4 ms·

>If your attitude, airspeed, and rate of climb are all looking normal, then if the AOA says you're stalling it's almost certainly wrong. Agreed - you can certa

>If your attitude, airspeed, and rate of climb are all looking normal, then if the AOA says you're stalling it's almost certainly wrong. Agreed - you can certainly sanity check the AOA data with other data sources. Unfortunately, I'm not sure that will always let you pinpoint AOA as the cause - imagine some nice dirt-loving wasps have built nests in all of your pitot tubes, or they've iced over, and now those values are locked in place. So your IAS and altimeter could both be reading normal despite the fact that you're in a dangerously fast descent at a high angle of attack. (A radar altimeter wouldn't have this issue, of course) Things like this have happened before. Of course, this would require your engines to have failed at approximately the same time as your airspeed and altitude data, but I can imagine failure modes in which that would be the case. (A particularly stupid autopilot attempting to reduce speed but not seeing the speed decrease, repeat in loop) > And it it says that your AOA is 70 degrees (which the Ethiopian airlines AOA sensor did) then it is definitely wrong. Or it's accurate and you're about to die unless you fix it. Air France Flight 447 comes to mind. (though 70 degrees is probably past the point of being recoverable) > MCAS was designed to blindly trust a single AOA sensor, which was known to be prone to failures. To call that inexcusable would be quite the understatement. No disagreements here.

lisper 8y ago
> imagine some nice dirt-loving wasps have built nests in all of your pitot tubes All of them? And I didn't notice any of them during preflight? And none of them were there on the previous flight? And I didn't notice that the airspeed was not alive on the takeoff roll? Not going to happen. > or they've iced over Again, pretty freakin' unlikely on takeoff flying out of Addis Ababa. And this is another thing a pilot can rule out by looking out of the window. If you're not in clouds, you're not picking up ice. Also, there are OAT (outside air temperature) sensors. > your engines to have failed Another thing that would be pretty apparent to the pilots. No matter how you slice it, Boeing screwed the pooch bigly.
- DuskStar 8y ago
  > > imagine some nice dirt-loving wasps have built nests in all of your pitot tubes > All of them? And I didn't notice any of them during preflight? And none of them were there on the previous flight? And I didn't notice that the airspeed was not alive on the takeoff roll? Not going to happen. You underestimate the abilities of people to fuck things up. Birgenair Flight 301 - one tube blocked by mud dauber wasp, leading to crash. [0] Later that year was the crash of Aeroperú Flight 603 - the static ports were covered with tape, which was never realized by the pilots. [1] (They continued flying as if their altitude and airspeed readings were accurate) > > or they've iced over > Again, pretty freakin' unlikely on takeoff flying out of Addis Ababa. And this is another thing a pilot can rule out by looking out of the window. If you're not in clouds, you're not picking up ice. > Also, there are OAT (outside air temperature) sensors. Not applicable in this instance, sure. But "are there clouds around" isn't something I'd expect the flight computer to be able to reliably detect, and that's what would have to make the decision here. > > your engines to have failed > Another thing that would be pretty apparent to the pilots. I'd agree that it SHOULD be. > No matter how you slice it, Boeing screwed the pooch bigly. Yep. But there's still more complexity here than people seem to want to acknowledge. 0: https://en.wikipedia.org/wiki/Birgenair_Flight_301 https://en.wikipedia.org/wiki/Birgenair_Flight_301 1: https://en.wikipedia.org/wiki/Aeroper%C3%BA_Flight_603 https://en.wikipedia.org/wiki/Aeroper%C3%BA_Flight_603
  - lisper 8y ago
    No technology is ever going to completely protect you against an incompetent pilot.

lisper 8y ago

> imagine some nice dirt-loving wasps have built nests in all of your pitot tubes All of them? And I didn't notice any of them during preflight? And none of them were there on the previous flight? And I didn't notice that the airspeed was not alive on the takeoff roll? Not going to happen. > or they've iced over Again, pretty freakin' unlikely on takeoff flying out of Addis Ababa. And this is another thing a pilot can rule out by looking out of the window. If you're not in clouds, you're not picking up ice. Also, there are OAT (outside air temperature) sensors. > your engines to have failed Another thing that would be pretty apparent to the pilots. No matter how you slice it, Boeing screwed the pooch bigly.

DuskStar 8y ago
> > imagine some nice dirt-loving wasps have built nests in all of your pitot tubes > All of them? And I didn't notice any of them during preflight? And none of them were there on the previous flight? And I didn't notice that the airspeed was not alive on the takeoff roll? Not going to happen. You underestimate the abilities of people to fuck things up. Birgenair Flight 301 - one tube blocked by mud dauber wasp, leading to crash. [0] Later that year was the crash of Aeroperú Flight 603 - the static ports were covered with tape, which was never realized by the pilots. [1] (They continued flying as if their altitude and airspeed readings were accurate) > > or they've iced over > Again, pretty freakin' unlikely on takeoff flying out of Addis Ababa. And this is another thing a pilot can rule out by looking out of the window. If you're not in clouds, you're not picking up ice. > Also, there are OAT (outside air temperature) sensors. Not applicable in this instance, sure. But "are there clouds around" isn't something I'd expect the flight computer to be able to reliably detect, and that's what would have to make the decision here. > > your engines to have failed > Another thing that would be pretty apparent to the pilots. I'd agree that it SHOULD be. > No matter how you slice it, Boeing screwed the pooch bigly. Yep. But there's still more complexity here than people seem to want to acknowledge. 0: https://en.wikipedia.org/wiki/Birgenair_Flight_301 https://en.wikipedia.org/wiki/Birgenair_Flight_301 1: https://en.wikipedia.org/wiki/Aeroper%C3%BA_Flight_603 https://en.wikipedia.org/wiki/Aeroper%C3%BA_Flight_603
- lisper 8y ago
  No technology is ever going to completely protect you against an incompetent pilot.