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

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.

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.

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

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

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.

(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.

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.

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.

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

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

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

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 ...................

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.

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".

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.

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:

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.

Remaining fuel
 

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

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)

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....

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?

Although the flight surfaces on the CRJ are hydraulically actuated, there is no computer in between the pedals and the control column deciding weather the crew are flying safely or not and maybe just making matters worse such as on other FBW aircraft I know. So the flight surfaces should have done exactly as commanded.

What are the chances of a scenario like UA232?

possibly any water at the bottom of the crater mixed with residual jet fuel. Thus they had to pump out the mixture before working to retrieve important bits. Nothing significant about this

Never "assume."

cf: https://en.wikipedia.org/wiki/Confirmation_bias

Assuming that the linkage was not jammed by a foreign object such as a tool or frozen water/deicing fluid.

Concur.

Or the AP was not engaged, as thats a 'computer' with a degree of authority over the flight controls. Or the stall protection COMPUTER didnt decide to do something. Or the Horizontal STabilizer Control Unit, likewise.

The number of aircraft where there isnt a computer of some kind involved nowadays is pretty small ....

Swedish AIBN wil have to wait for summer for any further recovery attempts.

NRK: Will have to wait until the ground thaws (Google translate)

It think the crash site is about at right distance for descent initiation.
Is it possible cargo shifted forward once aircraft pitched down?

I believe a CRJ 200 is highly sensitive to load distribution but I'm sceptical it could be loaded with a c of g so far forward that elevator control became impossible. Bear in mind that at forward C of G limit there is enough elevator authority to rotate or flare the aircraft at takeoff or landing speeds and in the cruise the elevator will have dramatically more authority (forces proportional to square of speed, subject to actuator/structural limits and altitude density effects). It was apparently carrying mail. Unless there was a cartoon lead ball, which didn't roll backwards under acceleration and pitch up on takeoff, it seems unlikely. But someone with a CRJ load schedule can probably determine a realistically bad load distribution and corresponding moment and comment...

In other words you mean less elevator authority ika? Low IAS at cruise level methinks.:ooh:

If the V/S reports are close to accurate then it seems inconsistent with a prolonged stall condition similar to other recent mishaps. The V/S seems just a bit too high... if we have 9000fpm then thats around 79kts and assuming a 45 degree path vector with forward speed of 9000 as well that gives us an aircraft speed of 111 knots. Now the IAS at higher altitude may be in stall territory but as they got down to lower levels then there should have been enough speed to give enough control authority to correct without losing more than a few thousand feet or less.
That is until you start considering other factors such as spatial disorientation and other human factors that have led to loss of control in other accidents.

One other CRJ crash I'm thinking about is the one where a couple of pilots on repositioning flight decided to try their hand at being test pilots and flew themselves right off the backside of the power curve, stalled the wing, cooked the turbines, and were never able to restart, and then ran out of altitude to make a runway. Yet there are still more differences than similarities here as the final impact in this crash seems much different as well the crew seeming to have a more catastrophic problem since they didn't have time to get more than a single mayday off.

Considering the location, there is a lot riding on getting the recovered memory modules to reveal their secrets.

That hole is not a stalled aircraft hole.

That is a very high speed near vertical hole.

AH reports today:

I sure hope they can get useable data from the recorders - if not it's going to really hard to determine much from what little is left of the aircraft :sad:

What sorry dog said! Sorry for not being clearer; air may be thin and IAS not that high at 33,000 feet but pretty soon after you start diving earthwards IAS and control authority will go up. There's a general surmise (not conclusive) from the images and other data that it went in fast, nose-first, in one piece rather than a stall or in flight break-up. At some point, let's say 15,000 feet, assuming (for this only) pilots were not incapacitated or disoriented, heading nose down at a fair pace, if one had functioning controls one would expect to pull up as far as possible (and as necessary throttle back). I don't know about others but if controls worked but a forward c of g hindered pull up, faced with the grim choice of the certainty of what the looming ground means versus the possibility of overstressing the airframe I'd probably spend my last 60 seconds pulling hard back until either the nose stopped pointing at the ground or the elevator came off! Since they haven't located separate debris suggesting elevator detachment/damage it suggests to me that a c of g issue alone is unlikely. Some form of control issue, whether trim runaway, multiple hydraulic failure etc and/or a crew incapacitation issue must be considered, in my humble view. But feel free to disregard. I suspect most will agree, apart from the tragedy, is that it is both very curious and, unless the memory proves recoverable, unlikely we will know.

If part of the elevator (or tail) departed at high altitude, it could potentially be many miles from the (main) crash site. Given the remoteness of that whole area, such relatively small part(s) might not be located for months or even years.
I'd think that since they were able make a Mayday call, crew incapacitation would be unlikely, but as pattern_is_full noted, never 'assume' anything.

Having flown this type for many, many years, I can say a HS failure/runaway was probably my biggest concern.

This is a quality-made airframe and engine combination, but the electronics/trim switch/elevator feel system left a lot to be desired.

"The electronics/trim switch/elevator feel system left a lot to be desired."
Thanks, FIRESYSOK. Good to hear from someone with experience in the type.

@Machinbird

I'm glad you clarified ...

In my earlier days, the term was code for "erase the tapes" :suspect:

Likely Stab Trim Runaway
 

Having flown both CRJ's and SE-DUX in its post cargo mod, I have to agree with the Stab Trim Runaway hypothesis. I haven't flown a 200 since 2011 but I know there was an SB or AW published after a couple of runaways in the U.S. a few years back. Whether DUX ever had it done will soon be revealed.
If I recall correctly the loads from OSL to TOS cubed out before they weighted out and were very well secured with a very simple system. In level flight or even in a normal 3 degree descent, the chance of trolleys coming loose was next to zero.

Re: post 78. Sometimes, someone posts something really good here. This is one of those times. Thank you.