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More Airbus deadly UI: http://en.wikipedia.org/wiki/Air_France_Flight_447 http://en.wikipedia.org/wiki/Air_France_Flight_447 The two sticks can be pointed in

by bagels 12y ago

More Airbus deadly UI: http://en.wikipedia.org/wiki/Air_France_Flight_447 http://en.wikipedia.org/wiki/Air_France_Flight_447 The two sticks can be pointed in different directions. The plane does not complain about this and averages the inputs. One pilot is pulling back, one is pushing forward, plane crashes. Clearly there are some human factors here, but from what I've read, on Boeing's aircraft pushing one stick causes the other to move, much more intuitive.

dredmorbius 12y ago
Boeing also uses a classic control column rather than a side-stick, emulating physical controls even though the actual mechanism is largely fly-by-wire.
ern 12y ago
It isn't only Airbus that has deadly UI. Boeing came in for some flak in the design of the 777's non-intuitive autothrottle modes in the Asiana 214 crash report. Pilot confusion with Boeing's autothrottle has also been implicated in other crashes.
- idlewords 12y ago
  Nothing about flying a plane is really intuitive. The Asiana crash was a pretty clear case of pilot error. At some point you have to either trust the pilots or just enable autoland.
  - ern 12y ago
    That's a fair point, and it was also made by an NTSB board member who appended a partial dissent to the report.
idlewords 12y ago
The Airbus vs Boeing approach to fly-by-wire is a bit of a religious issue, like type safety or memory management in our world. Many words have been written on both sides. I think the UI issue in AF447 is much less clear cut. It's more a lack of any indicator that pilots are making opposite inputs, rather than a misleading or confusing display. Airbus did not anticipate that a pilot would stall a plane and fly it directly into the ocean. There was a whole chain of events (including some appalling human factors) that led to the tragedy there. The avionics teams at both companies have put an incredible amount of thought into how these systems are designed, and how they fail. The differences are instructive, but we should refrain from being quick to judge which is more or less intuitive.
- acqq 12y ago
  If it's really so implemented, averaging "full left" and "full right" inputs to the "keep going straight" response is deeply wrong. Apparently missing mechanical feedback really contributed to the accident.
- omegant 12y ago
  Sorry but you are wrong, it´s not a religious issue, it´s a clear IU mistake by Airbus. I´m currently flying A-320, I´ve also flown B 737(300 and 800), and MD88. It´s true that at the beginning the new airbus received a lot of heat from pilots. After all they were trying to reinvent cockpits UI from 0. This led to a series of design accidents (due to initial design mistakes ) like the one on the article. The initial idea it´s not bad: reducing weight (removing all mechanical and hydraulic controls), inventing the glass cockpit, simplified system management, etc.. It took over a decade to polish the cockpit (and the whole airplane, that had tons of electronics related failures all around) to it´s actual safe and workable state. Those issues, plus the idea that pilots had to readjust your whole idea of a cockpit, were the ones that created that opposition. The opossition it's almost gone now, although in general we pilots still prefer Boeing aircraft (at least in Europe). Airbus airplanes fly very nicely and are great too. But now that we are used to the new IU, the concept problems are still there. Main diference between flying normal fly controls and a moving auto-throttle and airbus fly-by-wire: -Airbus throttle levers don´t move while the auto-thrust is changing the power setting. All the other airplanes as far as I know do it. -Airbus side-sticks don´t move when the autopilot or the other pilot is giving an input. Also as somebody explained above, the inputs are added, you can end with a double (or zero input), if you forget to push the priority button (in stress situations like last second corrections to land it´s easy to forget it). Why this is a mistake? because when flying a modern airliner you have an excess of information to process, all at once. A moving auto-throttle let´s you know what the engines are doing through your hands, without having to look at a tiny indicator at the instruments. Also it let´s you override the auto-throttle briefly because you need more power or less power at a given moment, without having to disconnect it. With airbus auto-thrust either the airplane or the pilot has the control, and you have to manually takeover. This may be dangerous at an approach that it´s already hard enough with cross winds or heavy rain. The same apply to the side-stick. Normal autopilots move the fly controls at the cockpit while actuating them. This let´s you know what the autopilot it´s doing. And of course when a pilot it´s flying manually, the other pilot knows exactly what he is doing ALL THE TIME. He can slightly correct a maneuver without having to take over the controls from zero. Airbus has wiped a layer of fundamental information available to the pilots, increasing the information overoosd through the vision. It´s the equivalent of driving a race car with a playstation control. Most of the time this information it´s not used(like in cruise), but you really, REALLY need it when things become hairy close to the ground. In fact I routinely disconnect the auto-thrust to land, with the Boeing and MD88 I kept it engaged. Airbus knows this, but it´s too late to change 20 years of airplane development. They´ll need to change too many things (systems, procedures, certification, instruction), also right now it´s easy to change from flying let´s say a A320 to a A 330, due to having very similar cockpits and systems (that´s a great idea). The conversion course it´s short and relatively cheap. Changing the controls would make this fleet changes much more expensive and time consuming to Airlines. Edit: overall small changes to improve clarity.
andyjohnson0 12y ago
Horrific. The stall alarm turned off because the control system didn't trust its inputs and couldn't decide whether it was still in a stall. But the crew interpreted the lack of alarm as the aircraft not being in a stall.
damian2000 12y ago
I came across this article that suggests warnings sounded when the two sticks were significantly different to each other, but in the stressful situation the warnings were probably ignored... "The investigation was unable to determine whether the copilot was aware of the pilot in command’s dual sidestick inputs, even though they resulted in aural ‘DUAL INPUT’ synthetic voice messages…The copilot’s focus on correcting the aircraft’s attitude and trajectory, together with the numerous FWS synthetic voice messages, may have resulted in the copilot not comprehending the significance of the aural ‘DUAL INPUT’ warnings…" From: http://criticaluncertainties.com/2011/09/16/pilots-in-the-loop-airbus-and-the-fbw-side-stick/ http://criticaluncertainties.com/2011/09/16/pilots-in-the-lo...
ericson 12y ago
Not surprisingly, the argument fly by wire versus manual input reminds me of countries that switched from medieval measurements to the modern metric system. This is one of the most difficult changes to make, as America’s multiple, but badly implemented attempts since anno 1700 show. Most people have the tendency to stick to what they know regardless whether it is cumbersome, costly, or hopelessly outdated. Yes, there is reason for this inertia and it is called HABIT. Most of us are happy with what we know irrespective of its drawbacks, because it does after all work, doesn’t it? There is a reason for this innate attitude, “it is much more difficult to unlearn something than learn something new”. Yet it can be done as almost 7 billion people on this planet confirm with metrication. It will probably take a new generation of pilots not wedded to manual flying to appreciate the advantages of fbw. If they would have to change back to manual flying they would have all the arguments many of the present pilots have against fbw, such is habit.

by bagels 12y ago

dredmorbius 12y ago

Boeing also uses a classic control column rather than a side-stick, emulating physical controls even though the actual mechanism is largely fly-by-wire.

ern 12y ago

It isn't only Airbus that has deadly UI. Boeing came in for some flak in the design of the 777's non-intuitive autothrottle modes in the Asiana 214 crash report. Pilot confusion with Boeing's autothrottle has also been implicated in other crashes.

idlewords 12y ago
Nothing about flying a plane is really intuitive. The Asiana crash was a pretty clear case of pilot error. At some point you have to either trust the pilots or just enable autoland.
- ern 12y ago
  That's a fair point, and it was also made by an NTSB board member who appended a partial dissent to the report.

idlewords 12y ago

The Airbus vs Boeing approach to fly-by-wire is a bit of a religious issue, like type safety or memory management in our world. Many words have been written on both sides. I think the UI issue in AF447 is much less clear cut. It's more a lack of any indicator that pilots are making opposite inputs, rather than a misleading or confusing display. Airbus did not anticipate that a pilot would stall a plane and fly it directly into the ocean. There was a whole chain of events (including some appalling human factors) that led to the tragedy there. The avionics teams at both companies have put an incredible amount of thought into how these systems are designed, and how they fail. The differences are instructive, but we should refrain from being quick to judge which is more or less intuitive.

acqq 12y ago
If it's really so implemented, averaging "full left" and "full right" inputs to the "keep going straight" response is deeply wrong. Apparently missing mechanical feedback really contributed to the accident.
omegant 12y ago
Sorry but you are wrong, it´s not a religious issue, it´s a clear IU mistake by Airbus. I´m currently flying A-320, I´ve also flown B 737(300 and 800), and MD88. It´s true that at the beginning the new airbus received a lot of heat from pilots. After all they were trying to reinvent cockpits UI from 0. This led to a series of design accidents (due to initial design mistakes ) like the one on the article. The initial idea it´s not bad: reducing weight (removing all mechanical and hydraulic controls), inventing the glass cockpit, simplified system management, etc.. It took over a decade to polish the cockpit (and the whole airplane, that had tons of electronics related failures all around) to it´s actual safe and workable state. Those issues, plus the idea that pilots had to readjust your whole idea of a cockpit, were the ones that created that opposition. The opossition it's almost gone now, although in general we pilots still prefer Boeing aircraft (at least in Europe). Airbus airplanes fly very nicely and are great too. But now that we are used to the new IU, the concept problems are still there. Main diference between flying normal fly controls and a moving auto-throttle and airbus fly-by-wire: -Airbus throttle levers don´t move while the auto-thrust is changing the power setting. All the other airplanes as far as I know do it. -Airbus side-sticks don´t move when the autopilot or the other pilot is giving an input. Also as somebody explained above, the inputs are added, you can end with a double (or zero input), if you forget to push the priority button (in stress situations like last second corrections to land it´s easy to forget it). Why this is a mistake? because when flying a modern airliner you have an excess of information to process, all at once. A moving auto-throttle let´s you know what the engines are doing through your hands, without having to look at a tiny indicator at the instruments. Also it let´s you override the auto-throttle briefly because you need more power or less power at a given moment, without having to disconnect it. With airbus auto-thrust either the airplane or the pilot has the control, and you have to manually takeover. This may be dangerous at an approach that it´s already hard enough with cross winds or heavy rain. The same apply to the side-stick. Normal autopilots move the fly controls at the cockpit while actuating them. This let´s you know what the autopilot it´s doing. And of course when a pilot it´s flying manually, the other pilot knows exactly what he is doing ALL THE TIME. He can slightly correct a maneuver without having to take over the controls from zero. Airbus has wiped a layer of fundamental information available to the pilots, increasing the information overoosd through the vision. It´s the equivalent of driving a race car with a playstation control. Most of the time this information it´s not used(like in cruise), but you really, REALLY need it when things become hairy close to the ground. In fact I routinely disconnect the auto-thrust to land, with the Boeing and MD88 I kept it engaged. Airbus knows this, but it´s too late to change 20 years of airplane development. They´ll need to change too many things (systems, procedures, certification, instruction), also right now it´s easy to change from flying let´s say a A320 to a A 330, due to having very similar cockpits and systems (that´s a great idea). The conversion course it´s short and relatively cheap. Changing the controls would make this fleet changes much more expensive and time consuming to Airlines. Edit: overall small changes to improve clarity.

andyjohnson0 12y ago

Horrific. The stall alarm turned off because the control system didn't trust its inputs and couldn't decide whether it was still in a stall. But the crew interpreted the lack of alarm as the aircraft not being in a stall.

damian2000 12y ago

I came across this article that suggests warnings sounded when the two sticks were significantly different to each other, but in the stressful situation the warnings were probably ignored... "The investigation was unable to determine whether the copilot was aware of the pilot in command’s dual sidestick inputs, even though they resulted in aural ‘DUAL INPUT’ synthetic voice messages…The copilot’s focus on correcting the aircraft’s attitude and trajectory, together with the numerous FWS synthetic voice messages, may have resulted in the copilot not comprehending the significance of the aural ‘DUAL INPUT’ warnings…" From: http://criticaluncertainties.com/2011/09/16/pilots-in-the-loop-airbus-and-the-fbw-side-stick/ http://criticaluncertainties.com/2011/09/16/pilots-in-the-lo...

ericson 12y ago

Not surprisingly, the argument fly by wire versus manual input reminds me of countries that switched from medieval measurements to the modern metric system. This is one of the most difficult changes to make, as America’s multiple, but badly implemented attempts since anno 1700 show. Most people have the tendency to stick to what they know regardless whether it is cumbersome, costly, or hopelessly outdated. Yes, there is reason for this inertia and it is called HABIT. Most of us are happy with what we know irrespective of its drawbacks, because it does after all work, doesn’t it? There is a reason for this innate attitude, “it is much more difficult to unlearn something than learn something new”. Yet it can be done as almost 7 billion people on this planet confirm with metrication. It will probably take a new generation of pilots not wedded to manual flying to appreciate the advantages of fbw. If they would have to change back to manual flying they would have all the arguments many of the present pilots have against fbw, such is habit.