Minnesota Crash

[Hank]

I'm leaning toward the funny wing shape being an artifact of the slow CCD sensor on the security camera. It starts scanning the image at the top of the screen, moving down one line of pixels at a time. During that time, the wing moved, just like when our spinning propellers get turned into wavy lines or venetian-blind-like objects. Never heard of anyone sending their prop out for overhaul because it looked curvy in a photograph. CCD images in modern cameras are completely unrelated to photographs taken with a real camera that focuses light onto film.

[carusoam]

Review of additional pieces of info….

Soooo much info coming in so quickly….

The Kathryns report really captures extensive detail….

including the NTSB interview.

and the best collection of ADSB data, better than flightaware for most data points available at the end of the controlled flight

https://globe.adsbexchange.com/?icao=acac80&lat=44.856&lon=-93.669&zoom=13.8&showTrace=2021-08-07&timestamp=1628375982

@1980Mooney is showing better ADSB data in his post above than I have captured here.  Actual flight data shown on the chart…

 

 

The flightaware data is about one point every minute or so…

The globe.ADSBexchange data is closer to every few seconds or so…

 

Expect that….

1) Something has caused the pilot to lose control in IMC

2) A high descent rate occurs

3) plane sheds parts of the tail

4) Wings fold and are shown post accident as two separate parts.

5) plane impacts the ground

6) It will be important for the investigation to know if CO, or exhaust system failure has anything to do with this accident…

7) Some tough weather close by, may be a consideration…

8) the order of this list may not be accurate….

 

PP thoughts only, not an accident investigator…

Best regards,

-a-

[DXB]

9 minutes ago, Hank said:

I'm leaning toward the funny wing shape being an artifact of the slow CCD sensor on the security camera. It starts scanning the image at the top of the screen, moving down one line of pixels at a time. During that time, the wing moved, just like when our spinning propellers get turned into wavy lines or venetian-blind-like objects. Never heard of anyone sending their prop out for overhaul because it looked curvy in a photograph. CCD images in modern cameras are completely unrelated to photographs taken with a real camera that focuses light onto film.

I imagine the scan here might be from the bottom since video appears to show the wings folding up before most of the fuselage disappears into the ground, if it was the hit to the ground that folded up the wings?

[Alan Fox]

I dont believe that the images are artifacts , Its not going to artifact just the wings and the tail , Those wings ARE folded up , both of them , The reason the plane hit at the attitude it hit is because the wind drag of the wings righted the aircraft , The fact parts were shed and fell seperately concludes a structural failure , No way Corrosion , Both the wings and tail would have to have been severely corroded , Sometimes things are exactly what they seem... The takeaway here is not the wings breaking , but the factors leading up to it....

[ragedracer1977]

1 hour ago, DXB said:

I imagine the scan here might be from the bottom since video appears to show the wings folding up before most of the fuselage disappears into the ground, if it was the hit to the ground that folded up the wings?

You're fooling yourself.  Somehow the camera distorted ONLY the wings?  The fuselage isn't distorted at all, even though it was moving in the same direction, but it somehow stretched the wings to exactly the length and shape they would be if they folded up? 

Listen to yourself. 

[Jerry 5TJ]

13 minutes ago, Alan Fox said:

The takeaway here is not the wings breaking , but the factors leading up to it....

Yes, the question I have is what caused the loss of control, not whether the structure failed after loss of control.  

[Will.iam]

Another logic to put a kink in an artifact theory is that the pitch attitude does not change through out the video. And the angle that airplane is coming down is nowhere near what forward flight would normally be if the wings were on normally. But if they were folded up you would get a greater speed vertically than forward. Remember that Air  France abus that crashed into the atlantic ocean a couple of years ago? It’s forward speed was less than 100 knots but it’s veritcal speed was in excess of 200 knots. I wouldn’t be surprised if the ASI will have an imprint at a speed much less than 80kts because it looks like an accelerated stall coming down way faster then moving forward as the crash site also confirms. The debris is not scattered a long distance as is common when you have forward speed it’s very short horizontally showing a very high vertical speed. folded up wings could give you a very high vertical with low forward or horizontal speed.  If this started at 2900 ft and the elevation is 900ft that is 2k to the ground. If they did get to 9600vvi down thats most of your horizontal energy changing to your vertical and would match the trajectory of the path in the video. Also that gives about 12ish seconds to impact and didn’t the adsb only gives an update every 15 seconds?  That could explain why no data points from normal to crash. If he did pop out of the wx disorientated and pulled back to try to save it wouldn’t there be at least another data point sent by the adsb before impact? 

[DXB]

36 minutes ago, Alan Fox said:

I dont believe that the images are artifacts , Its not going to artifact just the wings and the tail , Those wings ARE folded up , both of them , The reason the plane hit at the attitude it hit is because the wind drag of the wings righted the aircraft , The fact parts were shed and fell seperately concludes a structural failure , No way Corrosion , Both the wings and tail would have to have been severely corroded , Sometimes things are exactly what they seem... The takeaway here is not the wings breaking , but the factors leading up to it....

We agree the loss of control is much more likely to have caused any structural failure here than vice versa based on what is known.  But some seem convinced that the main spar snapped in the middle before the plane ever contacted the ground, whereas others are far from convinced. Do you think an uncompromised Mooney spar would break under the structural loads encountered after unrecoverable loss of control that happened fairly close to the ground?

[Yetti]

I am going with this.  When the plane first enters the video behind the 7 of the time code stamp.  The wings are in proper place.  You can see the top of the empanage.  Then the next position the wings are folded.  Then the next position the plane hits the ground.   It is common for the spilled coke to run back to the spar and do things to it.   Probably OK for normal flight.  Not OK for a hard pull up.

[chriscalandro]

Is it that unbelievable that the airplane broke up, or are some of you really that hard headed?

 

in the video, at least the left horizontal stab and elevator are missing. The wings are clearly folded up indicating that the spar snapped. 
 

a camera isn’t going to create artifacts like that. It’s not possible and that’s not what happened. 
 

What you see is what you’ve got. 

[EricJ]

I'm not seeing any video artifacts other than the usual less-than-perfect resolution due to the sampling and compression. 

It is starting to look like somehow the wing got pitched to an extremely high angle of attack at high speed, and perhaps that generated enough drag to snap the spar.   If it is that simple, I'd think it would have happened before.    I'm also still puzzled how it could happen, although, maybe the stab/elevator fluttering did that just as it was departing the airplane.

If so, it's not unlike the Galloping Ghost crash at Reno in 2011, where a trim tab failure pitched the airplane up and g-loc'ed the pilot.

There may be multiple factors at play here that we won't know for a while.

 

[Yetti]

2 blocks away is not that far.  So they probably separated just prior to impact.  I'm done speculating.   Very tragic event.  I feel for the families.  Not supposed to turn out this way.

[Shadrach]

46 minutes ago, EricJ said:

I'm not seeing any video artifacts other than the usual less-than-perfect resolution due to the sampling and compression. 

It is starting to look like somehow the wing got pitched to an extremely high angle of attack at high speed, and perhaps that generated enough drag to snap the spar.   If it is that simple, I'd think it would have happened before.    I'm also still puzzled how it could happen, although, maybe the stab/elevator fluttering did that just as it was departing the airplane.

If so, it's not unlike the Galloping Ghost crash at Reno in 2011, where a trim tab failure pitched the airplane up and g-loc'ed the pilot.

There may be multiple factors at play here that we won't know for a while.

 

What makes it all the more puzzling is that there’s absolutely no data in flight aware that indicate the aircraft was subjected to the speed nor the pitch change needed to generate the force required to compromise the  spar. 

Edited August 9, 2021 by Shadrach

[Alan Fox]

I dont believe that this is anything other than a wind shear event ,  A fighter pilot will lose conciousness at 8 Gs without a suit , I would guess a 70 year old man maybe 4 or 5 ,  The wings have been tested to 8 Gs without failure ,  Remember before you pass out , you will release the yoke , and unload the wing , So the event that broke the wing had to be extremely quick  , possibly hundreths of a second ,  Once the wing stalls , it also unloads ... 

 

[DXB]

56 minutes ago, chriscalandro said:

Is it that unbelievable that the airplane broke up, or are some of you really that hard headed?

 

in the video, at least the left horizontal stab and elevator are missing. The wings are clearly folded up indicating that the spar snapped. 
 

a camera isn’t going to create artifacts like that. It’s not possible and that’s not what happened. 
 

What you see is what you’ve got. 

It's not unbelievable that the spar snapped before ground contact but it's without known precedent for this airframe and thus worthy of close scrutiny before drawing the conclusion.  We have a good idea how the tail components can disintegrate in the air after loss of control - less so for this particular wing spar design unless it has severe pre-existing compromise.  The wing cannot conclusively be said to be compromised in the first frame though it cannot be excluded either.  The spar is clearly snapped in the second frame, though only the tail appears to be contacting the ground.  The details of the image capture technology used at the extreme speeds involved at that instant do have bearing on interpretation of whether the spar broke before or after striking the ground.

[Shadrach]

45 minutes ago, 1980Mooney said:

When you zoom in on the ADSB-Exhange map it shows data every second just before the crash. The last data point is about 200 ft from impact.

He lost 800ft in about two seconds... using round numbers that is 24,000FPM  (236kts) or roughly 1000fpm faster than the terminal velocity of a baseball sized steel ball.

[Shadrach]

2 minutes ago, DXB said:

It's not unbelievable that the spar snapped before ground contact but it's without known precedent for this airframe and thus worthy of close scrutiny before drawing the conclusion.  We have a good idea how the tail components can disintegrate in the air after loss of control - less so for this particular wing spar design unless it has severe pre-existing compromise.  The wing cannot conclusively be said to be compromised in the first frame though it cannot be excluded either.  The spar is clearly snapped in the second frame, though only the tail appears to be contacting the ground.  The details of the image capture technology used at the extreme speeds involved at that instant do have bearing on interpretation of whether the spar broke before or after striking the ground.

Perhaps not but losing 800ft in 2 secs with little increase in forward speed suggest the wings folded well out of the frame. The town is roughly 1000msl. He descended from 2200msl to 1100msl in 3 seconds. His forward speed actually diminished during the descent.

[bradp]

1 hour ago, 1980Mooney said:

When you zoom in on the ADSB-Exhange map it shows data every second just before the crash. The last data point is about 200 ft from impact.

If that ADSB track is correct the aircraft descended 1100ft in 3 seconds.  That’s a vertical speed of 22,000 fpm!  If start GS was 145 kias, and end was 121 kias (lost 24 kias ground speed).  If accelerating that loss was due to a vertical component of acceleration and the total velocity vector could still be increasing over time. 

So horizontal velocity vector was near 121 kts.  Vertical velocity vector was somewhere near 218 kts straight down.  Distance between the 5th ping and the 1st (last) ping is about 500 ft on the map.  
 

The descent angle vector was about 63 degrees down. Total velocity vector was an estimated (just estimated if I remember any basic physics ) -  250 kts at least if I plug it into a vector calculator ( @aviatoreb help request).  If we look at the ultimate load factor chart from the commercial pilot syllabus, we’d see that when Vne is exceeded structural failure can be expected to occur.  When Vne exceeded and a load factor applied (say he pulled a load factor of more than 1), control surfaces and structural parts  can and will be shed.  

Someone who’s good at math and has had more than an hour sleep help me out here. 
 

 

[bradp]

Looks like three of us posted pretty much the same interpretation of the ads b data 

[jlunseth]

https://kstp.com/news/ntsb-resumes-investigation-into-small-plane-crash-that-killed-3-victoria/6202221/

This is a video from a local TV station showing an NTSB rep stating that the elevator and horizontal stabilizer had departed the aircraft prior to the crash, it is a little after 1:50 on the video. Several others have mentioned this, but it seems to be getting ignored in the “artifact” debate. The lack of a stab and elev would explain the nose up attitude seen during the fall in the crash video. As the NTSB rep says, lacking a horizontal stabilizer and elevator the plane would not continue to fly. The video also shows the right wing being handled by two workers. That is immediately after the NTSB rep speaking in the video. The wing is upside down with the flaps visible. It is a little difficult to see all of the tip, which is partially blocked by a pickup, but there is no apparent damage to the wingtip area that would have been caused by that wing hitting the ground first with the plane tilted right. The wing is essentially intact except for the maroon colored “wingwalk” area.

For those just tuning in, I am putting “wingwalk” in quotes because I know that there is no wingwalk on the port side, but it helps to explain the area of this wing that was painted maroon top and bottom - about the first two feet from the fuselage on both sides.

Early reports are pointing towards an inflight breakup, whether the wings folded or not we will know soon enough. 

[Shadrach]

So this could be entirely consistent with a low altitude IMC upset leading to and overspeed in descent followed by an abrupt pitch command that comprised the spar.
 

I would like to know more about how flight aware computes forward speed. I have made rapid descents (not this rapid) in the past and flight aware seemed accurate in it measurement of both forward and vertical speed.  I had assumed ADSB exchange capable of the same. 

[Shadrach]

7 hours ago, 1980Mooney said:

There is no way the wings folded well out of the frame:

1 - There is no way a plane can fly in a nose high attitude without wings.  The wings had to be attached and functional as well as the horiz. stab.  The picture clearly shows nose high.  Otherwise it would be like an arrow going nose down.

2 - As shown in pics and noted by observers both wings are within 20 ft of each other and the fuselage at the crash site.  If they folded well before they would be elsewhere.

Maybe you know that. But I don’t.  The only thing I think I know for sure is that that the wings failed. While it seems likely they would depart the airframe entirely, it is not a given. There are steel landing gear linkages running through both wings in addition to steal attach points at the cage. The symmetry in the photos suggests the failure was symmetrical. It matters little at this point at what altitude they failed. If I had to guess I would bet the failure occurred a few hundred feet below the cloud deck. If indeed they were intact in the first frame as some suggest, It’d be nice to have someone who knows more about videography calculate the speed with which they folded nearly 90°.

Edited August 9, 2021 by Shadrach

[jlunseth]

14 minutes ago, 1980Mooney said:

 

1 - There is no way a plane can fly in a nose high attitude without wings.  The wings had to be attached and functional as well as the horiz. stab.  The picture clearly shows nose high.  Otherwise it would be like an arrow going nose down.

With respect, the aircraft is not flying at all towards the end of the flight and in the video. It is falling like a leaf. The vertically folded wings would have the effect of keeping the aircraft upright. There would be a “parachute effect,” that is, the wings would cause drag in an upward direction, keeping the belly down. It may even have been rotating around a vertical axis. The aircraft is nose up simply because its center of gravity is behind wherever the center of the upward drag effect of the wings is.

[chriscalandro]

1 hour ago, DXB said:

It's not unbelievable that the spar snapped before ground contact but it's without known precedent for this airframe and thus worthy of close scrutiny before drawing the conclusion.  We have a good idea how the tail components can disintegrate in the air after loss of control - less so for this particular wing spar design unless it has severe pre-existing compromise.  The wing cannot conclusively be said to be compromised in the first frame though it cannot be excluded either.  The spar is clearly snapped in the second frame, though only the tail appears to be contacting the ground.  The details of the image capture technology used at the extreme speeds involved at that instant do have bearing on interpretation of whether the spar broke before or after striking the ground.

Are you an expert in image capture technology?  I am, and my day job consists of me determining, resolving, and explaining video artifacts.  There are not artifacts that suggest the wing was not detached when it entered the frame.

 

anybody that has ever built a paper airplane knows that airplanes with intact wings don't fall straight down.

[A64Pilot]

What confuses me is how do you build the vertical velocity that the data seems to show in a nose up attitude in 2,000 ft or less, or any attitude except nose straight down.

‘I can see how wings up may contribute to the nose up attitude, the shuttle cock thing, but it seems in the first frame that they weren’t up?

Lose the horizontal and the nose will drop, not come up?

What is the max velocity of a dense object dropped from 2,000 ft?  Not that a aircraft is dense, they aren’t at all. How do you get to over 200 kts from 2,000 ft without being nose straight down and wide open, especially with the gear hanging out in the wind?

I’m not throwing any theories because frankly what appears to have happened, doesn’t seem possible.

Edited August 9, 2021 by A64Pilot