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I haven't heard of it ever activating except in the incident/accident flights. It's required for certification, but you would either have to be mishandling the

I haven't heard of it ever activating except in the incident/accident flights. It's required for certification, but you would either have to be mishandling the plane or get in some extreme weather for MCAS to activate. Think about it like the Antilock brakes on your car. Suppose the wheel position sensor fails. It's fine if the car puts up a warning light and says that you don't have antilock brakes anymore. You can drive fine without them until you can get them fixed with a minor safety impact. It's not fine if the wheel position sensor fails and this causes the car to slam on the brakes going 65mph down the highway.

inferiorhuman 7y ago
I haven't heard of it ever activating except in the incident/accident flights. You wouldn't hear about it unless the activation was triggered by egregious pilot error and you're scouring aviation news sites. It's not fine if the wheel position sensor fails and this causes the car to slam on the brakes going 65mph down the highway. Been there, done that. It's an unpleasant failure mode, but it is survivable.
CydeWeys 7y ago
ABS isn't the best example because it does prevent lots of accidents in its own right, including a >50% prevention rate of some types of accidents in rainy, snowy, or icy weather. The overall fatal accident reduction is 15% for cars and 27% for trucks and light trucks. Source: https://crashstats.nhtsa.dot.gov/Api/Public/ViewPublication/811182 https://crashstats.nhtsa.dot.gov/Api/Public/ViewPublication/... And, anecdotally, I've had ABS kick in in some occurrences for which I was very thankful.
- perl4ever 7y ago
  The first thing I read in your link seems to be the opposite of what you wrote: "ABS has close to a zero net effect on fatal crash involvements." Further down, there is a chart which seems to show that ABS is associated with a huge increase in fatal accidents in inclement weather, and a large increase in side impact accidents, both fatal and non-fatal. Maybe there's something obvious I'm missing?
- cameldrv 7y ago
  Having a safety system that rarely fails to prevent an accident is much different statistically than a safety system that rarely causes an accident. Suppose the crash probability on a normal flight is 1/1E7, but without MCAS it's 100x more dangerous, or 1/1E5. Suppose MCAS failure probability is 1/1E6, the probability of an additional crash due to the failure of MCAS is 1/1E11, which is acceptable. The problem is that in practice, the crash probability if MCAS fails is empirically 2/3 instead of 1/1E5, because MCAS actually causes the crash rather than merely failing to prevent a crash.

inferiorhuman 7y ago

I haven't heard of it ever activating except in the incident/accident flights. You wouldn't hear about it unless the activation was triggered by egregious pilot error and you're scouring aviation news sites. It's not fine if the wheel position sensor fails and this causes the car to slam on the brakes going 65mph down the highway. Been there, done that. It's an unpleasant failure mode, but it is survivable.

CydeWeys 7y ago

ABS isn't the best example because it does prevent lots of accidents in its own right, including a >50% prevention rate of some types of accidents in rainy, snowy, or icy weather. The overall fatal accident reduction is 15% for cars and 27% for trucks and light trucks. Source: https://crashstats.nhtsa.dot.gov/Api/Public/ViewPublication/811182 https://crashstats.nhtsa.dot.gov/Api/Public/ViewPublication/... And, anecdotally, I've had ABS kick in in some occurrences for which I was very thankful.

perl4ever 7y ago
The first thing I read in your link seems to be the opposite of what you wrote: "ABS has close to a zero net effect on fatal crash involvements." Further down, there is a chart which seems to show that ABS is associated with a huge increase in fatal accidents in inclement weather, and a large increase in side impact accidents, both fatal and non-fatal. Maybe there's something obvious I'm missing?
cameldrv 7y ago
Having a safety system that rarely fails to prevent an accident is much different statistically than a safety system that rarely causes an accident. Suppose the crash probability on a normal flight is 1/1E7, but without MCAS it's 100x more dangerous, or 1/1E5. Suppose MCAS failure probability is 1/1E6, the probability of an additional crash due to the failure of MCAS is 1/1E11, which is acceptable. The problem is that in practice, the crash probability if MCAS fails is empirically 2/3 instead of 1/1E5, because MCAS actually causes the crash rather than merely failing to prevent a crash.