Ethiopian airliner down in Africa
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Rubbish. I have 21 years in safety related systems including design and certification and you NEVER, NEVER use a single fallible input to drive a safety critical system. And then to give it full authority driving a critical control surface, allowing it to trim full down? Breathtaking incompetence. Also, you ALWAYS design to fail-safe. This doesn't mean what most people think. It doesn't mean it will never fail. It means it will fail in a safe state. AOA disagree is an absolute obvious failure and yet MCAS failed in the most unsafe state that it could possibly have.
A 16 year old electronics student with a week's training in safety related systems design would have done a better job.
A 16 year old electronics student with a week's training in safety related systems design would have done a better job.
There are numerous other systems in aircraft which are single point of failure which require pilot intervention: engine failures, for whatever reason, are one. Pressurization where the motors controlling the outflow valves can fail and human intervention is required, hydraulic systems where if the main system fails certain services are not available (Centre system in the large Boeings as an example).
I can go on and on with other examples of systems in aircraft which are not a "single fallible input to drive a safety critical system". In some cases like an engine failure, there is no possible solution to get around this due to physics so that is why we have trained, professional pilots flying airliners and why there is a separate endorsement to fly multi-engine aircraft. We do not live in a utopian world in aviation so we manage it by education and training.
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Boeing's Emergency AD says nothing of the sort.
It's not up to Boeing what an airline does or doesn't put in its FOM - the AD refers instead to the Airplane Flight Manual (AFM), where Boeing does have the ability to require changes as the AFM forms part of the aircraft certification.
One might have hoped that Avherald would understand the difference between the two publications.
It's not up to Boeing what an airline does or doesn't put in its FOM - the AD refers instead to the Airplane Flight Manual (AFM), where Boeing does have the ability to require changes as the AFM forms part of the aircraft certification.
One might have hoped that Avherald would understand the difference between the two publications.
It turned out, that only very cursory knowledge about the stab trim runaway procedure exists amongst the flight crew of Ethiopian Airlines even 5 months after the EAD was distributed. In particular, none of the conditions suggesting an MCAS related stab trim runaway was known with any degree of certainty. In that context the recommendation by the accident flight's first officer to use the TRIM CUTOUT switches suggests, that he was partially aware of the contents of the EAD and reproduced some but not all of the provisions and not all of the procedure, which may or may not explain some of the obvious omissions in following the procedure in full
Crash: Ethiopian B38M near Bishoftu on Mar 10th 2019, impacted terrain after departure
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There was a time in my aviation career when one would be subjected to the whims of a sadistic simulator instructor whose only job was to present you with a host of malfunctions and upsets to which there was only one correct initial response: Turn off the magic, set the pitch, set the power, monitor the performance, trim the aircraft, move to a safe altitude. You did this again and again and again until it was impressed upon you that there will come a time when you really have no clue what is going on and that the only safe harbor was, Turn off the magic, set the pitch, set the power, monitor the performance, trim the aircraft, move to a safe altitude. After some passage of time without sufficient evidence that this was a "cost-effective" use of sim time, this type of relatively unstructured training was replaced with what has largely become a set of scripts consisting of known problems and known answers.
There was a time in my aviation career when one would be subjected to the whims of a sadistic simulator instructor whose only job was to present you with a host of malfunctions and upsets to which there was only one correct initial response: Turn off the magic, set the pitch, set the power, monitor the performance, trim the aircraft, move to a safe altitude. You did this again and again and again until it was impressed upon you that there will come a time when you really have no clue what is going on and that the only safe harbor was, Turn off the magic, set the pitch, set the power, monitor the performance, trim the aircraft, move to a safe altitude. After some passage of time without sufficient evidence that this was a "cost-effective" use of sim time, this type of relatively unstructured training was replaced with what has largely become a set of scripts consisting of known problems and known answers.
Watching the live news conference from Chicago, the Chief Exec gives me precisely zero confidence that Boeing are on top of this. He cannot bring himself to admit that the MCAS, as designed and fitted, had a major role in the accidents.
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formulaben - why should you fear such an outcome? Surely our role in commercial aviation is to be as safe as reasonably practicable, whichever way that is achieved? MCAS Mk I was an example of poor automation which then meant a continued, or even increased, reliance on SkyGods. If the automation had been half decent, none of us would be discussing suicidal HAL and the ability of flight crews.
“The MCAS system met with our design and quality criteria and this was a series of events” or something along those lines.
I find that statement incredible. The arrogance. This was a clearly flawed system which has cost the lives of 300 people.
The question I ask - do you agree that a 737-100 is the same aircraft as a 737-9 in terms of TCDS?
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what 737 Driver is trying to tell all of us ...
Many on here seem 'niggled' by 737 Driver's posts. The posts are well written, thought provoking and factual ... but if I were to sum up exactly what 737 Driver
is trying to say, it's simple ..
BOTH PLANES WERE FLYABLE !
There was nothing mechanically/electronically/software wrong that was stopping these planes continuing to fly!! FACT
There was no 'show stopper' !!
is trying to say, it's simple ..
BOTH PLANES WERE FLYABLE !
There was nothing mechanically/electronically/software wrong that was stopping these planes continuing to fly!! FACT
There was no 'show stopper' !!
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formulaben, I don't think it's that simple. For sure, I don't want children of the magenta, I see enough of them already. But equally, I think the 'better pilot' nut is far more difficult to crack than writing a more failsafe bit of software. In fact, I would want to know what you think makes a better pilot.
I want safer flying which, with a safety manager hat on, means that all elements of the system are considered. This includes from design, manufacture, training, oversight, flight crew etc. The lot.
If we end-up blaming the pilots and then allowing Boeing to get away with a fudge then we have failed as part of the industry.
I want safer flying which, with a safety manager hat on, means that all elements of the system are considered. This includes from design, manufacture, training, oversight, flight crew etc. The lot.
If we end-up blaming the pilots and then allowing Boeing to get away with a fudge then we have failed as part of the industry.
meleagertoo, #4589
‘how can it be possible for two professional pilots on a type with a known and highly public failure mode to appear not to be aware of it's symptoms when it occurs to them?’
You appear blinded by hindsight.
The first symptoms and alerts immediately after takeoff were of low speed, approach to stall, erroneous air-data. The crew managed this situation correctly, concluding UAS.
Note that the alerts and annunciations for UAS are similar, identical to the emergency AD re MCAS except there was no trim activity.
Subsequently, flap retraction, MCAS moved the trim. Previous discussions have considered the salience of trim activity and time required to conclude a failure in an intermittent system.
The combination of increased stick force - ‘fly the aircraft’, and UAS could be interpreted as control difficulties - speed error could affect the feel of the aircraft - as would trim.
Thus the crew required a step change in their mindset to associate the revised situation with MCAS, or at least trim problems and then isolate the trim system.
Surprise, startle; the original problem understood, now its not !
‘how can it be possible for two professional pilots on a type with a known and highly public failure mode to appear not to be aware of it's symptoms when it occurs to them?’
You appear blinded by hindsight.
The first symptoms and alerts immediately after takeoff were of low speed, approach to stall, erroneous air-data. The crew managed this situation correctly, concluding UAS.
Note that the alerts and annunciations for UAS are similar, identical to the emergency AD re MCAS except there was no trim activity.
Subsequently, flap retraction, MCAS moved the trim. Previous discussions have considered the salience of trim activity and time required to conclude a failure in an intermittent system.
The combination of increased stick force - ‘fly the aircraft’, and UAS could be interpreted as control difficulties - speed error could affect the feel of the aircraft - as would trim.
Thus the crew required a step change in their mindset to associate the revised situation with MCAS, or at least trim problems and then isolate the trim system.
Surprise, startle; the original problem understood, now its not !
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formulaben, I don't think it's that simple. For sure, I don't want children of the magenta, I see enough of them already. But equally, I think the 'better pilot' nut is far more difficult to crack than writing a more failsafe bit of software. In fact, I would want to know what you think makes a better pilot.
I want safer flying which, with a safety manager hat on, means that all elements of the system are considered. This includes from design, manufacture, training, oversight, flight crew etc. The lot.
If we end-up blaming the pilots and then allowing Boeing to get away with a fudge then we have failed as part of the industry.
I want safer flying which, with a safety manager hat on, means that all elements of the system are considered. This includes from design, manufacture, training, oversight, flight crew etc. The lot.
If we end-up blaming the pilots and then allowing Boeing to get away with a fudge then we have failed as part of the industry.
Stop putting words in my mouth.
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I'm sorry, I didn't think I was putting words in your mouth. My point is that if we are in a safer place with reliance on automation then we shouldn't be wringing-our hands because we may perceive this would be at the cost of airmanship.
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Just like a goalkeeper who dives the wrong way during a penalty shoot out. Last line of defence and he failed. Clearly should have trained better.
Any pilot who looks at the FDR tapes in detail and doesn't get a shiver going down their spine, and a feeling in the back of their mind "yep, on a bad day, that could have been me" is either genuinely a superhero or has an overestimation of their own abilities. Which is just as dangerous as low abilities.
Any pilot who looks at the FDR tapes in detail and doesn't get a shiver going down their spine, and a feeling in the back of their mind "yep, on a bad day, that could have been me" is either genuinely a superhero or has an overestimation of their own abilities. Which is just as dangerous as low abilities.
I have read both reports and have imaged them in my mind about what I would do in a similar circumstance. For the part between lift-off to flap retraction when it was solely an unreliable airspeed condition, I thought of the case early in my career when I was an FO on a B737-200 and we got stick shaker immediately upon lift-off (no other bells or whistles). I recall the incident clearly; myself and the Captain looked at each other in surprise, we confirmed that the engines were putting out the expected power (EPR), the attitude of the aircraft was correct and the controls were not mushy...no reason to believe that we were in a stall. The second thought was training we received about UAS in the simulator as I believe UAS was a result of AF447. This time there was bells and whistles (no stick shaker) but again revert to basic flying principles (power and attitude) to get some air underneath you first before troubleshooting but at all times someone flying the aircraft. In fact, the sole purpose of the PF (pilot flying) is to fly the airplane while the PNF (pilot not flying) does the troubleshooting/drill. Note that 0 of the 4 pilots in the accident aircraft did the UAS drill and that the incident aircraft the day before did and survived. That is not a coincidence as they were able to control the speed of the aircraft and were able to manually trim the aircraft.
With regard to when MCAS kicks in, yes, that will get your attention however MCAS is so aggressive (i.e. it is neither subtle nor insidious) anyone that knows how to hand fly an aircraft will immediately sense that something is wrong with the flight controls, pull back on the control column and trim aggressively to return to an in trim condition. And I don't mean little, tiny bursts of trim but holding the thumb switch down and really letting it rip.
Trimming out the control forces is an instinctive and unconscious action that 737 Driver has so nicely articulated that is a fundamental skill that pilots with 5 hours of flying time have. I was an instructor in the RCAF on jets and beginning with the second flight with a student (the first flight was a freebee for the instructor to demonstrate the aircraft including his aerobatic sequence!) we harped on trimming the aircraft. Once the student made trimming instinctive, theirs lives and that of their instructor got a whole lot better. This is long winded way of saying that it is impossible for a trained pilot to a) not trim the aircraft and hence nullify MCAS, and b) not determine that the trim is in a runaway (for whatever reason) and disable the trim using the emergency procedure.
I don't believe that doing what one has been trained to do requires superhuman skills; it is a matter of being trained and being prepared. And by being prepared I mean knowing the emergency drills for the aircraft. Perhaps I am "superhuman" in that regard as I regularly review them, particularly the memory items as the memory ain't what it used to be at 59 years of age. Rather than being superhuman, I subscribe to the notion that a professional pilot should know the memory emergencies for their aircraft. Call me old fashioned.
737 Driver,
your ‘default training’, choice of action, appears to differ from many pilots.
Consider. Having assessed the situation, choose the action according to that situation; not a rigorous follow SOPs / training without question.
The ‘automaton’ approach - follow SOPs, could favour selection of a procedure before assessment and then making the situation fit that mental model; it stifles wider thoughts and adaptation.
Aircraft are not flown via ‘mantra’, by rote; pilots are well trained, skilful individuals, doing their best in difficult circumstance, why then tell them what to do in ‘every’ situation, where ‘every’ situation is only known to them.
Your pedantic focus on procedure - set power as per standard UAS, could reduced the aircraft’s ability to continue climbing when departing for a hot / high airfield, with potential terrain issues; would this be considered, or just follow SOPs adding risk to an emergency situation.
Lengthy posts #4590, and bolded text does not replace the required, well-considered arguments to support a point of view.
your ‘default training’, choice of action, appears to differ from many pilots.
Consider. Having assessed the situation, choose the action according to that situation; not a rigorous follow SOPs / training without question.
The ‘automaton’ approach - follow SOPs, could favour selection of a procedure before assessment and then making the situation fit that mental model; it stifles wider thoughts and adaptation.
Aircraft are not flown via ‘mantra’, by rote; pilots are well trained, skilful individuals, doing their best in difficult circumstance, why then tell them what to do in ‘every’ situation, where ‘every’ situation is only known to them.
Your pedantic focus on procedure - set power as per standard UAS, could reduced the aircraft’s ability to continue climbing when departing for a hot / high airfield, with potential terrain issues; would this be considered, or just follow SOPs adding risk to an emergency situation.
Lengthy posts #4590, and bolded text does not replace the required, well-considered arguments to support a point of view.
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Having had dealings with the media before and knowing how they like to twist facts, it would be irresponsible of the Boeing CEO to accept full responsibility for these accidents. MCAS is just one piece of the puzzle.
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You appear blinded by hindsight.
The first symptoms and alerts immediately after takeoff were of low speed, approach to stall, erroneous air-data. The crew managed this situation correctly, concluding UAS.
Note that the alerts and annunciations for UAS are similar, identical to the emergency AD re MCAS except there was no trim activity.
The first symptoms and alerts immediately after takeoff were of low speed, approach to stall, erroneous air-data. The crew managed this situation correctly, concluding UAS.
Note that the alerts and annunciations for UAS are similar, identical to the emergency AD re MCAS except there was no trim activity.
There was no indication whatsoever of an approach to a stall either as the indicated airspeeds were all increasing and the attitude of the aircraft was normal. We cannot tell from the FDR whether the controls were "mushy" or not. But for argument's sake, lets say it was an impending stall - what is the memory drill for that? Lower the nose to reduce alpha then slowly add power being careful not to let the nose pitch-up too much and re-enter the stall. This drill was not done so take your pick, normal take-off (with no changes in pitch/power) with bells and whistles or an impending stall without doing the stall recovery?
‘how can it be possible for two professional pilots on a type with a known and highly public failure mode to appear not to be aware of it's symptoms when it occurs to them?’
You appear blinded by hindsight. ??? How on earth do you figure that? But something had them blinded, that's for sure.
The first symptoms and alerts immediately after takeoff were of low speed, approach to stall, erroneous air-data. The crew managed this situation correctly, concluding UAS. They never even started UAS! Had they concluded it the autothrust would have been disconnected, speed/pitch/thrust under control and flying reasonably normally, not trudging through more or less normal after t/o actions with no atempt to deal with anything else, even including engaging a/p at 400' with a stickshaker going????
Note that the alerts and annunciations for UAS are similar, identical to the emergency AD re MCAS except there was no trim activity. Having read the AD, Lionair reports and discussions they'd know to be only anticipating MCAS activity at flap retraction. Events and sequence were all but identical to LionAir. I rest my case! How could crew on a type that had just suffered such a well publicised accident not recognise the similarities?
Subsequently, flap retraction, MCAS moved the trim.Re-read last comment above. How was it not blindingly obvious at this point? Previous discussions have considered the salience of trim activity and time required to conclude a failure in an intermittent system.
The combination of increased stick force - ‘fly the aircraft’, which they didn't do, did they? and UAS could be interpreted as control difficulties - speed error could affect the feel of the aircraft - as would trim. I suspect they never looked at the speed, or they'd have made the connection between full thrust, overspeed etc etc. And the mythical 'completion of UAS' would have ascertainied which speed indications were reliable/in error so that's not a sound answer.
Thus the crew required a step change in their mindset to associate the revised situation with MCAS which ought to have been in the forefront of their mindset , or at least trim problems and then isolate the trim system. Go and re-read that line again! This should all have been complete deja-vue! Inexplicable trim problems four months after the last big accident - how can memories be that short?
Surprise, startle; the original problem understood, now its not ! I don't think they understood much at all I'm afraid.
If a whole bus-load of people in your previously bear-free neighbourhood were eaten by bears a couple of months ago in the scariest event your neighbourhood has ever seen and you were wandering home one night - fat, dumb and happy others might quite reasonably question the appropriateness of your low-key mental state. Is it wise under the circumstances? But even with one's attention being on the path if you sudenly hear unfriendly animal noises right behind you do you really think - oh - that sounds unusually large and fierce for a raccoon but instead of doing the racoon drill all I'll do is carry on as normal and maybe throw it some peanuts- and just carry on strolling eyes-front as the thing bellows away behind you? It never occurs to you to have a suspicion about what's actually growling? And when you hit the moonlight where you know it'll attack if it actually is a bear you still just stroll on oblivious no thoughts of bears in your mind at all? - indeed you begin to run which is going to make it bite all the harder? And even when it's chewing your arm off your'e still saying, "nice Rocky, have another peanut?" instead of pulling out your bear-gun because you didn't read the newspapers or talk to the neighbours who all said that would be a pretty good idea under the circumstances? Didn't the fact you were even carrying a bear gun suggest to you that even with a runawway bear chewing your ass it might just be there for a useful reason?
Many posters citing weak piloting skills, human error, are biased by hindsight, with further biases of believing that all pilots will think and behave the same way (or as they do - earned dogmatism effect) or as trained. These views also represent ‘fundamental attribution error’ seeking the nearest - in action, or last person in a chain of events - timeline.
In reality many of these issues reflect the same difficulties that the accident crews experienced; how to make sense of the situation, choosing a course of action, and opportunity to act.
Posts suffer similar deficiencies in ‘airmanship’ and ability to ‘fly the aircraft’; unable to understand the current situation, think critically and review what is currently known. This ‘lack of airmanship’ is a weakness in thinking skills or ability to use them wisely; particularly with the wisdom of hindsight. First ‘fly you mind’, then act - only post comments after well considered thought; where thought should is based on skills training and particularly practice of those thinking skills.
Pursuing the ‘blame game’, embedded in ‘responsibility’, might be a self-satisfying generation of individual understanding, but this offers little opportunity to learn due to premature closure, from those who already have the (their) ‘answer’.
Other people in this forum also seek understanding, using a cautious evaluation and review, involving skills of critical thinking, which similarly are core values in airmanship.
If posters are unable to achieve a suitable level of thinking given the enlightenment of hindsight, and the luxury of time and wealth of additional information, then they should heed the possibility that they could take similar deficiencies of thought - airmanship, situation awareness, assessment, and judgement into their flight decks.
In reality many of these issues reflect the same difficulties that the accident crews experienced; how to make sense of the situation, choosing a course of action, and opportunity to act.
Posts suffer similar deficiencies in ‘airmanship’ and ability to ‘fly the aircraft’; unable to understand the current situation, think critically and review what is currently known. This ‘lack of airmanship’ is a weakness in thinking skills or ability to use them wisely; particularly with the wisdom of hindsight. First ‘fly you mind’, then act - only post comments after well considered thought; where thought should is based on skills training and particularly practice of those thinking skills.
Pursuing the ‘blame game’, embedded in ‘responsibility’, might be a self-satisfying generation of individual understanding, but this offers little opportunity to learn due to premature closure, from those who already have the (their) ‘answer’.
Other people in this forum also seek understanding, using a cautious evaluation and review, involving skills of critical thinking, which similarly are core values in airmanship.
If posters are unable to achieve a suitable level of thinking given the enlightenment of hindsight, and the luxury of time and wealth of additional information, then they should heed the possibility that they could take similar deficiencies of thought - airmanship, situation awareness, assessment, and judgement into their flight decks.
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A careful reading of my posts would indicate that the method I am preaching presupposes that the crew is unsure of the nature of the situation, and as such does not have a default SOP to follow. Certainly, if the crew has correctly identified the situation and malfunction, they most certainly should resort to the appropriate procedure. These accident crews did not. In absence of any other guidance, they flailed around until they lost control of the aircraft. Hence the mantra: When faced with an undesired aircraft state, unknown malfunction, or loss of situational awareness...., well you should know the drill by now.
Last edited by 737 Driver; 29th Apr 2019 at 17:53.