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Computers Key To Air France Crash
Michael_Curator writes "It's no secret that commercial airplanes are heavily computerized, but as the mystery of Air France Flight 447 unfolds, we need to come to grips with the fact that in many cases, airline pilots' hands are tied when it comes to responding effectively to an emergency situation. Boeing planes allow pilots to take over from computers during emergency situations, Airbus planes do not. It's not a design flaw — it's a philosophical divide. It's essentially a question of what do you trust most: a human being's ingenuity or a computer's infinitely faster access and reaction to information. It's not surprising that an American company errs on the side of individual freedom while a European company is more inclined to favor an approach that relies on systems. As passengers, we should have the right to ask whether we're putting our lives in the hands of a computer rather than the battle-tested pilot sitting up front, and we should have right to deplane if we don't like the answer."
A gazillion years ago, I rode on some airline (Muse? Love? Some weird four letter name) about two days before they were scheduled to shut down, and I guess the pilot just felt like flying figure-8s over the Grand Canyon ("bad weather in Las Vegas", yeah, right).
It was really something, a view like you would not believe, and if we had not been doing our figure-8s over something that impressive, I would have been really pissed, because my tummy was also doing figure-8s.
From everything I've read the landing in the hudson seems like a fluke. Apparently landing in water is far more dangerous than landing on land. Granted, with lots of buildings all around him I'm not sure the pilot had a lot of options.
I did take some exception to the term "battle-hardened" - a fair percentage of pilots who go through serious air emergencies end up dead, and since so few emergencies happen few pilots are experienced with them. On the other hand, the flight computer has the experience of every simulated and real emergency any plane has ever been through. Sure, humans can practice in the simulator as well, but the reality is that costs mean that no individual gets that much time in the simulator. Due to the magic of software when one flight computer knows how to handle some situation, they all do.
I suspect the Boeing design reflects the American legal system. If the plane goes down and it is the pilot's fault, you can sue the pilot. Maybe you can even sue the airline who trained him. On the other hand, if the plane goes down and the pilot had no control then you can sue the aircraft manufacturer. Never mind that the design saves lives - better to allow thousands to die at somebody else's hands than one to die at your own. Gotta love the tort system.
For the same reason we'll allow tens of thousands to die every year in auto accidents due to driver error but we'd never consider automating driving because maybe somebody might die every year or two due to a computer error.
Gosh, that was such a terribly worded article summary I can't decide if the author is a regular 'editor' of /. or just a typical reflection of the poor taste and low competence of the /. editors. Would you prefer one lump of incompetence or two with your /. articles?
Anyway, I'd hate to generalize from my poor abilities as a former pilot, but I tend to favor machines over humans. As Einstein noted, there are no limits to human stupidity, but you can design any degree of redundancy you want into mechanical systems. The simple question is cost versus probabilistic safety.
As should be expected from /., the treatment of the design trade-off in the article summary was amazingly shallow. In extreme cases, the designers create planes that cannot possibly be flown by humans. Such fly-by-wire planes may involve control optimization with negative dynamic stability and feedback loops that can only be satisfied at computer speeds. In particular I'm thinking of a fairly recent jet fighter that had to have PROPER corrective feedback something like every tenth of a second.
As regards the storm, I actually came close to getting killed when something like that caught me off guard. Scaling those possibilities up... Well, that's a big chunk of the reason I mostly avoid flying these years.
With regards to planes, my fuzzy recollection is that the DC-10 had the worst safety record for commercial airplanes. However, every time I look at a 747 it boggles my imagination that the thing can fly. Continuing with Airbus, I remember an interesting crash in Nagoya a few years ago that involved the pilots essentially getting into an argument with the fly-by-wire system...
Freedom = (Meaningful - Coerced) Choice != (Speech | Beer^2), and sad sock puppets' bad mods avail them naught.
you can thank all the shitty pilots in the US airways on the breaking of the pilots union.
that union had some STANDARDS for who they would let fly.
If you cannot keep politics out of your moderation remove yourself from the Mod Lottery.. NOW!
That's pretty much what Boeing has done. The computers can fly the planes all day long. When something isn't right, the pilot can override the system simply by flying the plane like normal.
Now with the terrain following radar, this isn't a situation a pilot would be wanting to override the computer on. well, unless the plane nose dives and the computer proves/indicates it is unreliable. Then you have a choice, let the computer crash you or let the pilot attempt to not crash you. Only with Boeing is that possible, with airbus, regardless of the situation, the computer takes precedence.
A well trained pilot would know when to trust the computers and when not to. They would also know how to maneuver and react in situations. It's like the pilot that landed his plane in the river after losing an engine to birds. I don't think a computer would have taken that option and not only would it have been likely that all the passengers would have been killed, but bystanders as the planes computer attempted to correct and eventually goes down in a populated street.
what people are forgetting is that the airbus plane DID return nearly full control to the pilot (nearly because there are still limits to things like how much roll one can request, but these COULD be built in mechanically in the absence of fly-by-wire).
The real issue here is that the computer system detected invalid input and handed the control back to the pilots (under "alternate law" which means most safety rules are disabled), but the pilots may not have had enough information to know whether the control was handed back to them in a safe state, and if not, how to correct.
On top of that, the airplane was flying fairly close to the coffin corner (where the airplane is capable of going too fast and too slow simultaneously, and at this point, in this situation, computers are really helpful). One possible issue is that a gust of wind could have caused "mach tucks" if they were going a little too fast (thus causing downward pressure on the nose during gusts). These could have placed significant stress on the airframe until things started to fail. I have some other theories and observations about debris and ACARS messages, but this isn't the time for that now. All I will say is that all indications are the airplane was flying too fast, and there is NO indication that the instructions Airbus has sent to pilots will remedy that problem because it is unlikely that the pilots would have had sufficient information to act on them.
There are two issues involved here that need additional discussion though:
1) Are airplanes built to withstand forces as well as they used to be? Would, say, a DC8 be able to withstand more turbulance than an A330?
2) Do FBW systems provide sufficient feedback for a pilot to feel the plane? Could accidents be avoided in cases like this by adding additional feedback?
LedgerSMB: Open source Accounting/ERP
Agreed. Second paragraph: "It's been well established that Air France Flight 447 went down because on-board computers received conflicting information from sensors on the outside of the plane." Does this come from CNN or the wild speculation on airliners.net? It certainly doesn't come from accident investigators, who really have no idea yet what happened. What was cause and what was effect has not been at all established.
As to the point: Airbus does have alternate laws and direct law, when situations warrant it. Basically the logic, reading the technical briefs linked off airliners.net, is that if the computer isn't sure what's going on, it puts up big warning signs telling the pilot they're in control. Depending on what sensors and information is missing or contradictory, different protections get disabled, with corresponding indicators displaying warnings. It wouldn't surprise me if there wasn't a way to override the systems in the first place and place the plane into alternate or direct laws. The author quotes no technical documentation whatsoever and just says "Boeing" and "Airbus" which is a ridiculously broad brush.
The blogger is, in short, presenting wild speculation and misleading generalizations as fact, and rewarded by the /. community with healthy ad revenue and page views.
it's all electronic control, rather than hydraulic/ pneumatic controls. meaning its more simple, but it's also more rigid: if your computer goes, so goes your aircraft. yeah, they use triple redundant systems, but how many electric surges do you need to take out 3 computer systems in an aluminum tube?
learned from this interesting comment:
http://community.nytimes.com/article/comments/2009/06/02/world/europe/02plane.html?s=3
intellectual property law is philosophically incoherent. it is your moral duty to ignore it or sabotage it
the computer refused to let the pilots power up and climb out at the end of the pass.
Citation needed. Jet Engines are typically slow to respond to power. I can't find any source that indicates it was a computer design flaw, rather than electrical or engine flaw. I've looked for OEB 19/1 "Engine Acceleration Deficiency at Low Altitude," which would be relevant, but is apparently unavailable online.
In other fields such as medical diagnosis, allowing doctors to override the algorithm has been shown to decrease overall accuracy. Sure, sometimes they override a computer mistake, but more often they override the truth with their own mistakes: (cite)
It was later shown that FBW was not at fault. The aicraft sunk too fast anyway and by the time the pilots realised it, it was too late.
Jets take a number of seconds to spool up. If yu find a video with sound, you'll notice that the jets spool up just before it hit the trees - some 5s after the pilots commanded them.
AND, there were a bunch of pilot procedural failures at the same time (e.g. never below 100ft AGL), not to mention poor managerial decisions in allowing the flight plan to go ahead in the first place.
i read somewhere about a pilot flying an empty cargo plane (large-size jet, iirc) back who put it through a vertical loop (vomit-comet style) just for fun. seriously annoyed the company, as it knocked a few thousand hours off the lifespan of the plane.
Pilots in the airforce do this kind of stuff all the time. My colonel once had a fighter try to steal his landing approach when he was flying an empty cargo plane. Empty those things have tons of lift, so he threw the plane on its side and outturned the fighter to make the landing.
And like those scenes in Top Gun:
When my dad was in Thailand during the Vietnam War, they got a new general in at Kurat AFB, and marshalled the whole base for this formal ceremony. Right in the middle of it, an F-4 pilot buzzed the crowd at a very low altitude (the general on the stage hit the deck). Nobody could figure out who did it ("oh, sorry sir, all the planes were in the hangar that day"), so the guy was never caught. But then again, they didn't try very hard either, since that's the culture in the Air Force.
You're remembering the popular media speculation of the time, now turned into myth, which, as is often the case, was completely misinformed. See links posted by myself and others above in this sub-thread.
I use Friend/Foe + mod-point modifiers as a karma/reputation system.
What got me was how quick people were to attribute a divine hand into it - 'The Miracle on the Hudson' and so on. They aren't calling AF 447 'The Arbitrary Smiting over the Atlantic' are they?
If we can put a man on the moon, why can't we shoot people for Apollo-related non-sequiturs?