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Fly-By-Wire Contributed To Air France 447 Disaster
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.'"
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.
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?
Are you under the impression that The Telegraph is an American publication?
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.
The first rule is: don't freak out. If you feel like freaking out is OK, then don't be a fucking pilot, mmkay? Pilots who freak out die. It's a time proven observation.
A pilot who doesn't know that the AoA and airspeed are sourced by the same set of vulnerable sensors is silly. Next time when you walk down the jetway have a look on your left before you enter the plane. You'll see the pitot tubes sticking out. As an engineer, they'd be the first things I'd distrust if their outputs would be in disagreement with other sensors. Icing happens all the time, it's more common than uncommon.
Those pilots had perfectly good input from the inertial platform, GPS and perhaps radio altimeter. They should have looked at their fine instruments, determined what their ground track speed was, what the attitude was, and figured out what to do. End of story.
A successful API design takes a mixture of software design and pedagogy.
Perhaps you're not a pilot too, and if you go read the technical briefs about the crash you'll find that "STALL, STALL, STALL" can be issued by this aircraft even when the aircraft is not stalling, and has no possibility of stalling.
If the guy flying the plane reacts to the STALL warning going off by pulling the stick back then you are already dead.
It's just a matter of time.
Every component in the system introduces the possibility of error, agreed.
People can detect and correct certain classes of error better than machines, but machines can detect and correct certain classes of error better than people.
People can self-repair, to an extent. Blake's 7 Liberator-style auto-repair is still sci-fi. Sadly.
Well-trained humans can identify errors in their training but can also forget the training that is correct. Computers cannot (yet) do either.
A perfect balance is what we need.
It's a small world and it smells funny; I'd buy another if it wasn't for the money; Take back what I paid (SoM)
That's one point against vi in the holy war with Emacs. System operating modes are distracting to humans. A state machine inside a state machine is loading short term memory too much in a critical situation.
First, I fail to see the relationship between joysticks and tactile feedback, secondly it's very possible and often done for fly by wire systems to provide force feedback and other haptic ques. The failure is with the designers of the system who opted to omit such feedback, not intrinsic to fly by wire.
To paraphrase Churchill... Never in the history of aviation blogging has so much crap been said to so many by one who new so little.
Vacuum system on an A330? The only vacuum system on an A330 is the toilet.
The static system worked fine. They knew their altitude all the way to impact.
The pitot was heated. It was heated from the moment the first engine was started, automatically. The pitot design was unable to cope with the amount of supercooled water thrown at it. The subsequent design had problems, too. The current pitots by Goodrich work fine.
Nobody 'put their head in the sand.' They made a fundamental error at the start and then were deeply confused as to what their problem really was.
Seeing you expound an A330 crash based on your light aircraft experience is like watching a model rocketeer tell us what went wrong with Challenger based on his experience with cardboard tubes with fins.
The accident report is painful to read because it was so avoidable. Your post made me as angry as the accident made me sad because you don't know squat about jet aviation yet feel free to tell us exactly what went wrong.
Never shake hands with a man you meet in a fertility clinic.