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Investigators Suspect Computers Doomed Air France Jet
DesScorp writes "Investigators working with the wreckage of Air France flight 447 believe the aircraft suffered cascading system failures with the on-board computers, eliminating the automation the aircraft needed to stay aloft. 'Relying on backup instruments, the Air France pilots apparently struggled to restart flight-management computers even as their plane may have begun breaking up from excessive speed,' reports the Wall Street Journal. Computer malfunctions may not be an isolated incident on the Airbus A330, as the NTSB is now investigating two other flights 'in which airspeed and altitude indications in the cockpits of Airbus A330 aircraft may have malfunctioned.'"
"The fancier they make the plumbing, the easier it is to stop up the drain." -Scotty
Why can't they use a battery-operated GPS-based measure of airspeed as a backup
Because GPS knows nothing about *airspeed*.
A GPS recorded speed of 100mph, into a 50mph headwind = 150 mph airspeed.
Flights are getting more and more automated. It used to be up to the pilot to take off and land, and the autopilot would fly the bit in the middle in good conditions. Now the autopilot takes off and lands too. The pilot is there in case of emergencies. But I would still wager that a computer would statistically be better than a human overall, otherwise the airlines wouldn't deploy this.
This case is of a plane travelling at such high speed and altitude that it only has a tiny window of opportunity between breaking up, stalling, or falling into the tempest below. If the computer systems keeping it in that window fail, then the pilot has little chance of actually fixing things. The alternative is to fly a lot more conservatively, with bigger margins of error. That would mean flying slower, and at lower altitude. Which means longer flights, that burn more fuel, hence cost more.
"I think it would be a good idea" Gandhi, on Western Civilisation
I think you both are thinking of the FAA. The whole purpose of the NTSB is to research and investigate civil transportation accidents. They then present their conclusions and recommendations to the regulating authority in that industry. For the airline industry, the FAA then has to implement any recommendations. For the most part, the FAA does not always implement all the recommendations due to cost, business concerns, practicality, national concerns, politics, etc.
In this case, the black boxes have not been recovered and it might be very difficult to pinpoint a cause without them. But the NTSB knows of similar cases that may have occurred in the US that did not lead to accidents. If there job wasn't to ensure that the fleet of aircraft in the US is safe, they may just sit on their asses and do nothing. But it is their job to ensure safety so they will investigate whether this might have led a situation similar to the Air France flight. They will probably share their data with Air France, the Brazilian authorities, Airbus, the FAA, etc when the investigation is concluded.
Well, there's spam egg sausage and spam, that's not got much spam in it.
it doesn't speed up the plane... but the plane is moving 150 mph compared to the air. That's air speed.
Let's reverse it.. A plane must travel so fast to stay in the air.. let's say 130mph to keep things sane. So if you have a plane flying at 140mph with no wind any direction, the plane will stay up. That same plane could slow to 125mph with a 15mph headwind, and still stay up since in effect the plane is "traveling" at 140mph. Now if there was a TAIL wind of 15mph while the plane was flying at 125mph, the effective speed of the plane would only be 110mph and it wouldn't be able to stay up, it would stall.
Last time I checked the air france black box recorder hasn't been located let alone pulled out of the ocean. Without having the black box how can the NTSB be making speculations as to the cause of the downed flight? Others are speculating things like the Rudder had problems, Turbulence, this computer bug.
Until they know what the actual cause is they should avoid speculation because it does absolutely nothing other then fill media headlines with non-sense.
The articles are pure FUD, and the summary is worse. The A330 doesn't need computers to "stay aloft" any more than your PSU needs an OS to power your motherboard. The rest of the functionality is pure gravy.
All these hysterical articles about computer failures always forget that the computers are a BONUS, and it is quite frankly becoming less and less insane to start believing in anti-Europe propaganda. It may indeed be true that pilots are becoming too accustomed to their presence, but in the meantime their high uptime has saved more lives from pilot error than the resulting complacency will ever cost.
This case is especially ridiculous, because modern computer controlled aircraft will actually handle sensor failures BETTER than ones without them. Had the Air France plane had the most up to date equipment, the computers would have used other sensors to estimate a safe range of approximate speeds and provided the pilots with a fast/slow indicator. It's even possible that this is exactly what happened, but something else went wrong.
Even if the computers just shut themselves down, it was still the sensor info that was invalid, so how would a plane without computers have fared any better?
It's also complete bullshit to say that the pilots can't override the computers. In normal flight, the computers *aid* the pilots. For example, avoiding a collision is easier in an Airbus, because pilots can just pull the stick back hard and the computers will automatically give the best possible climb performance, closer to the stall speed than a Boeing pilot would ever dare to go. Meanwhile, the pilot can look out the window instead of at an instrument panel!
This is what happened with the "infamous" crash into the forest. The pilot was too low and slow, and when he did pull up, the aircraft didn't "let him" because even maximum performance wasn't enough and the plane would have dropped like a stone had it been a Boeing. The computers probably saved everyone who did walk away from that crash!
IF the computers actually malfunction, they will turn themselves off. If they don't, the pilots can turn them off manually.
Scary stuff.
The Wall Street Journal article oversimplifies the problem with the Airbus
design philosophy. In effect; Too Damn Much reliance on the automated flight
control system for basic safety-of-flight.
A prime example?
Rudder hinges.
Airbus has notoriously
http://en.wikipedia.org/wiki/American_Airlines_Flight_587
underbuilt the rudder hinges on the A300 (and, no doubt, the A330) in the
interest of lightness and efficiency. They have chosen to rely on the
automated flight control system to limit loads on the structure, instead of
building the necessary robustness into that structure.
This is great when flight conditions are all peachy, but in a thunderstorm, at
night, with sensors (iced-up pitot tubes?) that are prone to failure, well
then you have a failure scenario that the designers never built into their
simulations, and the rescue/recovery teams in the south Atlantic find the
rudder 37 miles from the rest of the wreckage.
Forwarded from a colleague (names redacted);
>> This from a friend and NWA pilot I flew the B-757
>> with out of our Tokyo base.........Now obviously on the A-330
>>
>>
>> Well, I'm sure you have all heard of the Air France accident. I fly
>> the same plane, the A330.
>>
>>
>>
>> Yesterday while coming up from Hong Kong to Tokyo , a 1700nm
>> 4hr. flight, we experienced the same problems Air France had while
>> flying thru bad weather.
>> I have a link to the failures that occurred on AF 447. My list is
>> almost the same.
>> http://www.eurocockpit.com/images/acars447.php
>>
>> The problem I suspect is the pitot tubes ice over and you
>> loose your airspeed indication along with the auto pilot, auto
>> throttles and rudder limit protection. The rudder limit protection
>> keeps you from over stressing the rudder at high speed.
>>
>> Synopsis;
>> Tuesday 23, 2009 10am enroute HKG to NRT. Entering Nara Japan
>> airspace.
>>
>> FL390 mostly clear with occasional isolated areas of rain,
>> clouds tops about FL410.
>> Outside air temperature was -50C TAT -21C (your not supposed to get
>> liquid water at these temps). We did.
>>
>> As we were following other aircraft along our route. We
>> approached a large area of rain below us. Tilting the weather radar
>> down we could see the heavy rain below, displayed in red. At our
>> altitude the radar indicated green or light precipitation, most
>> likely ice crystals we thought.
>>
>> Entering the cloud tops we experienced just light to moderate
>> turbulence. (The winds were around 30kts at altitude.) After about
>> 15 sec. we encountered moderate rain. We thought it odd to have
>> rain streaming up the windshield at this altitude and the sound of
>> the plane getting pelted like an aluminum garage door. It got very
>> warm and humid in the cockpit all of a sudden.
>> Five seconds later the Captains, First Officers, and standby
>> airspeed indicators rolled back to 60kts. The auto pilot and auto
>> throttles disengaged. The Master Warning and Master Caution
>> flashed, and the sounds of chirps and clicks letting us know these
>> things were happening.
>> The Capt. hand flew the plane on the shortest
>> vector out of the rain. The airspeed indicators briefly came back
>> but failed again. The failure lasted for THREE minutes. We flew the
>> recommended 83%N1 power setting. When the airspeed indicators came
>> back. we were within 5 knots of our desired
Both are important.
Too little airspeed = too little lift and a stall (which is very dangerous on something as big as an airliner, though theoretically recoverable at that altitude granted you'll waste quite a bit of fuel and scare the living daylights out of the passengers).
Too much airspeed = shock waves rip the wings right off the plane. They're not fighters and while those wings actually are pretty strong they can only make them so heavy and be able to carry payload.
The actions of the computer? How did the computer make the problem worse?
Here's the chain of events in an A330:
1. Computer in control
2. Sensors fail
3. Computer: "sorry dudes, you're on your own"
4. Pilots in control
5. Pilots: "Fuck"
Here's the same for a B767:
1. Pilots in control
2. Sensors fail
3. Pilots: "Fuck"
No, you're completely wrong. First of all, hydraulics move the control surfaces on all large aircraft. Nothing else has enough power while being light enough.
Old aircraft controlled the hydraulics with mechanical cables, newer ones with electrical cables (Boeing too). The computers in question are not needed for electrical signaling to the hydraulics systems.
The damage required to make the aircraft completely unflyable would be so severe it would affect any aircraft, and it has nothing to do with how well the computers are working.
When the computers went bye-bye, the pilots had complete control of the aircraft, as designed. Furthermore, the computers didn't malfunction - they turned themselves off because they couldn't trust the damaged sensors, but *neither could the pilots*. To characterize this as a computer problem just because they shut down is stupid and dishonest.
Remember that the Wall Street Journal authors apparently have no knowledge whatsoever of technical things. That doesn't stop them from writing articles about technical things, however.
Air France didn't begin replacing the malfunctioning pitot tubes in the Airbus until April 2009, and the tubes were not replaced yet in the crashed aircraft. The computers were not at fault apparently; there is no reason to suspect a computer malfunction.
Notice that the Wall Street Journal article, Computer Failures Are Probed in Jet Crash, says exactly that: "... seemingly beginning with malfunctioning airspeed sensors..." The "airspeed sensors" are the pitot tubes, which in the Airbus have been known for many years to collect ice in unusual conditions, and to stop giving reliable data.
The computers did what they were programmed to do, apparently. They stopped operating when they calculated that the data was bad. At that point the pilots needed to fly the plane themselves. However, the aircraft was operating in what is known in the aircraft industry as the coffin corner". There was apparently no way a human could fly the aircraft safely at the speeds necessary to get the craft to France in time, since in a severe thunderstorm the airspeed could not be known accurately enough to prevent overstressing the aircraft.
The Wall Street Journal apparently has NO new information. Here is a quote from the article: "The Air France crash could become the first since the 1980s in which U.S. and European investigators try to piece together a probable cause in a high-profile crash without the help of information from at least one of the plane's black boxes -- the digital recorders containing detailed flight data and cockpit conversations from the flight." There is apparently NO honest reason for the Wall Street Journal to publish an article now, claiming "Computer Failures".
Quote from a June 25, 2009 Aviation Week article, EASA: No Action Soon On A330 Pitot Tubes published three days ago: "The pitot tubes have come under fire in the wake of the crash of AF447 because the accident aircraft, an A330-200, broadcast maintenance messages just before all contact was lost, indicating inconsistent speed information and potential problems with the pitot tube."
Should the Wall Street Journal be trusted for financial information? Apparently the publication did NOTHING to stop the present corruption in the financial departments of the U.S. government. Warren Buffett very publically called derivatives "financial weapons of mass destruction" beginning in 2002. The corruption was caused by the removal of laws designed to prevent fraud, at the beginning of George W. Bush's first term.
Apparently the Wall Street Journal always serves the profit of its advertisers and others in the U.S. financial industry. If publishing the article at this time and in the way it did indicates anything other than ignorance, it could be theorized that someone connected with the publication has investments in Air France or Airbus Industries.
Other similar incidents concerning the Airbus 330 are being investigated, according to a June 25, 2009 Associated Press news release, US panel probes 2 incidents involving Airbus A330s. The Wall Street Journal has access to the Associated Press, obviously. Why did it publish its misleading article two days later, which appears to blame the "computers"? The REAL story is apparently that apparently such incidents with the Airbus are common.
Here
tl;dr version:
On two occasions I have been asked, 'Pray, Mr. Babbage, if you put into the machine wrong figures, will the right answers come out?' I am not able rightly to apprehend the kind of confusion of ideas that could provoke such a question.
--Charles Babbage
This signature serves no purpose other than to help you see which posts were made by me.
There are certification bodies in the US, Europe and many other countries that define what that margin is. The greater the margin the heavier the plane will be, the more fuel it will need and the less load it will be able to carry. So your question really is asking if all these certification bodies are idiots. They are not and are definitely better at it than your armchair speculation. Simple evidence is looking at the rate of crashes and fatalities over time despite the increasing amount of air travel.
How come you don't walk around always wearing a bulletproof vest? Why aren't all your house doors, windows and walls armoured? Because there are costs and benefits and they all have to weighted together to come up with something appropriate.
It would not tear apart in simple level flight within the normal speed range. It could be torn apart going too fast (ie beyond the certification limits imposed by those national bodies) but even then would not be in level flight but likely dropping. It was a massive thunderstorm with huge air currents they were going through. This is an example of what planes can survive where the plane looped, parts flew off and the wings got permanently bent. This is an example of a certification test for wing strength. FAA regulations require that wings survive 1.5 times (150 percent) of the highest aerodynamic load that the jet could ever be expected to encounter during flight for 3 seconds. That applies to all airliners. The pitot tubes keep being mentioned because they tell you how fast you are going relative to the surrounding air. If they iced over then you don't know and going to slow will result in a stall, going fast increases discomfort and going too fast can result in bits of the plane breaking off.
But to be clear it required abnormal circumstances to break apart. Way beyond anything normally or abnormally encountered. If the circumstances happened with any regularity then you would hear about this kind of accident more often.
The fault messages are generally intended for maintenance so that when the plane arrives they can be repaired as quickly as possible and the plane turned around. They also help with long term tracking of wear and tear. Current blackbox recorders record a huge amount of data which would be infeasible to transmit, especially when it has to go via satellite such as when over oceans. Plane crashes are very rare (that is why they make the news) and it is even rarer to not find the blackboxes.
You overestimate the ability of humans. We are long gone from the days of the lonesome hero sweating it with the control stick. A flying plane is a complex mechanism. You have many control surfaces, air pressures and speeds, centre of gravity, fuel consumption, engine abilities, aerodynamics etc all to take into account. A computer program can do all of that so many times better than a human which includes being both more economical and reacting quicker. The people who make planes are not idiots. Ultimately you have to take the underlying tools you use as is. For example I don't see you insis