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Ethiopian airliner down in Africa

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Ethiopian airliner down in Africa

Old 4th May 2019, 02:03
  #4841 (permalink)  
 
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Originally Posted by 737 Driver View Post
A MCAS failure presents itself as runaway stab trim. This uncommanded motion can be caused by a number of different malfunctions, MCAS being only one of them. The runaway stab trim procedure is agnostic as to the underlying cause of the the malfunction.

The procedure itself calls for disengagement of the Autopilot, use of Main Electric Trim (yoke trim switch) as necessary, disengagement of the Autothrottles, and if the runaway has not ceased, use of the stab trim cutout switches. Once all electric trim has been terminated, you would use manual trim as needed until landing.

Though it is not currently procedure, if you had a good idea that the problem really was MCAS (presumably because of an erroneous AOA or airspeed input), you could extend the flaps and restore the electric trim since MCAS only works with the flaps up. Technically, engaging the autopilot would also cause MCAS inputs to cease, however, our manuals contain warnings that the autopilot may not stay engaged with an erroneous AOA or airspeed.
i am not a pilot, but if i remeber well, the last memory item for a runaway trim stabilizer is grab and hold...not crank
I do not want to argue, please correct me if I am wrong
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Old 4th May 2019, 02:18
  #4842 (permalink)  
 
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Originally Posted by 737 Driver View Post
This was actually one of the first issues that I checked into when I started looking at these accidents. To date I have found no evidence to suggest that the electric motor could stall under the loads present in the accident scenarios. If you think about it, in the final stages of the Ethiopian crash the stab motor was perfectly able to move the stab to near its limit against the opposing forces.
Thanks for that 737 driver.
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Old 4th May 2019, 02:21
  #4843 (permalink)  
 
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Originally Posted by FrequentSLF View Post
i am not a pilot, but if i remeber well, the last memory item for a runaway trim stabilizer is grab and hold...not crank
I do not want to argue, please correct me if I am wrong
Well, not exactly the last step, but close. I know of no instance where the cutout switches haven't worked. Among my colleagues on the 737, the most often technique discussed if one were to ever to be exposed to this situation is for the non-flying pilot to place his foot firmly on the trim wheel. Works much better than the hand. The trim system is designed such that if the cockpit trim wheel is stopped, the stab itself will not move because of a clutch mechanism that favors the trim wheel.
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Old 4th May 2019, 02:26
  #4844 (permalink)  
 
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Originally Posted by Matt48 View Post
I would like to see a stick shaker attached to a judges chair and then watch him make some complicated judgement with all that racket and distraction going on, but he won't die if he gets it wrong.
Originally Posted by MurphyWasRight View Post
Still a surprisingly 'normal day at the office, although they would not be the first crew to ignore stick shaker and complete a flight, and no I am not referring to Lion air but a US crew report in safety database.
Cognitive dissonance... So, is the stick shaker so startling and confusing that we should expect pilots to loose the ability to make rational judgements and control the aircraft when it is active, or is it a just normal day at the office, set FL 320 and continue?

Either way you slice it, the pilots had airspeed disagree and stickshaker immediately after takeoff. None of memory items on the UAS NNC checklist were executed. Counter to multiple instructions in that checklist, they continued to attempt to engage the autopilot when their training taught them they should not have. MCAS was no factor for the first one minute, fifteen seconds of the flight. Startle factor does not last a minute and fifteen seconds.

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Old 4th May 2019, 02:38
  #4845 (permalink)  
 
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Originally Posted by FrequentSLF View Post
i am not a pilot, but if i remeber well, the last memory item for a runaway trim stabilizer is grab and hold...not crank
I do not want to argue, please correct me if I am wrong
First - there is an IF statement before that action. You only do it if the runaway continues after having selected STAB TRIM CUTOUT.

Second - that is the last memory item on the checklist, but it is not the last item. After finishing the memory items, the crew, using the QRH, should execute the non-memory (reference) items. The first reference item is "Stabilizer - Trim Manually." Note - this excerpt is from an NG, but I believe that we earlier had compared it to MAX in one of these threads and found no or negligible differences.


Last edited by slacktide; 4th May 2019 at 02:46. Reason: clarification
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Old 4th May 2019, 03:35
  #4846 (permalink)  
 
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I’m sure when slacktide has his vibrator go off and slacks up, he would his have thumbs twiddling, fingers groping and setting 70% Ann one and pitch down to 4 degrees��
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Old 4th May 2019, 04:38
  #4847 (permalink)  
 
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Originally Posted by slacktide View Post
Startle factor does not last a minute and fifteen seconds.
Second dumbest statement I've seen this week. (Apologies for the harsh tone, I'm just done with superheroes who fail to understand cognitive impairment at times of unexpected and excessive stressors.)

For all you freaking hero pilots out there who would have just flown the effing airplane away from the troubles:

I wrote, probably a week ago now, of my own experience, as an eminently qualified, level-headed and relatively "calm when the crap hits the fan" type. For the heroes here who cannot understand cognitive stress-induced impairment I suggest you go back and read it- you might learn something.

You (yes you guys and all of us) simply cannot predict the cognitive impairment you will suffer (and we all suffer some form of it- unless one of us is God, in which case hallelujah!!) when the shit really really hits the fan. You cannot simulate this in a simulator, and most of you who have had to deal with emergencies of one form or another have also never dealt with it.

It is what happens when a big neon sign lights up your entire brain at once, screaming "YOU ARE ABOUT TO DIE!!" The fact that you might be able to overcome that knowledge will still not dampen your body's reaction to that realization, and you will, as a result, function at a fraction of your normal rate.

I know most of you- even the ones sympathetic to this reality, are certain you won't fade for even a moment, that your professional work and pride will keep you from ever experiencing such a complete disconnect from events.

I'm here to tell you that you are wrong.

No one will ever accurately depict what happened in either of those two cockpits. An audio tape reveals nothing of what is going on inside the minds of those four pilots. People pontificating here about their personal traits would be well-advised to consider that fact, and the one that says they are equally as likely, independent of their training, to suffer cognitive impairment when faced with a similar circumstance.

Regards, sorry for the rant-
dce
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Old 4th May 2019, 05:39
  #4848 (permalink)  
 
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Originally Posted by wonkazoo View Post
dumbest freaking effing hallelujah shit DIE rant
Temper your emotion. The startle response has been studied and documented for decades, and the results are used as a part of the design and certification of aircraft around the world. Instead of resorting to profanity, which may feel powerful to you but adds no value, I suggest that you read some of the original research and publications of Dr. Michael Gillen, PhD. Dr. Gillen also happens to be an ATP and is/was a 737 line check airman at United Airlines. His research indicates that impairment can last for up to 30 seconds following a strong startle event. He also published a great paper a few years ago (based on a study involving 40 different crews) comparing the effect of training recency on response to startle effect. This paper was used by the FAA as part of defining the new UPRT training requirements, which the FAA now requires as a result of the unacceptable pilot performance demonstrated on AF447. He found that crews who did not have recency in UPRT training consistently failed to meet ATP minimum standards, while crews who did have recent training, met the ATP standards.

The Ethiopian crew did not perform to standards. If, instead of flying a revenue flight on a 737MAX, they happened to be in a simulation session on an 737NG, and they were given stick shaker and airspeed disagree at rotation, how do you think the check airman would have rated the subsequent performance? Would he have said "Gee, too bad that stick shaker was annoying you. I'll forgive your failure to execute any of the required checklist items. You're cleared for another 6 months."

Last edited by slacktide; 4th May 2019 at 05:53.
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Old 4th May 2019, 06:41
  #4849 (permalink)  
 
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Excellent rant wonkazoo,
Startle, long or short duration, according to the perceived situation, according to personal disposition, experience; Experience, again questioning where this came from and how formed.

Startle can be reinvigorated, even continuous, particularly in situations where action taken for the situation does not improve conditions; not cure a ‘problem’, because the problem is more often unknown in startling situations. Then … if you follow procedures, (the essential items; don’t quibble about SOPs, nothing is standard when startled) the aircraft / system does not respond as you, design, or regulator expected.

http://www.icao.int/Meetings/LOCI/Pr...Strategies.pdf

http://pacdeff.com/pdfs/W%20Martin%2...esentation.pdf

http://www.flightsafetyaustralia.com...tartle-factor/

http://safetyforum.alpa.org/LinkClic...%3d&tabid=1004


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Old 4th May 2019, 07:30
  #4850 (permalink)  
 
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I suppose if Boeing "did everything right" they'll have a hard job justifying firing anyone for "doing something wrong" here?
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Old 4th May 2019, 07:35
  #4851 (permalink)  
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Fact is that even if your brain is short circuited by fear of death, that's exactly in those moments that pilots should be real pilots, I mean resource to INSTINCTS, BASIC INSTICTS.
A "pilot" who hears the tremendous noise of 500 knots (!) and doesn't even touch those tho things in the middle of the pedestal (also called trust levers) to pull them back.... well, should be doing another job (and I put it nicely)....
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Old 4th May 2019, 08:28
  #4852 (permalink)  
 
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All this grandstanding makes me wonder if some of you have been in an emergency, a real emergency?
I've been fortunate/unfortunate enough to have been in a few, albeit maritime, not aviation related.
Everytime I was surprised to see "highly trained professionals", and I mean highly trained, we had realistic training once a week for these eventualities, totally break down and be unable to function. I not talking 30 seconds, 90 seconds, but unable, period.
Aviation is of course a totally different ballgame.
Per
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Old 4th May 2019, 09:25
  #4853 (permalink)  
 
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slacktide @
His research indicates that impairment can last for up to 30 secs following a strong startle event.
When you discuss research or complex engineering it would be necessary to share and discuss definitions first. That by itself is not simple thing in a forum format. In order to do it right I imagine that you would need a constant exchange of combinations of 'post+attachments'. Most research has a strict scope. So I sincerely wonder what your definition of "startle" is (how it combines with other effects). And it would be interesting to have a link to a public document of your Dr.

"Startle" basically suggests a 'short duration' experience/event. Your answer and that research does not seem to cover short and longer duration 'freezes'. And short and longer duration 'confusion'. Let alone other short, mid and long term effects.

Some of the other posters have shared and explained experiences that indicate that there is more than what you seem to suggest.

What strikes me in some posts on this thread is the absolute 100% conviction that some seem to reflect. I have been in situations where my life was directly threathened and also in situations where people got a heart attack while driving. In all cases I reacted very good ... did a number of the right things and did them right ... But what I saw around me made it clear to me that there is a lot of grey in between the black and white. And that when such a situation would happen again that I myself included and others should and could not expect to react in the same manner. I think that is what some of the posters appear to want to share. And the apparent or even clear rejection of that experience may explain some of their emotion.

We would all agree that training is at the least very important. But, I also note that there are things that can be improved by training but not to a 100% success. An interesting old example used to be research in the military. You train infantry soldiers with 100% heavy loads. But when they fired rounds over their heads they could only lift 50%. It is well researched that the body can take over. Elite soldiers are trained in more challenging and dangerous settings, so training helps a lot. But even elite soldiers die,both in training (even SAS) and in daily and combat ops. So no 100%. Planes are designed toward 100% safe but I never heard an experienced designer say that he is 100% sure.
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Old 4th May 2019, 09:34
  #4854 (permalink)  
 
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Originally Posted by LEM View Post
Fact is that even if your brain is short circuited by fear of death, that's exactly in those moments that pilots should be real pilots, I mean resource to INSTINCTS, BASIC INSTICTS.
And how do you suppose we *should* go ahead and make sure we got people with the "right stuff" up front? Are you suggesting we simply strap trainees into an actually crashing plane and see if they can save it by using their superior instincts? You can't know things that cannot be effectively tested and anyone who thinks they will certainly keep functioning rationally and effectively in an incident is kidding themselves.
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Old 4th May 2019, 09:39
  #4855 (permalink)  
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Originally Posted by LEM View Post
Fact is that even if your brain is short circuited by fear of death, that's exactly in those moments that pilots should be real pilots, I mean resource to INSTINCTS, BASIC INSTICTS.
A "pilot" who hears the tremendous noise of 500 knots (!) and doesn't even touch those tho things in the middle of the pedestal (also called trust levers) to pull them back.... well, should be doing another job (and I put it nicely)....
LEM, with the greatest stretch of the imagination, I just don't see any part of Part 61 or the MOS that requires heroic competency to be present in all aviators seated forward of Row 1. It may be nice to find, and it does occur occasionally, but the system cannot depend on heroic intervention to make up for stupidity in the fundamental design. Part 25 expressly demands that extreme levels of competency, heroics etc must not be relied on to save the day, and that is the fundamental problem with where the industry finds itself with JT610, and ET302. I don't object to people maintaining skills at a high level, in fact that he highly desirable, but it is not what the industry has achieved or demands, and on occasion, it has bitten back, as it did with AA587.

The industry has a bit of a problem, and that is not going away anytime soon. The explosive growth of the industry and the nonsensical regulatory environment result in the current training and recurrent matrices, that cover the obligatory requirements but are not going to achieve exceptional levels of competency leading to legendary aerial feats; the training, system and design needs to be robust enough to achieve an acceptable level of risk for the industry, and that is the problem at present.




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Old 4th May 2019, 09:42
  #4856 (permalink)  
 
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Per,

Both you and wonkerzoo speak the truth with the authority of having been there. I was subjected to a particularly nasty emergency very early in my flying career. Although we did a number of things wrong, we survived. It made me re-think many things about aviation, the most important being how one may react when something totally unexpected, outside any previous normal training regime, suddenly 'hits one in the face'.

It not only made me study much more diligently everything I could find out about the aircraft I was flying and about aviation in general, but it also led me to studying all the books I could find on the psychology of human reactions to fear and excessive workloads. The so-called 'startle effect' was not known by that name in those days, but my reading made very clear the way in which the primative part of the human brain can take over in extremis. Good training definitely helps to combat this, but, as Per has said, even the best trained individual can falter.

However much we study and behave and train as professionals, even the coolest skygod may find he has feet of clay.
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Old 4th May 2019, 09:52
  #4857 (permalink)  
 
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Originally Posted by alf5071h View Post
Excellent rant wonkazoo,
Startle, long or short duration, according to the perceived situation, according to personal disposition, experience; Experience, again questioning where this came from and how formed.

Startle can be reinvigorated, even continuous, particularly in situations where action taken for the situation does not improve conditions; not cure a ‘problem’, because the problem is more often unknown in startling situations. Then … if you follow procedures, (the essential items; don’t quibble about SOPs, nothing is standard when startled) the aircraft / system does not respond as you, design, or regulator expected.

http://www.icao.int/Meetings/LOCI/Pr...Strategies.pdf

http://pacdeff.com/pdfs/W%20Martin%2...esentation.pdf

http://www.flightsafetyaustralia.com...tartle-factor/

http://safetyforum.alpa.org/LinkClic...%3d&tabid=1004
Thanks for the interesting links, which together shed some light on the current discussion.

I would add another factor, the difference between procedural memory and semantic memory. Pilots will have been repeatedly trained to do certain procedural operations on NG simulators, which become part of ingrained muscle memory. With the introduction of the B737 MAX, there were insufficient simulators. Differences training was done on a computer, which became part of factual recall memory.

IMO the combination of procedural training on a B737 NG, plus semantic training of the MAX differences, may create a mental conflict in determining the right choice of actions. The addition of stress factors, would make the failure to respond correctly much higher.

Reference: Declarative Memory (Explicit Memory) and Procedural Memory (Implicit Memory) - Types of Memory - The Human Memory
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Old 4th May 2019, 10:10
  #4858 (permalink)  
 
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UAS recovery in particular needs to be a reflex response, (like trimming, or immediately dipping the nose if the stall warning goes off), but it is not trained sufficiently in my view. I don’t always monitor both speed tapes when PM as we climb out on busy or complicated departures but I definitely should.

In the light of this accident and other fatal accidents in the last few years; every SIM session should have a mandatory event which requires ignoring everything else and reverting to basic pitch and power - not pre-briefed or even mentioned; just sprung on every crew at any moment, any phase of flight.

Regarding surprise reaction; We once had the overspeed warning go off in a Dash 8, because PM had missed bringing the flaps up owing to radio calls and a very busy departure. This beeping was going on for about 40s before we both realised what it was. Not proud to admit that at all, but these things happen.

I’m sure this will have been mentioned, so apologies but, is there an AoA disagree warning on the 737?

Last edited by Uplinker; 4th May 2019 at 10:22.
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Old 4th May 2019, 10:40
  #4859 (permalink)  
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uplinker #4860
I’m sure this will have been mentioned, so apologies but, is there an AoA disagree warning on the 737?

The $80,000 upgrade, and the warning that got lost in the mystery of not having that upgrade, will, I hope, become a courtroom issue.
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Old 4th May 2019, 11:25
  #4860 (permalink)  
 
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Originally Posted by Ancient Mariner View Post
All this grandstanding makes me wonder if some of you have been in an emergency, a real emergency?
I've been fortunate/unfortunate enough to have been in a few, albeit maritime, not aviation related.
Everytime I was surprised to see "highly trained professionals", and I mean highly trained, we had realistic training once a week for these eventualities, totally break down and be unable to function. I not talking 30 seconds, 90 seconds, but unable, period.
Aviation is of course a totally different ballgame.
Per
I agree with your observation. I think we all aspire to function well under severe pressure or danger. The truth is even we cannot predict how we will operate under intense pressure let alone how somebody else will perform. Training does help, provided it is sufficient to make the actions required second nature but still does not recreate the pressure of facing death. I have been in a number of high stress situations and in hindsight performed reasonably well in two but failed miserably in another resulting in the death of a friend. My father was an resistance fighter during WWII and was accustomed to life and death situations for over 4 years of his life continuously. I always admired his ability to function under the most intense danger and pressure... but there is no training that can replace experience. Many people luckily do not have the benefit of observing themselves in the most extreme of circumstances.

I too have witnessed well trained peoples minds become empty and acknowledge all the training in the world cannot predict a poor reaction to the ultimate stress. From my own experience I can say that in the two circumstances that I performed well, I immediately had a clear crystalized understanding of what was required. In the event that I did not perform well, I was unsure of the best course of action at the time. What I find difficult to read in this thread are people that have assumed what happened and assumed that it was immediately clear to the pilots what was required. Flying pitch and power is a little more stressful when you are a few feet AGL. I will reserve judgment on the pilots until further information is available and even then do not believe that Boeing should have ever placed them in that situation.
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