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To be fair, it sounds like this crash caused airlines and regulators to demand much more adverse event training, including high-altitude stall recovery. But acc

To be fair, it sounds like this crash caused airlines and regulators to demand much more adverse event training, including high-altitude stall recovery. But according to the article, Airbus hasn't addressed the split control issue…

local_issues 3y ago
There isn't a "split control issue," the split control setup is fundamental to the way the Airbus control schema works. Changing it would be a non-starter.
- mholt 3y ago
  According to the author, the split control design mitigated communication between pilots, since one cannot feel what the other is doing. That seems like a crucial functional omission.
- ericbarrett 3y ago
  It seems like an avionics warning—“conflicting control input” or the like—would go a long way here, and not change anything fundamental. Maybe Airbus implemented that since?
  - cccbbbaaa 3y ago
    There is an audible “dual input”, which was triggered on this flight.
    - ericbarrett 3y ago
      Interesting, thanks! I’ve read a few accounts of this crash and never picked up on that.
      - Mawr 3y ago
        Note that hearing is one of the first things that stop working when a human is under stress [1]. [1]: https://youtu.be/Dl-Fl66Jfao?t=1674 https://youtu.be/Dl-Fl66Jfao?t=1674
- cyberax 3y ago
  Why? The split control never made any fucking sense. It resulted in several crashes where inputs were averaged.
- nwallin 3y ago
  You say this as if the split control setup is a feature and not a bug. Can you go into why this is the case? For me at least, it seems like the condition where both pilots are inputting control on the stick or rudder is always an error condition. Even if they're both inputting the same inputs. The scheme directly contributed to the crash for two reasons; obviously if the co-pilot wasn't pulling back on the stick, they would have been able to get out of the stall. But additionally, the two crew members were spending crew resources on redundant tasks: both of them thought that they were the ones aviating and the other was in charge of figuring out why the flight computer seemed to be behaving badly. Possibly if one of them did dedicate their attention to the flight computer, they'd have figured out what the actual flight parameters were.
logifail 3y ago
> this crash caused airlines and regulators to demand much more adverse event training, including high-altitude stall recovery Q: How many pilots would attempt a stall recovery if the aircraft's instruments were not indicating they were stalled?
- turnsout 3y ago
  In the case of 447, they were warned about a stall, repeatedly.
  - logifail 3y ago
    > In the case of 447, they were warned about a stall, repeatedly It's not that simple. When the aircraft's computer considered the inputs invalid, the stall warning was muted. When they decreased the pitch (would be essential to recover from the stall!) the stall warning sounded. "The angle of attack had then reached 40°, and the aircraft had descended to 35,000 feet (10,668 m) with the engines running at almost 100% N1 (the rotational speed of the front intake fan, which delivers most of a turbofan engine's thrust). The stall warnings stopped, as all airspeed indications were now considered invalid by the aircraft's computer because of the high angle of attack. The aircraft had its nose above the horizon, but was descending steeply. Roughly 20 seconds later, at 02:12 UTC, Bonin decreased the aircraft's pitch slightly. Airspeed indications became valid, and the stall warning sounded again; it then sounded intermittently for the remaining duration of the flight, stopping only when the pilots increased the aircraft's nose-up pitch. From there until the end of the flight, the angle of attack never dropped below 35°."[0] [0] https://en.wikipedia.org/wiki/Air_France_Flight_447 https://en.wikipedia.org/wiki/Air_France_Flight_447
    - mardifoufs 3y ago
      Jesus Christ what a terrifying situation. I read about this over and over again and it's still mind boggling how multiple systems and "exceptions" collided resulting in the worst scenario possible. I know the pilots are also to "blame" in a way, but man... The safety systems sure do have a lot of obscure modes and different ways to handle error and failures...

local_issues 3y ago

There isn't a "split control issue," the split control setup is fundamental to the way the Airbus control schema works. Changing it would be a non-starter.

mholt 3y ago
According to the author, the split control design mitigated communication between pilots, since one cannot feel what the other is doing. That seems like a crucial functional omission.
ericbarrett 3y ago
It seems like an avionics warning—“conflicting control input” or the like—would go a long way here, and not change anything fundamental. Maybe Airbus implemented that since?
- cccbbbaaa 3y ago
  There is an audible “dual input”, which was triggered on this flight.
  - ericbarrett 3y ago
    Interesting, thanks! I’ve read a few accounts of this crash and never picked up on that.
    - Mawr 3y ago
      Note that hearing is one of the first things that stop working when a human is under stress [1]. [1]: https://youtu.be/Dl-Fl66Jfao?t=1674 https://youtu.be/Dl-Fl66Jfao?t=1674
cyberax 3y ago
Why? The split control never made any fucking sense. It resulted in several crashes where inputs were averaged.
nwallin 3y ago
You say this as if the split control setup is a feature and not a bug. Can you go into why this is the case? For me at least, it seems like the condition where both pilots are inputting control on the stick or rudder is always an error condition. Even if they're both inputting the same inputs. The scheme directly contributed to the crash for two reasons; obviously if the co-pilot wasn't pulling back on the stick, they would have been able to get out of the stall. But additionally, the two crew members were spending crew resources on redundant tasks: both of them thought that they were the ones aviating and the other was in charge of figuring out why the flight computer seemed to be behaving badly. Possibly if one of them did dedicate their attention to the flight computer, they'd have figured out what the actual flight parameters were.

logifail 3y ago

> this crash caused airlines and regulators to demand much more adverse event training, including high-altitude stall recovery Q: How many pilots would attempt a stall recovery if the aircraft's instruments were not indicating they were stalled?

turnsout 3y ago
In the case of 447, they were warned about a stall, repeatedly.
- logifail 3y ago
  > In the case of 447, they were warned about a stall, repeatedly It's not that simple. When the aircraft's computer considered the inputs invalid, the stall warning was muted. When they decreased the pitch (would be essential to recover from the stall!) the stall warning sounded. "The angle of attack had then reached 40°, and the aircraft had descended to 35,000 feet (10,668 m) with the engines running at almost 100% N1 (the rotational speed of the front intake fan, which delivers most of a turbofan engine's thrust). The stall warnings stopped, as all airspeed indications were now considered invalid by the aircraft's computer because of the high angle of attack. The aircraft had its nose above the horizon, but was descending steeply. Roughly 20 seconds later, at 02:12 UTC, Bonin decreased the aircraft's pitch slightly. Airspeed indications became valid, and the stall warning sounded again; it then sounded intermittently for the remaining duration of the flight, stopping only when the pilots increased the aircraft's nose-up pitch. From there until the end of the flight, the angle of attack never dropped below 35°."[0] [0] https://en.wikipedia.org/wiki/Air_France_Flight_447 https://en.wikipedia.org/wiki/Air_France_Flight_447
  - mardifoufs 3y ago
    Jesus Christ what a terrifying situation. I read about this over and over again and it's still mind boggling how multiple systems and "exceptions" collided resulting in the worst scenario possible. I know the pilots are also to "blame" in a way, but man... The safety systems sure do have a lot of obscure modes and different ways to handle error and failures...