Air Asia Indonesia Lost Contact from Surabaya to Singapore
Who says they were opposing each other?
It has nothing to do with handflying skills. Aeroplane was commanded into stall and kept there because crew was totally unable to comprehend what happened. They couldn't recover? They never attempted recovery because they had no idea they needed to recover from self-inflicted stall.
I would not go as far to suggest that it is pathological. If former fighter pilots can succumb to it, I don't feel many of us are safe.
...and when it breaks it will leave you with control of single elevator while Airbus system of stick priority leaves you flying with both! Another clear example of classic controls superiority over Airbus FBW.
Probably later, but what difference would that make?
Pulling full aft stick/yoke is something crews always do?!? It must be very hard life in the cockpit if one has always be alert to the subtle difference of doing after start controls check and flying the approach.
Was not. I know. I have read the report.
Airbı provide tactile cues through seat of one's pants. See video posted by unworry.
Must be on PPRuNe.
Originally Posted by A0283
was he slumped over his stick
Originally Posted by Bergerie1
That is why a tactile cue is needed for a stall warning.
Originally Posted by Diversification
Somewhere I read after the turboprop crash that this pulling surprisingly occurred in 80 % of tested pilots.
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Freedom of Speech on Flightdeck
Having read several official accident reports and their transcripts in almost all I see a common factor of poor crew communications. Conversely in successfully averted incidents it appears high standard and professional communications are a common factor.
Why would flight crew fail to professionally communicate for several minutes during these incidents?
Are these some factors?
Why would flight crew fail to professionally communicate for several minutes during these incidents?
Are these some factors?
- Were CVRs routinely analyzed by airlines for job performance rating/CRM. If so then is there pressure to not say something dumb/self incriminating lest it affect job prospects.
- Is there a need for increased CVR monitoring, analysis and feedback.
- Personality conflict and ego's.
- Focus on overly sterile cockpit to the point of affecting crew performance.
- Sloppy adherence to SOP.
- Airline culture: standards inherited from top down or poorly enforced.
- Training
- Regulation
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For a few years we have been 'beating our gums' on here (rather typing fingers) about lack of basic skills and pilots doing the opposite of what is required. How many serviceable large jet a/c stalled & crashed before FBW, and how many since? In my memory the balance shows a decay of skills when it should be the opposite. It is not the inherent fault 0f FBW.
We here beat our gums. I wonder what the worldwide authorities & training departments are doing? Whatever they are doing it is taking a long time to have a reverse effect. This might sound simplistic, but if they found a single design flaw, ATC procedural error, equipment failure, SOP error that caused a fatal crash, the 'never again brigade' would be up in arms. Things would change and fast. How many pilot induced stall crashes have there been in the past 5 years, and has there been the same reaction from authorities, to find the TRUE cause & solution, as there would have been to a technical crash? I don't think so.
We here beat our gums. I wonder what the worldwide authorities & training departments are doing? Whatever they are doing it is taking a long time to have a reverse effect. This might sound simplistic, but if they found a single design flaw, ATC procedural error, equipment failure, SOP error that caused a fatal crash, the 'never again brigade' would be up in arms. Things would change and fast. How many pilot induced stall crashes have there been in the past 5 years, and has there been the same reaction from authorities, to find the TRUE cause & solution, as there would have been to a technical crash? I don't think so.
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Uhh clandistino ???
Say what ?? Provide source for ' single elevator " comment. Do you really believe each control column only controls one side of elevator ??
Maybe on your video game ??
..and when it breaks it will leave you with control of single elevator
Maybe on your video game ??
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Uhh CONSO ???
Suggest you read your FCOM or see:
http://www.ntsb.gov/investigations/A...ts/AAB0201.pdf
See Page 18:
"The captain's and first officer's control columns have authority to command full travel of the elevators under most flight conditions and normally work together as one system. However, the two sides of the system can be commanded independently because of override mechanisms at the control columns and aft quadrant. Therefore, if one side of the system becomes immobilized, control column inputs on the operational side can cause full travel of the non failed elevator"
Dumb... really dumb!
@Clandestino,
Correct.
Whereas everyone else provides both seat of pants + stick shaker.
Provide source for ' single elevator " comment. Do you really believe each control column only controls one side of elevator ??
http://www.ntsb.gov/investigations/A...ts/AAB0201.pdf
See Page 18:
"The captain's and first officer's control columns have authority to command full travel of the elevators under most flight conditions and normally work together as one system. However, the two sides of the system can be commanded independently because of override mechanisms at the control columns and aft quadrant. Therefore, if one side of the system becomes immobilized, control column inputs on the operational side can cause full travel of the non failed elevator"
Maybe on your video game ??
@Clandestino,
Airbı provide tactile cues through seat of one's pants.
Whereas everyone else provides both seat of pants + stick shaker.
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I know that such ideas are usually met with hate toward "conspiracy theorists" however..
Where flight recorder gets it data? As i understand, this is not direct data from sensors, but, data from flight computer.
Is it completely impossible to theorize that pilots actually provided correct inputs? What if, it was software that commanded maximum pitch?
Some similarities with pilot version of 26 June 1988; Air France A320; Flight 296Q crash?
Where flight recorder gets it data? As i understand, this is not direct data from sensors, but, data from flight computer.
Is it completely impossible to theorize that pilots actually provided correct inputs? What if, it was software that commanded maximum pitch?
Some similarities with pilot version of 26 June 1988; Air France A320; Flight 296Q crash?
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- Were CVRs routinely analyzed by airlines for job performance rating/CRM.
- Is there a need for increased CVR monitoring, analysis and feedback.
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Is it completely impossible to theorize that pilots actually provided correct inputs? What if, it was software that commanded maximum pitch?
A more surprising omission in the AirAsia report is the THS chart. This would be an important visual to educate readers.
Perhaps instead of a stall warning there should be a large pop up QRH procedure!
Last edited by xcitation; 10th Dec 2015 at 01:43.
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Why would flight crew fail to professionally communicate for several minutes during these incidents?
Some of the standard terms (e.g. Stall) are just to simple to cover all the real situations that could occur. Also the up/down discussions (meaning nose up/down or climb/descend?) are sometimes dirsturbing...
To understand "push the nose down" if your colleage screams "we are going down" is beyond typical human brain capacity (your brain would think "up" not "down" in that case). The same is with negation, never scream "don´t pull" at somebody, scream "push". Our brain is poor with the opposite of words heard, our brain is designed to identify, not to exclude something.
Unfortunately human factors is not yet an independent science, it is covered by a lot of different disciplines these days (ergonomy, neurology, psychatry...), they do not produce a lot of output useful for aircraft designers or training programme providers yet.
It is almost impossible to fix that issue, as long as there are different mother tongues on this planet and crews are international.
Stall warning
Whereas everyone else provides both seat of pants + stick shaker.
The question is then; in the cases under discussion, did the crew fail to recognise the stall condition, or recognise it but fail to react effectively? There is some evidence that at least one pilot in both the AF and Air Asia recognised a need to push forward on the stick.
Should Airbus provide tactile artificial stall warning in reversionary flight control laws? Historically, aircraft were designed to give natural stall warning through buffet. Where this was inadequate, or the consequences of a full stall were intolerable (deep stall, for example), artificial stall warning was added in the form of stick shakers or even AoA protection in the form of stick pushers. Another important certification requirement is that the pilot be able to clearly identify the stall itself. The following is the relevant part of CS25:
d) The aeroplane is considered stalled
when the behaviour of the aeroplane gives the
pilot a clear and distinctive indication of an
acceptable nature that the aeroplane is stalled.
(See AMC 25.201 (d).) Acceptable indications of
a stall, occurring either individually or in
combination, are –
(1) A nose-down pitch that cannot be
readily arrested;
(2) Buffeting, of a magnitude and
severity that is a strong and effective
deterrent to further speed reduction; or
(3) The pitch control reaches the aft
stop and no further increase in pitch attitude
occurs when the control is held full aft for a
short time before recovery is initiated.
If the above cannot be satisfied through the natural characteristics of the aeroplane, then the manufacturer must fit artificial devices. In the case of the Airbus types under discussion, deterrent buffet is always reached before the point of stall, and the stall itself is naturally benign. The deterrent buffet is of such a magnitude that I doubt a pilot would reliably feel a stick shaker. Aerodynamic buffet has always been the classic natural indication of stall, from the most basic light aircraft upwards. The Airbus doesn't have a stick shaker because it doesn't need one! Whether we as an industry are training pilots to correctly respond to a stall is another question...
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The probability of being in Alternate or Direct Law AND the crew allowing the aircraft to get into the stall regime is minute
The same reason why the aircraft has to revert to a different law might also cause the crew to do strange things. These events are not necessarily independent. So in the end the probability of being in alternate Law might be exacly the same as the one one that a crew is confused. And it may both happen at the same time because of the same reason.
It needs to be very carefully evaluated, which failures are really independent (and their combination therefore highly remote), and which are resulting from a common cause or from each other, and hence are not so remote.
It is clear that we can not design aircraft for the combination of all possible events and conditions, but it should also be clear that we can not claim all events to be unrelated.
(1) A nose-down pitch that cannot be readily arrested
Should Airbus provide tactile artificial stall warning in reversionary flight control laws?
Volume,
I agree with you completely. However, it remains true that the aircraft remains flyable without stalling in Alternate and Direct Laws, as other crews have demonstrated. So there remains an additive element to this.
Re your other points; the quote I made is from the certification requirements, not advice to pilots! The aim is indeed that the aircraft should 'tell you something'. Likewise, your point about artificial stall warning is correct; natural buffet is independent of air data and can be relied upon regardless of the state of the aircraft's systems. That's the beauty of it.
On a technicality, loss of data is not the only reason why an Airbus might revert from Normal Law. Loss of Normal Law doesn't necessarily mean that your air data is bad.
It is clear that we can not design aircraft for the combination of all possible events and conditions, but it should also be clear that we can not claim all events to be unrelated.
Re your other points; the quote I made is from the certification requirements, not advice to pilots! The aim is indeed that the aircraft should 'tell you something'. Likewise, your point about artificial stall warning is correct; natural buffet is independent of air data and can be relied upon regardless of the state of the aircraft's systems. That's the beauty of it.
On a technicality, loss of data is not the only reason why an Airbus might revert from Normal Law. Loss of Normal Law doesn't necessarily mean that your air data is bad.
Last edited by ExV238; 10th Dec 2015 at 09:02.
Clandestino, re “pulling full aft stick …” - normal.
To clarify the point in my post, which had previously considered the hypothesis that the crew followed the FD, then following the commanded roll and pitch could be normal behaviour.
The pilot might not appreciate the magnitude of the stick input, particularly if the FD control laws are not optimised for such a situation; also, if the FD computation and/or normal use assumes that the commands are continually nulled, i.e. a director vice a recovery indicator for a gross deviation. Thus a large roll angle and subsequent loss of altitude could result in a significant FD demand, where its magnitude could be interpreted as requiring a large stick input.
Furthermore, consider how the FD is used; is it normal to follow a combined path, pitch and roll together, or alternatively separate the axis, nulling roll independently of pitch, (which FD format did this aircraft have - single or split cue?).
If a sequential axis response was made then a FD roll demand at a high bank angle could be interpreted as having a significant pitch component; obviously this is speculative.
Another view might also conclude that the stall was induced by the FD and SOP.
Thus there may be greater safety value in considering how crews fly the FD in normal operation and how SOPs are interpreted – always follow the FD ??! .
Another ‘SOP mantra’ is ‘fly the aircraft’, but what does ‘fly’ mean.
A better approach is Aviate, Navigate, Communicate, … which should be more likely to generate the question ‘what does ‘Aviate’ mean'. Many posts focus on stick and rudder skills (fly) overlooking the preceding need to understand the situation – 90% of human thought involves understanding; when and where are the skills of understanding taught.
Some recent views of awareness suggest that we should be teaching the identification of situations where SOPs should not be followed (how to identify them), opposed to always follow SOPs.
ExV238, re ‘fail to recognise …’, see Errors in Aviation Decision Making: Bad Decisions or Bad Luck?
The decison to pull CBs?
Peter H, for info, http://xstar.ihmc.us/research/projects/EssaysOnHCC/
See Sensemaking (2), Janus principle (training), boiled frog (procedural drift)
To clarify the point in my post, which had previously considered the hypothesis that the crew followed the FD, then following the commanded roll and pitch could be normal behaviour.
The pilot might not appreciate the magnitude of the stick input, particularly if the FD control laws are not optimised for such a situation; also, if the FD computation and/or normal use assumes that the commands are continually nulled, i.e. a director vice a recovery indicator for a gross deviation. Thus a large roll angle and subsequent loss of altitude could result in a significant FD demand, where its magnitude could be interpreted as requiring a large stick input.
Furthermore, consider how the FD is used; is it normal to follow a combined path, pitch and roll together, or alternatively separate the axis, nulling roll independently of pitch, (which FD format did this aircraft have - single or split cue?).
If a sequential axis response was made then a FD roll demand at a high bank angle could be interpreted as having a significant pitch component; obviously this is speculative.
Another view might also conclude that the stall was induced by the FD and SOP.
Thus there may be greater safety value in considering how crews fly the FD in normal operation and how SOPs are interpreted – always follow the FD ??! .
Another ‘SOP mantra’ is ‘fly the aircraft’, but what does ‘fly’ mean.
A better approach is Aviate, Navigate, Communicate, … which should be more likely to generate the question ‘what does ‘Aviate’ mean'. Many posts focus on stick and rudder skills (fly) overlooking the preceding need to understand the situation – 90% of human thought involves understanding; when and where are the skills of understanding taught.
Some recent views of awareness suggest that we should be teaching the identification of situations where SOPs should not be followed (how to identify them), opposed to always follow SOPs.
ExV238, re ‘fail to recognise …’, see Errors in Aviation Decision Making: Bad Decisions or Bad Luck?
The decison to pull CBs?
Peter H, for info, http://xstar.ihmc.us/research/projects/EssaysOnHCC/
See Sensemaking (2), Janus principle (training), boiled frog (procedural drift)
Last edited by safetypee; 10th Dec 2015 at 10:12.
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Human factors
@Volume
My impression is that human factors is not a science as such, and wonder if it should be. It is an umbrella label that covers a lot of different subjects (just like 'structures engineering' could cover loads, stress, stiffness, fatigue, etc).
When you dig deep into specific aspects of accidents you run into multiple factors. So you have to study them all and use the published knowledge.
Human factors indeed do not tell you what and how to design, or who to listen to. But you can and shall certainly make use of knowledge of all these aspects under that label while working on designs in design teams. Design teams consisting of people with a lot of different specialisms. I would expect that multiple people in these teams have knowledge of multiple human factors aspects.
A good designer tries to read as much as possible on as many aspects as possible. And uses and applies that while designing. I would say that modern aircraft are not and can not be designed without serious knowledge of a range of especially these human factors aspects. I have certainly seen a lot of that knowledge being applied to designs that happily fly around today.
To further improve on that you would need a lot of detailed information. And that may well be the real challenge.
What could be very useful to engineers to go beyond what they can do now, is information that is not directly available today. In such cases the engineer would not be interested in the specific airline or pilot as such. He just would like to see if pilots (new, bad, average, expert) act and react in the way the design (by lack of deeper knowledge) assumes. What he can use is information based on pilots interviews, and he of course uses test pilot inputs. The engineer would also like to have data that supports pilots statements and is accurate enough for design input (see Volume's post). In quite a few cases you have data that is available to airlines but not to design engineers. In this AirAsia case we see that KNKT investigators withhold CVR information that would certainly have been studied under human factors for years to come. Which is shocking.
There are multiple reasons why the ideal flow and type (think about video of instruments or even pilots) of information is not directly available. Every party that delivers information would wants to be sure that the information is only used for the intended purpose, and cannot be misused or even used against them. Which is hard nut to crack indeed.
Unfortunately human factors is not yet an independent science, it is covered by a lot of different disciplines these days (ergonomy, neurology, psychatry...), they do not produce a lot of output useful for aircraft designers or training programme providers yet.
When you dig deep into specific aspects of accidents you run into multiple factors. So you have to study them all and use the published knowledge.
Human factors indeed do not tell you what and how to design, or who to listen to. But you can and shall certainly make use of knowledge of all these aspects under that label while working on designs in design teams. Design teams consisting of people with a lot of different specialisms. I would expect that multiple people in these teams have knowledge of multiple human factors aspects.
A good designer tries to read as much as possible on as many aspects as possible. And uses and applies that while designing. I would say that modern aircraft are not and can not be designed without serious knowledge of a range of especially these human factors aspects. I have certainly seen a lot of that knowledge being applied to designs that happily fly around today.
To further improve on that you would need a lot of detailed information. And that may well be the real challenge.
What could be very useful to engineers to go beyond what they can do now, is information that is not directly available today. In such cases the engineer would not be interested in the specific airline or pilot as such. He just would like to see if pilots (new, bad, average, expert) act and react in the way the design (by lack of deeper knowledge) assumes. What he can use is information based on pilots interviews, and he of course uses test pilot inputs. The engineer would also like to have data that supports pilots statements and is accurate enough for design input (see Volume's post). In quite a few cases you have data that is available to airlines but not to design engineers. In this AirAsia case we see that KNKT investigators withhold CVR information that would certainly have been studied under human factors for years to come. Which is shocking.
There are multiple reasons why the ideal flow and type (think about video of instruments or even pilots) of information is not directly available. Every party that delivers information would wants to be sure that the information is only used for the intended purpose, and cannot be misused or even used against them. Which is hard nut to crack indeed.
Clandestino,
Perhaps my one liner posts are a little too cryptic! First, I will come clean - I have never been qualified on Airbus types, though I have on several occasions flown some of their simulators. All my experience of jet types was on VC10s, 707s and 747s, on each of which I did CofA testing which included lots of stalling.
Having watched the video you mentioned it seems clear that, in what I would call a 'normal stall environment' as done in flight testing and training, there is a considerable degree of natural pre-stall buffet. Thus there is no certification requirement for artificial protections such as stick shaker and/or stick pusher as in the T-tail VC10.
However, as others have mentioned, and I know to be the case, when under high stress the first cognitive sense to 'fail' is hearing. The person under extreme stress just does not hear what is being said to him/her. This is one of the main reasons why, on aircraft requiring artificial protections, a stick shaker was used.
It would appear, in both the Air France and the Air Asia accidents, for most of the time the pilots did not recognise they were in a stall despite the aural alarms and voice shouting 'Stall, Stall, Stall'. Thus, it seems to me, a stick shaker, even though it may not be required under current certification rules, might have provided an additional warning stimulus when the pilot's hearing channel was blotted out by stress.
Perhaps my one liner posts are a little too cryptic! First, I will come clean - I have never been qualified on Airbus types, though I have on several occasions flown some of their simulators. All my experience of jet types was on VC10s, 707s and 747s, on each of which I did CofA testing which included lots of stalling.
Having watched the video you mentioned it seems clear that, in what I would call a 'normal stall environment' as done in flight testing and training, there is a considerable degree of natural pre-stall buffet. Thus there is no certification requirement for artificial protections such as stick shaker and/or stick pusher as in the T-tail VC10.
However, as others have mentioned, and I know to be the case, when under high stress the first cognitive sense to 'fail' is hearing. The person under extreme stress just does not hear what is being said to him/her. This is one of the main reasons why, on aircraft requiring artificial protections, a stick shaker was used.
It would appear, in both the Air France and the Air Asia accidents, for most of the time the pilots did not recognise they were in a stall despite the aural alarms and voice shouting 'Stall, Stall, Stall'. Thus, it seems to me, a stick shaker, even though it may not be required under current certification rules, might have provided an additional warning stimulus when the pilot's hearing channel was blotted out by stress.
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A wild ride
A wee bit off topic- but the ability to recover from unexpected aircraft attitudes when everything turns to worms comes from skill, practice, and bucu luck
For a stunning example of EXTREME upsets and recovery- the following is classic
Chuck Yeager Interview -- page 2 / 8 -- Academy of Achievement
scroll down to the section that starts
there is a short video that follows - film taken from a cockpit camera.
My explanation is that he recovered one axis at a time.
For a stunning example of EXTREME upsets and recovery- the following is classic
Chuck Yeager Interview -- page 2 / 8 -- Academy of Achievement
scroll down to the section that starts
And on the fourth flight, I think it was on December 12, everything went beautiful. The drop was right on speed, and the chambers ignited when you flick the switch. The profile was beautiful. The only thing that happened, on the climb out, on all four chambers running and you're really accelerating - you fly off of a little eight ball flight indicator for attitude reference.
My explanation is that he recovered one axis at a time.