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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.'"
And that's why I always go for the isle seat. :)
I dunno, the NTSB usually drags their feet before stating anything. They usually don't make statements about suspicion of what may have happened without specific evidence. This seems like an unusual announcement from them, not their usual style. I wonder if they are compelled to state a truth that they fell won't be properly addressed otherwise. After all, Airbus is built in Europe not the US.
"The fancier they make the plumbing, the easier it is to stop up the drain." -Scotty
It would be ironic if the flight computers contributed to the accident, given the focus on designing them to prevent humans from contributing to accidents. Interesting video showing an A320 "refusing" to be crashed: At about 3 minutes, the software prevents roll beyond 67 degrees. At about 4:30, an attempt is made to stall the aircraft, at which time the software overrides the throttle settings. http://www.youtube.com/watch?v=LO5l6_d6yck [youtube.com]
Second, the US announcement of the two computer failures, neither of which caused an accident, presumably has nothing at all to do with Boeing's recent embarrassment over continuing delays and cancellations to the Dreamliner, and a desire to damage Airbus?
From scarped cliff or quarried stone she cries "A thousand types are gone, I care for nothing, no not one."
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.
So the trains in DC collided because even while the human operator tried applying the breaks the computer overrode the engineer and kept the train moving at a good speed. And now the investigators of the air france flight are saying computer failures on that flight caused the plane to stay at a high-inoperable speed, despite the pilot's best effort to slow down? Does it sound to anyone else like the computer revolution from Terminator, the Matrix, nearly every other future sci-fi movie is taking place? We never should have let them start beating us in chess now the computers are getting all uppity.
...the way aerospace (life critical and specialized or specific field oriented) software is created, it is highly bug free, quite the opposite of feature creep bloat you see everywhere else, but even at the code level there is avoidance of function calls that can introduce another level of abstraction and complexity and contribute to bugs and failure. It is in this way that using the process of elimination we can come to some conclusions about where error is or can most certainly exist, philosophy.
On a hardware level, we have redundant backups and check system....
As such there is one area that neither software nor hardware has but only as a secondary or implimentation of, position.
Human error in concepts, beliefs, philosophies, abstraction definition variation, etc... That which exist before the hardware and software and often what hardware and software creation is inspired by, directed by, guide lined by, etc..
If the philosophy base is wrong then its limitations will manifest through the software and hardware created under such a philosophy and eventually show the limitations, via failure to perform.
There are plenty examples of human philosophy errors, such as how it wasn't until the early 1990's that the Catholic Church exonerated Galileo over his observation the earth revolved around the sun.
The Atlanta Centennial park bombing where the 911 system failed because no-one gave the park an address..... or is the philosophy of programming a 911 system to require an address the error? Or is it a good thing that all things needing 911 are at an address?
My pet peeve of the computer industry, the button on the front of the computer marked with a 0 & 1 symbol(s), yet over engineering has resulted in the meaning of those symbols to be more than "off & on" and this went further in removing the hard on off switch so that when the software based power switch failed, you have to physically unplug the computer from the wall, or take teh battery out.
The correct philosophy for such a switch would be a multi position switch, which the consumer doesn't have to know more than is obvious... And ultimately the motivating philosophy behind the software switch is that of creating an OS that needs a shutdown sequence and time for it. When you think of this "0&1" switch, what better representation of distorting the most basic and fundamental concept of computers with overcomplexifabulocation can there possible be?
Software and hardware is not where the error lies in this Air France tragedy, even if there is failure or limitations found there in hardware and software, but the failure is in not providing a manual override. And if the technology has been made to complex for manual control.... then let grandma crawl under the desk to unplug the damn computer....shut it down until the real problem is fixed.
BTW, due to the competitive commercial nature of aerospace software development tools, there is a level of incompatibility between them and as such there is also motive for playing the lockin game regardless of any "unforseen" risk to others. Perhaps there is a place for open source software here!!!
Don't bow down to the stone image (Stone = computer hardware - Image = software) of the beast of man, for the beast is error prone and his image can be no better. Instead take a closer look at the code.... with many eyes.....
Yes, because what we really need is pilots who can program in assembly while rewiring the control panel with their toes. Blindfolded. At mach 15.
You've watched one too many holywood flicks. If your computers crap out while airborne, you don't have time to troubleshoot and diagnose. You just follow the preset procedures, and hope that one of them works before you hit the ground.
It is possible that you are at stall speed and moving several hundreds of km per hour in relation to the ground according to your GPS.
The winds are very strong higher up and if you're in a tail wind, the above scenario is very possible.
Have you thought this out? Why would flying into a headwind speed up the plane? Just sayin'...
It doesn't speed up, it just faces as much air resistance as it would face flying 150 mph with no wind. That's a quite significant value if you want to figure out if your plane is going to break apart or not...
A GPS recorded speed of 100mph, into a 50mph headwind = 150 mph airspeed.
Have you thought this out? Why would flying into a headwind speed up the plane? Just sayin'...
Lets say the pilot wants to fly at 500 knots AIS (Indicated Air Speed). They set ground speed to 500 knots with GPS but the air is going the other way to 100 knots. Airspeed is now 600 knots.
http://michaelsmith.id.au
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.
Pitot tubes were invented in the 1700s by the French Engineer Henry Pitot and later modified for airspeed measurements. They are also used to measure aerodynamic speed in Formula racing cars too among other uses. Here is a comprehensive article following the crash investigation that is informative with photographs and the timeline of theories.
I read both the articles posted. They do not qualify as the best investigation reports. They seem to be building "What if" scenarios from all data that is available. Other A330 failures (no recent crashes reported) and Other places where ice in Pitot tubes led to failure (The Wikipedia article has a lot of information on this and planes which had problems notably, the X31.) The investigators are clearly under pressure to say what they have found and they are unable to report "nothing" to the press. With no luck in recovering the Black Box, the investigators (like they talk about Pilots not good at flying aircraft without the aid of in-flight safety systems) have to do it the old forensic way (reminds me of Crichton's Airframe). That is going to take time and the press, the Aircraft companies using A330s are impatient to know why.
Clearly no recent theory has come close to deducing the true reason for the crash. As I remember the first news item that appeared on the AF447 was that the plane "vanished" from Radar and was sought for by the Brazilian Air Force before the crash site was positively identified. The last exchanges between the Pilot and the Aircraft tower followed by an automated message from the aircraft remain the main clues apart from the debris in this horrific accident.
No Greater Friend, No Greater Enemy! (Lucius Cornelius Sulla)
There are a couple of aspects about the A330 problems that amaze me:
1. How can an airplane be allowed to carry passengers when the margin to airframe disintegration is so narrow? I can understand falling out of the sky if it stalls, but to be able to tear the airplane apart in level flight? What happened to margin of safety in airframe construction -- or is that whole concept now obsolete?
2. If the airplane can send fault messages home, why don't blackbox data streams get sent as well? At least that way there would be some situation info available as opposed to none.
3. In some ways reliance on flight computers is like reliance on spreadsheets or calculators -- if you do not understand what is going on and are not capable of doing it yourself then you cannot tell if the software is correct. Essentially, if the computer says it is so then it is, and you either survive or not.
This is why I really want any airplane I'm flying to LISTEN to me, not argue with me... At no point should a computer be able to override pilot input. Also, i want a solid mechanical link between the controls I'm pushing on and the control surfaces on the wings... That way, even if EVERY computer on the plane dies, I can still control the damn thing...
And yes IAAAP... (I Am An Airline Pilot)
To go for the car analogy:
Imagine a (large) conveyor 100 miles long, stable enough for you to drive on in your car. Now drive from it's start to it's end in one hour. The distance you traveled is 100 miles, right?
Now imagine that conveyor moving in the opposite direction (i.e. towards you) at 50 mph. To still get from your starting point to your destination in an hour, you're doing 150 mph road speed. The GPS will still report 100 mph, but your car's tachymetre will report 150 mph, the wheels will revolve as is necessary to go 150 mph and, if you add 50 mph of headwind, even the air resistance will be equal to doing 150 mph without wind.
In an environment where the you need to stay in a 10 mph zone in order to avoid either stalling, rapid descent, crash, death if going too slow or plane breaking apart in mid-air, rapid descent, crash, death; it's quite helpful to know an accurate measurement. It's like Speed, except the bomb will blow up when your axle speed drops below 145 and the bus will spontaneously disintegrate at 155. Also, there's varying levels of wind. Also, you're driving on slicks. Through some kind of rally track half of which is concrete, the other half sand/dirt and the other half is jell-o.
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.
What about, you know... manual control?
Sure there are no mechanic cables anymore, but a wire controls the low-level hardware.
But at least it has to have just as basic piece of electronics that has no software or big complexity, and that allows you to manually steer the plane.
(No, that is not too hard to do, even on such big jets. You just have to be more careful about quick actions, stalling the plane & co.)
A piece of electronics that is so simple, that the only thing killing it, is an electric shock right into its mainboard.
Electronics failure is never a cause! (Because: What would that be?)
The reason usually is a software error, that electric shock, or some other external source.
Any sufficiently advanced intelligence is indistinguishable from stupidity.
Did the pilots shut down the flight computers in an effort to get the controls to respond appropriately? Professional Pilots are "do-ers", and right or wrong, they ALWAYS have a reason for their choices.
Did the flight computer failure mode fail to (dis)engage? I've heard about the manual control levels that an Airbus flight system degrades through. It looks like the computer wouldn't get out of the way soon enough, so the flight crew kicked it in the head.
They received the airplane in a un-recoverable, un-flyable, disintegrating condition from mach turbulence destroying lift and ultimately the aircraft. (coffin corner)
Cascading failures generally occur from a synergy of multiple causes. In this case:
- A narrow flight envelope due to altitude and varying wind-speed in the storm. (had they climbed, trying to avoid the storm?)
- Pilot over-reliance on automated flight assist in marginal conditions.
- Failure of physical airspeed instruments due to severe icing from a massive updraft.
- Increased thrust from engines ingesting water contained in the 100mph updraft. (coffin corner!)
- Altitude increase from 100 mph updraft. (coffin corner!)
- Inappropriate computer control responses, destabilizing flight dynamics, leading to overspeed and unrecoverable loss of lift (mach stall).
- Turbulence and chaos of a severe storm masking the initial flight computer deviations.
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
The problem largely is that the difference between airspeed and ground speed can mean the difference between supersonic airflow over the airframe, or not enough to maintain flight. At cruising altitude (FL300 and above) you don't have a very large speed differential between these two danger areas, so windshear is something you want to avoid. (i.e. Thunderstorms)
Your question about wind speed is a little difficult to answer, it would depend on the aircraft type, but then it also depends upon what you are doing in the aircraft too, straight and level, in a turn, high g, and so on, so there are a whole host of factors to consider.
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.
Like any other part of the plane, the computer is just another instrument designed and manufactured by people. Blame the programmer, the tester, the lack of analysis. The cause of this accident has nothing to do with computers. They just do what we tell them to. Leave them alone.
I think you meant "flight computer" rather than autopilot. But yeah, I hear ya. Also, WAY too many drivers these days have problems operating their car when the throttle sensor craps out, the brake-lines bleed dry, and the steering wheel snaps off.
Now Fred Flinstone ... THERE was a REAL driver! Ah, how I long for the Good Old Days ....
To confuse things further - you're not actually using indicated airspeed but true airspeed. :)
The indicated airspeed at those altitudes is often on the order of 300 knots when the plane is really travelling around 500 knots relative to the air and 600 relative to the ground.
Put it this way - in space if you're travelling at mach 20-30 the airspeed indicator would probably read zero. When you hit an air molecule you're moving very fast relative to it, but so few hit the sensor that it reads zero. Anywhere in-between space and sea level the gauge acts accordingly...
Okay. That's just silly.
There is clearly some major pressure to build a presentable story to the public if they're floating ideas like these ones. If the PR is successful, Official Culture will soon include passenger jets which will break up from 'excessive' flying.
A significant air blast from one of the increasingly frequent falling rocks from outer space could easily account for this disaster, and could explain some of the more peculiar details.
--Quoted from this article which digs into the idea of this event being another case of "Is it just me ore do there seem to be a lot more ROCKS FROM SPACE falling around our ears lately?".
-FL
Remember the DC-10 that crashed in IOWA? It took two guys trying to control it without hydraulics. Personally, given the choice of hydraulics OR electric motors, I would take electric motors. Electric is CHEAP AND SAFE to have redundant electrical lines. In addition, losing one, does not mean that you lose the whole aircraft like Walt Lux did in the AA dc-10 that crashed at O'hare. The problem with the Airbus is that Airbus designed the CPU to take control of the craft. If the pitot tubes are blocked, the sensor will think that the aircraft is moving at 0 knots and will DIVE IT. Since it still does not know the speed, it will continue to dive it faster and faster until stress ripped the plane apart. Sadly, this has happened on MULTIPLE issues with the plane, and had it all blamed on "PILOT ERROR". When this is done, I think that AA and several other companies will be suing the pants off Airbus for their design as well as hiding facts.
I prefer the "u" in honour as it seems to be missing these days.
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.
And nobody is arguing that the fly by wire system is what failed here.
I assume these kinds of modern planes can't even fly without a computer anymore.
You're wrong. They can.
This video shows an Airbus pilot switching off the flight computers then barrel rolling an A320:
http://www.youtube.com/watch?v=P2KygSyVE58
Any belief that Airbus pilots are somehow under the communist thumb and that square-jawed Boeing pilots would heave manfully at the controls and save the say is, um, 100% laughable.
FTA: "...the crew apparently shut down or tried to reboot their primary and secondary computer systems."
Where do they get this garbage? Do they make it up based on their experience with Windows ME?
FWIW, Airbus have *five* flight computers (not "primary" and "secondary") and any one of them can fly the 'plane. If they're all gone then the aircraft is already in little bits so no, you wouldn't ever be under the dashboard trying to 'reboot' them instead of flying (whatever 'reboot' means - they're designed to reboot themselves under a watchdog timer).
No sig today...
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
This video shows an Airbus pilot switching off the flight computers then barrel rolling an A320:
http://www.youtube.com/watch?v=P2KygSyVE58
It's a full scale simulator not a real aircraft, you can see the border of the simulator room projection screen outside of the cockpit. Do you really thing that a man performing a barrel roll with a jumbo jet have the time to explain in a relax manner what's happening ?
It's only a demonstration about how the flight computers limit the human command to stay in flight parameters ( and prevent you to attend stupid maneuver like a barrel roll).
I think he's flying a simulator, and not risking an actual airplane.
How does this show that real A320s don't have five flight computers or that any one of them can fly the plane or that a crew would never be under the table trying to 'reboot' them?
"you can see the border of the simulator room projection screen outside of the cockpit"
Really? I thought it was the pilot *saying* it's a simulator that gave the game away.
No sig today...
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.
This video shows an Airbus pilot switching off the flight computers then barrel rolling an A320: http://www.youtube.com/watch?v=P2KygSyVE58
Give me a break. This whole thing was taken in a simulator, which are *programmed* to behave how they think the airplanes will behave, using recorded data from test flights to help. Because they do not test the airframes in extreme attitudes (especially barrel rolls), they have little to no data with which to program the simulator, making demonstrations like this complete nonsense.
At 3:02 into the video you just posted, the pilot admits, "Not a maneuver you'd normally see in an airliner, and in fact you probably couldn't do it in a real airplane."
I'm not sure what you were trying to prove. This video doesn't prove anything.
Any belief that Airbus pilots are somehow under the communist thumb and that square-jawed Boeing pilots would heave manfully at the controls and save the say is, um, 100% laughable.
LOL, this is the absolute definition of the straw man argument. The great-grandparent never made such a claim; just an apolitical observation that he was scared that computers fly the planes and not skilled pilots.
Stop trying to turn this engineering discussion into a US vs. Europe, Boeing vs. Airbus religious war. Your post is a troll, I'm afraid.
You are correct in stating that a pitot tube malfunction is not a computer malfunction. The question becomes how did the pilots handle that. Your 100% correct in stating that a plane could accelarate through "coffin corner" and break apart. I'm suprised that there isn't a better web reference than WSJ for updates to an aircraft story.
In Soviet Russia ^H^H^H America, The bank finances YOU!
You seem to know what you're talking about, so I'll ask you. The airframe that I maintain uses all heated air data sensors. They don't just get warm; they are a serious hazard when the plane has just landed or the sensors are being tested. I am curious since I have not worked on commercial liners, but aren't heated probes de rigeur on airframes that fly above a certain altitude?
Or was this an error of the heating system, or what?
Just curious.
-b
No offense, but I've stopped responding to AC's.
You're right and wrong. If you had said that the primary flight computers are optional, you'd be right, but the computers are most certainly not optional in the Airbus FBW design according to the pilots on PPRuNe and several other sources that I consider highly reliable.
The Airbus design requires at least one of the five flight control computers to be working even for direct law (what most people would call "full manual" control). In the event that the three primary computers are down, either of the two secondaries can take over as a primary and can process the direct law commands from the controls and pass them directly on to the various control surfaces. If all five computers go down, however, IIRC, the only things you can control are the throttle and the rudder. (There's a cable that goes directly from the controls to a box that automatically engages manual rudder control if you lose all five flight control computers.) While it is possible to land a plane under ideal circumstances with just rudder control and throttle, it ain't gonna happen in a bad storm.... There is no direct connection for any other Airbus control surface, as far as I've been able to determine.
Also, the computers did NOT all go down. IIRC, two computers (PRIM1, SEC1) plus the ISIS (Integrated Standby Instruments System) modules failed. A failure in PRIM1 could be caused by a clogged pitot tube, but I don't think SEC1 should care at all about the ADIRU data. Its sole purpose is to be there in case all the primaries go down.
No, something very bizarre happened up there. My first suspect is the Kapton insulation used on the wiring. It has been implicated in two aircraft fires on the ground, and it was used in Airbus aircraft until after this particular A330 was built. If the SEC1 computer was somehow getting sporadic power surges, it's possible that it sent bad control data out to the rudder, snapping off the tail of the aircraft. It's also possible that they attempted a shutdown of a lot of the computers and ended up getting more manual control over the rudder than they bargained for. In full manual, it is completely possible to rip the tail off one of these birds by stomping the pedal too hard....
Indeed, such a tail failure was the cause of the crash of American Airlines flight 587 (an A300). A similar failure occurred in an A310, Air Transat flight 961 (the pilot somehow managed to bring that thing down in mostly one piece), and there's another report of a FedEx A300 exhibiting random tail rudder motion without the pilot pushing on the pedals and that this caused similar severe damage to the rudder. So it would not at all be hard to believe that some computer problem rips the tails off these things occasionally....
Check out my sci-fi/humor trilogy at PatriotsBooks.
No, a handheld GPS would be useless. It can't give you airspeed or attitude. Also, you need line of sight to the satellites. Next time you're on an airliner, try and use a handheld GPS and see how well that works through the skin of the airplane. My Garmin GPSMAP 195 (an actual aviation handheld GPS) cannot always get a satellite fix in a commercial airliner. In an emergency, its not really a big deal where you are or what your groundspeed is. If you don't know your airspeed or attitude (the two things a GPS will *not* give you) you *will* die.
Disclaiminer: I am an aerospace engineer and a pilot.