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B-738 Crash in Russia Rostov-on-Don

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B-738 Crash in Russia Rostov-on-Don

Old 28th Apr 2016, 07:33
  #1381 (permalink)  
 
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Rule 0: don’t crash.

It will be very enlightening if the full report produces some answers as to why an experienced crew managed to dive what appears to be a serviceable aircraft into the ground in conditions that were not that unusual. I expect we will get a lot of the “how” but be prepared for the possibility of very little “why”, apart from the obvious, e.g. loss of SA and 12 seconds of high-rate ND trim, which effectively sealed their fate.

There could be some clues in what modes the AFDS was in and whether it was being followed or not. There’s also the issue that what you need to do in a microburst (WEM) is very different to encountering positive wind gradient but all training goes into the first scenario.

Humans very occasionally behave irrationally for no apparent reason, probably due to the statistical nature of our neural networks. You can do the same task for years but one day you do it differently for no reason that you can ascertain; tiredness probably doesn't help, either. One also has to ask the question: “would the autopilot and autothrottle have done it better after a long flight and multiple missed approaches?"
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Old 28th Apr 2016, 09:38
  #1382 (permalink)  
 
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One also has to ask the question: “would the autopilot and autothrottle have done it better after a long flight and multiple missed approaches?"
How do you propose that it is engaged after 100% N1 was commanded ?
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Old 28th Apr 2016, 09:58
  #1383 (permalink)  
 
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I do not buy the crew fatigue hypothesis. I would be wide awake in a go-around, especially in bad turbulence and a unusual attitude.
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Old 28th Apr 2016, 10:04
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Latetonight, apparently you have been fortunate enough never to suffer fatigue.
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Old 28th Apr 2016, 10:34
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My thoughts exactly. It's a bit like saying " I don't buy being tired in the last km of a double marathon, I'd be sprinting my arse off".
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Old 28th Apr 2016, 10:52
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I do not buy the crew fatigue hypothesis. I would be wide awake in a go-around, especially in bad turbulence and a unusual attitude.
Fatigue does not mean being tired. Yawning does not mean being fatigue. Fatigued means possessing reduced brain function which is often only apparent in hight workload situations.
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Old 28th Apr 2016, 11:25
  #1387 (permalink)  
 
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How do you propose that it is engaged after 100% N1 was commanded ?
I leave the correct answer to someone type rated as I never flew the NG but if it’s anything like the older ones, arm the AT if it isn’t already, then choose from two taps on the TOGA switches, pressing the N1 button, LVL CHG, VNAV and probably some others.

My point was that if automation is available and would reduce the workload, thereby freeing up monitoring capability, it might be a good idea. It’s very possible that this accident wouldn’t have happened if the AP and/or AT had been engaged...
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Old 28th Apr 2016, 11:37
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So initial "pilot error" spin didn't gather momentum so now indirectly blaming pilots thru "illusion" theory thru planted reports.

latetonite

Use captain's roster as your itinerary to fly as economy passenger, when you reach home after one week immediately go on a overnight drive.
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Old 28th Apr 2016, 12:21
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My point was that if automation is available and would reduce the workload, thereby freeing up monitoring capability, it might be a good idea. It’s very possible that this accident wouldn’t have happened if the AP and/or AT had been
Good point big picture, but in my mind after TOGA button and a fist full of thrust in a light 73 there is little hope of being able to engage automation. Control yoke pressure has to be completely released which isn't going to happen when you are struggling to keep the nose from rearing up. Same as on the classic.
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Old 28th Apr 2016, 12:25
  #1390 (permalink)  
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You flew his roster, did you latetonight? For months on end? Don't judge unless you have been there.
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Old 28th Apr 2016, 13:30
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Good point big picture, but in my mind after TOGA button and a fist full of thrust in a light 73 there is little hope of being able to engage automation. Control yoke pressure has to be completely released which isn't going to happen when you are struggling to keep the nose from rearing up. Same as on the classic.
Initially, I agree with you, as it’s likely out-of-trim and somewhat of a handful. However, in the time it takes to get to 3,000’, one would have hoped for an opportunity to sort things out in terms of pitch trim and automation. Even if you just let go and engaged the autopilot, it would sort itself out to some degree - maybe not pretty but at least the stabiliser would be returned to a normal position for the stage of flight rather than trimmed into oblivion.

There was an excess of speed and thrust, so why was the response to pitch/trim down and reapply full thrust? This could likely give the answer but we may never know...
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Old 28th Apr 2016, 14:42
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Initially, I agree with you, as it’s likely out-of-trim and somewhat of a handful. However, in the time it takes to get to 3,000’, one would have hoped for an opportunity to sort things out in terms of pitch trim and automation.
Nothing makes sense with this accident.
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Old 28th Apr 2016, 20:16
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totally agree with Framer! The 737 is a blunt instrument in the wrong or tired hands. I guess all airplanes respond far better to smooth application of all controls AND power.

Never been a fan of giving it a handful....
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Old 28th Apr 2016, 20:40
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But you are forgetting these guys were not novices and they'd done it before. The u$64,000 question is "why was it done differently and like a novice?"
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Old 28th Apr 2016, 22:42
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However, in the time it takes to get to 3,000’, one would have hoped for an opportunity to sort things out in terms of pitch trim and automation. Even if you just let go and engaged the autopilot, it would sort itself out to some degree
I see what you are saying but I don't think it is practical in this particular circumstance.
I departed two weeks ago at a weight close to what they would have been ( mid fifties) and even with a reduced climb thrust I was holding significant forward pressure on the yoke as we cleaned up and held nose down trim for two or three seconds continuously. That is normal, but I would not have liked to let go of the yoke in order to engage the a/p prior to adding an appropriate amount of trim. This situation would have been much worse because of the thrust applied. What I am saying I guess is that I don't think automation should be used to get out of a situation. It's a great tool to use and may prevent you getting into the situation, but once you are there ( 100%N1 18 degrees NU in this case) then stabbing at buttons is not the answer.
I think this comes down to the PF's brain operating in a degraded mode due to fatigue, which lead to inappropriate actions which then could not be recovered from.
The antidote to illusions is fast reliable mental processing of the visual information presented on the PFD, with good training this counters the 'seat of the pants' illusion. If you are processing information slowly or not at all, the illusion is all you have to act on. So if they do run with an 'illusion' it still suggests fatigue in my mind.
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Old 28th Apr 2016, 23:05
  #1396 (permalink)  
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I get what you're saying Framer but if it's the last resort, or one of, then podging the AP button might just save the day. It would be counterintuitive and it would take a firm frame of (unfatigued) mind and an awareness of "I've lost the plot" to do in a nose high snafu. But if the worlds falling apart around your ears and you can sort it out then I say podge away.
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Old 28th Apr 2016, 23:20
  #1397 (permalink)  
 
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Yeah fair enough. I have a reluctance to see this viewed as an automation management problem as opposed to a fatigue problem I guess. Hopefully time will tell.
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Old 28th Apr 2016, 23:54
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Possibly it's a bit of both.
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Old 29th Apr 2016, 05:25
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... but if it's the last resort, or one of, then podging the AP button might just save the day.
Autopilot won't engage if the trim is too far out.
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Old 29th Apr 2016, 08:52
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FGD135: Almost correct.

On the B737 it's the case that one can only engage an autopilot if there is no control loading on the yoke.

It is for that reason (on the B737 for sure) that it's the PF that selects / presses the autopilot button (as opposed to asking the PNF to do it) as only the PF knows if any pressure is being applied (by himself/herself) to the yoke. Indeed, the engaging of an autopilot is (or should be) the only time that the PF ever makes a selection on the MCP when they are the PF (i.e. during manual flight).

If the PF is applying any kind of control loading to the yoke (e.g. because the aircraft is out-of-trim) then the autopilot will not engage.

The Boeing B737 FCTM also states: "The airplane should be in trim, and the flight director commands should be satisfied before autopilot engagement. This prevents unwanted changes from the desired flight path during autopilot engagement."

For a prime example of f'ing up the activation of an autopilot, look no further than the Ethiopian (ET409) B737 crash out of Beirut on 25th Jan 2010.
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