition; the autopilot was maintaining wings level by the use of aileron and spoilers only.

[Autopilots normally do not control the rudder in climb, cruise, or descent.  They use only the ailerons, spoilers, elevators and horizontal stab trim.]

When he hit that disconnect switch, the plane rolled rapidly and entered a dive.  Although the plane exceeded the speed of sound, tearing parts off and causing major structural damage, the Capt. was able to make a recovery at a few thousand feet over the Pacific Ocean, after he broke out of the clouds and could see his attitude via outside visual reference.  There were, incredibly, only two serious injuries to the 274 passengers and crew.

I suppose, as the planes get larger, and more complex, the more automation is necessarily required.  But, it certainly must be approached with caution.
Title: Are aircraft "overautomated"?
Post by: graham.d on 07/08/2011 09:03:50
You sound like a bunch of Luddites :-) I agree with np_complete that there is some confusion in the discussion between full automation and efforts to reduce complexity of information presentation. The facts are that air accidents have trended down significantly since a peak around 1980 despite the increase in air travel. Also most accidents are down to pilot error. Of course caution is needed when introducing automation; in fact caution is needed when designing any safety critical device. The reason Airbus Industries have introduced greater automation is that they have a view that in emergency situations the flow of data can be too great for a human to respond to. Crudely, the pilot can still take over but the default is with the automated systems. As has been discussed before, it is doubtful that the pilot who landed safely on the Hudson River, following a bird strike, would have been able to do so without the automated flight controls afforded by the A320 aircraft.

I agree that pilots should still get practice and be able to fly when needed and they do, and I believe are required to, manually fly and land aircraft periodically. I reckon I can tell the automated landings because the approach requires fewer corrections and the landings are usually much smoother putting less stress on the aircraft's landing gear!

And frankly, when car driving is fully automated (and it will be eventually) I would expect a significant decrease in accidents despite faster journey times. Bring it on!
Title: Are aircraft "overautomated"?
Post by: np_complete on 07/08/2011 10:26:22
@Geezer: I respectfully disagree :-) As graham.d (and pretty much all scientific literature on the topic of aviation accidents) pointed out, the primary cause for accidents is human error (of which one causation tends / tended to be information overload - which is due to data acquisition not automation).

Actually, I am referring to automation.

"Modern aircraft are so extensively automated that the crew don't have much oportunity to actually fly the plane. In fact, one of the main problems they face is boredom."
In fact even on autopilot, pilots are a busy out: for example RyanAir (and all other European airliners) require complete cross-checks to be made every 15 minutes. Not too much time for boredome.


"Consequently, when things go wrong, and the automation shuts down, their lack of experience can cause problems."
Except that this was never the case - critical systems are designed with redundancy, graceful degradation, n-version development etc etc in mind - there has never been a case in which an ENTIRE critical system failed atomically.

With regards to their "lack of experience": Airline pilots are required by (European) law to undergo simulator tests (which also involve "manual" piloting) every six weeks to eight. Failing one of these tests will cause you to lose your job.

"Reading the latest on Air France 447 reminded me of some prophetic statements "
I don't mean to sound like a *****, but this isn't even remotely releated to your argument with regards to automation :-) Basically what happened was that the pitot tubes iced over during, giving false altitude / airspeed indications. This is a relativly common occurence, and there are well defined procedures for dealing with this. The junior pilot (the captain went to rest - which too, is a common procedure for long distance flight) seems to failed to follow these procedures. So, in essence, the accident is due to an overconfidence bias on behalf of the pilot as opposed to an over-automated cockpit lulling him to a false sense of security / experience. And who knows? Maybe an on-board decision support system could have helped him follow procedures.

Yes, your argument of inexperience stands - but I fail to see how automation correlates with inexperience.


@graham.d: " The facts are that air accidents have trended down significantly since a peak around 1980 despite the increase in air travel. Also most accidents are down to pilot error. Of course caution is needed when introducing automation;"
Very good point - as anectodal evidence we could also point towards the maritime industry - one that is often the least automated transport sector. Even within US and European coastal areas (which are deemed the safest in the world), accidents are skyrocketing. In Europe alonge, 624 merchant vessels (500 - 5000gt category) were involved in 540 accidents (groundings. collisions, fires) - in most of these, a simple heading prediction on part of the VTS would have prevented injuries, loss of lives and millions worth in damages.
Title: Are aircraft "overautomated"?
Post by: SeanB on 07/08/2011 17:37:13
Also remember that in the AF case the system did not fail gracefully, but the erroneous speed and altitude input eventually caused the system to disconnect and leave all input to the pilot suddenly. It still gave false information, and there was no other way for the pilot to determine the correct from the incorrect information. The icing problem was known, but it was low priority, and there was not enough caution given to pilots as to weather that would lead to icing as a thing to be avoided. This was aggravated by the high altitude, where the plane is in a narrow safe flight speed range to stay in, and where the icing caused the aircraft to leave this safe speed, whilst still showing the speed was correct.

A case of automation being good, but that it was driven mostly by wanting to remove the most expensive item in the cockpit, the third pilot/flight engineer.
Title: Are aircraft "overautomated"?
Post by: Geezer on 07/08/2011 17:58:41
No reason to get so defensive guys  [:D]

The automatic system didn't fail, but it was incapable of handling the particular set of circumstances presented to it, so it handed control back to the crew. It appears they didn't know what to do under the circumstances either. It's always easy to second guess a situation after the fact, but I get the impression that AF447 need not have plunged into the Atlantic.

Call it an over-dependence on automation if you prefer, but it has been a concern in the airline industry for some time. Of course, we can always stick our heads in the sand and pretend everything is just fine the way it is.
Title: Are aircraft "overautomated"?
Post by: graham.d on 07/08/2011 18:46:08
I think the airline industry's concern revolves around the competing marketing of Boeing vs Airbus Industries. Boeing have been playing catch-up and have been trying to knock Airbus Industries' more automated approach.

Nobody would suggest that issues should not be addressed, especially when there has been a major accident, but it would be wrong to blame a whole concept rather than to take an informed approach as to what aspects need to be improved.
Title: Are aircraft "overautomated"?
Post by: Geezer on 07/08/2011 19:14:18
My question had nothing to do with Boeing v Airbus. I suspect the circumstances that affected AF447 could just as easily have affected a Boeing aircraft.

It's a general question about what happens when things become highly automated, and it probably applies to all sorts of systems. Unless we can take automation to the point where the crew is no longer required under any circumstance, we need to maintain the right balance between the actions of the automatic systems and the actions of the crew.
Title: Are aircraft "overautomated"?
Post by: graham.d on 07/08/2011 21:06:35
You're right about your initial question. These issues do have to be addressed with care and caution. It just seemed that the discussion was tending towards a retro=better approach :-) As I suspect many of us are of a similar vintage, it can appear rather negative to a younger reader. And I do think that, in the case of aircraft systems, much care is taken; I think the improving record regarding aircraft accidents verifies this. In any case, whatever forethought is put in, we all know it can never be 100%.
Title: Are aircraft "overautomated"?
Post by: Geezer on 07/08/2011 22:10:17
Oh! Retro would not work. You couldn't hope to fly a modern aircraft without all sorts of automation working properly. The concern is that the crew becomes too detached from the workings of the aircraft and, in exceptional circumstances, they don't have the experience to make appropriate decisions.

More automation is inevitable, and I don't know what the solution is. It may actually be better automation, or a slightly different paradigm. Call me an old fuddy-duddy, but personally, I'd be happier if the instrumentation and controls in the latest aircraft looked more like an aeroplane and less like a video game.
Title: Are aircraft "overautomated"?
Post by: graham.d on 07/08/2011 23:14:49
Here are a few views of aircraft instruments:

This is an A380:
http://www.gillesvidal.com/blogpano/cockpit1.htm

And here is a modern 737-800:
http://www.aviafilms.com/photos/boeing-737-800-cockpit.jpg

This is an older 737:
http://aviafilms.com/photos/old-737-classic-cockpit.jpg

For comparison, here is a Cessna-150:
http://aviafilms.com/photos/cessna-150-instrument-panel.jpg

When I was learning to fly many years ago, I found (even then with the simple craft I was flying) that the hardest part was managing all the information. The actual flying of the aircraft was the easy bit. It got easier with time but it was still tricky if something disturbed the routine. I really can't imagine how pilots manage these beasts with all the data they have to deal with. When I had a go in a Phantom simulator last year, it surprised me how simple the controls were and how very ergonomically they were arranged. I guess that, in the case of a Phantom, this was a distinct policy and also the design is rather old.

Modern aircraft are rather similar to a computer game. But people can get quite good at playing these games too. It's a matter of practice and having a degree of natural ability and, I have to say, being young helps.
 
Title: Are aircraft "overautomated"?
Post by: Geezer on 08/08/2011 01:20:09
I see the 787 retains the more traditional "steering wheel" arrangement - not that it's mechanically connected to anything!
Title: Are aircraft "overautomated"?
Post by: Geezer on 09/08/2011 05:09:21
According to this there was a standby airspeed indicator on AF447 that seemed to be working properly.

I wonder if this gent is correct, or does he have an axe to grind?

"The crash illustrates “another aspect of automation confusion,” according to Greg Feith, a Colorado-based industry safety consultant and former crash investigator for the U.S. National Transportation Safety Board.” The A330′s automated systems were “based on the concept that pilots would never get themselves into the position” in which they ended up on Flight 447, Mr. Feith said. So the sequence of events “defies all the logic built into the automation.”

http://uprta.org/wsj-air-france-crash-report-likely-to-alter-pilot-training/
Title: Are aircraft "overautomated"?
Post by: Geezer on 09/08/2011 08:09:23

Airline pilots are required by (European) law to undergo simulator tests (which also involve "manual" piloting) every six weeks to eight. Failing one of these tests will cause you to lose your job.


Jolly good, but apparently it's only recently become possible to simulate stall conditions. Unless they were trained to recover from a stall with a real aircraft, pilots only have the benefit of the correct theoretical response to a stall.
Title: Are aircraft "overautomated"?
Post by: graham.d on 09/08/2011 09:51:37
I find it hard to believe that they do not train pilots on stall recovery because the pilots "would never get themselves into the position". The systems may have given ambiguous data but there is little doubt (for any pilot) about a stall warning and the procedure is the same on all aircraft - which is to push the nose down and increase the airspeed. The fact that there is a stall warning system means the aircraft has been designed with a potential stall in mind so it is astounding that there is no specific training via a simulator. Airspeed indicators can go wrong in a stall because the airflow over the detectors can become turbulent and periodically disrupted; they were probably falling quite fast but not always so the airflow was parallel to the aircraft and the airspeed indicators will not work properly in this case. There would be no doubt about the altimeter's rate of descent though. I'm also surprised that they could not get alternate data on speed (not exactly airspeed but probably a close enough indication) from a GPS system though I expect that there may have been a degree of panic.

The pilot's responses seem to be poor no matter what the aircraft was. It seems a very elementary mistake to make. A corrollary to arguments about over-automation is that it leads to not requiring skilled operators (pilots in this case). The comment about the need for more training is a key point though it should also be mentioned that it needs people with the right inherent skills too. This statement may considered non-PC today but not everyone is cut-out to do any job and one hopes that the dumbing down of the requirements, in this case to be an airline pilot, does not go too deep.

I am surprised that the aircraft systems could not have recognised a stall and got out of it automatically - there was plenty of altitude to make a recovery. Clearly a major software bug! Or maybe the pilot had switched to manual control on some systems. It will be interesting to see the final report.
Title: Are aircraft "overautomated"?
Post by: SeanB on 09/08/2011 12:22:05
Airbus does not allow any switch to manual operation unless the triply redundant control system cannot agree, and declares itself failed. This removes all of the augmentation and limit controls built into the system. It seems a failing was having all the air data feeds coming from a single probe, it would have been better to have had 2 ( even if one was not ideally placed, but was able to provide some meaningful data) or more input sensors, 3 better, provided the input is provided to each component of the flight computer and each can vote as to what it considers a valid input. Still not a good idea to rely on this instead of having a proper rated heater, and even better a 2 stage heater and thermostat, that is capable of detecting potential icing conditions and switch to a high power deice mode for a short while ( hey, I should patent this, but now it is Public Domain) to clear the ice.

As to training for stall on real aircraft, remember that certain aircraft ( MD80 AFAIK, but any T tail will do) is quite capable of stalling and staying stalled in the "right" wrong stall area, as the control surfaces are then in a turbulent airflow, and have no or little effect. Better to train in a simulator where you can practice recovery using engine power, as these stalls often are going to require more altitude than what they have to recover.
Title: Are aircraft "overautomated"?
Post by: graham.d on 09/08/2011 15:09:54
Sean, I had a look at the training manual and the situation they were in seems quite well covered. It says that the airspeed indication will be unreliable in a stall (I think there are three sensors) and actually recommends using GPS data as I suggested (I had not read this before). It has got a de-ice facility and has a procedure for getting out of a stall situation. I feel these must have been practiced if they are in the training manual but, in any case, they do not seem unusual.

Some aircraft are difficult in a stall as you say, and powering out is usually recommended. I am not sure whether that is necessary in this aircraft but thrust is recommended in any case.
Title: Are aircraft "overautomated"?
Post by: Geezer on 09/08/2011 17:04:10
I noticed on that website there's is a bit of a rethink going on regarding stalls. It says that, traditionally, too much emphasis was put on maintaining altitude. Perhaps that explains why the junior pilot on 447 initially tried to pull the nose up.

It also strikes me that there is a lot of circular thinking going on. If simulators could not simulate a stall, how were the crew expected to be properly trained without stall training in a real aircraft? Seems to suggest a "well, we know that's never going to happen" mindset.
Title: Are aircraft "overautomated"?
Post by: graham.d on 09/08/2011 17:47:19
Where did you see that simulators can't emulate a stall? I find that hard to believe as it would not seem difficult (relatively speaking). When the aircraft stalled it was at considerable altitude so fairly safe from a ground impact. Well one would have thought so! I think actually that, for this aircraft, the recommendation is actually to increase thrust, level the wings and try to achieve a slight nose up attitude (this from memory of the lengthy training manual but have not checked). It looked like the manual did cover this situation but that the pilot did not follow procedure.
Title: Are aircraft "overautomated"?
Post by: rosy on 09/08/2011 17:57:51
Quote
Seems to suggest a "well, we know that's never going to happen" mindset.

Well, maybe.

To do live training they'd presumably have to genuinely stall a genuine plane. Probably repeatedly. The risk of accidental stalling is clearly a real one, and a stall of a loaded passanger plane which leads to a crash will likely lead to the death of several hundred people... but that doesn't necessarily mean that live training is the right thing to do.

If stalls in modern, highly automated planes are very rare, if for example there is a reasonable expectation that most pilots wouldn't encounter a stall in their career otherwise (and I have no idea what the stats are, but it must be something for which stats exist), more live training would not necessarily be expected to save more lives in the long run.. because if stall training killed a significant number of crews that would add up! (Leaving aside the fact that if pilots dropped several planes out of the sky in training, it might obviate the need for training entirely.. because it would put the public right off those models, I'd think!)
Title: Are aircraft "overautomated"?
Post by: SeanB on 09/08/2011 18:15:25
Most stalls occur in the region in which recovery is impossible - right near the ground, generally with some bad outcomes. Mostly too slow, to low and too little power. Most dangerous part of flying is take off and landing, and the part in between is generally pretty quiet, may be a little turbulent, but weather is worse nearer the ground and nearer the top of the flight envelope.

The AF plane was unfortunately operating at the edge, and the accident pushed it into a region that was supposed to never be entered as being a known danger. A combination of poor route selection and a known flaw in the plane design, which in the end resulted in the crash.
Title: Are aircraft "overautomated"?
Post by: Geezer on 09/08/2011 19:47:21

Where did you see that simulators can't emulate a stall?


I thought it was on that site, but I can't find now it either! I'll try to retrace my steps and dig it up. I was quite surprised when I read it too.

I'm pretty sure it's easy enough to simulate the stall. I got the impression that what was lacking was the simulators' ability to handle the recovery accurately.
Title: Are aircraft "overautomated"?
Post by: Geezer on 09/08/2011 20:03:38
Quote
Seems to suggest a "well, we know that's never going to happen" mindset.

Well, maybe.

To do live training they'd presumably have to genuinely stall a genuine plane. Probably repeatedly. The risk of accidental stalling is clearly a real one, and a stall of a loaded passanger plane which leads to a crash will likely lead to the death of several hundred people... but that doesn't necessarily mean that live training is the right thing to do.

If stalls in modern, highly automated planes are very rare, if for example there is a reasonable expectation that most pilots wouldn't encounter a stall in their career otherwise (and I have no idea what the stats are, but it must be something for which stats exist), more live training would not necessarily be expected to save more lives in the long run.. because if stall training killed a significant number of crews that would add up! (Leaving aside the fact that if pilots dropped several planes out of the sky in training, it might obviate the need for training entirely.. because it would put the public right off those models, I'd think!)

There does not seem to be much real stall training at all. I see some people are suggesting that there ought to at least be live training in trainer aircraft. (I can understand why the airlines would not be too keen to run the risk of pranging one of their nice aircraft.)

Is it true that an airliner at cruising altitude has to operate within a narrow window of parameters to avoid stalling?
Title: Are aircraft "overautomated"?
Post by: Geezer on 09/08/2011 23:43:43

Where did you see that simulators can't emulate a stall?


I thought it was on that site, but I can't find now it either! I'll try to retrace my steps and dig it up. I was quite surprised when I read it too.

I'm pretty sure it's easy enough to simulate the stall. I got the impression that what was lacking was the simulators' ability to handle the recovery accurately.

This is it, but it's not very clear how new the technology actually is.

"That’s because pilots are supposed to never allow a plane to reach a stall in the first place, and because earlier-generation simulators were not able to mimic a full stall.

But thanks to new simulator technology, “now you can put someone in a stall scenario and let them recover,” Babbitt said."

http://uprta.org/faa-to-seek-major-changes-in-pilot-training/

Title: Are aircraft "overautomated"?
Post by: Geezer on 10/08/2011 01:15:04
Sorry if I'm becoming a bit obsessed with this one!

If I remember correctly, accurate airspeed data becomes more critical at greater altitudes (because of reduced air density). That being the case, there should be no circumstances under which the automatic systems, or the crew, ever get suspect airspeed data.

Why don't they calculate it based on what the engines are doing? Would it not be possible to estimate airspeed from air density, turbine speeds and fuel consumption, or maybe they already do that?
Title: Are aircraft "overautomated"?
Post by: graham.d on 10/08/2011 08:57:21
The manual recommends (as I guessed at) using GPS data to get, at least, ground speed. The only problem with this is that at high altitude there can be a large difference between airspeed and ground speed because of the very high winds that can be encountered. In any case, if the stall warnings are going off then it is perfectly possible to increase the thrust and use the artificial horizon instruments to level the craft and to restore a safe flying attitude. It seems like the pilot did not believe the aircraft was in a stall but in a dive. It is a very fundamental error in any aircraft to believe your senses rather than the instruments. It is very basic training in light aircraft to NOT depend on your senses when recovering from a spin, for example, especially in low visibility situations.

Rosy, every pilot would have had some live training on a stall recovery in some aircraft though maybe not in every aircraft he is expected to fly. It should have been done in a simulator though but it looks like the early simulators did not cover this fully (from Geezer's post), which is very surprising, though the omission seems to have been corrected now. Every pilot should be aware of what to do in a stall though. It does look like a case of insufficient practice; the stall would have put the aircraft into an intermediate mode (alternate law, as opposed to normal law and direct law) between fully automatic and manual modes, as the feeds from the airspeed pitot tubes had become unreliable. I suspect he had too many things to think about - OK if you practice enough but not good if you have to look up what to do! We will probably never know exactly.
Title: Are aircraft "overautomated"?
Post by: Geezer on 31/08/2011 03:27:57
It ain't just me  [:D]

http://news.yahoo.com/ap-impact-automation-air-dulls-pilot-skill-070507795.html
Title: Re: Are aircraft "overautomated"?
Post by: alancalverd on 29/08/2022 04:32:17
Can't imagine why I didn't get stuck in to this one earlier! A couple of quick points:

Elementary stall training always takes the form of "nose down, power up",and every pilot will have done a fair bit of this in a trainer before progressing to first solo. The PA38 "Tomahawk" trainer was even designed to enter the deep stall and spin condition of a T-tail. Problem with the AF flight was failure to recognise the stall condition when flying on standard instruments, and possibly relying on autopilot altitude hold in turbulent conditions (this will stall most trainers). ALT HOLD is hardly modern automation, though.

The essence of all stalls is excessive angle of attack, hence AOA indicators on modern airliners - optimum lift/drag ratio (i.e. economic cruise) can occur quite close to the critical AOA.

But the problem with the 737MAX   was indeed excessive automation, coupling the faulty AOA probe directly to the stabiliser trim and not telling the pilot how to disengage it.

Success of the Hudson landing was nothing to do with automation but a lot to do with engaging the auxiliary power unit, thus maintaining electric and hydraulic services, and the fact that the pilot was a national gliding champion, with hundreds of "power off" landings to his name.

Not sure how far back other folks' memories go, but I have stalled some vintage simulators including an original US Navy Link  trainer and the last ever session in a Trident III. Very realistic, even into an incipient spin.
Title: Re: Are aircraft "overautomated"?
Post by: paul cotter on 29/08/2022 09:21:43
Quick question, alancalverd. How can you handle a deep stall if the elevators are effectively non functioning?
Title: Re: Are aircraft "overautomated"?
Post by: evan_au on 29/08/2022 10:09:27
One of the big problems with automation is called "sensor fusion"
- All critical aircraft systems are (at least) duplicated, so there are multiple possible sensor inputs
- Each input has its own random and systematic errors
- Knowing which inputs are valid, and which is invalid is not so obvious
- Some aircraft control systems solved this by just taking inputs from one of the redundant inputs (eg just one pitot tube or one angle-of-attack indicator). But if that single input fails, the control system won't be able to detect the fault, and will produce wrong instructions to control systems.

I heard of an air force fighter pilot who retired to become a commercial airline pilot. He described his new role as "hours of pure boredom, interspersed with seconds of sheer terror...".
Title: Re: Are aircraft "overautomated"?
Post by: Bored chemist on 29/08/2022 10:55:05
Looking at this  now, (I can't recall if I saw it earlier" I see the report into the incident said ". Both of these circumstances resulted from Alaska Airlines' attempts to cut costs".
(according to this)
https://en.wikipedia.org/wiki/Alaska_Airlines_Flight_261
If you have a big plane, with big control surfaces and big forces, then it's impossible for muscle power to move them (usefully).
Some level of automation becomes inevitable.
The automation itself wasn't the problem.
Cost-cutting was.
Title: Re: Are aircraft "overautomated"?
Post by: alancalverd on 29/08/2022 16:38:57
Quick question, alancalverd. How can you handle a deep stall if the elevators are effectively non functioning?
RTFM! A production aircraft will have been tested in all conceivable flight modes, load distribution limits will have been set, and recovery from "unusual attitudes" will be in the book (pace Boeing, perhaps).

If you haven't read the book, change something and see what happens. Full power may restore enough airflow to give elevator authority, or cut the power to idle and wait: if the center of gravity is within design limits the aircraft should eventually nose-down and start to fly again. In extremis, kick on full rudder and blip the throttle, which may initiate a spin and thus get one wing flying, then recover or abandon ship as per the flight manual.

Either way the condition is best avoided: all aircraft can bite if you mistreat them.
Title: Re: Are aircraft "overautomated"?
Post by: alancalverd on 29/08/2022 17:00:56
f you have a big plane, with big control surfaces and big forces, then it's impossible for muscle power to move them (usefully).
Some level of automation becomes inevitable.
There's a difference between automation (plane makes decisions or moves controls in an attempt to follow preset instructions - conventional autopilot or even autoland system) and servo assistance (power steering in one or more axes). But in either case most civil  aircraft can be "hand flown" with enough muscle power if there is no airframe damage. An independent trimmer circuit may allow slow changes if the primary hydraulics fail.

The difficult area is in "fly by wire" where the pilot's control input is not directly connected to the engines or control surfaces but interpreted and executed as efficiently as the airframe will allow, or an inherently unstable aircraft is maintained in a pilot-mandated condition by rapid servo action so it "feels" stable.  Problem with such systems is that the aircraft is not humanly flyable if you switch off the electronics. 

The weasel word is "airframe damage". The Alaska Airlines disaster seems to have resulted from a primary mechanical failure rather than an automation or servo fault.
Title: Re: Are aircraft "overautomated"?
Post by: alancalverd on 29/08/2022 17:10:33
I heard of an air force fighter pilot who retired to become a commercial airline pilot. He described his new role as "hours of pure boredom, interspersed with seconds of sheer terror...".
Much the same from a just-retired airline captain of my acquaintance, who described his career as 40 years of boredom and 20 minutes of panic, for which he was well paid. 
Title: Re: Are aircraft "overautomated"?
Post by: evan_au on 30/08/2022 01:37:33
Quote from: Paul Cotter
How can you handle a deep stall?
The crash of a stalled commercial airline in Russia occurred because:
- The pilots knew that autopilot was on
- The pilots were not aware that autopilot is automatically disconnected if the human pilot makes a sudden change to the controls
- The stall would have been automatically recovered if the human pilot had just released the controls, allowing autopilot to resume
- Not helped by the fact that the pilot had one of his children at the controls...
30 minutes podcast:  https://timharford.com/2022/05/cautionary-tales-when-the-autopilot-switched-off/
Title: Re: Are aircraft "overautomated"?
Post by: alancalverd on 30/08/2022 15:21:03
So there we have it. Autopilot on can kill you, autopilot off can kill you. I repeat - all aircraft bite if you mistreat them.

Round about lesson 001 your basic skills instructor will demonstrate the use of  aerodynamic trim controls. Set the cruise power, set the attitude that gives you constant height for that power, point it where you want to go, then trim so that the plane flies "hands and feet off" in a straight line. Followed by the maxim "This machine is designed to fly, you are not. Now leave the bloody thing alone until we get to Birmingham."

And now they want to automate cars.
Title: Re: Are aircraft "overautomated"?
Post by: evan_au on 30/08/2022 22:50:09
Quote from: alancalverd
And now they want to automate cars.
My hybrid car has a vision system that allows it to follow well-marked lanes (assuming there is no roadwork with missing paint)
- It will slow down and stop at traffic lights (provided there is someone stopping ahead of you)
- It will return to cruise speed when the lights turn green (provided the car ahead of you moves off)
- It is vital to know what situations it can and cannot handle. Unfortunately, cars are spaced a lot closer than planes, and the drivers have less training, so constant vigilance is essential

This car has a safety feature that detects if your hands are off the wheel, and slows the car to a stop.
- It's sort of like a copilot - you can feel their hands on the wheel, too...