Minnesota Crash

[toto]

It’s particularly hard (as a layperson) to understand how that amount of deformation could occur within the same 1/100th of a second. We have three images, all in the .06 timestamp, and the third one would require a massive amount of force and movement. But we see no impact. 

Security cameras often have slow frame rates, but the fact that we have three clear frames in the same hundredth of a second implies either a pretty decent frame rate or a fair amount of AI interpolation. 

[Davidv]

As someone on Beechtalk pointed out, the frame where the right wing is bent upwards also looks to have fuel spray.  Could it be that the plane was coming down so quickly that the video frame rate was too slow to capture the right wing hitting the ground first which caused breakage and the upward snapping effect?  I just find it highly unlikely that the plane would have come down flat if the wing failure happened at a higher altitude.

[EricJ]

I'm wondering if there was a recent structural repair or something that failed, or a lot of corrosion that was never caught in annual.

Even the first pic shows at least the left wing is way out of place.   The attitude of the aircraft suggests control was already lost and it was a paperweight at that point.

It's definitely odd since we know the Mooney spar is very, very strong in that area.   Something very unusual had to happen for that kind of failure.

[ragedracer1977]

Here's an overhead from a news video. First grab you can see the trailer to the left that is in the crash video. Second grab, both wings are all that's left.  They were clearly broken off the airframe. When? That's the debate. 

[DXB]

10 minutes ago, EricJ said:

Even the first pic shows at least the left wing is way out of place. 

I wondered about that too, but to me the position looks roughly correct from the vantage point of the camera.  Still I can't exclude the spar started to fail in flight, causing a loss of control, and finally gave way fully around the moment of first ground contact of the tail.

Edited August 8, 2021 by DXB

[ragedracer1977]

8 minutes ago, 1980Mooney said:

The wings do not appear to be "folded up" when it is 40 ft. off the ground and falling vertically.  Upon impact of course everything crumpled up.   But that does not seem to be the cause of why it "fell out of the sky".  

The weather at the time was 1100-1300 ft. OVC.  The wind was 8-12 mph from the East and NE.  He was putting along at about 100-110 kts ground speed.  IMC but seems rather benign.  He started making S turns without informing the Tower.

Looks very folded up to me.  I can see way more of the underside than I should be able to

[MikeOH]

13 minutes ago, EricJ said:

I'm wondering if there was a recent structural repair or something that failed, or a lot of corrosion that was never caught in annual.

Agreed with that; I'm partial to corrosion as I struggle to see what repair, other than a center section spar improperly done repair, could cause this.

The mystery, though, is the wing failure seems to have occurred IMMEDIATELY prior to the plane striking the ground.  Something else entirely must have happened well before the plane's wings were torn off.  How did the pilot get to that situation?

[Urs_Wildermuth]

Quote from a News Report,

<blockquote>The Carver County Sheriff says there is debris in two places, at the site along Highway 5 and then in an area to the south.</blockquote>

https://granthshala.com/fatalities-reported-after-plane-crashes-in-victoria-minnesota/

[EricJ]

31 minutes ago, 1980Mooney said:

The wings do not appear to be "folded up" when it is 40 ft. off the ground and falling vertically.  Upon impact of course everything crumpled up.   But that does not seem to be the cause of why it "fell out of the sky".  

The weather at the time was 1100-1300 ft. OVC.  The wind was 8-12 mph from the East and NE.  He was putting along at about 100-110 kts ground speed.  IMC but seems rather benign.  He started making S turns without informing the Tower.

 

 

 

It looks way out of whack to me.   You can see the right main landing gear but the left is obscured.   If the left wing is where it should be, then the left stabilizer is way out of whack (so I think the left wing is already failing).

The severity of the improper wing angle in the first pic suggests that the failure may have been in progress for a while and didn't get to total failure until the end.   If the wing distorts much at all, aileron control will be immediately compromised, which may explain the wandering directional control prior to the crash.

[Raymond J1]

31 minutes ago, ragedracer1977 said:

Looks very folded up to me.  I can see way more of the underside than I should be able to

But we can also see the main right gear much more than we should see if plane flat

[Raymond J1]

8 minutes ago, EricJ said:

It looks way out of whack to me.   You can see the right main landing gear but the left is obscured.   If the left wing is where it should be, then the left stabilizer is way out of whack (so I think the left wing is already failing).

The severity of the improper wing angle in the first pic suggests that the failure may have been in progress for a while and didn't get to total failure until the end.   If the wing distorts much at all, aileron control will be immediately compromised, which may explain the wandering directional control prior to the crash.

Or the plane is tilted to the right.

[EricJ]

1 minute ago, Raymond J said:

Or the plane is tilted to the right.

I'd expect to see the stabilizer tilted as well.   It isn't.

[Raymond J1]

2 minutes ago, EricJ said:

I'd expect to see the stabilizer tilted as well.   It isn't.

We guess the situation of the left horizontal plane on the vertical plane, there is like a double edge.

[Yetti]

20 minutes ago, 1980Mooney said:

Both wings are on the ground within 15 ft of what is left of the fuselage and engine cowling.   We can argue all day about whether the plane came apart when it was within feet of the ground descending at 3200 fpm per ADSB-Exchange data in a 40-45 degree nose high apparent stall.  But none of this speculation begins to explain how he got into the situation....why he started making S turns and descending from 2700 ft.

If they came off higher they would be further away.  That said could have been a heart attack due to increased work load.

[DXB]

59 minutes ago, EricJ said:

It looks way out of whack to me.   You can see the right main landing gear but the left is obscured.   If the left wing is where it should be, then the left stabilizer is way out of whack (so I think the left wing is already failing).

The severity of the improper wing angle in the first pic suggests that the failure may have been in progress for a while and didn't get to total failure until the end.   If the wing distorts much at all, aileron control will be immediately compromised, which may explain the wandering directional control prior to the crash.

I think we may be close to the limit of what can be interpreted from this single low quality frame, though your opinion is a plausible one. The left stab, gear, and degree of roll on the plane are very hard to make out. I do see what you mean though about the disparity in angle between the wing and the stab. Modeling the expected view of that M20M based on height, distance, and angle of the camera relative to the plane position might offer a little more info to support or refute your interpretation.  However a wing spar failure in flight on either a vintage metal Mooney or a modern one like this one is unprecedented even with extreme turbulence, which I doesn't appear to have been encountered here. I believe there was a K a while back that bent a wing in a thunderstorm but managed to land safely.  By contrast, loss of spatial orientation in IMC after an avionics failure is a relatively common event and would also explain the meandering course, and so I'm a little biased toward that possibility in absence of conclusive evidence to the contrary.  Spar failure under these circumstances would be a chilling finding; sadly the wreckage may also not be in good enough condition to discern the difference. 

 

Edited August 8, 2021 by DXB

[hammdo]

It is possible a micro-burst happened with Pilot trying to keep altitude - causing the stall - ATC radar would not know about those. So many thing could have happened - it is so sad the outcome... horrifying to watch...

-Don

[toto]

This has landed on Kathryn's Report. She's always good at aggregating these things..

http://www.kathrynsreport.com/2021/08/mooney-m20m-257-tls-bravo-n9156z-fatal.html

[DJE22]

2 hours ago, DXB said:

As far as I can tell, these are the only 3 frames that provide any insight.  Am I missing one?  In the first one, the spar appears intact. In the second one it has clearly snapped (barring a video artifact which I am having trouble imagining).   In that one, is not clear whether the tail is contacting the ground or not, but part of it may be obscured by grass in the frame so it seems plausible (compare contour of the visible red paint under the tail to the same area in the frame above).  In the third frame, the fuselage has cratered /disintegrated but the folded wings are still clearly visible (also artifact?).  I'm really not sure what's going on here.

I original thought both wings appeared folded upward (now it appears maybe only right wing but there’s an appearance of a double exposure / artifact / two wings — middle frame); however the underside of the wing is red…all the way up it to tip? Or just inboard?  
also, if one imagines the lines of the belly and tail section, I can now “imagine” (from the pic) that the tail has, in fact, hit the ground. I say this because the slope upward of the lower aft belly (tail section) in the frame seems more aggressive than what the actual upward slope of the belly tail section of a Bravo. And if the tail has actually hit the ground in frame two, would that cause the snap?

 

[Davidv]

3 minutes ago, Hyett6420 said:

 No.  If you do a frame by frame analysis you see the plane come in intact.  Then the right wing hits hard.  THEN the left wing folds upwards.  I assume by the force of the impact on the right wing hitting the ground at 9000fpm snapped bolts amd the left wong folded at THAT point not up higher in the air.  

Yes, I also think this is exactly what happened based on the fuel spray on the right side of the plane while the aircraft is seemingly still in the air.  I think it had in fact hit right wing first and the frame we're seeing is a split second later when it's rolling to the left.  Both wings are apparently 15 feet from each other at the site.

[bradp]

Seems like the wing fold is an effect not a cause. 
 

If this was a piper we’d be expecting a wing fold if he came down at 9000 fpm and ended up in that 45 nose up attitude.  Looks like the unhappy ending of an air show low level pull out of a loop or similar.  Nose up accelerated stall high g loading of underside of wing with failure of the underside spar web.  I’m unfortunately betting this was an unusually attitude recovery gone horribly wrong.  
 

Seem like either SD in INC or incapacitation is most likely cause 

 

@Scott Dennstaedt, PhD Scott were there CBs in the area at the time or the accident? 

[EricJ]

1 hour ago, ragedracer1977 said:

Here's an overhead from a news video. First grab you can see the trailer to the left that is in the crash video. Second grab, both wings are all that's left.  They were clearly broken off the airframe. When? That's the debate. 

The good news here is that the wing structure can be inspected and analyzed to see what failed and why.   It does look like maybe there's a light pole or something in the path, but I'm still skeptical that an impact with a pole would do that.

 

[EricJ]

32 minutes ago, DXB said:

I think we may be close to the limit of what can be interpreted from this single low quality frame, though your opinion is a plausible one. The left stab, gear, and degree of roll on the plane are very hard to make out. I do see what you mean though about the disparity in angle between the wing and the stab. Modeling the expected view of that M20M based on height, distance, and angle of the camera relative to the plane position might offer a little more info to support or refute your interpretation.  However a wing spar failure in flight on either a vintage metal Mooney or a modern one like this one is unprecedented even with extreme turbulence, which I doesn't appear to have been encountered here. I believe there was a K a while back that bent a wing in a thunderstorm but managed to land safely.  By contrast, loss of spatial orientation in IMC after an avionics failure is a relatively common event and would also explain the meandering course, and so I'm a little biased toward that possibility in absence of conclusive evidence to the contrary.  Spar failure under these circumstances would be a chilling finding; sadly the wreckage may also not be in good enough condition to discern the difference. 

 

I agree on all your points.   Even if it struck what appears to be a light pole in the overhead shots I wouldn't expect that to cause the spars to fail like that, but who knows.   Since the wings survived the crash I'm hoping we get to learn the details.

[Shadrach]

2 hours ago, DXB said:

Could the tail striking with enormous force with the nose up transmit enough horizontal load to the main spar to break it?  It is designed to take enormous vertical loads but much weaker to horizontal stress I believe?

The wings appear to be in the same position in every frame I see. The earliest frame is low quality but it does not look appreciably different in terms of wing position from any of the others.

[jlunseth]

1 hour ago, toto said:

When I look at the earliest image, it looks like the underside of the wings is painted in the maroon color. Then suddenly in the "folded" images, the underside is white. Am I looking at this wrong?

If you look at the picture of the aircraft in the hangar on aircraft.com, the first two or three feet - basically the wingwalk area - is painted maroon top and bottom. The same color shows at the bottom of the folded wings. The NTSB will have the full video and will make a determination.

[DXB]

19 minutes ago, Shadrach said:

The wings appear to be in the same position in every frame I see. The earliest frame is low quality but it does not look appreciably different in terms of wing position from any of the others.

Really? Frames 1 and 2 look radically different to me.