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In what way do you find the number of air disasters surprising? What number would be unsurprising?

by sk5t 8y ago

ken 8y ago
It's not the number, but the number with the same general cause. Any failure of a complex system has multiple causes, and the NTSB/FAA usually responds to incidents with multiple recommendations, to eliminate any possibility of this chain of events happening again. This has been remarkably successful. It's surprising to me that airline designers continue to add sensors and computers and automation, when in so many of these cases it's the automation which itself is the problem. Would the NTSB ever issue a recommendation like "Your aircraft is too complex" or "You rely on too many computers"? It seems to me like that could be a valid cause, but it's simply not in their vocabulary.
- ams6110 8y ago
  Overall, flying is safer now than in the days of manual control or more simplistic autopilot. The problem seems to me to be that when things do fail, the cause and effect may not be obvious to the crew so they struggle to understand why the plane is doing what it's doing, and how to correctly respond.
- WalterBright 8y ago
  > It's surprising to me that airline designers continue to add sensors and computers and automation, when in so many of these cases it's the automation which itself is the problem. New features can indeed raise unanticipated problems. But that automation isn't added for the lulz, it is added to address other safety problems. The safety record has gotten dramatically better over the decades, and that speaks for itself. > Would the NTSB ever issue a recommendation like "Your aircraft is too complex" or "You rely on too many computers"? It seems to me like that could be a valid cause, but it's simply not in their vocabulary. Neither of those vague hand-wavy recommendations are actionable, so the NTSB would never issue them.
  - tialaramex 8y ago
    Although vague concerns aren't themselves actionable, the actions that could be recommended in both cases would be research. To look into whether "too many computers" is actually causal and what might be done about that. My guess is "No" but if the investigators thought we need to check that's what they'd recommend. But most often what's needed is smarter machines, not less of them. Inadequate engine performance during take off is a periodic cause of problems. Research was done into whether airports could add markers so that pilots could tell if their acceleration was less than expected. That went nowhere because humans don't have an accurate sense of acceleration or time passing. Today new Airbus jets integrate their position over time and will warn audibly "Check acceleration" if underperforming, long before V1 (maximum abort speed). Meanwhile a common underlying cause of inadequate performance is entering incorrect air temperature, modern Boeings will delete input temperatures that don't resemble the measured temperature at an air intake when the engines switch on. Pilots must enter a plausible temperature and try again, or perform a fully manual take off. So investigators now might recommend one or both of these countermeasures be adopted, or that the research be done again knowing these options exist.
    - sokoloff 8y ago
      The NTSB seems to take the overall view that automation in airliners is generally reliable, though balances that with the view that pilots must be prepared to take over for unanticipated circumstances (United 1549). https://www.ntsb.gov/news/speeches/CHart/Documents/hart-20180125.pdf https://www.ntsb.gov/news/speeches/CHart/Documents/hart-2018... Small nit: V1 is the takeoff decision speed, not the maximum abort speed. If the decision is made to abort right at V1, the airplane will continue to accelerate for a second or so while the crew implements the first action to effect the abort/RTO.

In what way do you find the number of air disasters surprising? What number would be unsurprising?

by sk5t 8y ago

In what way do you find the number of air disasters surprising? What number would be unsurprising?

ken 8y ago

It's not the number, but the number with the same general cause. Any failure of a complex system has multiple causes, and the NTSB/FAA usually responds to incidents with multiple recommendations, to eliminate any possibility of this chain of events happening again. This has been remarkably successful. It's surprising to me that airline designers continue to add sensors and computers and automation, when in so many of these cases it's the automation which itself is the problem. Would the NTSB ever issue a recommendation like "Your aircraft is too complex" or "You rely on too many computers"? It seems to me like that could be a valid cause, but it's simply not in their vocabulary.

ams6110 8y ago
Overall, flying is safer now than in the days of manual control or more simplistic autopilot. The problem seems to me to be that when things do fail, the cause and effect may not be obvious to the crew so they struggle to understand why the plane is doing what it's doing, and how to correctly respond.
WalterBright 8y ago
> It's surprising to me that airline designers continue to add sensors and computers and automation, when in so many of these cases it's the automation which itself is the problem. New features can indeed raise unanticipated problems. But that automation isn't added for the lulz, it is added to address other safety problems. The safety record has gotten dramatically better over the decades, and that speaks for itself. > Would the NTSB ever issue a recommendation like "Your aircraft is too complex" or "You rely on too many computers"? It seems to me like that could be a valid cause, but it's simply not in their vocabulary. Neither of those vague hand-wavy recommendations are actionable, so the NTSB would never issue them.
- tialaramex 8y ago
  Although vague concerns aren't themselves actionable, the actions that could be recommended in both cases would be research. To look into whether "too many computers" is actually causal and what might be done about that. My guess is "No" but if the investigators thought we need to check that's what they'd recommend. But most often what's needed is smarter machines, not less of them. Inadequate engine performance during take off is a periodic cause of problems. Research was done into whether airports could add markers so that pilots could tell if their acceleration was less than expected. That went nowhere because humans don't have an accurate sense of acceleration or time passing. Today new Airbus jets integrate their position over time and will warn audibly "Check acceleration" if underperforming, long before V1 (maximum abort speed). Meanwhile a common underlying cause of inadequate performance is entering incorrect air temperature, modern Boeings will delete input temperatures that don't resemble the measured temperature at an air intake when the engines switch on. Pilots must enter a plausible temperature and try again, or perform a fully manual take off. So investigators now might recommend one or both of these countermeasures be adopted, or that the research be done again knowing these options exist.
  - sokoloff 8y ago
    The NTSB seems to take the overall view that automation in airliners is generally reliable, though balances that with the view that pilots must be prepared to take over for unanticipated circumstances (United 1549). https://www.ntsb.gov/news/speeches/CHart/Documents/hart-20180125.pdf https://www.ntsb.gov/news/speeches/CHart/Documents/hart-2018... Small nit: V1 is the takeoff decision speed, not the maximum abort speed. If the decision is made to abort right at V1, the airplane will continue to accelerate for a second or so while the crew implements the first action to effect the abort/RTO.