5 ms·

> When he came they all continued doing random things indicating none of the three had any flight training that they remembered. Power + Attitude = Performanc

> When he came they all continued doing random things indicating none of the three had any flight training that they remembered. Power + Attitude = Performance. Every PPL knows this, as did the three AF pilots that night. They deserve more credit. We know the pilots received an audible stall warning the moment PFD's and STBY ASI failed and the A/P & A/T disengaged. That was a false stall warning, moments later they received another real stall warning. They were flying at night entering turbulence with unreliable and conflicting data with flight control laws that went from Normal Law to Direct Law. The ASI is showing 25+ knots over the max limit while at the same time stall warning is going off. The plane is in direct law mode so any side-stick input could rip it appart. I'm going to wait until more data is released before making a conclusion, there are too many whys.

lucasjung 15y ago
I'll start by saying that I fly for a living, and have logged hours in so many different types of aircraft that I've lost count (I suppose I could check my logbook...), everything from bug-smashers to helicopters to supersonic jets (barely more than zero in the helos, though). EDIT: I should also mention that I have an MS in aeronautical engineering, and specialized in stability in control and avionics (the things that went wrong in this mishap)./EDIT I agree 100% with the assessment that the new information does not deepen the mystery, it pretty much explains everything. The quote from gp about lack of flight training is excessive, but it is in the right direction: those guys screwed up big time, and a big contributing factor was almost certainly inadequate training in dealing with emergencies of this nature. They screwed up because their SA bubbles just completely collapsed because they were getting conflicting information from their instruments: simultaneous stall and overspeed warnings. Situations like that are exactly why we still need real, human pilots in these aircraft, because a properly trained crew, who truly understand the systems will be able to put together the clues to figure out what's really going on. A disproportionate amount of my training as an aviator has been dedicated to understanding all of the ways that the systems in the aircraft I fly can break. It's critical to understand not just the common failure modes, but also the interactions between them (what we call "compound emergencies"), especially when following the procedures for one emergency can exacerbate a concurrent emergency. The thin is, in this situation they didn't even have a compound emergency: the only failure was in the pitot-static system. This is an aircraft which requires a sophisticated automated flight control system to remain stable in many flight regimes, and that automated flight control system is utterly dependent on reliably accurate data from the pitot-static system. In that context, these guys should have been drilled heavily on all the ways that the pitot-static system could fail, the manifestations of those failure modes, and how to respond to them. For example: "If you get simultaneous overspeed and stall warnings and your VSI is deeply negative, you are in a stall and need to ignore the overspeed warning and execute stall recovery procedures." Actually, when I word it that way, they shouldn't even have needed special training to figure that out: the VSI should have made it obvious.
- CamperBob 15y ago
  Situations like that are exactly why we still need real, human pilots in these aircraft, Or sensors that aren't unreliable pieces of junk. I'll fly with a computer that has accurate SA over a human that doesn't, any day of the week.
  - borism 15y ago
    exactly! to OP: For example: "If you get simultaneous overspeed and stall warnings and your VSI is deeply negative, you are in a stall and need to ignore the overspeed warning and execute stall recovery procedures." Actually, when I word it that way, they shouldn't even have needed special training to figure that out: the VSI should have made it obvious. wow, and how were they supposed to know that VSI is reliable? but it is in the right direction: those guys screwed up big time, and a big contributing factor was almost certainly inadequate training in dealing with emergencies of this nature. I think you're too early to jump onto conclusions based solely on impartial and interim report. You're not alone though - seems that opinion of internet experts is divided between putting full blame on pilots or putting full blame on sensors. I think actual situation was a bit more complex than that.
    - epochwolf 15y ago
      Because the VSI doesn't use the pitot tubes? IIRC, it uses a gyroscope. [Confirmed: http://news.ycombinator.com/item?id=2595230 http://news.ycombinator.com/item?id=2595230 ] The chance of having a failure of two separate, redundant systems is unlikely. Pitot tube failure in a thunderstorm is far more likely than gyroscope failure. Anyway, the computer had reported loss of reliable airspeed so they should have ignored all instruments that use airspeed and fly on what's left. There are procedures for this kind of failure. It looks like they didn't follow them. Nova did a program on this. It's on netflix. http://www.netflix.com/WiMovie/70148706 http://www.netflix.com/WiMovie/70148706 They showed the correct solution was to fly the plane based on angle of attack and throttle settings. You don't need airspeed to keep the plane in the air long enough to figure something else out.
      - 15y ago

lucasjung 15y ago

I'll start by saying that I fly for a living, and have logged hours in so many different types of aircraft that I've lost count (I suppose I could check my logbook...), everything from bug-smashers to helicopters to supersonic jets (barely more than zero in the helos, though). EDIT: I should also mention that I have an MS in aeronautical engineering, and specialized in stability in control and avionics (the things that went wrong in this mishap)./EDIT I agree 100% with the assessment that the new information does not deepen the mystery, it pretty much explains everything. The quote from gp about lack of flight training is excessive, but it is in the right direction: those guys screwed up big time, and a big contributing factor was almost certainly inadequate training in dealing with emergencies of this nature. They screwed up because their SA bubbles just completely collapsed because they were getting conflicting information from their instruments: simultaneous stall and overspeed warnings. Situations like that are exactly why we still need real, human pilots in these aircraft, because a properly trained crew, who truly understand the systems will be able to put together the clues to figure out what's really going on. A disproportionate amount of my training as an aviator has been dedicated to understanding all of the ways that the systems in the aircraft I fly can break. It's critical to understand not just the common failure modes, but also the interactions between them (what we call "compound emergencies"), especially when following the procedures for one emergency can exacerbate a concurrent emergency. The thin is, in this situation they didn't even have a compound emergency: the only failure was in the pitot-static system. This is an aircraft which requires a sophisticated automated flight control system to remain stable in many flight regimes, and that automated flight control system is utterly dependent on reliably accurate data from the pitot-static system. In that context, these guys should have been drilled heavily on all the ways that the pitot-static system could fail, the manifestations of those failure modes, and how to respond to them. For example: "If you get simultaneous overspeed and stall warnings and your VSI is deeply negative, you are in a stall and need to ignore the overspeed warning and execute stall recovery procedures." Actually, when I word it that way, they shouldn't even have needed special training to figure that out: the VSI should have made it obvious.

CamperBob 15y ago
Situations like that are exactly why we still need real, human pilots in these aircraft, Or sensors that aren't unreliable pieces of junk. I'll fly with a computer that has accurate SA over a human that doesn't, any day of the week.
- borism 15y ago
  exactly! to OP: For example: "If you get simultaneous overspeed and stall warnings and your VSI is deeply negative, you are in a stall and need to ignore the overspeed warning and execute stall recovery procedures." Actually, when I word it that way, they shouldn't even have needed special training to figure that out: the VSI should have made it obvious. wow, and how were they supposed to know that VSI is reliable? but it is in the right direction: those guys screwed up big time, and a big contributing factor was almost certainly inadequate training in dealing with emergencies of this nature. I think you're too early to jump onto conclusions based solely on impartial and interim report. You're not alone though - seems that opinion of internet experts is divided between putting full blame on pilots or putting full blame on sensors. I think actual situation was a bit more complex than that.
  - epochwolf 15y ago
    Because the VSI doesn't use the pitot tubes? IIRC, it uses a gyroscope. [Confirmed: http://news.ycombinator.com/item?id=2595230 http://news.ycombinator.com/item?id=2595230 ] The chance of having a failure of two separate, redundant systems is unlikely. Pitot tube failure in a thunderstorm is far more likely than gyroscope failure. Anyway, the computer had reported loss of reliable airspeed so they should have ignored all instruments that use airspeed and fly on what's left. There are procedures for this kind of failure. It looks like they didn't follow them. Nova did a program on this. It's on netflix. http://www.netflix.com/WiMovie/70148706 http://www.netflix.com/WiMovie/70148706 They showed the correct solution was to fly the plane based on angle of attack and throttle settings. You don't need airspeed to keep the plane in the air long enough to figure something else out.
    - 15y ago