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> this crash caused airlines and regulators to demand much more adverse event training, including high-altitude stall recovery Q: How many pilots would attempt

> 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...
  - turnsout 3y ago
    Yes, all of that is true, but the stall warning did sound almost immediately once autopilot disengaged—the crew was just too freaked out to know what to do with the warning.

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...
- turnsout 3y ago
  Yes, all of that is true, but the stall warning did sound almost immediately once autopilot disengaged—the crew was just too freaked out to know what to do with the warning.