Go Back  PPRuNe Forums > Flight Deck Forums > Rumours & News
Reload this Page >

B-738 Crash in Russia Rostov-on-Don

Rumours & News Reporting Points that may affect our jobs or lives as professional pilots. Also, items that may be of interest to professional pilots.

B-738 Crash in Russia Rostov-on-Don

Old 25th Mar 2016, 20:43
  #681 (permalink)  
 
Join Date: Jul 2004
Location: Found in Toronto
Posts: 615
Likes: 0
Received 0 Likes on 0 Posts
"Do not worry, pull!" as the aircraft nosed over into a dive.

The dive looks to me like Ice Contaminated Tailplane Stall and now the voice transcripts sound to me like Ice Contaminated Tailplane Stall.

Two men puling can override a runaway trim or stab, but all the pulling in the world won't recover from a stalled tail.
Lost in Saigon is offline  
Old 25th Mar 2016, 20:48
  #682 (permalink)  
 
Join Date: Jul 2007
Location: UK
Posts: 36
Likes: 0
Received 0 Likes on 0 Posts
Slightly better translation than google:

?????.Ru: ?? ????????, ????: ? ??? ?????? ?????? "??????" ?? ??????? ?? ????????



Today revision "Vesti" program has at its disposal information that leads us back to the recent disaster, "Boeing" in Rostov-on-Don. This interpretation of the last words from the CVR, a minute before the collision with the ground. The document is not official, from sources in the commission of inquiry, which shifted voice recorder information on paper. Without claiming to be the truth - it is only the investigation findings - Now we try to simulate the situation that prevailed before the disaster aboard.
Thus, Boeing-737-800 company FlyDubai in harsh weather conditions was not able to land in Rostov and the aircraft commander - 37-year-old Aristos Socratous decides to try to land a 2nd time. At this time, the autopilot is engaged. Time 1 hour 40 minutes 00 seconds GMT.

CVR transcript:
-‘Going around’
-‘Climbing to 50’
-‘Climbing to 50’

"Climbing to 50" – means climbing to height of 1500 meters. Boeing climbed at an angle of 15 degrees, it is normal mode. In these shots we see how the plane goes up, going beyond the view of the camera. Climbing continues on autopilot for 40 seconds. Before reaching this height, the commander disengages the autopilot. The reason is not yet clear.
Maybe the plane ran into atmospheric scissors (pilot slang), which could violently shake it. But exactly after this second, after the autopilot disconnect the Boeing dives to the ground.
And these are the words of transcripts translated us into the Russian language for clarity
01:40:40GMT“Do not worry, do not worry, do not worry!”
01:40:45GMT “Don’t do this, don’t do this, don’t do this!”
01:40:50GMT ‘Pull! Pull! Pull!
01:40:54GMT ‘Aaaaaa’

That is, the pilots could not do anything with the aircraft, which flew nose to the ground, such is the version of the experts.

By disabling the autopilot, pilot tried to bring "Boeing" in horizontal flight, but at this moment the stabiliser which is located at the keel went into ‘dive mode’. In this mode, the elevator is no longer effective and practical does not respond to control inputs. The pilots apparently did not realize that the sharp dive is responsible by the stabilizer.
The question is- why has the stabiliser switched to ‘dive mode’? This mode is activated by a button the pilots call ‘Knyupel’ That is, during turbulence by going into manual mode, the pilot could have accidentally activated the ‘knyupel’, and he did not notice, as he complained before about chronic fatigue. Otherwise - it is an unprecedented surprise from the automatic system.
During the last six seconds of the recording, according to our source, the screams heard were inhumane. We chose not to play them.
Plane crashes with acceleration at 1 hour 41 minutes and 00 seconds GMT killing all 62 people. Once again, the official conclusions about the causes of the disaster can only be made after the results of the investigation.
spitfire_sl is offline  
Old 25th Mar 2016, 20:53
  #683 (permalink)  
 
Join Date: Jul 2005
Location: btw SAMAR and TOSPA
Posts: 566
Likes: 0
Received 0 Likes on 0 Posts
The animation shows that the horizontal stabilizer is in the full down position when the autopilot becomes disconnected and cannot be countered by pulling the yoke.
threemiles is offline  
Old 25th Mar 2016, 20:59
  #684 (permalink)  
 
Join Date: Sep 2013
Location: USA
Posts: 84
Likes: 0
Received 0 Likes on 0 Posts
"catch the knyupel" I would assume means "bump the yoke". But that didn't really make sense to me in context because they were just previously talking about stab trim. And nothing related to stab trim in my mind could be translated as "joystick". Who knows.
core_dump is offline  
Old 25th Mar 2016, 21:01
  #685 (permalink)  
 
Join Date: Jul 2000
Location: Jackson Hole, WY
Posts: 7,634
Likes: 0
Received 3 Likes on 3 Posts
Autopilot stab trim motor malfunction?

"bump the yoke" could mean Control Wheel Steering reversion with AP engaged.
737er is offline  
Old 25th Mar 2016, 21:01
  #686 (permalink)  
aox
 
Join Date: Mar 2015
Location: UK
Posts: 227
Received 0 Likes on 0 Posts
For some reason, it seems that automatic translations render the word кнюпел only as a transliteration. It probably means button or lever.
aox is offline  
Old 25th Mar 2016, 21:08
  #687 (permalink)  
 
Join Date: Jul 2007
Location: UK
Posts: 36
Likes: 0
Received 0 Likes on 0 Posts
In the context of the video simulation, they refer to the knyupel as the button on the yoke on the left side.
From a the Russian language translation, it doest make sense to me and I don't know what they are referring to with regards to the knyupeli. I cannot guess what they are talking about. We have to take into account poor interpretation from the TV channel and representation of this data to the masses.
spitfire_sl is offline  
Old 25th Mar 2016, 21:09
  #688 (permalink)  
aox
 
Join Date: Mar 2015
Location: UK
Posts: 227
Received 0 Likes on 0 Posts
For some reason, it seems that automatic translations render the word кнюпел only as a transliteration. It probably means button or lever.
Solved: it was a misprint - put кнюппель instead in Google or translate

Seems to be joystick
aox is offline  
Old 25th Mar 2016, 21:12
  #689 (permalink)  
 
Join Date: Jul 2000
Location: Jackson Hole, WY
Posts: 7,634
Likes: 0
Received 3 Likes on 3 Posts
Button on yoke is probably referring to AP disconnect. Still doesn't make sense.
737er is offline  
Old 25th Mar 2016, 21:13
  #690 (permalink)  
 
Join Date: Jul 2005
Location: btw SAMAR and TOSPA
Posts: 566
Likes: 0
Received 0 Likes on 0 Posts
Knypel: The video shows that the commander triggers stab trim on the yoke.
threemiles is offline  
Old 25th Mar 2016, 21:15
  #691 (permalink)  
 
Join Date: Jul 2000
Location: Jackson Hole, WY
Posts: 7,634
Likes: 0
Received 3 Likes on 3 Posts
Is he trimming nose up or down?
737er is offline  
Old 25th Mar 2016, 21:23
  #692 (permalink)  
 
Join Date: Sep 2013
Location: USA
Posts: 84
Likes: 0
Received 0 Likes on 0 Posts
A captain once told me (jokingly, I thought) that one way to deal with runaway stab trim is to grab the _other_ guy's hand and forcibly jam it in the trim wheel. I'm not sure what kind of conversation would result in that event, but it sure might sound a lot like "Don't worry, don't worry." "Don't do this!"
core_dump is offline  
Old 25th Mar 2016, 21:23
  #693 (permalink)  
 
Join Date: Jul 2007
Location: UK
Posts: 36
Likes: 0
Received 0 Likes on 0 Posts
Just listening to the news report again:

quote: 'The 'dive mode' is activated by a button called 'knyupeli'

What the news report is implying is that the pilot could have accidentaly touched this 'knyupel' and not have noticed. Or this is a unprecedented act from the automatic system.

Im no 737 pilot, but i think the news report refers to the stabiliser trim button as the knyupeli, and that the pilot accidentally used it incorrectly because of fatigue, not realising the dive is cause by the trim button. Is such a thing possible?

Once again, im just translating. It doesnt make sense to me, and we have to account to news media dumbing down the raw data and not presenting it correctly.
spitfire_sl is offline  
Old 25th Mar 2016, 21:28
  #694 (permalink)  
 
Join Date: Jul 2000
Location: Jackson Hole, WY
Posts: 7,634
Likes: 0
Received 3 Likes on 3 Posts
One possibility: Autopilot on as thrust comes up on miss. 737 tends to try to pitch up strongly. If AP is on the AP must roll in lots of nose down trim to stay engaged. If it over trimmed nose down on the go around and they turned off the AP as they were pulling power off it could have been trimmed very nose down for new condition. I've seen this but not this extreme. The airplane pitches over abruptly and its quite startling.
737er is offline  
Old 25th Mar 2016, 21:29
  #695 (permalink)  
aox
 
Join Date: Mar 2015
Location: UK
Posts: 227
Received 0 Likes on 0 Posts
Originally Posted by 737er
Is he trimming nose up or down?
I haven't watched the video, but to retranslate the automatic translations given above, it sounds like they are suggesting the trim was accidentally moved fully or very forward without the pilots realising for a few moments.

edit: cross-posted with two posts above
aox is offline  
Old 25th Mar 2016, 21:30
  #696 (permalink)  
 
Join Date: Jul 2000
Location: Jackson Hole, WY
Posts: 7,634
Likes: 0
Received 3 Likes on 3 Posts
Thought of that too spitfire. I wonder if the stab trim brake system prevented them from manually trimming up with the yoke that far back.



° The stabilizer is held in position by a dual brake system. Either stabilizer brake can maintain the position set by the trim system. In the event of a dual brake failure, and without pilot response, airloads can drive the stabilizer to its mechanical stops. Main electric trim can resist this motion, but control column opposition will make the condition worse.

A Control Column actuated Stabilizer Trim Cutout Switch stops operation of the main electric and
autopilot trim when the control column movement opposes trim direction.
737er is offline  
Old 25th Mar 2016, 21:33
  #697 (permalink)  
 
Join Date: Jul 2005
Location: btw SAMAR and TOSPA
Posts: 566
Likes: 0
Received 0 Likes on 0 Posts
FDR data will show if stab trim was triggered from the flight deck or was a runaway.
Looks like full TOGA on a light aircraft, high GA platform altitude, excessive climb rate, still significant acceleration, lot's of energy involved.
threemiles is offline  
Old 25th Mar 2016, 21:34
  #698 (permalink)  
 
Join Date: Jul 2004
Location: Found in Toronto
Posts: 615
Likes: 0
Received 0 Likes on 0 Posts
I doubt it was runaway stab trim. It would be impossible to not see the trim wheels running to full nose down trim. If it starts to runaway, the cutout switched should stop it instantly.

https://vimeo.com/34501723

https://www.youtube.com/watch?v=ULCrAZyNk34
Lost in Saigon is offline  
Old 25th Mar 2016, 21:41
  #699 (permalink)  
 
Join Date: Aug 2014
Location: Montreal
Age: 53
Posts: 71
Likes: 0
Received 0 Likes on 0 Posts
Here is the video link on youtube (it doesn't come with dozens of advertisings)

https://youtu.be/kEjEGHYGh4A?t=125

It would be interesting to have the translation about stabilizer pitch down (at 2:06), it was commanded?
_Phoenix_ is offline  
Old 25th Mar 2016, 21:41
  #700 (permalink)  
 
Join Date: Jul 2000
Location: Jackson Hole, WY
Posts: 7,634
Likes: 0
Received 3 Likes on 3 Posts
Autopilot trim motor runs very slow and not very noticeable. Could be insidious. Manuel electric trim runs quick with flaps out.
737er is offline  

Thread Tools
Search this Thread

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service

Copyright © 2024 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.