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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 25th Mar 2016, 09:39
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185kts is the ground speed. During the last moments the aircraft would have been doing around 320-330kts at impact.
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Old 25th Mar 2016, 09:56
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One consideration I have not yet seen anything about is the weight and balance issue ie how the payload was distributed.
A 30% load factor, if not distributed through the cabin appropriately can lead to extreme trim conditions on any aircraft type. And I mean where passengers were actually sat as opposed to how the load sheet shows them to be. Baggage, in common with most LoCo operators was probably light and misloading of these alone would probably not make much difference but in combination with wrongly sat passengers it could make a difference. A poor physical trim of the aircraft could well contribute to any subsequent handling difficulties, as being discussed predominantly on this thread.
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Old 25th Mar 2016, 10:25
  #643 (permalink)  
 
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Rachman,

That is not correct.

On several types, including for example B744, seating of passengers has no effect on mass & balance calculations.

B737 is also not that critical by the way.

The aircraft seemed to be accelerating to flaps-up speed when the upset occured. This might have nothing to do with a botched g/a, but with flight controls and icing.
What will be the effect of a wing when the Leading edge devices retract on schedule but the leading edge itself is seriously contaminated?...
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Old 25th Mar 2016, 10:30
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they went from a positive 4,000 FPM climb to a negative 15,000 FPM in about 6 seconds.
Is that true? That would mean almost 20ms^-2 AVERAGE accelaration i.e. -2g

EDIT: 737 seems to have a limit of -1g with the flaps down. And acceleration of 2 engines at full thrust on empty plane is only 0.58g
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Old 25th Mar 2016, 10:32
  #645 (permalink)  
 
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Originally Posted by Sciolistes
185kts is the ground speed. During the last moments the aircraft would have been doing around 320-330kts at impact.
A bit less than that, based on the FR24 data - about 275 kts - but we won't argue. Certainly enough to spoil everyone's day.
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Old 25th Mar 2016, 10:35
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6 deg on the ground, I think from the metar. Probably not icing on app and go around
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Old 25th Mar 2016, 10:57
  #647 (permalink)  
 
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I never thought I'd say this (and I know there are reasons for RT) but RT is doing an excellent job at reporting on the fatigue problem in UAE airlines.
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Old 25th Mar 2016, 11:01
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Yes, yes PKP, but they had only climbed to 3500' . Air at that point only just getting to 0 deg (CB not withstanding) Thanks for the mountaineering advice....
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Old 25th Mar 2016, 11:16
  #649 (permalink)  
 
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My concern is not so much icing during the approach or G/A itself, but accrued icing during the approach preparation in the hold and vectors towards the ILS.

Time over time again, I have seen crews putting faith on the " wiper/bolt" ice indication to estimate wing icing. This is completely wrong and extremely dangerous. Still, some people even teach this during line-training

To me, the upset occured at the moment that the Leading Edge Flaps/Slats became UP. This rings an alarm bell to me.
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Old 25th Mar 2016, 11:49
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Any similarity between the BA Boeing crash at LHR and this event in terms of fuel ice crystals, waxy fuel, fuel pump failure and thrust failure?

Fuel line/pump/system commonalities across the fleets?

The only time I've seen a 737 fly like this was a SE go-around that was not caught in time and over she went.

Perhaps an engine failure in the GA due the above?
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Old 25th Mar 2016, 11:55
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Time over time again, I have seen crews putting faith on the " wiper/bolt" ice indication to estimate wing icing. This is completely wrong and extremely dangerous. Still, some people even teach this during line-training
It seems the instructors are putting too much faith into the FCOM info that states:
Wing Anti-ice Operation - In Flight
Ice accumulation on the flight deck window frames, windshield center post, or on the windshield wiper arm may be used as an indication of structural icing conditions and the need to turn on wing anti-ice.
It seems pilots seem to use to wing light more to put it in your face than using it for its original purpose.
That said,newer models do have an icing caution light to alert crew while icing is being accumulated.
I believe the 737 was certified up to 3 inches of ice without controllability issues.
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Old 25th Mar 2016, 11:59
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Perhaps an engine failure in the GA due the above?
Such failures are the most trained in sims...doubt they would be caught on it.
However stall recoveries do not seem to be...last line if
defense to manual flying issues.
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Old 25th Mar 2016, 12:15
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Remember the airframe is super cold after a long flight and holding. 6 degrees on the ground in those conditions would provide perfect conditions for ice accrual in flight IMHO.
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Old 25th Mar 2016, 12:46
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Is that true? That would mean almost 20ms^-2 AVERAGE accelaration i.e. -2g
Newton is turning in his grave...
That's simple physics a = dv/dt.
(hope moderators agree to kill this myth of large negative gees)


The graph of vertical speed is almost a straight line, therefore the acceleration "a" was almost constant for that segment. What that means? The PF didn't move the column control or the aircraft control system didn't respond.
I would put my money on possibility that PF passed out. The PM had very little time (10-12 sec) to notice and react, possible he was watching the middle console running checklist or programing FMS.
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Old 25th Mar 2016, 14:03
  #655 (permalink)  
 
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Remember the airframe is super cold after a long flight and holding. 6 degrees on the ground in those conditions would provide perfect conditions for ice accrual in flight IMHO.
Nope,irrelevant.
The only ice accretion due to long flight would be fuel frost on the top surface of the wing,very little if any performance issue.
The only reason of a stall would be,failure to engage AP while believing it was and not monitoring or reengaging the AP but not the AT, speed decaying after having manually reduced it to avoid flaps overspeed,or retracting flaps without a speed increase..possibly only using speed trend rather than actual speed.
In any case ,a stall warning gives enough time to react and perform the necessary maneuver unless of course both crews are tired,slow to respond and worse react in the opposite manner than necessary.

Very easy to fix the schedule issues,,,make it a legal requirement to limit change of circadian rythm each month...but hey that costs money ...
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Old 25th Mar 2016, 14:13
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Originally Posted by Old Boeing Driver
Just for info. Check this video of a deep stall in the 737.

https://www.youtube.com/watch?v=kkYXhLwlHrg
That is in a simulator that is so far out of its certified flight envelope that it has nothing to do with what the real airplane would do.

It extrapolates somewhat and the behaviour may or may not be reasonable, but you can't use it "for info" on 737 stall behaviour.

I'd be surprised if anyone has flown a real 737 to 90 pitch angle just to see what happens and create data for a simulator.


Bernd
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Old 25th Mar 2016, 14:25
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Bernd

I realize it was in a simulator, and I agree unrealistic in real flying.

However, something happened very quickly when they went from a positive rate, to level, to a high rate of descent.

Early in my 737 career, we did approaches to stalls in the airplane, and flew them well into the stick shaker. No one ever went so far as to complete the stall to a break, but it was always interesting.

Regards.
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Old 25th Mar 2016, 14:36
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Closer analysis of the Rostov upper air ascent for 00Z 19 March 2016 (for what it is worth!) reveals to me the following air temperature readings at the bottom:

Surface +5.2C
2063ft +0.6C
916mb (c2333ft) -0.3C
4275ft -2.3C

FZ level c2200ft
At 180 knots the ram rise would be about 4 deg C so "practical"height of 0 deg c isotherm would be higher than this.
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Old 25th Mar 2016, 14:40
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Originally Posted by PKPF68-77
A typical temperature lapse rate is 0.6C per 100 metres.
You do not have to be very high to get below freezing with a surface temp of 6C.
Just ask the mountaineers in your country if you do not believe airmen.
Yes, 0 degrees at about 1000 m above AD.
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Old 25th Mar 2016, 15:06
  #660 (permalink)  
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Originally Posted by 737er
If their rumored rosters are correct then I think fatigue will also be a serious factor on this one especially considering how their day way going. Lots of stuff going on when you are holding for bad weather and getting close to bingo fuel. Like someone else posted, math you can normally do in your head all of a sudden requires a calculator and tests show it has as a serious effect as being drunk. Reflexes slow. Instrument scan slows markedly. Stuff you do almost reflexively when well rested requires pause and much extra thought. Fighting off tunnel vision becomes a personal war.
Indeed. To some extent someone can realise their performance is dropping off, though not necessarily quite how much. And then what can they do about it?

A couple of pages ago someone said it was simply not professional to fail to find ways to avoid this.

I thought that was a bit unsympathetic. I replied, a bit long-windedly, to the effect that whilst a car driver can stop at the next rest area, that can hardly be suggested as an option for pilots.

My post has been removed, but I still wonder what that person was thinking of. There was something about possible adrenaline rush keeping people alert for a while, but without corresponding mention of detrimental effects as it wears off.
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