4 ms·

From what I read from the preliminary report, it's established that the stall warning sounded. If it had not been audible on the CVR, they would probably have n

by gnaffle 15y ago

From what I read from the preliminary report, it's established that the stall warning sounded. If it had not been audible on the CVR, they would probably have noted it. One problem was that the stall warning stopped due to high angle of attack even though the plane was stalled, and it started again when the nose was lowered and the AOA was in the "valid" region again. This might have confused the pilots in a situation when they already had inconsistent airspeeds etc. to deal with.

StavrosK 15y ago
Ah, yes, I read that too. It was so frustrating that the pilot kept pulling up all the time, it makes no sense. You'd think that at some point he'd stop and reassess, but I guess he was too confused and shocked to do it...
- gnaffle 15y ago
  Yes, maybe a combination of shock, confusion or distrust in the instruments was a factor. It will be interesting to see what the human factors group of the investigation comes up with. I'm sure that the flight training will also be investigated, there has been concerns that improper stall recovery technique is being taught by some instructors: http://www.caa.co.uk/docs/33/012010.pdf http://www.caa.co.uk/docs/33/012010.pdf (And of course, in planes that are not certified for stalls, you can't really practice full stalls and have to train on approach to stalls instead.)
  - jrockway 15y ago
    (And of course, in planes that are not certified for stalls, you can't really practice full stalls and have to train on approach to stalls instead.) Of course, very little airliner training happens outside a simulator, which can you can stall without damaging anything.
    - lutorm 15y ago
      On the other hand, it's not obvious to me that the simulator would behave correctly in this regime either. Having the simulator work correctly in a deep stall is probably not high on their list of priorities. It's possible that this was even the first time ever that an Airbus had been stalled like that, so maybe no one actually knew how it would behave.
      - jrockway 15y ago
        Yes, that's possible. I remember reading an article by the author of X-Plane about how stalls are mostly simulated by trying it in the real aircraft and programming something similar, because the airflow dynamics are too difficult to model in real time. (Incidentally, the Cessna 172 is nearly impossible to stall in X-Plane, but somewhat easier to stall in FlightGear. I wonder who's closer :)
        gnaffle 15y ago
        By easier, do you mean that you have to exert more back pressure to have it stall, or that it quickly gets out of the stall? I think it can vary a bit depending on weight and the exact model you're flying. In some models it's difficult to maintain the stall because the nose will just drop. You should get an introductory flight lesson, then you could ask do have a stall demonstrated and see which flight simulator matches best. There are a lot of signs you don't get outside a full motion simulator, such as wing buffeting and "mushy" controls.
        jrockway 15y ago
        I've been meaning to start taking lessons so I can get a private pilot's license, but it's hard when you live in downtown Chicago without a car. There are a couple schools at MDW, but you'll eventually have to drive to the suburbs as MDW does not let students fly solo out of the airport. Probably for good reason :)
        crikli 15y ago
        Yup, intentional stalls give plenty of warning in a trainer. It's the stalls caused by uncoordinated flight during a steep bank or snap spins caused by exceeding critical angle of attack, regardless of speed, that will kill you. The first is easy to get into in a trainer like a C172. The second won't happen (safely) unless you're in something with a bit less lift and more power, like a Pitts.
- onli 15y ago
  It's especially frustrating for me because i remember all the times i crashed in a simulator due to stall until i understood what was happening. I don't even remember the name of the simulator, i'm not even an amateur-pilot - but that makes that report almost unbelievable, that something like this happened in a real flight to a real pilot.
  - lutorm 15y ago
    unbelievable, that something like this happened in a real flight to a real pilot Actually, most fatal crashes are "stall-spin accidents", where pilots stall the airplane near the ground without sufficient altitude to recover. But those are not cases where you keep the airplane in a deep stall for 90s. When you stall an airplane in VFR, it's obvious what happens. No one would persist in keeping the airplane at 20 degrees positive pitch while descending at thousands of feet per minute without realizing the airplane is stalled. But here, without outside references and with obvious confusion about the state of the airplane, it was apparently beyond these guys. (Except the captain, whose comment about "no, don't climb" seems to indicate he was on the right track, but by then it was too late.)
    - chc 15y ago
      Actually, only the less experienced copilot, Bonin, appeared to be in favor of climbing. The other repeatedly told him to level out or dive, and apparently thought Bonin had listened (which would explain why he was so baffled). As the OP points out, neither that copilot nor the captain seemed to realize that Bonin had been futilely trying to climb the whole time until that moment at the end when the captain ordered him to stop.

by gnaffle 15y ago

StavrosK 15y ago

Ah, yes, I read that too. It was so frustrating that the pilot kept pulling up all the time, it makes no sense. You'd think that at some point he'd stop and reassess, but I guess he was too confused and shocked to do it...

gnaffle 15y ago
Yes, maybe a combination of shock, confusion or distrust in the instruments was a factor. It will be interesting to see what the human factors group of the investigation comes up with. I'm sure that the flight training will also be investigated, there has been concerns that improper stall recovery technique is being taught by some instructors: http://www.caa.co.uk/docs/33/012010.pdf http://www.caa.co.uk/docs/33/012010.pdf (And of course, in planes that are not certified for stalls, you can't really practice full stalls and have to train on approach to stalls instead.)
- jrockway 15y ago
  (And of course, in planes that are not certified for stalls, you can't really practice full stalls and have to train on approach to stalls instead.) Of course, very little airliner training happens outside a simulator, which can you can stall without damaging anything.
  - lutorm 15y ago
    On the other hand, it's not obvious to me that the simulator would behave correctly in this regime either. Having the simulator work correctly in a deep stall is probably not high on their list of priorities. It's possible that this was even the first time ever that an Airbus had been stalled like that, so maybe no one actually knew how it would behave.
    - jrockway 15y ago
      Yes, that's possible. I remember reading an article by the author of X-Plane about how stalls are mostly simulated by trying it in the real aircraft and programming something similar, because the airflow dynamics are too difficult to model in real time. (Incidentally, the Cessna 172 is nearly impossible to stall in X-Plane, but somewhat easier to stall in FlightGear. I wonder who's closer :)
      - gnaffle 15y ago
        By easier, do you mean that you have to exert more back pressure to have it stall, or that it quickly gets out of the stall? I think it can vary a bit depending on weight and the exact model you're flying. In some models it's difficult to maintain the stall because the nose will just drop. You should get an introductory flight lesson, then you could ask do have a stall demonstrated and see which flight simulator matches best. There are a lot of signs you don't get outside a full motion simulator, such as wing buffeting and "mushy" controls.
        jrockway 15y ago
        I've been meaning to start taking lessons so I can get a private pilot's license, but it's hard when you live in downtown Chicago without a car. There are a couple schools at MDW, but you'll eventually have to drive to the suburbs as MDW does not let students fly solo out of the airport. Probably for good reason :)
        crikli 15y ago
        Yup, intentional stalls give plenty of warning in a trainer. It's the stalls caused by uncoordinated flight during a steep bank or snap spins caused by exceeding critical angle of attack, regardless of speed, that will kill you. The first is easy to get into in a trainer like a C172. The second won't happen (safely) unless you're in something with a bit less lift and more power, like a Pitts.
onli 15y ago
It's especially frustrating for me because i remember all the times i crashed in a simulator due to stall until i understood what was happening. I don't even remember the name of the simulator, i'm not even an amateur-pilot - but that makes that report almost unbelievable, that something like this happened in a real flight to a real pilot.
- lutorm 15y ago
  unbelievable, that something like this happened in a real flight to a real pilot Actually, most fatal crashes are "stall-spin accidents", where pilots stall the airplane near the ground without sufficient altitude to recover. But those are not cases where you keep the airplane in a deep stall for 90s. When you stall an airplane in VFR, it's obvious what happens. No one would persist in keeping the airplane at 20 degrees positive pitch while descending at thousands of feet per minute without realizing the airplane is stalled. But here, without outside references and with obvious confusion about the state of the airplane, it was apparently beyond these guys. (Except the captain, whose comment about "no, don't climb" seems to indicate he was on the right track, but by then it was too late.)
  - chc 15y ago
    Actually, only the less experienced copilot, Bonin, appeared to be in favor of climbing. The other repeatedly told him to level out or dive, and apparently thought Bonin had listened (which would explain why he was so baffled). As the OP points out, neither that copilot nor the captain seemed to realize that Bonin had been futilely trying to climb the whole time until that moment at the end when the captain ordered him to stop.