5 ms·

"Boeing said that selecting full reverse too quickly upon landing before the aircraft has fully transitioned to ground mode could cause the system to activate."

"Boeing said that selecting full reverse too quickly upon landing before the aircraft has fully transitioned to ground mode could cause the system to activate." That sounds like apple's "you are holding it wrong" when "antenagate" happened. Not something I want to hear from an aircraft company where people's lives depend on it working.

Jhndb 8y ago
Going off your quote it just looks like they're describing the symptom?
- mikeash 8y ago
  It’s a completely neutral statement, and air travel has a strong culture of not accepting “just don’t screw up” as a solution.
  - abfan1127 8y ago
    Airbus has a limitation on one of their airplanes for Rudder Range - https://www.usatoday.com/story/travel/flights/2012/11/19/airbus-rudder/1707421/ https://www.usatoday.com/story/travel/flights/2012/11/19/air...
  - aurailious 8y ago
    NTSB is probably the best example of a safety investigation agency. Air travel in the US is extremely safe for many good reasons.
chrisper 8y ago
It doesn't at all. It's an explanation why it might happen.They never said that this behavior won't be fixed or changed. It's not blaming the pilots.
- dajohnson89 8y ago
  There is a notion of blame wrapped up with "too quickly".
  - eganist 8y ago
    There's a further implication that an instruction, but not a failsafe, exists to prevent the given condition. E.g. "do not reverse thrust until ground mode has fully activated." but no check to actually prevent the crew from doing so. I'm not a lawyer; couldn't tell you where the fault would split in that case, but if my hunch about the lack of a failsafe for a given instruction is correct... it's still a surprise to me. I'd expect existing avionics production procedures to catch this sort of thing.
    - phkahler 8y ago
      >> I'd expect existing avionics production procedures to catch this sort of thing. The older I get, the more I believe your expectation is wrong. Lessons learned are rarely transferred to new people who were not present when the lesson was initially learned. I've even worked at companies that try to compile a database of "lessons learned", but they never instruct anyone to read through the whole thing. Even if they did, when confronted with a large amount of material how much of it actually sticks? The we move on to more procedural methods like fault-tree analysis, FMEA, etc... That's great and can help a lot, but it's still a GIGO process and new people need to learn how to do it well. There are always new people learning new things.
      - marcosdumay 8y ago
        In software, we usually encode lessons learned as tests and static analysis. There is a reasonable level of success on that. Aviation usually encode them on checklists. They have a much higher degree of success (probably because of culture, not medium), but failures happen some times too.
  - teraflop 8y ago
    "Too quickly" appears to be the article's wording, not Boeing's, although I couldn't find a copy of the actual bulletin to confirm that.
Someone 8y ago
Reading between the lines, and having read other comments here, I can interpret Boeing’s remark as “if the pilots or the on-board software try to reverse engines when it still is really, really dangerous, the Thrust Control Malfunction Accommodation system (TCMA) will try to make matters less bad, in some cases by shutting down the engines instead”. They may have to fine-tune that system, but from a safety perspective, this event had a good ending, and making its decision system more complex also carries risks, so, maybe, nothing has to change.
- marcosdumay 8y ago
  > when it still is really, really dangerous More apt would be "when the computer is not sure that isn't really, really dangerous".
hodgesrm 8y ago
Aircraft are very different from cell phones. There are a number of things you can do as a pilot that will cause them to crash or stall especially if something unusual like a sensor or engine failure occurs. Pilots spend a lot of time in simulators practicing how to fly the plane in a variety of such situations as well as under normal operating conditions. Or as my neighbor says: "I've dealt with hundreds of engine fires!" (He flies A320s.)
gomijacogeo 8y ago
Next from Boeing: a car where, if you unlatch your seatbelt before the engine stops, the airbags deploy.

Jhndb 8y ago

Going off your quote it just looks like they're describing the symptom?

mikeash 8y ago
It’s a completely neutral statement, and air travel has a strong culture of not accepting “just don’t screw up” as a solution.
- abfan1127 8y ago
  Airbus has a limitation on one of their airplanes for Rudder Range - https://www.usatoday.com/story/travel/flights/2012/11/19/airbus-rudder/1707421/ https://www.usatoday.com/story/travel/flights/2012/11/19/air...
- aurailious 8y ago
  NTSB is probably the best example of a safety investigation agency. Air travel in the US is extremely safe for many good reasons.

chrisper 8y ago

It doesn't at all. It's an explanation why it might happen.They never said that this behavior won't be fixed or changed. It's not blaming the pilots.

dajohnson89 8y ago
There is a notion of blame wrapped up with "too quickly".
- eganist 8y ago
  There's a further implication that an instruction, but not a failsafe, exists to prevent the given condition. E.g. "do not reverse thrust until ground mode has fully activated." but no check to actually prevent the crew from doing so. I'm not a lawyer; couldn't tell you where the fault would split in that case, but if my hunch about the lack of a failsafe for a given instruction is correct... it's still a surprise to me. I'd expect existing avionics production procedures to catch this sort of thing.
  - phkahler 8y ago
    >> I'd expect existing avionics production procedures to catch this sort of thing. The older I get, the more I believe your expectation is wrong. Lessons learned are rarely transferred to new people who were not present when the lesson was initially learned. I've even worked at companies that try to compile a database of "lessons learned", but they never instruct anyone to read through the whole thing. Even if they did, when confronted with a large amount of material how much of it actually sticks? The we move on to more procedural methods like fault-tree analysis, FMEA, etc... That's great and can help a lot, but it's still a GIGO process and new people need to learn how to do it well. There are always new people learning new things.
    - marcosdumay 8y ago
      In software, we usually encode lessons learned as tests and static analysis. There is a reasonable level of success on that. Aviation usually encode them on checklists. They have a much higher degree of success (probably because of culture, not medium), but failures happen some times too.
- teraflop 8y ago
  "Too quickly" appears to be the article's wording, not Boeing's, although I couldn't find a copy of the actual bulletin to confirm that.

Someone 8y ago

Reading between the lines, and having read other comments here, I can interpret Boeing’s remark as “if the pilots or the on-board software try to reverse engines when it still is really, really dangerous, the Thrust Control Malfunction Accommodation system (TCMA) will try to make matters less bad, in some cases by shutting down the engines instead”. They may have to fine-tune that system, but from a safety perspective, this event had a good ending, and making its decision system more complex also carries risks, so, maybe, nothing has to change.

marcosdumay 8y ago
> when it still is really, really dangerous More apt would be "when the computer is not sure that isn't really, really dangerous".

hodgesrm 8y ago

Aircraft are very different from cell phones. There are a number of things you can do as a pilot that will cause them to crash or stall especially if something unusual like a sensor or engine failure occurs. Pilots spend a lot of time in simulators practicing how to fly the plane in a variety of such situations as well as under normal operating conditions. Or as my neighbor says: "I've dealt with hundreds of engine fires!" (He flies A320s.)

gomijacogeo 8y ago

Next from Boeing: a car where, if you unlatch your seatbelt before the engine stops, the airbags deploy.