Automated Aircraft

[scroggs]

cortilla, you are wrong - by a country mile. If you are going to talk about the Airbus flight laws, please have the decency to read up about the subject first. As you yourself admit, you have not flown an Airbus - and you display your lack of knowledge brilliantly.

[cortilla]

Scroggs,

Am i wrong in thinking then that if you pulled back on the sidestick this will send a message to the computer which will then do the 'thought process' of "okay this person wants a nose up attitude, let's see with the current parameters can we do it. ahh yes we can okay here you go pilot friend here's some nose up" but if the pilot keeps on pulling back on the stick the computer will then think "hang on if we pull the nose up any further, then we're gonna go into a stall. Now, programming states that this is a bad plan. therefore no sorry i'm not gonna give you any more nose up".

I seem to remember an airbus crash (and i'm not airbus bashing, i'm all for them and think fbw systems in a/c is a great concept) when they first came out,. The pilot wanted to climb but the computer would not let him, and therefore the a/c crashed into the forest. Again in this situation the pilot could not override the computer.


"When alpha exceeds alpha prot, elevator control switches to alpha protection mode in which angle of attack is proportional to sidestick deflection.
Alpha max will not be exceeded even if the pilot applies full aft deflection "

Oh sorry i got the angles wrong for the AOB

"Pitch limited to 30 deg up, 15 deg down, and 67 deg of bank.
These limits are indicated by green = signs on the PFD.
Bank angles in excess of 33 deg require constant sidestick input.
If input is released the aircraft returns to and maintains 33 deg of bank"

and another bit which says the computer has ultimate control.

High Speed Protection:

Prevents exceeding VMO or MMO by introducing a pitch up load factor demand.
The pilot can NOT override the pitch up command.

Okay i will admit that other laws come into effect if there are failures of systems, but that's not what i'm talking about here, i'm talking in the normal situation with all the systems operational.

[alexban]

Again,why anyone would like to fly outside the normal anvelope? You think more than 30 deg up,or 67 deg bank is not out of normal? I would like to invite you to one of the test flights on the 737,to see what more than 60 deg bank means.It's nothing like a cesna,or some glider.
Nice of buses to have this limitations,it can avoid some pilot error .You have to be a heck of a pilot to do a level >60 deg bank turn,i feel.
Regarding to that forest accident,if I'm not wrong,the cause was not the computer.It was a CRM problem,both pilots forgetting to advance throtles for a go-around.It was a CFIT,if I remember well.But it is a long time since then,so I maybe wrong.This case was presented some years ago to one of our crm classes.
Regarding alpha protection.Boeing doesn't have this limitations on commands.So what will hapen,on a 737 ,if you apply full aft deflection,exceding the stall AOA? Nothing more than extra-g,stall warning followed by a very nice and controlable stall of the plane.Why would you want that? Beats me You wanna make a loop?
15 deg down?...gee

[cortilla]

I'm not saying that you would want to do any of the things mentioned in my previous posts, i'm just saying that you can't. therefore the pilot does not have ultimate control, but the computer does. That's all i've been trying to say in these posts. Crikey this has deviated a bit from my original post.

Oh yeah, i'd love to go on one of them test flights you mentioned. Reckon it'll be a lot of fun

as regards to the mulhouse accident there are two versions to what happened in the crash, the official airbus version (which has been brought into question) and the pilot's version. just put in a quick excerpt. Which one you want to believe is up to you.

"The Black Boxes were taken undamaged from the aircraft 2 hours after the crash, but unfortunately they have been out of control of justice for 10 days, and since May 1998 it is proven that the Flight Data Recorder was substituted during this period. The Lausanne Institute of Police Forensic Evidence and Criminology (IPSC) comes to the conclusion that the Black Boxes used in the trial to declare the pilot guilty are NOT the ones taken from the aircraft.

The aircraft was new, Airbus was waiting for commands, a lack of confidence in the highly computerized aircraft would have meant a commercial disaster - not only for the manufacturer, but also for the French administration, which has a share in the European Airbus consortium.

The Official Version
The French minister of transportation (Louis Mermoz), the company (Air France) and the aircraft manufacturer (Airbus Industry) declared with precipitation shortly after the accident that the aircraft was beyond any doubt. The final report (published 18 months after the accident) comes to the same conclusion, but the authenticity of the data on which the report has always been very doubtful, and since May 1998 it is proven by the report of the Lausanne IPSC that the Flight Data Recorder (DFDR) was substituted after the crash. For 10 years the media have not stopped reporting about the anomalies which have accompanied the technical investigation of the accident from the beginning.

The Captain's Version

Captain Asseline flew the aircraft manually. He had been instructed by Air France to overfly the airfield at 100 ft above ground. When he increased throttle to level off at 100 ft, the engines did not respond. So after some seconds he got worried and thought there was something like a short-circuit in the completely computerized throttle control. So he pulled the throttle back all the way and forth again. By that time the aircraft had touched the trees.

After the accident, Captain Asseline was very astonished when he saw on an amateur video tape that the gear was only 30 ft above ground when the aircraft was passing over the runway. He affirms the altimeter of the Airbus A320 indicated 100 ft. "

(source http://www.airdisaster.com/investiga...96/af296.shtml)

[scroggs]

I'm not going to get diverted into the causes of the crash you mention, though I believe there are logical explanations behind it with the control logic that existed at the time.

The limitations imposed by Airbus's flight control system in Normal Law are more than adequate for all manouevres that may be required in operating the aircraft. They can be overridden if absolutely necessary, though it's not a particularly simple thing to do.

There is nothing sinister about the actions of these flight control computers; they do not fly the aeroplane for you (autopilots have been doing that since WW2). They simply have used rather basic computer technology to prevent sloppy handling from allowing the aeroplane to stray outside the manouevre envelope. Those limits are not significantly different from those of any commercial aircraft.

The computers make no 'decisions' as such. They simply monitor various parameters and, if any one parameter is approaching a limit, control inputs are automatically applied to attempt to keep that parameter within its designated limit. It is a simple 'if parameter X=this, then control input Y = 3 bananas (or whatever). This is a world away from free decison making in a constantly changing multi-dimensional environment.

And I repeat the point I made earlier: no commercial aircraft with pilotless flight decks are in development or currently proposed. All the aircraft that are envisaged at the moment will continue to be manned by two pilots. Given the life-cycle (now and envisaged) of modern aircraft, that suggests that piloted commercial airliners will remain the predominant species in service for at least the next 50 years.

[Lemurian]

If I may add a comment to Scroggs' post.
If one thinks of flying outside the envelope,he is a fool.If he does fly outside the envelope,he will be a dead fool,very probably.
I have now flown airbuses for the past eight years and I love the airplane for its responsiveness,its liveliness and the precision of piloting it provides.
Furthermore,and I really mean it,for any plane maker not to have adopted a windshear protection similar to the one Airbus offers is IMHO downright criminal.

cortilla,
For a real job of accident reporting please refer to Macarthur Job's "Air Disaster",volume 3.pp 11 to 24.Conspiracy theories are only good in good novels.
By the way,below 200 feet,a good pilot would refer to a radio altimeter;lots more accurate than baro pressure with a Mickey mouse QNH setting.
Mr Kilroy very generously forgets to mention that the crew deactivated the alpha floor function,thus preventing an automatic Go around thrust setting with the increase of AoA.
Anybody who has flown high-bypass engined a/c will know that a six second delay from idle to full thrust is common.at 100 kts (which was the speed he was at...),that translates into some 300 m.The length of the display area was just over 600 m.
Let's face it :the pilot was low on energy,low on altitude,low on thrust...the only thing that was high was his attitude,so high he couldn't see the coming forest...he got it all wrong.Anyairplane other than an Airbus would have stalled long before hitting the trees,very probably dissymetrically and the loss of lives would have been a great deal greater.
Closed case.
for you,being slightly to the left of me...Does it mean you are hanging for dear life from my pitot tubes?

Scroggs,
I see you're just about to record your 2000th post.Do I get a beer?

[cortilla]

fair points made by all. i'd have to agree it'd be a bad plan to want to fly outside the envelope. Although to be fair the barrel roll by Tex Johnston on the prototype 707 whilst (what i only assume must be) outside the normal envelope was still impressive. Oh can i get a beer aswell for pushin scroggs up to those 2000 posts.

Oh and i know a mate at uni doing a phd developing pilotless civilian transporter. He's workin with a major aircraft company, although they'll only use some ideas to improve further piloted aircraft and not actually make a pilotless aircraft (yet).

[scroggs]

Ah, sorry chaps. The number of posts is fairly meaningless - each time Pprune goes through a reincarnation, or ancient threads are deleted, the number changes. I think my real total is over 5000, but I can't be sure. One day I'll get a life....

[Notso Fantastic]

cortilla, there's a sort of ruthless inescapable logic there. To develop a pilotless aeroplane, you have to invest incredibly heavily to produce automatics with enough redundancy to replace a human pilot (who really doesn't cost all that much), and then invest with a limitless horizon to beef up those automatics to cope with significant external factor failures like damage to the vehicle, weather and infrastructure failures!
When I start seeing train services (and not limited transit vehicles) without drivers and vehicles on roads without drivers, then I'll start seeing what's coming, but for now, it's a fun thing to speculate about, but nobody of this generation will climb aboard! We got 50 years folks!

[cortilla]

Then again, all things going well, i reckon i'll still be alive in fifty years (and the state of pension schemes nowadays probably still working too) also look how quickly we went from the first motorised flight to jet and supersonic a/c. Also look at the speed of development from my old BBC (them were the days) to the latest computers in airbus aircraft. I hope it takes ages, otherwise i'll be out of a job, but these things happen very quickly when someone's motivated to make it. Especially seeing as the technology is here, it just needs a little refinement.

[willfly380]

a boy who witnessed the flight flight at kitty hawk has also as a senior adult seen man walk on the moon. so what are we talking about........

[scroggs]

....and that was 35 years ago! The rate of change in aerospace technology since then has slowed somewhat, I'd venture.

[cortilla]

sorry to bring this up again, but it's relevant.

Read an interesting article in flight from this week (june 8-14 issue) on page 12 titled 'Unmanned' aircraft puts controlles airspace to the test.

Basically talks a proving flight this time last week when the german aerospace centre used a fokker VFW614 (looks to be around a 30-40 capacity jet when it was used as an airliner tho not sure). BAsically the airline goes to show that the aircraft could operate in controlled airspace with no input by the 2 safety pilots in the a/c. the aircraft was controlled completely by a ground operator using ATC datalink and voice transmissions. The only thing the safety pilots had to do was take off and land as the auto land was inop.

' The UAV has to file a flight plan like ordinary flightr, and this is also entered into its control computer as part of its mission programme. it is then controlled by pilots operating a console on the ground....'

Whilst the technology is not completely radical, i do think its the first time it's been used in a civvie aircraft in controlled airspace (ie with other aircraft operating in the same airspace).

Like i said the technology is coming quicker than you think.

cheerso

[scroggs]

Remote control is not the same as autonomous intelligent automatic flight. Replacing the pilots with controllers on the ground is fine for military UAVs, but is a waste of time for commercial passenger-carrying aeroplanes. Where's the saving? And what's the point? Who'd pay to fly on your airline if even the pilots don't get on board!

[Jimmenycricket]

While I agree in principle that unmanned aircraft for combat would be safer, I don't feel that it is a good idea to have a computer decide what is a good target and what isn't. Personally, I don't want to be flying along and be shot down because somebody couldn't see me properly in his computer screen 10,000 miles away. As for passenger aircraft, I agree that the human factor in determining whether the most efficient way is the safest way is still better than leaving it to the computer, the fact is that if it will reduce ticket prices, people would probably go for it anyways. That's just no good, I haven't even gotten to fly one yet... So if they could just hold off on the automated systems for 50 or 60 years, I would really appreciate it.

[SLF]

scroggs - a couple of points

....and that was 35 years ago!

I agree there have not been huge advances in aircraft design during those 35 years, merely incremental steps. In computing however, essential for any degree of autonomy, there have been many orders of magnitude of progress.

Where's the saving? And what's the point?

If we agree that the take-off and landing are the most complex areas to automate, then the first "unmanned" planes may have automated cruise but remote-controlled take-off and landing. A single pilot or ATC-er could be landing a dozen an hour.

[northwing]

Once upon a time when you got into a lift there was a man in it to operate it for you. Now there isn't. The technology to run driverless trains exists and is in service now. That's why the driver on the Victoria line is always reading the paper when the train comes in. He gets extra money because it is so boring.

UAVs are currently achieving crash rates of about 1 per 100 flights. (I saw one crash last February.) This is not good enough for taking grannies to Majorca but they will get better as experience is gained and I believe that the pilotless passenger jet will come. The interesting thing is that an operator is needed on the ground and one of the things that is becoming apparent is that this chap needs to have exactly the sort of airmanship skills that a pilot has. The non pilots just don't realise that theaircraft might hit the brown bits on the flat map.

[Bealzebub]

The big difference is that when a fault does occur on an automated train or an elevator or whatever, the thing just stops (usually). Then someone with a ladder and a toolbox comes along in due course to let everybody out or off. The problem with an airliner is that this option doesn't exist. If a fault occurs gravity will eventually win and the commercial repercussions are all too obvious.

Perhaps one day it will all happen but thankfully I doubt it will be in mine or my childrens lifetimes.