PPRuNe Forums

PPRuNe Forums (https://www.pprune.org/)
-   Rumours & News (https://www.pprune.org/rumours-news-13/)
-   -   CRJ down in Sweden (https://www.pprune.org/rumours-news/572882-crj-down-sweden.html)

The Ancient Geek 9th Jan 2016 18:35

FWIW
The contents of the mayday call they reportedly made should have given the investigation team some early clues.

er340790 9th Jan 2016 18:55

I was struck by the similarities with the relatively small but deep impact craters left by those 1990s 737 rudder-hard-overs and the Flight 93 757 that crashed at Shanksville on 9/11.

Apparently the total obliteration of the aircraft is not just due to the speed and angle of impact. As the aircraft noses deeper, the rear sections are met by rebounding shattered wreckage from the front of the aircraft, blasting back out of the crater, the combination of these forces is what practically pulverizes all material.

Any parts located are going to be small. Very small. Black boxes included.

Tu.114 9th Jan 2016 20:57

However, on the Germanwings crash site in the Alps, both the recorders were found mostly readable. This was a rather high energy impact as well.

merkurius 9th Jan 2016 21:04

Elevator runaway
 
This is an open question to all operating crj pilots how to recover elevator runaway trim on high level cruise?

All my thoughts to the involved familys. RIP

MrSnuggles 9th Jan 2016 21:29

Information from Haverikommissionen (SHK), the Swedish equivalent to AAIB/NTSB/BEA. This link will be updated as the information comes in:

Utredningar - Olycka i Lappland med flygplanet SE-DUX av typen Canadair CRJ 200


Under lördagen har den ena av de svarta lådorna (FDR) hittats. Den är kraftigt demolerad och SHK:s tekniska utredare arbetar med att undersöka om minnesenheten är intakt. Enheten kommer därefter att transporteras till ett laboratorium där informationen kan läsas ut. Det kan ta någon vecka innan detta är gjort.
Delar av den andra svarta lådan (CVR) har också hittats. Den enheten är däremot inte intakt och den del som innehåller minnesfunktioner har ännu inte hittats. Arbetet med att hitta återstående delar kommer att fortsätta.
My translation:

During Saturday, one of the black boxes (FDR) has been found. It is seriously damaged and the technical investigators at SHK are working to find out if the memory unit is complete. The unit will after that be transported to a laboratory to read the information. This could take another week.
Parts of the other black box (CVR) has also been found. That one is not complete and the part containing the memory module has not yet been retrieved. Work to find remaining parts will continue.

cappt 9th Jan 2016 21:58


Originally Posted by merkurius (Post 9233710)
This is an open question to all operating crj pilots how to recover elevator runaway trim on high level cruise?

All my thoughts to the involved familys. RIP

(1) Control wheel ....Assume manual control and override runaway.
(2) Both stab trim disc... Press, hold, and release.

There's more but these are the first steps.

MrSnuggles 9th Jan 2016 22:38

I have not heard nor seen any reference as to what was said in the mayday call. I'd really like to know. Will update as soon as I find out.

This is a very strange crash, not many planes have accomplished such an obliteration, the biggest pieces are around 50cm diam so far. It was a very nose down attitude.

Rescue teams pumped about 200kgs of jet fuel from the hole made by the plane.

It seems like the whole plane is accounted for, nothing indicates that something (wing/elevator/etc) fell off the plane. The hole is not yet explored though, hopefully new information will emerge tomorrow, Sunday, when they will try to dig. There are obstacles for the snow mobiles so the only way in and out is via helicopter so everything has to be flown in. Weather is still -20C or worse, winds are varying so add a good amount of wind chill to that. Good thing is that it has not been snowing so everything is smooth working.

AAKEE 10th Jan 2016 10:30

For the mayday call, it said somewhere in media that it was just the mayday, without ny further information in the transmission. Of, corse, media isn't that reliable at all times. I'll see if I can find a link.

skadi 10th Jan 2016 15:41

Both memory modules of CVR and FDR were found saturday resp. sunday

Investigations - Accident in the arctic north of Sweden to a Canadair CRJ 200 aircraft (SE-DUX)

skadi

valkyrie42 10th Jan 2016 15:48

..........And sadly human remains may they RIP

Se NRK:s unika bilder från olycksplatsen - Nyheter | SVT.se

Yankee Whisky 10th Jan 2016 15:59

Cappt reference posting
 
Quote;"(1) Control wheel ....Assume manual control and override runaway.
(2) Both stab trim disc... Press, hold, and release.

There's more but these are the first steps. "




(Manual control) At any speed ? Including cruise ...................

Machinbird 10th Jan 2016 18:43


(Manual control) At any speed ? Including cruise ...................
I think he means direct human control instead of through the autopilot. Not un-boosted elevator control (If that is even possible in a CRJ).

For those postulating complete loss of the HS scenarios, you can probably discount that accident chain. Yes, the aircraft would pitch nose down initially, but it would continue pitching, much like the Metrojet crash, and the impact would be with much lower energy.

With any high speed departure of a THS equipped aircraft from level flight, Mach-tuck could make it harder to recover and would probably require judicious use of HS trim if it got into that range-but that is all theoretical test pilot stuff. There is also the Hoot Gibson maneuver that can be used to shave off unwanted speed. (Dropping the Gear) Results not guaranteed.

Mad (Flt) Scientist 10th Jan 2016 21:20


Originally Posted by Machinbird (Post 9234526)
I think he means direct human control instead of through the autopilot. Not un-boosted elevator control (If that is even possible in a CRJ).

CRJ elevators are fully hydraulic, multiple actuators per surface, no manual reversion at all. So yes, "manual control" in this context means "hands on the controls".

cappt 11th Jan 2016 01:14

Yes any speed.
When you say elevator runaway on the CRJ it is actually a stabilizer trim runaway as that is what is trimmed for flight.
The CRJ has a movable horizontal tail in which the entire horizontal stab is trimmed as needed for flight. The Elevators attached to the rear of the stab can overcome a runaway trim situation. The elevators and rudder are powered by all 3 hydraulic systems (1,2,3). Three PCU actuators (1,2,3) are on each the rudder and elevator. In the event of one bad PCU actuator the other two will overpower the bad one.

zac21 11th Jan 2016 02:54

Fuel remaining ?
 
Could somebody please explain how is it possible that jet fuel could be 'pumped out of the crater' after such impact ?
I find it extremely hard to believe that either 200 litres or 200 KG of jet A1 could remain :confused::confused::confused:

Machinbird 11th Jan 2016 04:01


Could somebody please explain how is it possible that jet fuel could be 'pumped out of the crater' after such impact ?
I'll try,
The best explanation has to do with the fact that there was very little horizontal velocity at impact and that some wreckage undoubtedly remained in the crater. Being a liquid, the fuel could lodge itself along the earth/snow at the sides of the crater and not be ejected by the rebounding earth and wreckage in the center of the crater. Later, it would drain downward and collect at the bottom. It appears to have been a very small fraction of the fuel load.

I once investigated another crash where the aircraft impacted nose down & wing down with some horizontal velocity. There the fuel load washed the fragmented wreckage out of the crater and distributed it systematically along the horizontal velocity vector.

zac21 11th Jan 2016 05:05

Remaining fuel
 
Thanks Mach,, but I still find it hard to believe " anything was remaining "

TwoStep 11th Jan 2016 13:13

The Swedish investigators say 1.5 cubic meters of liquid, mostly jet fuel was recovered. Isn't that 1,500 liters, not 200.

Investigations - Accident in the arctic north of Sweden to a Canadair CRJ 200 aircraft (SE-DUX)

Smott999 11th Jan 2016 13:21

Continental 2574?
 
Similarities perhaps with the Conti Express 2574 in Texas 1991?

Believe they lost a leading edge of the HS resulting in abrupt unrecoverable nose down....

Petercwelch 11th Jan 2016 15:08

Cargo problem vs. something broke
 
Can we assume that a problem with cargo e.g. Fire would have happened more gradually and not resulted in such a brief message and descent?


All times are GMT. The time now is 17:28.


Copyright © 2018 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.