Great narrative, but factually wrong on at least two accounts:
>If the pilots has switched a button to re-enable autopilot, everyone on board would have lived. But they didn’t. One co-pilot made a single, absurd mistake–for twenty full minutes–that brought the plane down.
First factual error: The button they should've switched is not the auto-pilot button (which they operate many times per flight), but the flight mode button (which most pilots never operate in their career). When the plane lost at least two of the three pitot tube readings, it went from the NORMAL "Law" to the ALT "Law", where the airplane doesn't guard itself against many pilot errors. When the pitots de-iced shortly thereafter, the plane did NOT go back to NORMAL "Law": it had to be switched there manually. The pilots did not do that and it seems to be the consensus so far (can't state that for certain before the official report is released) that they did not realize they were flying the plane in ALT and then DIRECT Law.
Second factual error: the "absurd mistake" lasted nowhere near 20 minutes. The first problem appeared at 2:10:03UTC and flying into the ocean occurred at 2:14:28UTC -- 4 minutes 23 seconds in all.
You are right about the 4 min, but there is no such a thing as a flight mode button. Normal, alternate and direct law change automatically depending the number of computers or inputs available. There is a big red ALTERNATE LAW at the HSI, also a big red STALL. The problem is not that they where in alternate law, is that they used the wrong maneuver to recover the plane.
As it's completely meaningless to have the autopilot operate out of normal law (why would the computer operate the plane outside of the envelope the computer considers safe?), isn't it safe to assume that re-engaging the autopilot would have put the plane back in normal law?
A core concept they drill into your head in flight training is the following axiom:
Aviate, Navigate, Communicate
(in that order)
First and foremost, keep the plane in the air. Then you can worry about where you're going (e.g. don't fly into terrain, start heading towards an airport). Finally, coordinate with others (e.g. controllers) to let them know what you're doing and seek guidance.
This axiom can be applied to lots of other areas, too, including startups. For instance, it explains why I don't blog: I'm concentrating on execution and strategy.
It's one of the reasons I wonder if the many prolific startup bloggers have their priorities straight.
The pilots were not making an 'absurd error'. They did not forget to fly the plane.
It is that what they thought they were doing was not what they were actually doing. Their mental model broke away from the reality. (They thought the plane was in 'normal mode' when it was actually in 'abnormal mode' -- an expression of which: one them declaring "this cannot be happening!")
Telling them just fly the airplane is not (quite) the solution -- they thought they were flying it.
But the remedy is sort-of basically correct. It just seems better expressed as: when nothing makes sense (your mental model has suddenly utterly failed), fall back to a more basic backup mental model and system -- like primitive manual override.
(How clear can such separation of a basic mode be? How practical would it be? How reliable? It leads to a set of engineering/UI questions . . . were they well designed in this particular case?)
I'm not so sure. They weren't flying the airplane, but rather were letting the computer fly it for them. (The control movements made by the one pilot who was horribly in error were not something that one would ever make if the controls were directly connected to the control surfaces.) Meanwhile, the computer was letting the humans fly. If the pilot in error had flown the airplane instead of driving the computer, everything would have come out fine. (And, while I'm not completely familiar with the Airbus's fly-by-wire system, I'm pretty sure that doing this still would have been safe in the event that the computer hadn't given up, either.)
They spent all this time trying to figure out what was wrong with the plane when their immediate concern should have been to get the nose down and get their airspeed up. Figuring out the underlying problem can wait. That's what "fly the airplane" is all about. Even if stuff is on fire, the first priority is to keep your speed up and don't run into anything hard.
I fully support this message; having performed an instrument rating renewal check just yesterday in sub-optimal weather I experienced a frozen pitot-tube (the thingie that measures dynamic pressure; or a component of the airspeed). Having no speed indication is scary in instrument conditions (i.e. no visibility) but continuing flying is the best decision you can make (that and turning on pitot-heat). But please apply this 'motto' to other fields as well. No matter how bad the situation is; do the thing you're supposed to do: Fly the damn airplane, Talk to your customer, Keep your hands on the steering wheel and: keep breathing.
The article was clearly not limited to literal flying, it ends:
So, the next time you’re in a crushing situation, remember how irrational humans are under stress and remember to FLY THE AIRPLANE.
After observing that people today tend need their brains much more now during moments of extreme stress, since it often involves interacting with machines, as opposed to just running away or putting up a (physical) fight.
I followed through the entire essay in complete agreement, but I wished the following paragraph had at least a reference pointing to its claim:
The human body’s physical “fight or flight” response evolved to help it evade a dangerous situation, which historically involved extreme physical exertion. The rush of steroids into the bloodstream essentially turns off unnecessary systems, including some higher thinking processes, to aid in escape.
When we make statements like this proclaiming we understand the complex workings of things like human physiology I always have to shake my head. We may be smart, us programmers and designers, but let's not pretend to understand the order and meaning of everything. And if you do understand and you have the means, provide some kind of reference to where the claim originates from so we can all learn more.
* edited because I sounded like a jerk and wanted to make my point clearer
It has in fact been shown in countless studies that corticosteroids (stress hormones that are released in situations like the ones I described in the article) cause cognitive deficits in humans and other animals. Here is one slightly strange example:
The present study investigated the acute effects of cortisol administration in normal healthy male volunteers on immediate free recall and recognition of pleasant, unpleasant, and neutral nouns using a between-subjects double-blind design. Two hours after cortisol (10 mg) or placebo administration, impaired recall and recognition of neutral and pleasant words was found in the treatment group, whereas recall and recognition of unpleasant words was similar in both groups.
This is a fairly straightforward matter of whether his statement is right or wrong, I don't think it's fair or helpful to describe it as "particularly arrogant".
I agree that in general, people's understanding of human physiology tends to be simplistic and wrong.
But Dustin's description here aligns with what is generally known and accepted, and he doesn't venture details beyond what anyone with with a sound understanding of physiology could reasonably claim to know.
If he's wrong, that would be easy to prove, in which cas you should do so, so he can amend his post.
The Professional Pilots Rumor Networks has a bunch of excellent discussions about AF447 (and other incidents). It's nice to get the perspective of people who fly for a living:
There's a subtle shoutout to The Checklist Manifesto - that book is amazing. I thought it was another GTD-style productivity book but it's not, it's a lot more than that. It studies several seemingly unrelated fields like medicine and construction to bring together unique insights into group collaboration and workflow on complex projects with lots of stakeholders. The chapter about venture capital has a bit of a Moneyball vibe to it.
+1000. I'm a PPSEL of the Cessna-exclusively-outside-the-soup variety, and these kinds of transcripts often bring me to tears. I understand the fascination with (and importance of understanding) accidents and human-error events especially, but the pilot in question was just about my age, and I can't begin to put myself in his shoes in the first moments of this tragedy without crushing pressure entering my guts.
An even more interesting air disaster is United Airlines Flight 173. Just prior to landing a malfunction caused the indicator for the landing gear being lowered to fail to indicate that it actually was lowered. The plane circled the airport while the crew concentrated on figuring out what was wrong. The plane ran out of fuel and crashed.
It's easy to get side tracked by a problem while losing sight of the big picture. That crash led to a complete rethinking of the way planes are flown.
It was also caused by "cockpit gradient" the flight engineer and FO knew about the problem but were reluctant to point it out to the captain (because it was such a silly little thing)
That is interesting. I'm sure I've read of planes doing a fly-by for the control tower to assess whether the landing gear is actually down or not in situations like this. Were there reasons something like this wasn't attempted in this case?
A vivid example of forgetting to fly the plane is the similar case http://en.wikipedia.org/wiki/Eastern_Air_Lines_Flight_401 where the landing gear light bulb was burnt out. While investigating this, the crew didn't notice that they were slowly descending and 101 people died when they hit the ground. Last words: "We're still at 2,000 feet, right?"
One thing this is, in my opinion, missing: panic is a weird state. You might even know that what you're doing is irrational. It doesn't really help, and to make things worse, people telling you what's rational don't actually help (you know that you're not doing the right thing, you feel helpless about it already, last thing you need is people passing judgement on you).
It's a tough problem, because sometimes panic attack strikes completely out of nowhere, even a person who was previously stable, even in situations less stressful than described (there's records of people panicking while crossing a street, to the point where they couldn't move). And it isn't always completely obvious to onlookers, and it might get your co-pilot, your climbing partner, or you.
> Unlike car accidents, which are often blamed on driver (and thus human) error, airplane crashes are considered engineering failures...
Forgive me if I'm misunderstanding something about the way these accidents are investigated and understood, but directly after this the author goes on to cite Air France 447, which many of us have by now read about in Popular Science, among other sources I'm sure, wherein it's made clear that that particular flight fell into the ocean for no other reason than a persistence fault on the part of the copilot who had control of the plane. So how does that qualify as an engineering error and not simply human error? Could the author mean by "engineering" such an abstraction as the engineering of flight training?
I think it means that any crash, even if caused by the pilots fault, is seen as a fixable technical problem, either in automation, equipment, reliability, or pilot training.
We don't send all car drivers back to get their license if somebody crashes his car. We do try to "fix" the pilots if something like this happens.
The cockpit has two switches, right next to each other, on the control panel. They're exactly the same size, shape, and color. They feel the same in your hand.
The only difference between these two switches are the labels. One says "Recover from Stall", the other "Self-Destruct".
After the explosion, is it "pilot error" that you pressed the wrong switch? Or is an engineering failure that those buttons were so indistinguishable to begin with?
He missed a word like "frequently" after "airplane crashes are", and that might confuse a few people (as it confused you). His point is - much like you said yourself - that most airplane crashes are often related to engineering failures (actual mechanical/system failures), but that in this particular case, it was human error.
>> The rush of steroids into the bloodstream essentially turns off unnecessary systems, including some higher thinking processes, to aid in escape.
>> So, the next time you’re in a crushing situation, remember how irrational humans are under stress and remember to FLY THE AIRPLANE.
The advice is good, but irrelevant as the article itself states it.
Maybe the first step in the checklist manifest should be to take a steroid inhibitor pill, or even better, always take some pill that only kicks in when steroids are above normal levels (if that could even be acomplished).
the co-pilot did fly the plane, incorrectly, for 4 min & 23 seconds. he was pulling back on the stick to climb because he didn't have all of his instruments (due to the icing of the sensor) or understand why the plane was not climbing. the reason the plane crashed was because he flew the plane wrong, not lack of flying the plane.
Flying the plane wrong is not flying. The point of the saying is to not get distracted by what's happening to the point that you fail to fly the airplane. And that's exactly what happened here.
I found the Popular mechanics article linked to in the OP well written and far more interesting. One of my family is a retired pilot so I'm gonna show him that article. The sad thing is, if they had gotten the captain into the cockpit a couple of minutes sooner, this may never have happened.
1: Panic. His brain's "we're falling out of the sky" alarm was louder than the plane's stall alarm. (The correct reaction to the first is the opposite of the correct reaction to the second.)
2: Mental error caused by UI confusion. "Stall speed" is shown on the airspeed indicator, and he knew his airspeed sensors had failed. Therefore, he concluded that the stall warning was wrong. (But, stall is not detected by the pitot system, it's detected by angle-of-attack sensors which were working just fine.)
3: Training. Pilots are casually taught "you can't stall this plane" because under "normal law", that's true. No matter what input you apply, the computer will not let you stall the airplane. Unfortunately, the plane was not in "normal law" at the time, because of the failed systems. (This is indicated somewhere, the information that the plane's not in normal law is available to the pilots.) I'm guessing that no instructor ever mentions those exact words in bullet-point form, but I'm guessing that someone has said, "just pull back as hard as you can, you can't stall this thing" when practicing, say, engine-out-on-departure procedures. And statements like that stick.
This has been mentioned in other articles about the crash, including ones that have been posted in HN.
Under normal conditions, when the flight computer is receiving airspeed and other telemetry normally, the fly-by-wire Airbus operates under "normal law", a mode where the pilot controls the aircraft but the flight computer prevents stalling and other dangerous situations. In this case, the pitot tube was frozen and the flight computer didn't receive proper airspeed data and went into "alternate law" mode, where the pilot controls the craft and there are no computer enforced limits. The co-pilot with the controls had probably not flown the aircraft under alternate law or incorrectly believed that he was operating under normal law, and had never heard the stall warning before. So either he thought that the stall warning was false and just another instrument malfunction or he just didn't understand it's meaning in the confusion.
One obvious improvement would be to replace the warning "Stall!" with "Stall! Stall protection disengaged!" when flying in alternative mode. Even better might be "Stall! Push stick forward!" when a stall is detected and the pilot is simultaneously pulling back on the stick.
I don't think more complex aural warnings would have accomplished anything [1]. (Edit) This guy basically had his brain disengaged due to panic and was useless at that point. The tragedy is that the other pilots couldn't prevent it.
The plane also warned them aurally that they were giving conflicting inputs. None of them "understood" it, in the sense that they thought about what that must have meant.
[1] Though, having the stall alarm go off when the stall was too deep is very, very weird and may have contributed to the issue.
(Edit: I initially said that pilots are deeply trained to use stick down to recover from a stall - but apparently this isn't really true for commercial pilots who are trained to avoid height loss when near a stall.)
Reminds me of the Zen story which recommends just focus on doing the next thing, no matter how chaotic or absurd the situation. "Before Enlightenment chop wood carry water, after Enlightenment, chop wood carry water."
[+] [-] RomP|14 years ago|reply
>If the pilots has switched a button to re-enable autopilot, everyone on board would have lived. But they didn’t. One co-pilot made a single, absurd mistake–for twenty full minutes–that brought the plane down.
First factual error: The button they should've switched is not the auto-pilot button (which they operate many times per flight), but the flight mode button (which most pilots never operate in their career). When the plane lost at least two of the three pitot tube readings, it went from the NORMAL "Law" to the ALT "Law", where the airplane doesn't guard itself against many pilot errors. When the pitots de-iced shortly thereafter, the plane did NOT go back to NORMAL "Law": it had to be switched there manually. The pilots did not do that and it seems to be the consensus so far (can't state that for certain before the official report is released) that they did not realize they were flying the plane in ALT and then DIRECT Law.
Second factual error: the "absurd mistake" lasted nowhere near 20 minutes. The first problem appeared at 2:10:03UTC and flying into the ocean occurred at 2:14:28UTC -- 4 minutes 23 seconds in all.
[+] [-] omegant|14 years ago|reply
[+] [-] mseebach|14 years ago|reply
[+] [-] dcurtis|14 years ago|reply
[+] [-] ibisum|14 years ago|reply
[deleted]
[+] [-] joshwa|14 years ago|reply
This axiom can be applied to lots of other areas, too, including startups. For instance, it explains why I don't blog: I'm concentrating on execution and strategy.
It's one of the reasons I wonder if the many prolific startup bloggers have their priorities straight.
EDIT: oops, just saw yread's comment below. http://news.ycombinator.com/item?id=3360071
[+] [-] hxa7241|14 years ago|reply
The pilots were not making an 'absurd error'. They did not forget to fly the plane.
It is that what they thought they were doing was not what they were actually doing. Their mental model broke away from the reality. (They thought the plane was in 'normal mode' when it was actually in 'abnormal mode' -- an expression of which: one them declaring "this cannot be happening!")
Telling them just fly the airplane is not (quite) the solution -- they thought they were flying it.
But the remedy is sort-of basically correct. It just seems better expressed as: when nothing makes sense (your mental model has suddenly utterly failed), fall back to a more basic backup mental model and system -- like primitive manual override.
(How clear can such separation of a basic mode be? How practical would it be? How reliable? It leads to a set of engineering/UI questions . . . were they well designed in this particular case?)
[+] [-] mikeash|14 years ago|reply
They spent all this time trying to figure out what was wrong with the plane when their immediate concern should have been to get the nose down and get their airspeed up. Figuring out the underlying problem can wait. That's what "fly the airplane" is all about. Even if stuff is on fire, the first priority is to keep your speed up and don't run into anything hard.
[+] [-] bulte-rs|14 years ago|reply
[+] [-] unwind|14 years ago|reply
So, the next time you’re in a crushing situation, remember how irrational humans are under stress and remember to FLY THE AIRPLANE.
After observing that people today tend need their brains much more now during moments of extreme stress, since it often involves interacting with machines, as opposed to just running away or putting up a (physical) fight.
[+] [-] yread|14 years ago|reply
I.e. make sure to stay in the air, know where are you flying and tell others about where you're going or what you've learned
[+] [-] n8agrin|14 years ago|reply
The human body’s physical “fight or flight” response evolved to help it evade a dangerous situation, which historically involved extreme physical exertion. The rush of steroids into the bloodstream essentially turns off unnecessary systems, including some higher thinking processes, to aid in escape.
When we make statements like this proclaiming we understand the complex workings of things like human physiology I always have to shake my head. We may be smart, us programmers and designers, but let's not pretend to understand the order and meaning of everything. And if you do understand and you have the means, provide some kind of reference to where the claim originates from so we can all learn more.
* edited because I sounded like a jerk and wanted to make my point clearer
[+] [-] dcurtis|14 years ago|reply
The present study investigated the acute effects of cortisol administration in normal healthy male volunteers on immediate free recall and recognition of pleasant, unpleasant, and neutral nouns using a between-subjects double-blind design. Two hours after cortisol (10 mg) or placebo administration, impaired recall and recognition of neutral and pleasant words was found in the treatment group, whereas recall and recognition of unpleasant words was similar in both groups.
See: http://ukpmc.ac.uk/abstract/MED/12820857/reload=0;jsessionid...
[+] [-] tomhoward|14 years ago|reply
I agree that in general, people's understanding of human physiology tends to be simplistic and wrong.
But Dustin's description here aligns with what is generally known and accepted, and he doesn't venture details beyond what anyone with with a sound understanding of physiology could reasonably claim to know.
If he's wrong, that would be easy to prove, in which cas you should do so, so he can amend his post.
[+] [-] mmcconnell1618|14 years ago|reply
http://www.pprune.org/rumours-news/466259-af447-final-crew-c...
[+] [-] alabut|14 years ago|reply
[+] [-] crikli|14 years ago|reply
[+] [-] feralchimp|14 years ago|reply
Rest in peace holmes, and don't take it personal.
[+] [-] InclinedPlane|14 years ago|reply
It's easy to get side tracked by a problem while losing sight of the big picture. That crash led to a complete rethinking of the way planes are flown.
[+] [-] yread|14 years ago|reply
[+] [-] dolbz|14 years ago|reply
[+] [-] kens|14 years ago|reply
Transcript: http://planecrashinfo.com/cvr721229.htm
[+] [-] drewblaisdell|14 years ago|reply
[+] [-] LaGrange|14 years ago|reply
It's a tough problem, because sometimes panic attack strikes completely out of nowhere, even a person who was previously stable, even in situations less stressful than described (there's records of people panicking while crossing a street, to the point where they couldn't move). And it isn't always completely obvious to onlookers, and it might get your co-pilot, your climbing partner, or you.
[+] [-] llambda|14 years ago|reply
Forgive me if I'm misunderstanding something about the way these accidents are investigated and understood, but directly after this the author goes on to cite Air France 447, which many of us have by now read about in Popular Science, among other sources I'm sure, wherein it's made clear that that particular flight fell into the ocean for no other reason than a persistence fault on the part of the copilot who had control of the plane. So how does that qualify as an engineering error and not simply human error? Could the author mean by "engineering" such an abstraction as the engineering of flight training?
[+] [-] gcp|14 years ago|reply
We don't send all car drivers back to get their license if somebody crashes his car. We do try to "fix" the pilots if something like this happens.
[+] [-] pkamb|14 years ago|reply
The only difference between these two switches are the labels. One says "Recover from Stall", the other "Self-Destruct".
After the explosion, is it "pilot error" that you pressed the wrong switch? Or is an engineering failure that those buttons were so indistinguishable to begin with?
[+] [-] fredoliveira|14 years ago|reply
[+] [-] gldalmaso|14 years ago|reply
>> So, the next time you’re in a crushing situation, remember how irrational humans are under stress and remember to FLY THE AIRPLANE.
The advice is good, but irrelevant as the article itself states it.
Maybe the first step in the checklist manifest should be to take a steroid inhibitor pill, or even better, always take some pill that only kicks in when steroids are above normal levels (if that could even be acomplished).
[+] [-] ditojim|14 years ago|reply
[+] [-] lutorm|14 years ago|reply
[+] [-] arjn|14 years ago|reply
[+] [-] bond|14 years ago|reply
[+] [-] jrockway|14 years ago|reply
1: Panic. His brain's "we're falling out of the sky" alarm was louder than the plane's stall alarm. (The correct reaction to the first is the opposite of the correct reaction to the second.)
2: Mental error caused by UI confusion. "Stall speed" is shown on the airspeed indicator, and he knew his airspeed sensors had failed. Therefore, he concluded that the stall warning was wrong. (But, stall is not detected by the pitot system, it's detected by angle-of-attack sensors which were working just fine.)
3: Training. Pilots are casually taught "you can't stall this plane" because under "normal law", that's true. No matter what input you apply, the computer will not let you stall the airplane. Unfortunately, the plane was not in "normal law" at the time, because of the failed systems. (This is indicated somewhere, the information that the plane's not in normal law is available to the pilots.) I'm guessing that no instructor ever mentions those exact words in bullet-point form, but I'm guessing that someone has said, "just pull back as hard as you can, you can't stall this thing" when practicing, say, engine-out-on-departure procedures. And statements like that stick.
[+] [-] exDM69|14 years ago|reply
Under normal conditions, when the flight computer is receiving airspeed and other telemetry normally, the fly-by-wire Airbus operates under "normal law", a mode where the pilot controls the aircraft but the flight computer prevents stalling and other dangerous situations. In this case, the pitot tube was frozen and the flight computer didn't receive proper airspeed data and went into "alternate law" mode, where the pilot controls the craft and there are no computer enforced limits. The co-pilot with the controls had probably not flown the aircraft under alternate law or incorrectly believed that he was operating under normal law, and had never heard the stall warning before. So either he thought that the stall warning was false and just another instrument malfunction or he just didn't understand it's meaning in the confusion.
[+] [-] ricardobeat|14 years ago|reply
[+] [-] elevenE|14 years ago|reply
[+] [-] seanos|14 years ago|reply
[+] [-] gcp|14 years ago|reply
The plane also warned them aurally that they were giving conflicting inputs. None of them "understood" it, in the sense that they thought about what that must have meant.
[1] Though, having the stall alarm go off when the stall was too deep is very, very weird and may have contributed to the issue.
(Edit: I initially said that pilots are deeply trained to use stick down to recover from a stall - but apparently this isn't really true for commercial pilots who are trained to avoid height loss when near a stall.)
[+] [-] jorkos|14 years ago|reply
[+] [-] AznHisoka|14 years ago|reply