Flight 447 'Black Box' Decoded 449
fermion writes "An initial report has been released by the BEA concerning the details of the last minutes of Flight 447 en route from Rio de Janeiro to Paris. According the report, the autopilot disengaged and stall warning engaged at 2 hours 10 minutes and 5 seconds into the flight. Less than 2 minutes later the recorded speeds became invalid. At 2 hours 14 minutes and 28 seconds, the recording stopped. The final vertical speed was recorded around 10,912 ft/min."
Umm, no... (Score:5, Insightful)
“So, we think that until impact they did not realize the situation, which for the family is what they want to hear — they did not suffer.”
A three minute decent at 10,000 ft/min over the middle of the ocean?
I'm pretty sure everyone onboard knew exactly how that was going to end about half way in.
Re: (Score:2)
If it's free fall, it would be 3 minutes of weightlessness. The end would be quite abrupt.
Re: (Score:3)
Not quite free fall. My back of the envelope calcuations (38000 feet in 3 mins 30 secs) shows that assuming constant acceleration, the descent acceleration would have been approx .5 m/s^2 . This is about what you would experience in an elevator going down before the elevator reaches constant speed.
Re: (Score:2)
Re: (Score:2)
It sounds like the plane was flown into the ocean. It was 12.7 km high at cruising altitude, so the rate of descent was 217 km/h. The cruising speed of an A330 is 871 km/h, so the pitch of the aircraft was roughly 14 degrees below the horizon.
In heavy turbulence it might be very difficult to tell if accelerations up and down balance out over the course of a few minutes, allowing a nose attitude to go unnoticed. The downward acceleration may well have begun in the minutes leading up to the "3 and a half minu
Re: (Score:3)
The articles I read stated that the nose was up, not down, and that was the problem, the plane was stalled, nose-up, flying too slow and falling out of the sky.
Then again, having read stuff I know something about in the media, I know not to believe anything I read in the media.
Re: (Score:3)
From my reading, it sounds like the stall warnings were not heeded due to the inputs mainly being nose-up, which is not how a stall is dealt with. The proper course would normally be nose down to regain speed and lift.
There would have been less room for error as the stall began because the plain was near its operating ceiling which would be around 38k feet, and speculation is that the plane may have been in a deep stall, where the AOA is sufficient to wash out the rear stabilizers behind the wings.
I think t
Re: (Score:3)
Its not free fall. Once the plane descends at a steady rate, the passengers inside would feel normal gravity.
Only if the plane continues to accelerate downwards would it continue to feel like free fall.
Having been in a plane that was intentionally stalled, It is pretty much like a roller coaster. No one expects a roller coaster at 35,000ft.
Re:Umm, no... (Score:5, Informative)
Really? Think about that again, please. The astronauts on board the International Space Station are not accelerating... they're in a continous free fall at a constant speed around the Earth (called orbiting).
Think about that again please. The ISS is in a free fall because it is constantly accelerating.
That's what's called orbiting.
What do you think keeps a spacecraft in orbit and from flying off in a straight line?
Yup, constant acceleration by gravity.
Acceleration in the physical sense doesn't always mean "change of speed".
If the acceleration is always perpendicular to an object's movement, it means
"change of velocity without change of speed", and that's exactly what
happens in a circular orbit. No, velocity and speed aren't the same thing.
Re: (Score:3)
...The astronauts on board the International Space Station are not accelerating... they're in a continous free fall....
Yikes. Oh public schools, how you have failed us!
Re: (Score:3)
If it were me, and I only had 3 minutes left, I'd grab a pen from my pocket and carve into my shoulder "4-8-15-16-23-42" to send a message to my family that 'even if the ending sucked, at least I will find happiness in purgatory.'
I'm sure the sharks that ate your body would have been impressed by your ingenuity and would have passed the message on to your family.
Re: (Score:3, Funny)
Re: (Score:2)
Re:Umm, no... (Score:5, Informative)
Re:Umm, no... (Score:4, Interesting)
Re:Umm, no... (Score:5, Interesting)
1. Unless it's pressurization system was faulty (it wasn't) the pressure change wouldn't have been great.
2. Unless accelerating, you wouldn't know you were going down (or up, or banked or upside down...).
So the claim that the passengers probably didn't think it was anything more than turbulence is not hard to believe.
It is perhaps surprising to non-pilots that you can be in unusual attitudes and not know it, pilots however are acutely aware. VFR (Visual Flight Rules) pilots flying into IMC (Instrument Meteorological Conditions - ie, zero visability) is a big cause of crashes, not because they can't see where they are going, but because they don't know which way is up.
Re: (Score:2)
To be clear, this was not a case of VFR into IMC, an airliner is basically IFR all the way these days.
Re: (Score:3)
Even with a glass cockpit there is usually a small set of old school instruments.
here is a image of the a330 cockpit: http://www.bus-fahrer.com/cockpitpageDATEIEN/a320cockpit.jpg [bus-fahrer.com]
looks to me like there is a mechanical artifical horizon and a compass on the left side of the center console area.
Re: (Score:2)
Re: (Score:2)
but because they don't know which way is up.
This is why all the pilots I know tie a washer to a string and tape it to the cabin ceiling. No matter what an instrument says, that washer will point down.
If you are buried in an avalanche you can use a similar trick to figure out what way the surface is, so you can dig yourself out.
Re:Umm, no... (Score:4, Informative)
Um no. The washer will hang in the direction opposing the acceleration you are undergoing. If you are upside down in the plane, diving toward the ground at 2G's, it'll feel like one G toward the floor of the plane (up).
Re: (Score:3)
I'm not sure what you mean by diving toward the ground at 2G's... but if you're inverted pulling +2G's it's always going to feel like +2G's regardless of your attitude... not one G.
Depends entirely on your frame of reference. Your parent meant 2G in the frame of Earth,
which would indeed feel like 1G in the plane. That's how you can fly inverted and still keep
your coffee in the cup.
(Earth's gravity isn't magically cancelling one G... it's actually a weak force that is easily overridden by acceleration forces.)
No magic here, but of course Earth is cancelling 1G. If you are in free fall, you are being accelerated
with 1G (roughly 9.81m/s^2). The G meter you are carrying will show you an acceleration of 0 (zero) in
your own - accelerated - frame of reference.
Where did you think the definition of 1G comes from?
Re:Umm, no... (Score:5, Insightful)
I don't think you know any pilots because if you did, you'd know that this little trick doesn't work. [citation [youtube.com]] rthille is correct.
Re: (Score:3)
With centrifical force, yes but strait down? No. (Score:2)
1. Unless it's pressurization system was faulty (it wasn't) the pressure change wouldn't have been great.
2. Unless accelerating, you wouldn't know you were going down (or up, or banked or upside down...).
So the claim that the passengers probably didn't think it was anything more than turbulence is not hard to believe.
This pre-supposes that the passengers felt approximately 1G of gravity downward from their point of view, which pilots normally carefully maintain for passenger comfort. A banked turn that maintains 1G of gravity downward by carefully controlling the turn rate feels "normal" as if the plane were flying straight. Pilots can't do this in an emergency when there are systems failures.
Remove that 1G of gravity like in a free-fall, or flying straight down, and the passengers are going to become acutely alarmed
Re:Actually, you're right. (Score:5, Informative)
What's most interesting in this case is that the systems warned the pilots of an impending stall, but then once they were in a stall, there was no warning at all, as if they had recovered from the stall. That's really unfortunate.
That's because once the airspeed drops below 60 knots, the input from the angle of attack vane is ignored by the flight computer. The computed angle of attack is how the flight computer determines the airplane is approaching a stall, so without a valid input from the AOA vane, the computer can't sound the stall warning. The AOA vane is just a triangle-shaped piece of metal sticking off the side of the airplane on a little lever, so the airflow naturally positions it, just like a weather vane. As the angle of attack changes, the vane moves, providing an input to the computer. Below about 60 knots, though, there isn't enough airflow to move the AOA vane to a reliable, steady position, so the information is discarded by the computer.
In this case, you're right, it was unfortunate because it provided a confusing result to the crew. They had pulled the airplane's nose up into a stall, and when the airspeed dropped below 60 knots, the stall warning stopped. At one point, the crew did lower the nose of the airplane, which caused an increase of airspeed, which is of course precisely what they needed, but as the airspeed increased beyond 60 knots, the stall warning suddenly started back up. That made them think that what they were doing was making the situation worse, not better, when in fact they were doing the right thing. They pulled the nose back up and then never got it back down until they hit the water. Even when valid, the AOA vane never indicated an angle of attack of less than 35 degrees - generally speaking, almost any general or commercial aviation wing will be well into a stall by about 15 or 16 degrees AOA.
Re: (Score:3)
Forgive the laymen for asking a stupid question: wouldn't it make sense to use accelerometers and gyroscopes to help to determine the attack angle and speed? Isn't a gyroscope a standard equipment in a cockpit?
It doesn't quite work like this. A gyroscope is set to a point in space and will always track that point. An artificial horizon will always show relative to the horizon. Angle of attack however is different as it has no bearing on the actual angle to the horizon. To explain this a little better, I shall go into a bit of detail and mention a little bit of aerodynamic theory.
Usually, a wing generates the most like with the least drag at about a 4 degree angle of attack (AoA). This is handy to know. When an ai
Re: (Score:3)
Not necessarily. Your kinesthetic senses sense changes in relative motion. If the "wrong" motion is maintained long enough your body will adjust and you will not sense anything out of the ordinary.
For pilots this can be seen sometimes in a bank, among other things. If you rely on the kinesthetic senses, you could find your body gets used to a bank angle, and when pulling out of the bank your body will sense that you are now banking in the wrong direction even if you are in fact level.
It's one of the reasons
Re: (Score:2)
Re: (Score:3)
Re: (Score:3)
Uhm, that's vertical speed. The problem is the plane slowed down to the point it couldn't maintain proper airflow over the wings. Thus the stall warning.... and well, the stall. Unexplained is why the pilots kept the nose of the plane up. I would imagine at some point that would cause a spin. The recovery procedure for a stall is full power and nose down until your airspeed comes up again.... your forward air speed.
My only thoughts is that the pilots didn't believe the stick shaker since they were pret
Nova Episode Theories Verified? (Score:4, Interesting)
I have been reading the report and there are some strange interesting passages. Here is a partial summary, focussing largely on pilot control inputs
Copilot is PF. Captain is PNF.
2 h 08 min 07: "...turbulence increased slightly and the crew decided to reduce the speed to about Mach 0.8"
2 h 10 min 05: "...the PF made a left nose-up input. The stall warning sounded twice in a row...Autopilot and auto-thrust remained disengaged for the rest of the flight."
2 h 10 min 16: "...The airplane’s angle of attack increased progressively beyond 10 degrees and the plane started to climb. The PF made nose-down control inputs and alternately left and right roll inputs... The airplane was then at an altitude of about 37,500 ft"
At 2 h 10 min 51: "...The thrust levers were positioned in the TO/GA detent and the PF maintained nose-up inputs...The trimmable horizontal stabilizer (THS) passed from 3 to 13 degrees nose-up in about 1 minute and remained in the latter position until the end of the flight...The PF continued to make nose-up inputs."
2 h 11 min 40: "...The airplane’s pitch attitude did not exceed 15 degrees and the engines’ N1’s were close to 100%..."
At 2 h 12 min 02: "...At that moment, the thrust levers were in the IDLE detent and the engines’ N1’s were at 55%. Around fifteen seconds later, the PF made pitch-down inputs..."
This much seems clear: the airplane was cleared for flight level 350 (35000 ft), and was likely at that altitude when the trouble started, assuming the altimeter was functioning. Stall warnings went off, and the airplane climbed to 38000 ft. It then descended rapidly, it seems with a monstrously high angle of attack. It also seems from the report that the nose of the plane was mostly pitched up through this, though I am not absolutely sure on this. This would imply a very bad stall...essentially the airplane was falling from the sky. One can speculate that the pilots were doing their best to recover from the stall with imperfect data on their airspeed.
To me the important period was between 2 h 08 min 07 and 2 h 10 min16. There was a decision to reduce speed, which would entail a reduction in thrust. Two minutes later, there was a stall warning, implying that the airplane's airspeed was out of the very narrow range required at that altitude (plus/minus 10 knots according to the Nova documentary, though I'm not sure it's so narrow). The question is, what caused those initial stall warnings? How did the airplane's speed get out of the proper range? Did the pilots forget to increase thrust after the autopilot reduced it? During those two minutes, was the airplane catastrophically slowing down?
Re: (Score:3)
The rest is just my speculation - it seems like he wasn't paying much attention, was letting the autopilot do its thing, then when he suddenly had to resume manual control, his first impulse was fear of crashing into the ground, so he yanked back the stick and went into a terrible stall from which they never recovered.
Recovering from a stall in a jet at altitude isn't as simple as cessna pilots might think, at least as far as I understand. Beginner pilots are told to push the stick forward to reduce angle of attack. But in a jet at altitude, pushing the stick forward can send you into an overspeed situation, which can also lead to a stall. So then the question is, if you don't know whether you are above or below, what do you do? Recovering from a stall when you are already well into it, especially if you don't have a
Remember this is an initial report (Score:2)
Re: (Score:2)
Yeah, can't fault the NTSC's way of doing this... refuse comment until you're sure you have something to report.
Re: (Score:2)
NTSC?
That's a video system. Do you mean the NTSB? They're not really involved either, it's the BEA [wikipedia.org].
Re: (Score:2)
i believe the speculation is that the heaters in the sensors were faulty/insufficient and they became clogged with ice. the flight envelope at high altitudes is very narrow and apparently very difficult to fly without reliably knowing the airspeed.
Re: (Score:2)
That is true on any situation, any altitude.
Re: (Score:2)
Re: (Score:2)
The training has proven to be entirely inadequate. This type of accident is far too common, since the earliest days. One guy should always be flying the plane, but all too often everybody's trying to troubleshoot the problem. and even in a storm it is possible to maintain control with a working artificial horizon and a fixed power setting as you point out.. Key word is 'situational awareness'. Lose that, then indeed, all bets are off. A lot more hours in the simulator are needed to burn this into the guy's
Re: (Score:2)
i would guess not. air closer to the ground is denser, supplying more lift ? hence "the flight envelope at high altitude is narrow" ?
Re: (Score:2)
That is true on any situation, any altitude.
Flying by the seat of their pants, most instrument qualified pilots should be able to guess airspeed well enough to stay flying below about 20K feet. Stall buffet indicates you are too slow. Screaming airflow: too fast. In the middle, just right.
Re: (Score:2)
Re: (Score:2)
Re: (Score:2)
The answer is pretty much in the report. The co-pilot put full thottle on and kept pulling up, probably not understanding that that they were losing altitude because they were in a stall situation.
Re: (Score:2)
Re: (Score:2)
Re:Remember this is an initial report (Score:4, Interesting)
I disagree with that synopsis, my understanding is the pilot started fighting the autopilot without disengaging it. The plane might have been fine if it had totally disregarded the pilot.
My understanding of what happened here is the autopilot was automatically disengaged (because it didn't believe the airspeed reading it received) and handed control over to a human, who proceeded to stall and crash the plane. It's too bad the autopilot wasn't programmed simply to do the best it could instead of handing over to the pilot (in the errant assumption a person would do a better job coping with the situation).
Re: (Score:2)
I'm not a pilot, but shouldn't increasing the throttle help recovering from a stall?
Re: (Score:2)
Re:Remember this is an initial report (Score:4, Informative)
Re: (Score:2)
The answer is pretty much in the report. The co-pilot put full thottle on and kept pulling up, probably not understanding that that they were losing altitude because they were in a stall situation.
Anybody who has spun a sailplane would know to put the nose down in that situation. Maybe these guys had never done that.
Re: (Score:2)
If it was the initial stall they must have really stuffed up. If you can get the aircraft flying at 20000 feet, you won't have to be anywhere near stall speed and you can fly manually as long as you want. Airliners are not jet fighters. Stall recovery should be straightforward, at least once you have lost some altitude. My uncle, when he was a flying instructor, said he would take a VFR qualified pilot into cloud and they would inevitably exit the cloud in a spiral dive, but airline pilots should be able to
10,912 ft/min (Score:3)
= 124 miles/hour
Re: (Score:2)
bah: 333,312 furlongs per fortnight
So much new and yet nothing new (Score:3)
What seems to be remarkable is that the trigger to the catastrophe has indeed been revealed to be the pitot tubes - something that was suspected very soon after the flight went down. To a layman like me, it is amazing that without the benefit of all the data that has been recovered from the flight data recorders, experts were able to get so close to the mark.
Now, one could flip this around and also say that given that so many observers were able to so accurately get to the initial trigger for the failure in the absence of hard data, it must mean that this was a really common failure mechanism that should occurred in the field only as a result of the problem being repeatedly ignored.
It is a triumph of technology that the flight data recorder survived under such extreme conditions for so long. It was a triumph of technology, that it was located and retrieved from such an extreme location. Surely, a species with such (magical?) technical expertise could have expended the effort into preventing such a failure?
Re: (Score:2)
What seems to be remarkable is that the trigger to the catastrophe has indeed been revealed to be the pitot tubes - something that was suspected very soon after the flight went down. To a layman like me, it is amazing that without the benefit of all the data that has been recovered from the flight data recorders, experts were able to get so close to the mark.
Now, one could flip this around and also say that given that so many observers were able to so accurately get to the initial trigger for the failure in the absence of hard data, it must mean that this was a really common failure mechanism that should occurred in the field only as a result of the problem being repeatedly ignored.
Since the pitot tubes were known to have problems before the crash and Airbus had recommended (but not required) their replacement prior to the crash, perhaps it's not so remarkable.
Re: (Score:2)
Airbus couldn't require anything from anyone, but several countries did require their replacement before the accident. Unfortunately, France wasn't one of them.
Re:So much new and yet nothing new (Score:4, Interesting)
To a layman like me, it is amazing that without the benefit of all the data that has been recovered from the flight data recorders, experts were able to get so close to the mark.
Airbus records remotely some telemetry data, this is how experts where able to make a sensible guess.
Surely, a species with such (magical?) technical expertise could have expended the effort into preventing such a failure?
Yes, of course. This will be taken in account in future projects and into airplane maintenance routines. But ya know, those damn birds are already very reliable. It's a disaster, my heart will be always with the families. But some times, you know, shit happens. We should always be aware of how fragile the human condition is and understand that despise all of our hard work into making things safe, some times the unexpected happens and a disaster awaits our destiny.
Yours sincerely,
Someone who deals with safety systems (not at Airbus ) and it's tired to see people blaming designers: we did our best.
Re: (Score:2)
That's a logical fallacy. If enough experts (and not-so-experts) predict enough different reasons for the flight failure, then when the real reason is discovered, some expert will be very close to the mark. You're filtering out the prior speculation and choosing the segment that happened to agree with posterior conclusions. It
Re: (Score:3)
With respect to your comment that this is a logical fallacy - its not so. The pitot tubes have been for the past two years the #1 reason put forward as the cause - by a wide margin. There have been no alternative theories so widely championed. Go back through the news articles and see for yourself. If you find that too difficult, you can use the wikipedia page on this disaster (look at the page history).
And if one did flip this around, one would be wrong. The characteristic of a common failure mechanism is that it is common. As such, it gets addressed by virtue of its repeated occurrence during repeated tests. If it does not occur frequently, then it simply isn't common.
I don't understand what you are trying to say here. You seem to be conceding that this was a commonly occ
Re:So much new and yet nothing new (Score:5, Insightful)
There is, it's called heated pitot tubes, and the FAA requires them for US carriers.
Re: (Score:2)
To a layman like me, it is amazing that without the benefit of all the data that has been recovered from the flight data recorders, experts were able to get so close to the mark.
If you recall, we did have the diagnostic messages that they airplane was sending back home, which, if I recall correctly, helped identify the cause the problem. The idea of the tubes freezing up was not a shot in the dark.
If God had meant for man to fly... (Score:2)
Then he wouldn't have put corrupt manufacturers and regulatory agencies in charge of the airplanes.
I've logged plenty of airmiles, but I'm never climbing aboard one of those hand grenades again in my life.
Seems to be pointing to pilot error (Score:2)
So far, the NOVA summary [pbs.org] is on target. In addition to the pitot tubes freezing, which is an obvious design flaw, it sounds like the pilots reacted improperly to the loss of speed data.
Good thread with an Airbus pilot and some experts (Score:5, Informative)
It's randomly on a car forum, but its worth a read. Some guys that know what they're talking about talk about what they think happened. They also include pics of various airbus cockpits for reference.
http://www.mye28.com/viewtopic.php?t=64381&postdays=0&postorder=asc&start=25 [mye28.com]
Here's the basic story, as I understand it:
- the pilots flew into a thunderstorm
- they were 100% blind, relying entirely on the glass-screen instruments
- once all 3 pitots froze, the redundant computers started disagreeing and then finally agreed that things were ugly
the effect in the cockpit is that a serious of cascading failures were unfolding, likely overwhelming the pilots.
additionally, there would be NO functional indicators for alt, speed, horizon, etc. Once the computers have faulted, they no longer share that information.
Also, as the computers degrade authority, in an Airbus the pilots get MORE control of the aircraft. This means that controls move through larger ranges.
As flight control reverts to failsafe mode, the controls in the cockpit do not "auto-zero". And the forcefeedback goes off line.
Effectively, the pilots are 100% blind, and the inputs they make have no feedback whatsoever. They cannot even tell if they have _stopped trying_ to turn.
Imagine being blindfolded. Your job is to put the end of a 4 ft long stick inside of a 1" circular hole in the floor. Except the stick is a peice of yarn.
That's what their instruments and control apparatus were like.
Now imagine that everything is beeping at you and you are in a plane in a thunderstorm, over the ocean, at night, and everything outside is total blackness.
You're fucked. Thoroughly and completely fucked.
Re: (Score:3, Interesting)
The information in the report is preliminary, and there has to be more to this story. Even the lowliest weekend warrior pilot earning the most basic instrument certification has to demonstrate an ability to fly in IMC with multiple instrument failures.
What I wan
Backup Mechanical Instruments Installed? (Score:3)
If Air France's A330-300 are set up the same as SAS' (430KB PDF [www.sas.se]), there should have been a cluster of mechanical backups just to the right of the pilot's primary glass displays, including an artificial horizon. Even if the backup sink rate, airspeed indicator, and altimeter were returning bogus values, the gyroscope and compass wouldn't, and ergo there would have been at least enough information to know which way the bird was pointing.
Re:Good thread with an Airbus pilot and some exper (Score:5, Insightful)
Alt. must have worked it is recorded correctly by the black box, I see no reason to believe horizon shouldn't have been working, so only visual and speed was impaired. That is still a difficult situation, so no reason to exaggerate it.
Re: (Score:3)
My information suggests that the sensors feeding the black box either cannot or were not made available to the primary flight instrument computers, astonishingly enough.
Given the amount of system isolation in aircraft this isn't entirely impossible to beleive. If you tie part B into part A's wiring in any way, you have to do more testing/verification than you would otherwise.
Re: (Score:3)
Correct, there were no instrument displays telling them they were level. The computers that decide that information disagreed with each other and gave up.
If you aren't a jet pilot, I would probably stop suggesting how it should have worked. Your suggestion to apply 5% more throttle could have destroyed the aircraft.
One thing I learned from this thread is the "Coffin Corner". Flights are operated very near the intersection of their absolute altitude and their absolute vmax.
This puts them in bad shape -- i
Actual report (Score:3)
The actual BEA report [bea.aero], which should be read before commenting, does not assign blame. That will come later.
At one point, the left side airspeed display showed 215 knots, far above stall speed. The backup airspeed indicator showed 185 knots, also above stalling speed. The right side airspeed display value isn't logged. Then all speeds showed as invalid. Given that conflicting information, at night in a thunderstorm over water with no outside visual cues, it's not totally unreasonable that the pilots, finding themselves losing altitude but thinking they had more airspeed than they did, tried to pull up.
Margin of error (Score:5, Interesting)
It seems very scary that on an aircraft with everything working but the airspeed indicators (and I understand that those are very important), after more than 3 1/2 minutes the aircrew was unable to prevent the plane from hitting the ocean. This was a state of the art aircraft. Makes you wonder how many close calls there have been that luckily didn't result in catastrophe.
Re: (Score:2)
Re: (Score:2)
200 km/h is terminal velocity, for a human anyway. I did some indoor skydiving and the airflow is between 190 and 200 km/h depending on how heavy you are. It puts those 300 km/h tornado winds into perspective. Thats more than one G, horizontally.
Re: (Score:2)
Irrelevant. A Library of Congress and an Archie comic both fall at the same rate.
Same here (Score:2)
Re: (Score:2)
Software can be programmed to care :)
Re: (Score:2)
Re: (Score:3)
Re: (Score:3)
I trust software more and more in the long run. And I m not a geek!!
Re: (Score:2)
Software can be made to be very safe and takes care of a lot of things in airliners these days. In theory, it is more than good enough to take off and land the planes on its own already.
However, when the software has not been programmed to deal with an unusual case, it will simply not work. For software, there really is no try, there is either do or do not.
Its failsafe is to complain about it very loudly and have something which can adapt better take over for it: a pilot. Someday we may have AIs in plane
Re: (Score:3, Insightful)
I trust software more and more in the long run. And I m not a geek!!
That's why.
Re:Airbus (Score:5, Informative)
Airbus is run by software. Boeing by pilots.
This is a delusion. Read up on Turkish Airlines Flight 1951 [wikipedia.org]. I mean, they programmed 737 to do what? Trust a single radio altimeter known to fail in the worst possible mode, producing false readings? Actually use these readings to automatically enter the landing flare mode with rather subtle indication to the pilots? Autothrottle reverting pilot's inputs? Sounds like scary automation to me.
The reality is, all modern commercial airliners are run by software. If you want an airliner run by pilots, go to Russia and fly some Tupolevs, there are still quite a few left (ehhehe).
Re: (Score:2)
This was clearly pilot error.
There are standard operating procedures for this situation, if the pilots had done NOTHING AT ALL, then the flight would have been normal.
Really? I'm not a pilot, but what happens when the auto pilot disengages (as it did in this case), but no pilot takes control? Does the plane keep flying straight and level?
How good is a computer at flying when it loses a key sensor input that tells it the plane's airspeed? Will the computer make the right decision when it thinks the airspeed is 50 knots and the plane is stalling, but in reality is 400 knots?
Re: (Score:2)
Will the computer make the right decision when it thinks the airspeed is 50 knots and the plane is stalling, but in reality is 400 knots?
Yes, it will detect that the speed measurements it is getting make no sense. It will disengage and let something whose sensors are still working take over, that being the pilot. That is what the right decision is.
What is not clear is why the pilots nosed up in a stall, even when getting stall warnings. It may be possible they did not know their altitude and thought they were low, or for some reason they distrusted the stall warnings they were getting. Given that the autopilot shut down, they may have as
Re: (Score:2)
i think what parent is saying is that the pilot put the plane's nose UP, actually creating the fatal stall. If left to fly level, the plane may have recovered.
Re: (Score:2)
Regular ScareBus electronic wonkiness?
Wow, the airline manufacturing industry has fanboys, too? Might I recommend "AirBu$"? That way you can also signify it's a for-profit corporation, which seems to play well around here. Regardless, I'm going to try and work the term "mach tuck" into daily speech, so thanks for that.
Perhaps the AutoPilot corrected for an indicated stall and boned everyone on board?
It sounds like the automated systems disengaged at the beginning of the descent and the 32-year-old co-pilot put the plane into a 35 degree up angle, and the plane stayed at that angle even until impact. Apparently by the time
Re: (Score:2)
Re: (Score:2)
The interesting part is the fact that they don't report any stall warning being heard on the CVR. I am not sure how it is implemented in Airbus planes, but the stall warning horn and stick shaker should make quite some ruckus that should be detectable on the CVR. This opens up more questions than it answers for now.
You mean something like this:
From 2 h 10 min 05 , the autopilot then auto-thrust disengaged and the PF said "I have the
controls". The airplane began to roll to the right and the PF made a left nose-up input. The stall
warning sounded twice in a row. The recorded parameters show a sharp fall from about 275kt
to 60 kt in the speed displayed on the left primary flight display (PFD), then a few moments
later in the speed displayed on the integrated standby instrument system (ISIS).
Or this:
At 2 h 10 min 51 , the stall warning was triggered again. The thrust levers were positioned
in the TO/GA detent and the PF maintained nose-up inputs. The recorded angle of attack, of
around 6 degrees at the triggering of the stall warning, continued to increase. The trimmable
horizontal stabilizer (THS) passed from 3 to 13 degrees nose-up in about 1 minute and
remained in the latter position until the end of the flight.
Re: (Score:2)
Re: (Score:2)
A bit like that pilot recently in the US. Aircraft stalled during approach due to ice on the wings. PIlot pulled up (the plane was going down right? When you want your elevator to go Up you press Up) and basically stalled the plane into the ground. I think airline pilots should be required to stay current in general aviation. Fly some ultralights, hang gliders, sailplanes, aerobatic planes or normal light aircraft. Hours flying a computerised airliner don't give you stick and rudder skills.
Re: (Score:2)
60 mph is a mile per minute. 10,000 feet is a bit less than two miles. 10,000 feet in one minute is two miles per minute. So, 120 mph vertically. That's a lot. It isn't totally out of reason for a gliding jet though. Big jets have a really crummy glide path. They go down almost as fast as they go forward.
Untrue - a 747 has a glide ratio of about 15:1, so at 30,000 feet, you've got around 80 miles to find an airport if all of your engines fail. Granted, it's a far cry from a 50:1 or better glide ratio you can find in a good sailplane, but it's also far from the space shutle's 1:1 hypersonic glide ratio.
Re: (Score:2)
Re: (Score:2)
Of course, of course, they didn't lose engine power, so glide ratio has nothing to do with this particular incident...glide ratio is not what dropped this plane into the ocean.
The parent poster claimed that a 10,000 ft/minute drop is within reason for a gliding jet, which is not the case unless there are other mitigating factors, like loss of hydraulics.
Re: (Score:3)
According to some media-released transcrips I have read, the plane was stalled for over three minutes and yet the pilots consistently kept the nose of the plane at an upwards angle. Piloting 101 states that if your plane is stalled, the proper maneuvar is to point the nose downwards and dive sharply to pick up enough airspeed so that you can swoop and obtain lift so that you are no longer stalled. Apparently the pilot's actions deviated from this almost universal practice and further doomed the situation.
I am not nor have I ever been the pilot of an aircraft, however I fly remote control planes and I've had to deal with stalls a time or two using such a tactic. If the pilots of 447 had executed such a practice, odds are the stall would have broken. Perhaps that accounts for the 'human error' portion of the blame, but it was significant. I realize that airspeed and altimeter tools are invaluable to flight, but with the loss of those a firm knowledge of aviatic physics can mean the difference between life and death. As it was here.
Of course, in this case, even the computer didn't have the data it would have needed to fly the plane - if the pitot tubes were blocked and not giving a speed reading, the pilots may have attempted to outguess the situation. They may have looked at thrust settings and maybe even GPS speed reports and concluded that there was no stall despite the warnings since they knew the airspeed was far above what was reported.
I trust that an airline pilot has enough training to know how to handle a stall, but if he kn
Re: (Score:3)
Do stall warnings use anything other than airspeed and angle of attack to warn about a stall, or are there some type of sensors on the wings to detect airflow and lift?
IANA-aeronautical-engineer, but I imagine that you cannot easily determine the actual angle of attack w/o sensors to detect airflow. The actual angle of the wing referenced to the ground (or other fixed reference) doesn't determine the angle of attack, it is relative to the windspeed around the winds. Thus the angle of attack is mostly inferred by sensors that measure windspeeds (mostly). AFAIK stall warnings often additionally use measurement devices that measure dynamic differntial pressure around (or
Re: (Score:2)
In the plane, stall buffet is impossible to ignore. Anybody who has flown a light aircraft will know to push the nose down. Unfortunately flying is more about filling in the forms and programming the onboard computer these days. Maybe the plane is at fault, by not making the pilots fly all the time.
Re: (Score:2)
Merely losing air speed really shouldn't result in a crash.
Unless some other system failed, this might be a case of pilot error due to vertigo.
The Garmin GPS I use while driving tells me how fast I'm going.
Your GPS tells your speed relative to the road, which, being firmly attached to the ground, is the speed you care about.
However, in a plane, your GPS tells you your speed relative to the ground, which could be plus or minus 300mph from your airspeed (depending on the speed of the jetstream) and I imagine that in the stormy conditions they were in, wind gusts could have made their airspeed even more variable and unpredictable with respect to ground speed.
Re: (Score:2)
Pilots simply do not know how to fly anymore
Yep. Send them all out to do spins in a sailplane. Twice a year.