Slashdot Mirror
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."
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.
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
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.
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?