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The root cause was Technical failure, not pilot error. The instruments were wrong and the burden of accuracy on such a technically complicated machine is on the

The root cause was Technical failure, not pilot error. The instruments were wrong and the burden of accuracy on such a technically complicated machine is on the aircraft. But that's too easy to sue for so the manufacturers of the systems press to blame the dead crew. This is standard corporate culture.

raldi 14y ago
The fact that the pilot ignored the continuous audible "Stall! Stall! Stall!" alarm and kept the control stick pulled fully back (the opposite of what you want to do in a stall) suggests to me that it's legitimate to place some of the blame on human error.
- ZoFreX 14y ago
  It's worth pointing out that the stall alarm goes off both when you go into a stall and when you come out of it, and you have to do very different things in those situations.
- jt2190 14y ago
  > The fact that the pilot ignored the continuous "Stall! Stall! Stall!" alarm > and kept the control stick pulled fully back The fact is that the black boxes recorded this behavior. Can we be 100% certain that the copilot actually did this? My concern is that we're still trusting the output of a system that has proven to be suspect.
  - raldi 14y ago
    Other than the airspeed sensors freezing up, I'm not aware of any other known malfunctions. What makes you say the system was "proven to be suspect"?
    - jt2190 14y ago
      I'm quoting Wikipedia's summary of the Report: * The stall warning deactivates by design when the angle of attack measurements are considered invalid and this is the case when the airspeed drops below a certain limit. * In consequence, the stall warning stopped and came back on several times during the stall; in particular, it came on whenever the pilot pushed forward on the stick and then stopped when he pulled back; this may have confused the pilots. * Despite the fact that they were aware that altitude was declining rapidly, the pilots were unable to determine which instruments to trust: it may have appeared to them that all values were incoherent. Personally, I'm not sure whether to believe that the copilot simply made an amateur mistake .
  - Coincoin 14y ago
    The copilot mentions he pulled the stick all along in the cockpit recording about 30 seconds before crashing. EDIT: When the pilot realized the error, he tried to correct, but it was already too late.
ZoFreX 14y ago
It was pilot error. An amateur pilot in the same situation would not have crashed the plane, as it was a really basic error. I don't mean to say the pilots were bad - just that with flying, as with all skills, being very advanced can make you quite bad at some of the basics. The instruments actually could not have done much better, without any external reference points there are some situations that are indistinguishable from air speed, pressure, and g-forces alone. Sadly, the stall profile they were in was one such situation.
- Tloewald 14y ago
  While one pilot made an error, the more senior pilot could not tell the error was being made because of the way the controls work. To put it in your terms - the same problem couldn't occur in a cessna.
  - ZoFreX 14y ago
    > the same problem couldn't occur in a cessna Frequently true! :D Although my personal mantra is "the same problem couldn't occur in a sailplane" ;)
crikli 14y ago
The pitot static system had demonstrated itself to be failing, leading the pilots to lose faith in their instruments. Let he who has flown in the soup with flaky instrumentation cast the first stone.
- sespindola 14y ago
  All (or most) comercial planes also have an amber LED alarm on the caution panel that says PITOT when the PITOT HEAT switch is turned off. If that alarm was functional and activated before they entered that stall profile, it was, in my opinion, some serious misjudgement by the pilots not to turn the pitot heat on. But then again, I've only flown a PA-38 on storm conditions, so take this with a huge grain of salt.

raldi 14y ago

The fact that the pilot ignored the continuous audible "Stall! Stall! Stall!" alarm and kept the control stick pulled fully back (the opposite of what you want to do in a stall) suggests to me that it's legitimate to place some of the blame on human error.

ZoFreX 14y ago
It's worth pointing out that the stall alarm goes off both when you go into a stall and when you come out of it, and you have to do very different things in those situations.
jt2190 14y ago
> The fact that the pilot ignored the continuous "Stall! Stall! Stall!" alarm > and kept the control stick pulled fully back The fact is that the black boxes recorded this behavior. Can we be 100% certain that the copilot actually did this? My concern is that we're still trusting the output of a system that has proven to be suspect.
- raldi 14y ago
  Other than the airspeed sensors freezing up, I'm not aware of any other known malfunctions. What makes you say the system was "proven to be suspect"?
  - jt2190 14y ago
    I'm quoting Wikipedia's summary of the Report: * The stall warning deactivates by design when the angle of attack measurements are considered invalid and this is the case when the airspeed drops below a certain limit. * In consequence, the stall warning stopped and came back on several times during the stall; in particular, it came on whenever the pilot pushed forward on the stick and then stopped when he pulled back; this may have confused the pilots. * Despite the fact that they were aware that altitude was declining rapidly, the pilots were unable to determine which instruments to trust: it may have appeared to them that all values were incoherent. Personally, I'm not sure whether to believe that the copilot simply made an amateur mistake .
- Coincoin 14y ago
  The copilot mentions he pulled the stick all along in the cockpit recording about 30 seconds before crashing. EDIT: When the pilot realized the error, he tried to correct, but it was already too late.

ZoFreX 14y ago

It was pilot error. An amateur pilot in the same situation would not have crashed the plane, as it was a really basic error. I don't mean to say the pilots were bad - just that with flying, as with all skills, being very advanced can make you quite bad at some of the basics. The instruments actually could not have done much better, without any external reference points there are some situations that are indistinguishable from air speed, pressure, and g-forces alone. Sadly, the stall profile they were in was one such situation.

Tloewald 14y ago
While one pilot made an error, the more senior pilot could not tell the error was being made because of the way the controls work. To put it in your terms - the same problem couldn't occur in a cessna.
- ZoFreX 14y ago
  > the same problem couldn't occur in a cessna Frequently true! :D Although my personal mantra is "the same problem couldn't occur in a sailplane" ;)

crikli 14y ago

The pitot static system had demonstrated itself to be failing, leading the pilots to lose faith in their instruments. Let he who has flown in the soup with flaky instrumentation cast the first stone.

sespindola 14y ago
All (or most) comercial planes also have an amber LED alarm on the caution panel that says PITOT when the PITOT HEAT switch is turned off. If that alarm was functional and activated before they entered that stall profile, it was, in my opinion, some serious misjudgement by the pilots not to turn the pitot heat on. But then again, I've only flown a PA-38 on storm conditions, so take this with a huge grain of salt.