Asiana 214 777 crash and an old post.
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Asiana 214 777 crash and an old post.
This is my old post from 2008: http://www.pprune.org/tech-log/34257...peed-prot.html
Interesting to see that what OBVIOUS for some pilots was not for the Asiana crew.
Interesting to see that what OBVIOUS for some pilots was not for the Asiana crew.
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Your point highlighted here was a design flaw & 'expression of it' in the functioning of the A/thr system. Regardless of how one reaches in HOLD-MODE, the point was the a/thr won't wake up in FLCH. And that is a dangerous situation because a pilot expects the A/THR to guard for speed.
Interestingly if you read the entire ASIANA 214 crash report (207 pages) following is CLOSE to what HOUBA is highlighting (BOEING received some flak as well) -
FINDINGS/CONCLUSIONS (apart from other factors)
Point 10. As a result of complexities in the 777 automatic flight control system and inadequacies in related training and documentation, the pilot flying had an inaccurate understanding of how the autopilot flight director system and autothrottle interacted to control airspeed, which led to his inadvertent deactivation of automatic airspeed control.
12. A review of the design of the 777 automatic flight control system, with special attention given to the issues identified in this accident investigation and the issues identified by the Federal Aviation Administration and European Aviation Safety Agency during the 787 certification program, could yield insights about how to improve the intuitiveness of the 777 and 787 flight crew interfaces as well as those incorporated into future designs.
RECOMMENDATIONS -
Require Boeing to revise its 777 Flight Crew Training Manual stall protection demonstration to include an explanation and demonstration of the circumstances in which the autothrottle does not provide low speed protection. (A-14-39)
--
Infact many pilots were unaware prior to this incident 2013 that such a loophole exists in automation. To such a level where FCOMs & FCTMs lacked the exclusive info.
--
Words by the author of the report -
Boeing issued a statement saying that it “respectfully disagrees with the NTSB's statement that the 777's auto-flight system contributed to this accident, a finding that [Boeing does] not believe is supported by the evidence.” Denial is the enemy of change. Such statements are perhaps issued by public relations personnel intent on protecting their brand.
However, this accident demonstrates that existing low airspeed alert systems that are designed to provide pilots with redundant aural and visual warning of an impending hazard due to low airspeed may not be adequately tailored to alert pilots to an impending hazard due to a combination of conditions (i.e., low airspeed combined with low altitude.
Yours was a great post HOUBA
just finished reading it. 
Interestingly if you read the entire ASIANA 214 crash report (207 pages) following is CLOSE to what HOUBA is highlighting (BOEING received some flak as well) -
FINDINGS/CONCLUSIONS (apart from other factors)
Point 10. As a result of complexities in the 777 automatic flight control system and inadequacies in related training and documentation, the pilot flying had an inaccurate understanding of how the autopilot flight director system and autothrottle interacted to control airspeed, which led to his inadvertent deactivation of automatic airspeed control.
12. A review of the design of the 777 automatic flight control system, with special attention given to the issues identified in this accident investigation and the issues identified by the Federal Aviation Administration and European Aviation Safety Agency during the 787 certification program, could yield insights about how to improve the intuitiveness of the 777 and 787 flight crew interfaces as well as those incorporated into future designs.
RECOMMENDATIONS -
Require Boeing to revise its 777 Flight Crew Training Manual stall protection demonstration to include an explanation and demonstration of the circumstances in which the autothrottle does not provide low speed protection. (A-14-39)
--
Infact many pilots were unaware prior to this incident 2013 that such a loophole exists in automation. To such a level where FCOMs & FCTMs lacked the exclusive info.
--
Words by the author of the report -
Boeing issued a statement saying that it “respectfully disagrees with the NTSB's statement that the 777's auto-flight system contributed to this accident, a finding that [Boeing does] not believe is supported by the evidence.” Denial is the enemy of change. Such statements are perhaps issued by public relations personnel intent on protecting their brand.
However, this accident demonstrates that existing low airspeed alert systems that are designed to provide pilots with redundant aural and visual warning of an impending hazard due to low airspeed may not be adequately tailored to alert pilots to an impending hazard due to a combination of conditions (i.e., low airspeed combined with low altitude.
Yours was a great post HOUBA
just finished reading it.
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Autothrottle wake-up is a customer option. Based on that, it is possible that not all 777's have it.
The only state where the autothrottle wakeup function is potentially active is when there is no mode. There is no mode when the display on the FMA for the autothrottle mode is....blank. But if it is blank and you are also in FLCH or TOGA, A/T wake-up will not activate when the other required activation conditions are met.
The only state where the autothrottle wakeup function is potentially active is when there is no mode. There is no mode when the display on the FMA for the autothrottle mode is....blank. But if it is blank and you are also in FLCH or TOGA, A/T wake-up will not activate when the other required activation conditions are met.
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Thanks Karan,
But the reason I ve reopened that post is because I felt that some posts where very aggressive against me. "Are you stupid?", "Only an idiot will do that", "I hope your are not carrying passengers...".
Real thing is that simulator test pilots like me have to try everything on the simulator, even stuff that looks stupid, reason being is that students in the sim will make mistakes and I have to make sure that the simulator reacts the same way as the real thing because we cannot afford to have "negative training" in the sim due to a improper simulation. Why would I press 2 times on FLCH??? Sorry folks, it is my job to try those things, checks all the timings, features and everything. Am I a sim tech that was not been able to be a pilot (and many sim techs knows more that actual pilots about the plane by the way and most of them have performed more ILS that you had) ? Absolutely not, I was an airline, Oceanic rating, operation in remote areas and very special airports like LSGS (with MD83!). Besides that I was software developer in avionics (FMS, GPS, Laser IRS, Aircraft display, radar) and instead of devoting my energy in flying A to B I ve devoted my life in building and certifying 777 simulators around the world to make flights safer. In the case of that feature I ve looked at many things like design document from Boeing, AIMS, autotothrust software code from the manufacturer (...) to confirm if it was a bug in implementation or whatever. Putting your signature on the tests documents besides FAA signature is not like signing a check. Bottom line, I would have expected a different reaction from some people and more respect for my work and my findings.
But the reason I ve reopened that post is because I felt that some posts where very aggressive against me. "Are you stupid?", "Only an idiot will do that", "I hope your are not carrying passengers...".
Real thing is that simulator test pilots like me have to try everything on the simulator, even stuff that looks stupid, reason being is that students in the sim will make mistakes and I have to make sure that the simulator reacts the same way as the real thing because we cannot afford to have "negative training" in the sim due to a improper simulation. Why would I press 2 times on FLCH??? Sorry folks, it is my job to try those things, checks all the timings, features and everything. Am I a sim tech that was not been able to be a pilot (and many sim techs knows more that actual pilots about the plane by the way and most of them have performed more ILS that you had) ? Absolutely not, I was an airline, Oceanic rating, operation in remote areas and very special airports like LSGS (with MD83!). Besides that I was software developer in avionics (FMS, GPS, Laser IRS, Aircraft display, radar) and instead of devoting my energy in flying A to B I ve devoted my life in building and certifying 777 simulators around the world to make flights safer. In the case of that feature I ve looked at many things like design document from Boeing, AIMS, autotothrust software code from the manufacturer (...) to confirm if it was a bug in implementation or whatever. Putting your signature on the tests documents besides FAA signature is not like signing a check. Bottom line, I would have expected a different reaction from some people and more respect for my work and my findings.
Last edited by Houba; 26th Aug 2017 at 16:56.
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Thanks Karan,
But the reason I ve reopened that post is because I felt that some posts where very aggressive against me. "Are you stupid?", "Only an idiot will do that", "I hope your are not carrying passengers...".
Real thing is that simulator test pilots like me have to try everything on the simulator, even stuff that looks stupid, reason being is that students in the sim will make mistakes and I have to make sure that the simulator reacts the same way as the real thing because we cannot afford to have "negative training" in the sim due to a improper simulation. Why would I press 2 times on FLCH??? Sorry folks, it is my job to try those things, checks all the timings, features and everything. Am I a sim tech that was not been able to be a pilot (and many sim techs knows more that actual pilots about the plane by the way and most of them have performed more ILS that you had) ? Absolutely not, I was an airline, Oceanic rating, operation in remote areas and very special airports like LSGS (with MD83!). Besides that I was software developer in avionics (FMS, GPS, Laser IRS, Aircraft display, radar) and instead of devoting my energy in flying A to B I ve devoted my life in building and certifying 777 simulators around the world to make flights safer. In the case of that feature I ve looked at many things like design document from Boeing, AIMS, autotothrust software code from the manufacturer (...) to confirm if it was a bug in implementation or whatever. Putting your signature on the tests documents besides FAA signature is not like signing a check. Bottom line, I would have expected a different reaction from some people and more respect for my work and my findings.
But the reason I ve reopened that post is because I felt that some posts where very aggressive against me. "Are you stupid?", "Only an idiot will do that", "I hope your are not carrying passengers...".
Real thing is that simulator test pilots like me have to try everything on the simulator, even stuff that looks stupid, reason being is that students in the sim will make mistakes and I have to make sure that the simulator reacts the same way as the real thing because we cannot afford to have "negative training" in the sim due to a improper simulation. Why would I press 2 times on FLCH??? Sorry folks, it is my job to try those things, checks all the timings, features and everything. Am I a sim tech that was not been able to be a pilot (and many sim techs knows more that actual pilots about the plane by the way and most of them have performed more ILS that you had) ? Absolutely not, I was an airline, Oceanic rating, operation in remote areas and very special airports like LSGS (with MD83!). Besides that I was software developer in avionics (FMS, GPS, Laser IRS, Aircraft display, radar) and instead of devoting my energy in flying A to B I ve devoted my life in building and certifying 777 simulators around the world to make flights safer. In the case of that feature I ve looked at many things like design document from Boeing, AIMS, autotothrust software code from the manufacturer (...) to confirm if it was a bug in implementation or whatever. Putting your signature on the tests documents besides FAA signature is not like signing a check. Bottom line, I would have expected a different reaction from some people and more respect for my work and my findings.
any question Should have a constructive answer/opinion, not a demeaning one. Thanx for sharing
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Autothrottle wake-up is a customer option. Based on that, it is possible that not all 777's have it.
The only state where the autothrottle wakeup function is potentially active is when there is no mode. There is no mode when the display on the FMA for the autothrottle mode is....blank. But if it is blank and you are also in FLCH or TOGA, A/T wake-up will not activate when the other required activation conditions are met.
The only state where the autothrottle wakeup function is potentially active is when there is no mode. There is no mode when the display on the FMA for the autothrottle mode is....blank. But if it is blank and you are also in FLCH or TOGA, A/T wake-up will not activate when the other required activation conditions are met.
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I'm not surprised people got excited about entering HOLD mode in a climb. Why would you? And if you interfere with the way an aircraft works you should expect some strange outcomes. But the bottom line is, if the automatics are not behaving as they should, you turn them off and fly manually.
As I have posted elsewhere, what do you do if your bathroom tap fails to turn off? Do you allow your house to flood and then sue the tap manufacturer? Or do you turn if the isolator? If that is stuck, what do you do next? Turn off the main supply, open up all other taps and reduce the pressure. The Asian crew, for whatever reason, watched as their bathroom flooded.
But who relies on the automatic speed protection systems? Fly as if they don't exist and you will be a great deal safer as a result.
PM
As I have posted elsewhere, what do you do if your bathroom tap fails to turn off? Do you allow your house to flood and then sue the tap manufacturer? Or do you turn if the isolator? If that is stuck, what do you do next? Turn off the main supply, open up all other taps and reduce the pressure. The Asian crew, for whatever reason, watched as their bathroom flooded.
But who relies on the automatic speed protection systems? Fly as if they don't exist and you will be a great deal safer as a result.
PM
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Autothrottle wake-up is a customer option. Based on that, it is possible that not all 777's have it.
The only state where the autothrottle wakeup function is potentially active is when there is no mode. There is no mode when the display on the FMA for the autothrottle mode is....blank. But if it is blank and you are also in FLCH or TOGA, A/T wake-up will not activate when the other required activation conditions are met.
The only state where the autothrottle wakeup function is potentially active is when there is no mode. There is no mode when the display on the FMA for the autothrottle mode is....blank. But if it is blank and you are also in FLCH or TOGA, A/T wake-up will not activate when the other required activation conditions are met.
When I say that autothrottle wake-up is potentially active when there is no mode...I mean no autothrottle mode. In other words, when the FMA is blank for the autothrottle, there may be wake-up capability. The compatible pitch modes that allow this capability to function are those other than FLCH or TO/GA and includes no pitch mode displayed in the FMA.
But who relies on the automatic speed protection systems?
Fundamental attribution error
This error, also called the correspondence bias, describes the tendency for observer’s to attribute other people’s behavior to internal or dispositional factors and to downplay situational causes. We all suffer to degree, often enhanced by hindsight bias.
It is a harsh reality that in today’s highly complex operations there are situations where combinations of factors interact in such a way it is impossible for humans to sufficiently understand and safely manage outcomes.
In part, these situations involve increased use of automation, changed pilot training, and an evolving operational environment, ATC, management, regulation, commercial pressure, etc.
Thus it is unrealistic to require even greater human capability in situations where the human is often found wanting, either due to limitations in awareness, understanding, memory and recall, workload management, or all of these, often seen in accidents.
As safety improves, there are fewer accidents, often unique to circumstance. If these exceed human capability, then demanding even more training and checks is unlikely to improve human performance, and also any change enables the possibility of introducing a new unforeseen problem.
The alternative is to consider other contributions; the technical systems, certification, ATC, etc. Previously, technical change, including software has been difficult and expensive, nowadays this cost is being balanced by the demands for safety, and particularly that it is very difficult to change the human condition (James Reason), nor be assured that new training will be effective.
It appears that some manufacturers, regulators, and even (unbiased) investigators have yet to accept these issues.
As for the 777, it is disappointing that even where technical solutions appear to be available, the human (training) solution is still chosen. Similarly relating to the 737 accident in AMS; the FAA (Boeing) comments in the appendix to the report, the ‘blame the human view’ prevails, enabling a defensive view of, ‘not our problem in design or certification’, to be maintained.
These are accidents of assumption; an assumption by design / regulators that the human will be able to manage; however few people are considering how much the circumstances in the initial assumption have changed over time.
It is a harsh reality that in today’s highly complex operations there are situations where combinations of factors interact in such a way it is impossible for humans to sufficiently understand and safely manage outcomes.
In part, these situations involve increased use of automation, changed pilot training, and an evolving operational environment, ATC, management, regulation, commercial pressure, etc.
Thus it is unrealistic to require even greater human capability in situations where the human is often found wanting, either due to limitations in awareness, understanding, memory and recall, workload management, or all of these, often seen in accidents.
As safety improves, there are fewer accidents, often unique to circumstance. If these exceed human capability, then demanding even more training and checks is unlikely to improve human performance, and also any change enables the possibility of introducing a new unforeseen problem.
The alternative is to consider other contributions; the technical systems, certification, ATC, etc. Previously, technical change, including software has been difficult and expensive, nowadays this cost is being balanced by the demands for safety, and particularly that it is very difficult to change the human condition (James Reason), nor be assured that new training will be effective.
It appears that some manufacturers, regulators, and even (unbiased) investigators have yet to accept these issues.
As for the 777, it is disappointing that even where technical solutions appear to be available, the human (training) solution is still chosen. Similarly relating to the 737 accident in AMS; the FAA (Boeing) comments in the appendix to the report, the ‘blame the human view’ prevails, enabling a defensive view of, ‘not our problem in design or certification’, to be maintained.
These are accidents of assumption; an assumption by design / regulators that the human will be able to manage; however few people are considering how much the circumstances in the initial assumption have changed over time.
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there are situations where combinations of factors interact in such a way it is impossible for humans to sufficiently understand and safely manage outcomes.
Is this the ultimate situation for which reversion to manual flight .. sort it out .. and then consider re-engaging the automatics may be what is required ? Still, a problem if the manual flight capability either has atrophied or was never existent ?
So far as understanding the finer ins and outs of what computers can do, if the programmers can't get it 100% under control, is there any basis for presuming that a pilot will do any better ?
Is this the ultimate situation for which reversion to manual flight .. sort it out .. and then consider re-engaging the automatics may be what is required ? Still, a problem if the manual flight capability either has atrophied or was never existent ?
So far as understanding the finer ins and outs of what computers can do, if the programmers can't get it 100% under control, is there any basis for presuming that a pilot will do any better ?
