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Fly-By-Wire Contributed To Air France 447 Disaster

Soulskill posted more than 2 years ago | from the costly-mistakes dept.

Transportation 319

Hugh Pickens writes "The Telegraph reports that although fly-by-wire technology has huge advantages, Airbus's 'brilliant' aircraft design may have contributed to one of the world's worst aviation disasters and the deaths of all 228 passengers onboard Air France Flight 447 from Rio de Janeiro to Paris. While there is no doubt that at least one of AF447's pilots made a fatal and sustained mistake, the errors committed by the pilot doing the flying were not corrected by his more experienced colleagues because they did not know he was behaving in a manner bound to induce a stall. The reason for that fatal lack of awareness lies partly in the design of the control stick – the 'side stick' – used in all Airbus cockpits. 'Most Airbus pilots I know love it because of the reliable automation that allows you to manage situations and not be so fatigued by the mechanics of flying,' says Stephen King of the British Airline Pilots' Association. But the fact that the second pilot's stick stays in neutral whatever there is input to the other is not a good thing. 'It's not immediately apparent to one pilot what the other may be doing with the control stick, unless he makes a big effort to look across to the other side of the flight deck, which is not easy. In any case, the side stick is held back for only a few seconds, so you have to see the action being taken.'"

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over use of tech (1, Insightful)

Anonymous Coward | more than 2 years ago | (#39836955)

And then we send robots down to gather the black boxes that recorded all the flight data.

Ever think we're relying a little too much on technology these days?

Re:over use of tech (5, Funny)

Anonymous Coward | more than 2 years ago | (#39837361)

Ever think we're relying a little too much on technology these days?

Yeah! Let's go smash up some looms!

More to it than that (5, Informative)

Anonymous Coward | more than 2 years ago | (#39836959)

This topic has been beaten to death by professional pilots and aviation experts on pprune.

Re:More to it than that (5, Informative)

kschendel (644489) | more than 2 years ago | (#39836989)

and airliners.net also. The ones who know what they are talking about are unanimous in that it had little to do with the non-backdriven controls; the pilots flying were so disoriented that it probably would have taken a giant flashing sign saying "you're falling out of the air, dummies!" to get them to nose down.

And anyway, FBW != back-driven controls. The thread title is wrong and misleading. Boeing uses FBW too, but they back-drive the yoke and throttles. This has been discussed plenty as well, and there's no inherent advantage to one way over the other.

Re:More to it than that (5, Informative)

PhireN (916388) | more than 2 years ago | (#39837137)

the pilots flying were so disoriented that it probably would have taken a giant flashing sign saying "you're falling out of the air, dummies!" to get them to nose down.

There was a recorded voice yelling STALL, STALL, STALL over and over again. They would have ignored the giant flashing sign too and blamed it on a computer error.
They were just that disorientated.

Re:More to it than that (5, Interesting)

beelsebob (529313) | more than 2 years ago | (#39837325)

Yes and no –the reason they were ignoring the voice saying STALL, STALL, STALL was because they believed that the computer software made it impossible to stall the aircraft, and that all the warning meant was "if you turn off all the computer assistance now, it'll stall", not "the computer assistance is already all off, I am stalling".

A second warning that doesn't ever sound in safe scenarios (e.g. FALLING, FALLING, FALLING) might just have made them twig to "crap, it really is stalling".

Re:More to it than that (0)

blippo (158203) | more than 2 years ago | (#39837521)

I think that the design of some parts of the flight management system is to blame, at least partly; Some minor changes might have changed everything.

When the airplane is in alternate law, a (not too annoying) warning sound could be played when the stick is pulled back fully, in order to remind a possibly confused and panicking pilot that there is no stall protection.

The stall warning ( or angle of attack warning ) should not be disabled due to low airspeed readings, at least not at altitude, to reduce the risk of making the pilots think they are worsening their situation when they are in fact improving it.

Re:More to it than that (5, Informative)

Richard_at_work (517087) | more than 2 years ago | (#39837535)

No, they were never taught that Airbus aircraft will prevent a stall, no airline teaches that - what they did was assume the stall warning was incorrect, because they did not do their memory check lists as required by Airbus and Air France.

Re:More to it than that (2, Insightful)

JimCanuck (2474366) | more than 2 years ago | (#39837627)

A second warning that doesn't ever sound in safe scenarios (e.g. FALLING, FALLING, FALLING) might just have made them twig to "crap, it really is stalling".

Perhaps your not a pilot, but hearing "STALL, STALL, STALL" is the computer's way of saying "I've lost the ability to generate lift and now we are falling unless you cause the plane to generate lift".

No this accident was a case of idiot pilots who thought their job was to have a good time in the cockpit instead of flying the plane.

Stall warning wasn't there, they needed AoA (1)

csirac (574795) | more than 2 years ago | (#39837401)

From what I've read, the stall warning actually went away when the co-pilot pulled the nose up. I can't recall if that's because the pitot tubes were still messed up, or simply that the airspeed was too low that the stall warning only came back when speed was restored.

I read on pprune that this may have been avoided if there was angle of attack indication in the cockpit (plus training to use them). Apparently AoA is already measured by these aircraft, and such a reading would be much less ambiguous than guessing about how close to or how deep into a stall you are from airspeed, attitude, flap/slat settings, etc.

Re:Stall warning wasn't there, they needed AoA (3, Informative)

Richard_at_work (517087) | more than 2 years ago | (#39837547)

The airspeed dropped to a level where it was ambiguous (below something like 60 knots indicated), and that killed the stall warning. It reactivated when they pushed the nose down, which increased the airspeed to above the threshold.

Re:More to it than that (4, Informative)

darkmeridian (119044) | more than 2 years ago | (#39837407)

Not only that, but the computer turned off the STALL warning when its sensors determined that it was going 60 knots in flight and decided it was wrong. It didn't tell the crew that it was shutting down the STALL warning due to sensor failure; it just stopped talking. When the co-pilot finally realized his mistake and began to nose down, the STALL warning turned back on again because the airplane had picked up speed. The co-pilot heard the STALL warning, freaked out, and began to pull up on the stick again. If he had kept nose down, the STALL warning would have gone away once the aircraft had sped up enough to get lift. It's a bizarre system all around.

Re:More to it than that (1)

timeOday (582209) | more than 2 years ago | (#39837289)

At one time there was a theory about a frozen airspeed sensor. Could the autopilot have recovered the plane, or was it also "disoriented" and refused to engage due to conflicting airspeed sensors?

Re:More to it than that (3, Insightful)

Kagato (116051) | more than 2 years ago | (#39837427)

I concur, fly by wire-by-wire had nothing to do with it. Side sticks are here to stay and popular with more than just Airbus. A linked or back-driven yoke may have helped, but there's a far more compelling argument to be made for having Angle of Attack sensors and feedback.

If there was an Angle of Attack readout on the dash board that likely would have created a cross-check opportunity. The technology has been around for decade, but really hasn't caught on (or been required) commercially.

Re:More to it than that (4, Informative)

Cochonou (576531) | more than 2 years ago | (#39837035)

Indeed, the article is surprising, or more accurately, void of new information
But there is another, worrying implication that the Telegraph can disclose for the first time: that the errors committed by the pilot doing the flying were not corrected by his more experienced colleagues because they did not know he was behaving in a manner bound to induce a stall. And the reason for that fatal lack of awareness lies partly in the design of the control stick – the “side stick” – used in all Airbus cockpits.
For the first time ? As you said, this has been beaten to death in various reports. There has already been an almost full transcript of the cockpit voice recorder leaked in a book [amazon.fr] months before. The last and final report from the investigators is scheduled to come out in June. They have put in place a special panel composed of pilots to try to understand the reactions of the crew (including seemingly ignoring the stall warnings, the apparent lack of confidence in the instruments, etc), and have dug into the history of flights during which pitots tube froze at high altitude. I think their conclusions might be slightly more revealing than the Telegraph copying-and-pasting other websites [popularmechanics.com] .

Re:More to it than that (2, Insightful)

Anonymous Coward | more than 2 years ago | (#39837055)

Yes, but it's important that the Americans bash Airbus at every possibly opportunity, lest their own sacred calf not be fattened.

Re:More to it than that (4, Funny)

Joce640k (829181) | more than 2 years ago | (#39837209)

Came here to see somebody post "Airbus=Scarebus"...

Am leaving disappointed.

Re:More to it than that (3, Funny)

CohibaVancouver (864662) | more than 2 years ago | (#39837307)

Came here to see somebody post "Airbus=Scarebus"...

How about "If ain't Boeing, I ain't going!"

That cover it for you?

Re:More to it than that (1)

Anonymous Coward | more than 2 years ago | (#39837541)

Scarebus by Stephen King.

Of the British Airline Pilots' Association, no less.

Re:More to it than that (0, Informative)

Anonymous Coward | more than 2 years ago | (#39837213)

Yes, but it's important that the Americans bash Airbus at every possibly opportunity, lest their own sacred calf not be fattened.

"The Daily Telegraph is a daily morning broadsheet conservative-leaning newspaper distributed throughout the United Kingdom and internationally. The newspaper was founded by Arthur B. Sleigh in June 1855 as the Daily Telegraph and Courier, and since 2004 is owned by David and Frederick Barclay."

In other words, Go Fuck Yourself.

Re:More to it than that (1, Insightful)

Anonymous Coward | more than 2 years ago | (#39837415)

It wasn't the Telegraph that submitted this story with the unnecessary "scare quotes" in an attempt to whip up anti-Airbus sentiment.

So please kindly Go Fuck Yourself.

Re:More to it than that (0)

Anonymous Coward | more than 2 years ago | (#39837551)

Thanks to pprune, arrse and similar sites it is good to know you don't have to rely on the old press for slanted crap.

So it could be argued that it wasn't FBW... (1, Redundant)

bhtooefr (649901) | more than 2 years ago | (#39836965)

...but rather it was a lack of force feedback. And that technology has existed, even on the consumer level (and no reason it can't exist at the airliner level that I know of), for many years.

Re:So it could be argued that it wasn't FBW... (0)

Anonymous Coward | more than 2 years ago | (#39837247)

It's not force-feedback, either, which does exist at the airliner level -- see, for example, every Boeing airliner.

In fact, Airbus side-sticks also have force-feedback, but it's governed by control laws not mimicking mechanical linkages (feedback force proportional to actuator force), but proportional to g-load demand and roll rate demand, with (AIUI) some modifications during landing. And even with actuator-proportional force-feedback to the stick in use, you could still have split-stick design where when one stick is in use, the other remains stationary. This is a bad design choice, IMO, and could be rectified with Airbus's side-sticks and demand-proportional control laws.

Fly by wire.... (5, Insightful)

mseeger (40923) | more than 2 years ago | (#39836973)

When i read the annotated black box transcript a few weeks ago, i asked airplane experts about this. They told me:

If one pilot pulls and the other pushes the stick, there is an optical and audio signal.

Also the person was questioned if he pulls the stick and he confirmed it. Unluckily it was already too late by then.

I am no expert, but the root cause was IMHO the crew ressource management and training problem.

Re:Fly by wire.... (0)

Anonymous Coward | more than 2 years ago | (#39837005)

Because I'm an absolute layman when it comes to aviation, could somebody explain what the advantage is to mechanically allowing different pilots to issue conflicting commands to a flying plane? Unless I'm misunderstanding, or failing to see some risk-benefit advantage, The Gut tells me that that's a bad idea from the start.

Re:Fly by wire.... (4, Insightful)

mseeger (40923) | more than 2 years ago | (#39837057)

The advantage would be immediate feedback... You would feel the other guys is acting against you. In this case nobody issued a different command, so no "conflict" was signaled.

The crew didn't recognise the pilot in control was not acting rational. With mechanical controls, somebody might have noticed that he was pulling all the time and acted upon it.

Re:Fly by wire.... (0)

Anonymous Coward | more than 2 years ago | (#39837101)

That's actually what I was getting at, though perhaps I worded it poorly. As I understand it, the system Airbus does NOT issue feedback between the two pilots. As in, there is no tactile communication between them. So what, aside from simple convenience, would be the advantage of this? It seems clear that a situation such as this is bound to happen with that line of intuitive communication between pilot and copilot severed.

Re:Fly by wire.... (3, Informative)

mseeger (40923) | more than 2 years ago | (#39837167)

Unaware of the real arguments, i would say: complexity. It would make a critical component more prone to problems.

Please be aware: The control stick in an Airbus is a small joystick today which is not in the "line of sight" of both pilots. You would have to look at it directly or put your hand there to notice it's position:

http://pnaconsult.com/yahoo_site_admin/assets/images/2.293181416.jpg [pnaconsult.com]

In Boeing 787 the stick is much bigger:

https://upload.wikimedia.org/wikipedia/commons/thumb/8/8a/787-flight-deck.jpg/800px-787-flight-deck.jpg [wikimedia.org]

Linking them makes more sense than in an Airbus.

I have talked to some pilots and they prefer the Airbus way, but i consider them biased in favour of Airbus.

Re:Fly by wire.... (0)

Anonymous Coward | more than 2 years ago | (#39837257)

Thanks for the response(s), I was actually completely unaware that a joystick design like that existed in commercial aircraft. I can see why pilots would prefer it, but it's hard to imagine such a design being safe, and sufficiently redundant. Still, I'll have to take a better look at the underlying mechanisms sometime, there's obviously much more to it than I realize.

Re:Fly by wire.... (2)

mseeger (40923) | more than 2 years ago | (#39837281)

That's why i think airplane security so interesting.

Their practices are much better than e.g. in IT.

And then there is the comparison to the aiport security, which is much worse than IT security ;-).

Re:Fly by wire.... (0)

ravenshrike (808508) | more than 2 years ago | (#39837275)

Why does the airbus design remind me of bad 80's science fiction?

Re:Fly by wire.... (2)

mseeger (40923) | more than 2 years ago | (#39837329)

Honestly, i believe it was the SciFi designers who copied ;-).

Re:Fly by wire.... (1)

cmarkn (31706) | more than 2 years ago | (#39837557)

That arrangement of the sidesticks looks like a potential training problem. When a pilot is promoted to captain, he has to learn to operate the stick with the left hand instead of the right, and the throttle with the right instead of the left. For a pilot with thousands of hours flying, this has to be somewhat disorienting that requires a serious amount of training to overcome.

Re:Fly by wire.... (5, Informative)

darkeye (199616) | more than 2 years ago | (#39837203)

the thing with the Airbus control system is that you issue 'change' commands to the plane. you issue a 'roll command' when you push the stick to the side, and you issue a 'G command' when you push it forward or back. the plane will remain in the new commanded state until commanded otherwise.

(now read the last sentence again, and chew on it, make sure you understand it thoroughly)

thus, the usual way to fly the plane is to issue small, well-intentioned commands, not to pull on a stick for minutes, as one of the pilots here did. and the plane will stay in the new situation. 'will stay' means that it will issue corrections on its own to maintain the commanded attitude. for example, after having been issued a roll command for a few degrees, the plane will stay in that attitude even of there are disturbing factors - say, turbulence. (as a result, in such a case it is an error for a pilot to try to manually compensate for turbulence-induced attitude changes, as the plane does it on its own anyway, and he will end up over-compensating)

all-in-all, this is a big change in the philosophy on how to fly a plane, even when flying alone, when compared to a 'legacy' system of direct physical coupling of control instruments to control surfaces.

as for simultaneous inputs: actually, one of the pilots can 'take over' command of the plane, and shut out the other one, if he so chooses. none of the pilots did this on this occasion. when having multiple inputs, the plane does signal that the other person is entering inputs as well (at least visually, maybe there is also an aural indication). although, as pointed out, there is no physical feedback on the stick that would signal the other pilots inputs. when both are entering commands, their commands are 'added together'. thus a full pull & a full push on the stick will cancel each other out. two 'small' pushes will results a 'big' push. this makes sense, so that either pilot can 'adjust' the planes behaviour in addition to what is already happening.

the point of not having physical feedback is to reduce strain on the pilots. this way, the stick is always centered, and when moving off center, the pilot knows he's issuing commands to the plane. if it was not so, the pilot wouldn't be sure in which state of the stick is it in a 'neutral' position.

I hope the above gives some background to the story.

Re:Fly by wire.... (0)

TheTrueScotsman (1191887) | more than 2 years ago | (#39837343)

the point of not having physical feedback is to reduce strain on the pilots. this way, the stick is always centered, and when moving off center, the pilot knows he's issuing commands to the plane. if it was not so, the pilot wouldn't be sure in which state of the stick is it in a 'neutral' position.

Only the pilot in command should have his hand on the stick; so linking the two together wouldn't have any of the problems you raise. It would, though, give valuable visual (and tactile if both pilots are trying to control the stick) information to the co-pilot.

There is one reason and one reason alone Airbus didn't link the sticks - and that's cost (both in higher building costs and extra weight).

Re:Fly by wire.... (4, Informative)

darkeye (199616) | more than 2 years ago | (#39837379)

Only the pilot in command should have his hand on the stick; so linking the two together wouldn't have any of the problems you raise. It would, though, give valuable visual (and tactile if both pilots are trying to control the stick) information to the co-pilot.

this is not how multi-crew cockpits (MCC) work - in these cases, both pilots have control. as said earlier, they can agree on only one of them giving direct inputs though.

this is all covered by CRM - Crew Resource Management - where the two pilots divide the tasks & responsibilities between them. both being young pilots (remember, the captain was sleeping at the time), they pretty much failed in applying proper CRM techniques. both were used to being the junior member of a multi-crew cockpit, thus neither of them took the initiative. this is quite evident from the transcript.

There is one reason and one reason alone Airbus didn't link the sticks - and that's cost (both in higher building costs and extra weight).

this is simply not true - adding feedback is neither expensive nor heavy in this case.

Re:Fly by wire.... (3, Informative)

wjsteele (255130) | more than 2 years ago | (#39837445)

There is one reason and one reason alone Airbus didn't link the sticks - and that's cost (both in higher building costs and extra weight).

>

The Airbus, like Boeings, have "Stick Shakers" to give feedback to the pilot. The stall waring indicator, in fact, does trigger the stick shaker, but once you get below a certain speed (like these pilots did) the aircraft thinks the plane is too slow to be flying so it must be taxing, so it turns it off.

Bill

Re:Fly by wire.... (3, Interesting)

iluvcapra (782887) | more than 2 years ago | (#39837563)

Issuing "small, well intentioned commands" is how it usually works, but in this case the flight controls had been switched into their alternate control law, due to the loss of reliable airspeed data. In alternate law the columns do what a "dumb" FBW system does, and stick displacement will reflect in contro surface deflection.

Re:Fly by wire.... (1)

Anonymous Coward | more than 2 years ago | (#39837047)

@mseeger - second that. It makes one wonder - the plane stalls and the inexperienced copilot attempts to stall it further by pulling the stick back - only to lose more speed. Difficult situation but training seems to have some shortcomings in this. Laymen would understand in order to gain speed one would have to level out, or descend. hard to imagine how one sits in a plane and some jackass can decide if you live or die.

Re:Fly by wire.... (3, Informative)

darkeye (199616) | more than 2 years ago | (#39837279)

while the co-pilots behaviour of pulling on the stick for minutes, and not recognizing the very simple stall-recovery process of pushing & gaining speed is, well, astonishing - there is a reason for his behaviour.

the reason is that such planes usually encounter stall-warnings on approach, when in a landing configuration, close to ground, and having a lot of excess power. in such occasions, the usual procedure is not to lower the nose & convert altitude to speed, but to simply 'power yourself out' of the stall situation - apply a lot of (available excess) power, and your speed will pick up, and you're not close to stalling anymore.

the fact that the co-pilot in question referred to TOGA (the Take-Off-Go-Around procedure) in the transcript, and the fact that they were using maximum thrust for most of the falling time also suggest that his idea of stall recovery was to power himself out of the stall.

this is quite unfortunate indeed, as any small-plane pilots instinct would have been simply to dip the plane's nose & recover easily.

Re:Fly by wire.... (3, Interesting)

wjsteele (255130) | more than 2 years ago | (#39837461)

in such occasions, the usual procedure is not to lower the nose & convert altitude to speed, but to simply 'power yourself out' of the stall situation - apply a lot of (available excess) power, and your speed will pick up, and you're not close to stalling anymore.

I'm not sure where you got that information, but that is not the correct course of action. Even in a low altitude situation, a stall can only be recovered by lowering the angle of attack... engine power and speed have absolutely nothing to do with it. A stall is an aerodynamic condition where the wings are not producing enough lift for flight. Pushing the nose over (to lower the angle of attack) allows the air to reattach to the wings which eliminates the stall condition.

Bill

Re:Fly by wire.... (5, Insightful)

Balinares (316703) | more than 2 years ago | (#39837063)

Yeah, but your version has the unfortunate side-effect of not making a Boeing competitor look bad. Can't have that, you know.

(Seriously, WTF is this summary? Fox News Scare Quotes around 'brilliant'? Really, Slashdot?)

Re:Fly by wire.... (4, Insightful)

mseeger (40923) | more than 2 years ago | (#39837113)

I work in IT security. Looking good/bad (even yourself) is a purely secondary issue, if you take your work seriously.

That work is the reason, i read everything i can about airline incidents. Because their security practices are decades ahead of the one in IT (even with the occasional screwups). Their analyses are usually quite good too. But there is nothing a journalist cannot disfigure, once he sets his mind to it :-(.

Re:Fly by wire.... (1)

PPH (736903) | more than 2 years ago | (#39837355)

About incidents, they are quite good. Unfortunately, they don't seem to respond worth a damn until there has been an incident. And all to often, its got to involve fatalities.

The software biz, albeit quite variable in its responses, does make attempts to plug discovered holes based on input from security researchers.

I've worked in both industries. And I know of some amazingly bad decisions that were made on the 777 and copied onto the 787. Even after the screw-up was discovered on the first model. Because fixing it would be a major PITA and expense to the customer as well as Boeing. Even going back to the 'old way' of doing things on the new model would raise an eyebrow over at the FAA. That would be a tacit admission of the error.

Re:Fly by wire.... (5, Insightful)

Registered Coward v2 (447531) | more than 2 years ago | (#39837093)

When i read the annotated black box transcript a few weeks ago, i asked airplane experts about this. They told me:

If one pilot pulls and the other pushes the stick, there is an optical and audio signal.

Also the person was questioned if he pulls the stick and he confirmed it. Unluckily it was already too late by then.

I am no expert, but the root cause was IMHO the crew ressource management and training problem.

While I agree it was a CRM issue; the control system design contributed to this, IMHO. Just because there is a visual and auditory clue at some point does not mean that is understood and remembered; or that it was even heard on more than a subconscious level. Having a visual clue helps, so when you look at a control you see the actual order to the system, rather than a neutral position. That helps operators realize what the system is doing and will help them realize when something is not in a position they expect for a given situation.

Personally, I prefer Boeing's approach of having the controls positioned where they represent the input the system is receiving, that allows a pilot to scan the controls and develop an accurate mental model of what the plane is being told to do; which they can then determine if it is appropriate for the current situation. Not having that picture requires much more inquiry and analysis which may take critical seconds away from correcting the problem.

This is not a problem unique to the aviation industry; I've seen it happen in others where there are complicated systems that have a myriad of controls and require an good understanding of the current conditions to ensure operators respond correctly. Three Mile Island is a good example of a similar set of conditions that lead operators to make bad decisions that were compounded by the control system design.

Unfortunately, it is far easier to say "pilot or operator error" than fix the underlying causes that lead to that error when they are system control related.

Re:Fly by wire.... (1)

mseeger (40923) | more than 2 years ago | (#39837131)

This is a "may be" issue. It may have helped, but to my best guess the answer is "probably not".

Both systems have advantages and disadvantages. This accident is far from being a killer argument in favor or against one system.

I wish the systems were not so much aligned with the manufacturers. That would make all analysis much easier ;-).

Re:Fly by wire.... (5, Informative)

bears (21313) | more than 2 years ago | (#39837481)

On an A320, the audio signal is to have the in-cockpit speakers bawl 'DUAL INPUT, DUAL INPUT' at you incessantly. It's not some small ding you can't hear.

Re:Fly by wire.... (1)

mseeger (40923) | more than 2 years ago | (#39837519)

I hope my comment did not imply that it would be a small ding ;-).

Re:Fly by wire.... (0)

legont (2570191) | more than 2 years ago | (#39837523)

Unfortunately, it is impossible to train airbus crew to fly the plane. Airbus autopilot has at least four different levels of automation called "laws" http://www.airbusdriver.net/airbus_fltlaws.htm [airbusdriver.net] . Each one is disengaged by autopilot itself, if necessary. Now, there is no way to manually switch between laws hence pilots can not learn them. On top of it, airbus flies differently so all their past experience is somewhat useless or even counterproductive. In a way, I know how to fly with my 150 hours better, than your typical airbus pilot. It is scary.

Re:Fly by wire.... (1)

mseeger (40923) | more than 2 years ago | (#39837607)

Not a very helpfull statement....

You don't and you shouldn't train situations like "DIRECT LAW" in a real plane (test pilots yes, but no regular pilot). That's what simulators have been invented for.

Concerning the differences between the Airbus planes: i heard differently from pilots flying both. But those statements were not completely without bias. So i consider this point as "being discussed".

yes, fly by wire downed the plane... (4, Informative)

bigmaddog (184845) | more than 2 years ago | (#39836981)

Did the same person write the title and the summary of this story? Fly by wire has nothing to do with the control stick and everything to do with how the control inputs are sent to the control surfaces; some control schemes simply permit some cockpit/stick design decisions that in turn led to what the story is actually talking about... Though, you know, I think they should go back to lever & cable systems, then the pilot wouldn't be able to stall the aircraft because he'd never be able to exert enough force to pitch up. :P

Re:yes, fly by wire downed the plane... (-1)

Anonymous Coward | more than 2 years ago | (#39837021)

You should stop writing until you get a clue. Fly by wire enables the split stick condition. When the sticks are tied together wig pushtubes and bellcranks, they don't split. Further, your wrongness is compounded by the existNces of aerodynamically balances control surfaces. The 60's era heavies could fly without hydraulic boost, albeit poorly. Look up the 707 flight controls and anti-servo tabs and whatnot.

Re:yes, fly by wire downed the plane... (4, Insightful)

vakuona (788200) | more than 2 years ago | (#39837065)

Fly by wire means your electric inputs are converted into physical inputs by some other system. The two control sticks could be joined together, and the system would still be fly by wire if there was no mechanical link between the controls and the actual surfaces you are controlling.

So who needs to get a clue now?

Re:yes, fly by wire downed the plane... (1, Insightful)

ceoyoyo (59147) | more than 2 years ago | (#39837091)

It sounds like the problem here was that the plane was NOT in it's full fly-by-wire mode. The flight computer had given some control back to the pilots when it lost the pitots, and the pilots screwed it up.

Feedback is important (1)

Whammy666 (589169) | more than 2 years ago | (#39836985)

I wondered why the pilots didn't respond to a stall by instinct. The feel of the plane should have been a major clue that something was wrong with their course of action. A lack of feel in the FBW system would certainly be a contributing factor in this kind of situation.

Re:Feedback is important (1)

ericloewe (2129490) | more than 2 years ago | (#39837039)

I'm by no means a pilot, but from what I've heard, you can't really tell unless you have some visual cue, like the ground in front of you, instead of below you.

Re:Feedback is important (4, Informative)

AC-x (735297) | more than 2 years ago | (#39837071)

FYI they belly-flopped the plane, the nose was actually pointing up the whole time they were falling.

Re:Feedback is important (2)

Registered Coward v2 (447531) | more than 2 years ago | (#39837049)

I wondered why the pilots didn't respond to a stall by instinct. The feel of the plane should have been a major clue that something was wrong with their course of action. A lack of feel in the FBW system would certainly be a contributing factor in this kind of situation.

The problem is your "feel" could be completely wrong when you lack visual clues and lead you to actions that worsen a situation. Pilots are trained to trust their instruments rather than what their body is telling them because of this.

Re:Feedback is important (0)

Anonymous Coward | more than 2 years ago | (#39837085)

You have no feel when flying without visual aids. Hard to understand without being through it. If you fly through cloud without instruments for about 10 or 20 seconds in a light aircraft trying to keep it straight and level you'd be amazed what your instruments say when you look back down at them.

Re:Feedback is important (3, Insightful)

trout007 (975317) | more than 2 years ago | (#39837097)

It's the same reason why a motion simulator ride at an amusement park can be so convincing. You feel like you are flying but you are sitting right there. Tilting backwards feels very similar to forward acceleration. Flying in a controlled banked turn feels alot like sitting still.

Re:Feedback is important (1)

gstrickler (920733) | more than 2 years ago | (#39837115)

As others noted, you can't always tell by feel alone, and they were flying in a storm at night, visibility sucked. Instruments and feedback on the controls are the best indicators in those conditions, and that plane doesn't give the same level of control feedback as others, so it all comes down to instrumentation.

Real cause is lack of angle of attack indicators (2)

csirac (574795) | more than 2 years ago | (#39837381)

They did get stall warnings, but only when they (briefly!) tried to put the nose down a bit, early on in the transcript. Pulling the nose back up, the stall warning went away - the plane's stall warning couldn't work at such low airspeeds or AoA (angle of attack).

So they had an alerting system that responded counter-intuitively. Pulling the nose up into a deeper stall actually made the stall warning go away. I've read on pprune that many pilots consider that if commercial airliners had AoA displayed in the cockpit (plus the training to use them) - apparently modern aircraft are already measuring AoA, it's just not displayed - it would be a far less ambiguous indication of stall and how deep it is, as opposed to guessing from a combination of airspeed, flap/slat settings, weight, attitude & wing loading.

You could almost say.. (0)

Anonymous Coward | more than 2 years ago | (#39836993)

The co pilot surrendered control of the aircraft to his colleague!

Re:You could almost say.. (-1)

Anonymous Coward | more than 2 years ago | (#39837025)

At least they didn't load their passengers while retreating from the roof of the embassy there, while waving white flags. American surrender-monkeys. https://www.google.com/search?q=vietnam+roof+of+embassy [google.com]

Boooo Airbus.... USA! USA! (-1, Flamebait)

bazmail (764941) | more than 2 years ago | (#39837017)

Yanks sure like to bash Airbus at every opportunity.

Re:Boooo Airbus.... USA! USA! (1)

Sponge Bath (413667) | more than 2 years ago | (#39837069)

Crass regionalism is a global phenomenon.

Re:Boooo Airbus.... USA! USA! (4, Insightful)

Oswald (235719) | more than 2 years ago | (#39837079)

Are you under the impression that The Telegraph is an American publication?

Re:Boooo Airbus.... USA! USA! (1)

jv lee (2048576) | more than 2 years ago | (#39837139)

FWIW, I also bash Boeing at every opportunity presented to me, then create a few opportunities on my own for good measure.

Re:Boooo Airbus.... USA! USA! (0)

Anonymous Coward | more than 2 years ago | (#39837265)

Yanks sure like to bash Airbus at every opportunity.

Ever since that first demo flight ended in a fiery crash because of a flaw in the fly-by-wire system, some people have been nervous about it. Funny how that works ;-)

Nonsense - Boeing fan at the wheel? (2, Interesting)

Anonymous Coward | more than 2 years ago | (#39837019)

The problem described in the summary has nothing whatsoever to do with fly-by-wire. Yes, there may be an opportunity for improvement in that there should be some force feedback from one stick to the other. By that does not mean the plane can not be flown by wire. Plus, the fundamental issue in this accident is an operator mistake not corrected for by the other people present. I.e. it's a crew training & management issue.

Just in case this is a Boeing fan doing some Airbus bashing: Boeing is using fly by wire as well in the 777 and later designs.

Re:Nonsense - Boeing fan at the wheel? (1)

thammoud (193905) | more than 2 years ago | (#39837263)

With mechanic control feedback. Pilots see each others actions.

Re:Nonsense - Boeing fan at the wheel? (1)

drerwk (695572) | more than 2 years ago | (#39837565)

Totally agree, but they would feel the action - which seems to me even better than see.

Begs the Question? (0)

Anonymous Coward | more than 2 years ago | (#39837033)

With its nose pointed too far upwards, it was little wonder that the Airbus had eventually lost momentum and stalled. But this analysis begs the question: even if one pilot got things badly wrong, why did his two colleagues fail to spot the problem?

Reporters are professional trained in how to write. Surely they should learn the use of this logical fallacy?!

Re:Begs the Question? (2, Insightful)

Anonymous Coward | more than 2 years ago | (#39837133)

It's not a logical fallacy, the use of the term "begs the question" has meant "raises the question" for quite some time now, it's mostly just pedantic assholes that refuse to recognize the difference.

Communication failure (1)

Hentes (2461350) | more than 2 years ago | (#39837037)

It wasn't mechanical feedback that was lacking. The crew should have communicated better.

Re:Communication failure (2)

ceoyoyo (59147) | more than 2 years ago | (#39837109)

Or somebody could have looked at the artificial horizon at any point, at the GPS ground speed indicator and/or the altimeter during the climb phase.

Only the airspeed indicators were out, and not even for the whole time. Were the pilots not looking at ANY of their instruments?

Re:Communication failure (1)

drerwk (695572) | more than 2 years ago | (#39837567)

The mechanical feedback facilitates a level of non-verbal communication. Assuming one seated pilot would know to push forward, he would at least feel - and that is much better than see that the pilot flying was not doing so.

Fbw and lack of feedback ... (1)

martin (1336) | more than 2 years ago | (#39837051)

The sticks dont follow either ie if rhe copilot pushes forward the pilot gets no feedback on his stick this is happening. This was an issue here not fbw itself.

Other factors at play also of course

Is this written by Boeing? (2, Insightful)

houghi (78078) | more than 2 years ago | (#39837059)

While there is no doubt that at least one of AF447's pilots made a fatal and sustained mistake, we still will blame the competitions system, so that they will buy ours and not theirs.

Don't get me wrong, Airbus would do the same. Or at least all of the governments involved.

Re:Is this written by Boeing? (-1)

Anonymous Coward | more than 2 years ago | (#39837127)

If the system cannot correct for the fatal and sustained mistake of one pilot, I'd say the system is to blame.

Hi Slashdot... (2, Insightful)

bazmail (764941) | more than 2 years ago | (#39837081)

Where's the editorial control today? How did they sneak this obvious industrial hit-piece past the editors? Didn't have your coffe yet huh?

And as there are mostly americans here on slashdot people will be only too willing to drink to anti-European kool aid.
I expected better from slashdot.

Re:Hi Slashdot... (0)

Anonymous Coward | more than 2 years ago | (#39837099)

Silly boy. Expecting better from Slashdot will doom you to disappointment every time.

Re:Hi Slashdot... (0)

Anonymous Coward | more than 2 years ago | (#39837125)

Where's the editorial control today? How did they sneak this obvious industrial hit-piece past the editors?

I don't think you've been reading slashdot for very long. Almost all editors have been shit for many years now.

Re:Hi Slashdot... (1)

rgbrenner (317308) | more than 2 years ago | (#39837315)

the editorial control today? this is your first day here isnt it?

"10 degrees of pitch" (0)

Anonymous Coward | more than 2 years ago | (#39837117)

Ye gods, what a horrible realization.

Any vindicated engineers? (0)

michaelmalak (91262) | more than 2 years ago | (#39837143)

I wonder if there was an Airbus engineer who had suggested mechanical feedback linking the sticks, was overruled, and now feels vindicated. And if so, I wonder whether the culture at Airbus will cause him to be promoted or to be fired.

Codsup (1)

GerryHattrick (1037764) | more than 2 years ago | (#39837147)

Read it ALL on pprune (ignore the permanent troll there), and you'll see that things were quick, but not necessarily simple. The sad guy who just 'pulled' to misleading 1g stall had his young wife in the back, so don't ever think he wasn't trying. I do believe think the sidestick movement (lack of) and logic (deltaT, not proportional) is suboptimal, but that wasn't all.

Attention, screeching children (5, Insightful)

Oswald (235719) | more than 2 years ago | (#39837179)

Red herring #1: This isn't news.
--Maybe not to some of us. But TFA is new, and in a more general publication than the sources many of you have cited.

Red herring #2: This is an American anti-Airbus hit piece.
--Probably not. The Telegraph is a UK publication, and the title seems deliberately designed NOT to call out Airbus. See #3...

Red herring #3: The title blames FBW, that is a separate issue from back-driven controls.
--Quite right. Perhaps the author wished to avoid seeming anti-Airbus; perhaps he just wasn't precise in his phrasing. You sure don't have to read far to find out the truth.

Red herring #4: This is bullshit. The pilots fucked up.
--Perhaps you're not familiar with the English phrase "contributed to." It doesn't mean the same as "caused." In any safety-critical occupation, a piece of equipment that obscures the actions of one of the team members impedes the type of cross-checking that was a major reason for using a team in the first place.

No system is perfect. People are perfectly free to say that they think this is a minor issue which will only come up in very rare circumstances, more than compensated for by merits of the side-stick. Others might argue that the risks outweigh the benefits. I am smart enough to know that I am not qualified to have an opinion on the issue.

I'm just tired of the hysteria here.

Re:Attention, screeching children (0)

Anonymous Coward | more than 2 years ago | (#39837259)

I suppose, yes, the FBW did contribute to the crash. It didn't stop the pilot doing something that it usually would have, had the air-speed pitot tubes been in working order.

Re:Attention, screeching children (1)

darkmeridian (119044) | more than 2 years ago | (#39837437)

The problem with over-automation is that pilots may not know exactly what to do in case of an emergency, where decisions have to be made in split seconds. I mean, the entire crash took eight minutes to unfold. The Airbus paradigm keeps the pilot out of the loop to minimize fatigue. The crew is used to computers doing all the nitty-gritty stuff. However, when there's a stall warning, it takes way too long for them to realize what's going on.

Just check what the guy's doing (2, Interesting)

petes_PoV (912422) | more than 2 years ago | (#39837189)

Apparently, it's not possible, or practical to just look and see what the driver is doing. It takes

a big effort to look across to the other side of the flight deck, which is not easy

Now, it's a long time since I've been on a flight deck, but they weren't that big. What's changed so much that it's such a huge imposition for someone to look at the guy in the other seat and see "oh yes, he's pulling back on the stick" and then maybe slap him around the head until he stops.

Editing? English? (1)

DogDude (805747) | more than 2 years ago | (#39837295)

Could somebody please translate this wonderful collection of words into English?

But the fact that the second pilot's stick stays in neutral whatever there is input to the other is not a good thing.

It seems like an important sentence, but I have no idea what it means.

Re:Editing? English? (1)

pipatron (966506) | more than 2 years ago | (#39837615)

Now, I'm not an expert in the English language, but I can try:

It means that whenever one pilot pulls his stick (no pun intended), the other pilot won't sense anything in his stick. The other pilot will simply not be aware that the first pilot is doing some (possibly incorrect and fatal) action.

An alternative would be for the sticks to be linked, either mechanically (difficult) or electronically using servo motors (easy and common even in commercial products).

Stephen King? (0)

Anonymous Coward | more than 2 years ago | (#39837331)

No relation I assume?

stall == high AOA, and no AOA indication (2)

darkeye (199616) | more than 2 years ago | (#39837349)

in my opinion the biggest issue was that the pilots weren't aware of the huge angle of attack (AOA) that they were maintaining, and AFAIK they didn't have an AOA indicator in the cockpit. it was also dark and in a big storm, thus there were no external references.

they had the plane pitched up about 10 degrees, which is not that big. they also had speed - they were close, but not below stall speed. but at the same time they were falling badly, which meant their angle of attack on the wing leading edge was at least 30 degrees if not more.

remember that the basic reason of a stall is always high AOA - not speed, not pitch, but high AOA.

of course, you 'should' be able to put it together - high pitch, large negative vertical speed -> high AOA. it seems the young co-pilot didn't. :(

The speed sensors froze up (1)

acoustix (123925) | more than 2 years ago | (#39837353)

Last year I watched a special on a TV network about this tragedy. I can't remember if it was History, Science, etc. But they had shown that there was a very good chance that all of the speed sensors on the plane had frozen over with ice. Those speed sensors are critical to the operation of a fly by wire plane regardless if it's being flown manually or by auto pilot.

I'll try to find the video or transcript because it was a very well thought out scenario of what likely happened. The experts on the show said there wasn't much the pilots could do if the sensors had actually frozen over.

Re:The speed sensors froze up (3, Interesting)

darkeye (199616) | more than 2 years ago | (#39837395)

yes, this was how the whole thing started - that they got an incorrect airspeed indication, and thus the autopilot disengaged. after a short while, the speed indication was correct again. unfortunately, human errors added up starting from there.

although I would argue that the first mistake that they made was to fly into the storm, which every one else navigated around at that time. in aviation, you have to have at least 3 mistakes in a row to have an accident - here, flying into the storm, the frozen airspace indicator and then human error.

No single cause (0)

Anonymous Coward | more than 2 years ago | (#39837363)

http://en.wikipedia.org/wiki/Fallacy_of_the_single_cause

nuff said. hysteria over.

A dangerous design practice (0)

Anonymous Coward | more than 2 years ago | (#39837387)

The gold standard for software design in the aircraft industry is model-based design.

Everything comes back to the requirements document. The trouble is that the requirements document can never be perfect no matter how much quality control the system has. It is always possible to have a set of circumstances that the writers of the requirements document never thought of.

With very complex systems it is wise to start with a basic design that will fail safe. It is possible to design nuclear reactors that don't need active cooling. They don't rely on pumps to keep the reactor from mellting down. It is possible to design aircraft that don't stall. Burt Rutan demonstrated that with his canards.

Start with an inherently safe design, don't try to make the system safe with complicated systems that can never deal with all the possible contingencies.

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