Minnesota Crash

[mhrivnak]

A claimed eye-witness account in the youtube comments:

"I saw the whole thing from start to finish. I was standing by my car in the holiday gas station across the street when I heard a low flying airplane, I looked up to see it approaching from the southwest in a steep left bank to the north, diving, and at a high rate of speed. It appeared the plane then attempted to level off abruptly at which point both wings folded up and it started plummeting to the ground. There were some small pieces of debris falling off, sounds like there were parts of the tail section found in yards to the south. It looked for a moment that the plane was going to come down right where I was in the parking lot but it passed overhead and hit the ground across the street. Have not heard anyone else mention the wings folding up but it was plain as day to me and also clearly visible in this footage right before impact."

[jlunseth]

I see there is a post suggesting there might have been an abrupt pull up by the pilot. That is a possibility, but in light of the fact that the stab and elevator departed, their loss may have caused an abrupt pullup motion. The pilot may have had no control at that point. Whether the loss of the stab and elevator caused a pullup, or an encounter with severe shear conditions inside a thunderstorm caused simultaneous loss of multiple aerodynamic surfaces, we cannot know at this point.

As for dxb’s thoughts, honestly, I think this has been a very professional debate so far. All the right questions have been asked including his. Anyone who has ever been part of a scientific debate knows that it is healthy to have multiple strong and competing views involved, that is what, hopefully, leads to finding out what the real facts are. I am impressed with the quality of this discussion, maybe the NTSB will see it and it will prompt some science-based questions during the investigation.

Bear in mind that this is the only time as far as any of us know, that there has been some evidence that a Mooney wing failed in flight. There had better be some strong questions asked on all sides.

[N201MKTurbo]

If the elevator came off wouldn't the plane pitch down?

[DXB]

The descent rate data is striking, and I must walk back my degree of incredulity of the in flight spar failure. I end up agreeing with those who are effectively saying "stop arguing about whether the spar was intact or not when an otherwise unflyable plane struck the ground - none of us need a spar in an unrecoverable condition." One could imagine that tail flutter during the brief initial 6000ft/min descent depicted and/or a hard attempt to pull out of that dive disintegrated the stab/elevator, precipitating the final 22000ft/min descent. Maybe that initial hard pull even momentarily created the Gs needed to compromise the spar? Then somewhere between the start of the steepest vertical descent of an unflyable aircraft and the moment of ground impact, the spar snapped outright.  That type of chain of events still seems much more likely than any structural failure as a primary cause of this tragedy.  

[jlunseth]

8 minutes ago, A64Pilot said:

‘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?

I personally don’t agree that that is the case. The wing root area that is painted maroon on the underside extends too far up the side of the cabin, as though the wings are folded in the first picture. But it is certainly a valid question to ask. Hopefully, the NTSB will have the original video and excellent tools to examine it with, and can ultimately give an answer.

[DXB]

23 minutes ago, chriscalandro said:

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.

I have zero expertise at all - I appreciate any you bring to the table.

[A64Pilot]

If you could pull hard enough to fail the aircraft and it seems he did, then logically the horizontal would go first as it has in other aircraft. an enormous amount of downward force can be generated at high speed with full up elevator.

‘If the wings didn’t fail at about the same time, then loss of the horizontal would result in a nose down pitching moment as of course the horizontal is pushing down while the wings lift up in normal flight.

‘But if the wings broke at about the same time as the Horizontal, then they could hold the nose up attitude similar as to how I believe Virgin Galactic handle re-entry.

‘Although it’s said eye witnesses are very often incorrect, what this one says sounds plausible?

[A64Pilot]

4 minutes ago, N201MKTurbo said:

If the elevator came off wouldn't the plane pitch down?

Yes, unless the wings departed very soon after

[0TreeLemur]

Pilot incapacitation. Loss of control.  Front seat passenger pulls hard aft on the yoke well above Va.   Ya'll know how sensitive the elevator is to slight yoke movements.  Imagine a passenger in a panic thinking that they've got to pull back hard.   That explains what you see.

The slightly nose up pancake configuration of before impact is not inconsistent with the aerodynamics.  The folded wings are in control of the attitude.

[Marauder]

I seem to recall an AD was issued around 2012 for tail attachment issues. Anyone remember the specifics and if it would apply to this plane?

Looking at the pictures, it does look like the left horizontal stabilizer is missing. What a loss of life. Two doctors and another person involved in the healthcare field.


Sent from my iPad using Tapatalk Pro

[A64Pilot]

4 minutes ago, 1980Mooney said:

And there in lies a major problem in the speculation that the plane was coming apart.   

 I don’t understand what you mean?

My supposition is the pilot or passenger broke the thing, not that it broke in normal flight, failure of the Horizontal and main wing spar nearly simultaneously seems to indicate a huge overload of the structure, either by a thunderstorm or pilot inputs or maybe both.

‘I just hope they were unconscious for the families sake

Edited August 9, 2021 by A64Pilot

[jlunseth]

16 minutes ago, N201MKTurbo said:

If the elevator came off wouldn't the plane pitch down?

It would depend on where the center of gravity is, with the possibility that the load may have shifted in severe turbulence. Also possible that the engine us running and the prop is acting to try to lift the nose, sort of like a helicopter blade would. Yes, normally you would be correct and I am only presenting it as a possibility.

I like A64’s word, “shuttlecock,” better than my description. If you think of the aircraft as falling like a shuttlecock instead of flying, then all of our normal aerodynamic ideas convert to something else. I also am mindful of the early witness description that the aircraft was spiraling, could be a stall/spin or could be a shuttlecock descent - or like many eyewitness descriptions could just be wrong.

[DXB]

Is it possible that the single second of video showing nose up attitude is really an instant of a much more complex tumbling trajectory?  The folded up wing configuration that might contribute to that attitude can't be confirmed until the very last image of the intact aircraft.

[Flyfalcons]

1 hour 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.

The wings were not detached.  They were attached and folded up, creating a significant nose-up condition with all that drag way up high.  Half of the horizontal stabilizer, which would help pitch the nose down, was missing.  The other half most likely folded up.

 

The plane had experienced a significant structural failure before coming into frame.

[jlunseth]

Thank you mhirvnak, that makes the most sense of all. Bear in mind the break out altitude was low all day, somewhere around 800. A witness would not have seen the plane until it broke out. The pilot may not have understood his attitude until he broke out. He may have tried to pull up and then everything went, or I suppose it is possible the stab departed because of flutter and that did it. Which one, we will probably never know. I think we do know now that the wing is not invulnerable.

[Flyfalcons]

5 minutes ago, 1980Mooney said:

Long body Mooneys are nose heavy. A shuttlecock (A64’s description which you like) falls nose down. 

The entire fuselage became the nose of the shuttlecock.

[ragedracer1977]

38 minutes ago, mhrivnak said:

A claimed eye-witness account in the youtube comments:

"I saw the whole thing from start to finish. I was standing by my car in the holiday gas station across the street when I heard a low flying airplane, I looked up to see it approaching from the southwest in a steep left bank to the north, diving, and at a high rate of speed. It appeared the plane then attempted to level off abruptly at which point both wings folded up and it started plummeting to the ground. There were some small pieces of debris falling off, sounds like there were parts of the tail section found in yards to the south. It looked for a moment that the plane was going to come down right where I was in the parking lot but it passed overhead and hit the ground across the street. Have not heard anyone else mention the wings folding up but it was plain as day to me and also clearly visible in this footage right before impact."

Eyewitness account matches the video perfectly.  I'm not sure why people think the wings folded between frames one and 2.  They were already folded.  For them to fold between frame one and 2 is a physical impossibility. 

[DJE22]

5 hours ago, carusoam said:

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-

Precisely!  I have not had a chance to review 1980Mooney ADSB info yet but I’ll bet much is revealed!

There was an early comment within this string that stated pilot was not Instr rated but not hearing nor seeing that any longer.  Do we have any confirmation?

[Shadrach]

On 8/9/2021 at 12:18 PM, 1980Mooney said:

Long body Mooneys are nose heavy. A shuttlecock falls nose down. 

I won't argue with you. It seems you understand the CG orientation of an aircraft with wings folded nearly 90 degrees and an unknown departure W&B.  I might posit that the G force during the pull up reoriented the plane in the tail down attitude and it did not have time to establish the stabilized descent that displays your theory.  

Edited August 10, 2021 by Shadrach

[Hank]

24 minutes ago, Marauder said:

I seem to recall an AD was issued around 2012 for tail attachment issues. Anyone remember the specifics and if it would apply to this plane?

That AD was to inspect the doubler plate bolted to the tail at the trim pivot. If it failed, the entire empennage would be at risk, not one horizontal stab.

Something strange went on here for sure!

[exM20K]

this one doesn't seem all that mysterious to me. LOC on an instrument approach (meandering across the LOC) due to incapacitation, vacuum / instrument failure, or other unknown, break out of the overcast at low altitude in unusual attitude at warp 9, big hard pull, and that's it.

Very sorry for the loss.

-dan

[Shadrach]

I've plotted the average descent and climb rates leading up to the crash.  He clearly was struggling to maintain pitch control if not roll as well.  Regardless of when the wings folded, this was clearly a loss of control followed by a severe overstress of the airframe.

The first plot is a larger picture of where the problem likely started or exacerbated. The second is a more granular plot of the final moments.  It must have been absolutely terrifying for all involved. thankfully the end was immediate and painless...RIP

Pitch control problem seems to become evident at 18:38:34

More granular look at final descent.

EDIT: Point of clarification, these calculations represent the average climb/descent rate required for the aircraft to achieve the altitude changes reported in each ADS-b return. The actual climb/descent rates performed by the aircraft likely varied quite a bit and the maximum climb/descent rate between ADS-b returns could be more quite a bit more than the average.

 

Edited August 10, 2021 by Shadrach

[DXB]

1 hour ago, mhrivnak said:

A claimed eye-witness account in the youtube comments:

"I saw the whole thing from start to finish. I was standing by my car in the holiday gas station across the street when I heard a low flying airplane, I looked up to see it approaching from the southwest in a steep left bank to the north, diving, and at a high rate of speed. It appeared the plane then attempted to level off abruptly at which point both wings folded up and it started plummeting to the ground. There were some small pieces of debris falling off, sounds like there were parts of the tail section found in yards to the south. It looked for a moment that the plane was going to come down right where I was in the parking lot but it passed overhead and hit the ground across the street. Have not heard anyone else mention the wings folding up but it was plain as day to me and also clearly visible in this footage right before impact."

If verifiable, that is a remarkable eye witness account of a spar snapping upon a conscious pilot trying to pull out of what the ads-b data indicates was 22,000ft/min dive in a still controllable aircraft just after exiting the clouds around 800 AGL .  At those speeds, I would have thought the tail would have already come apart and exerting such control authority would be impossible.

Edited August 9, 2021 by DXB

[Hank]

Wow, that penultimate 30,000 fpm descent is 340 mph DOWN!

[Will.iam]

The eye witness said they saw the airplane in a steep left bank and then rolled and pulled up as the wings folded. Rolling g’s as they call it is higher on the wings than straight g pulls. In acrobatic formation flying in the military we had g limits for the T-37. 6.7 g and a lower rolling g limit. So we were alway taught to roll then pull because if you combined the roll and pull you will exceed the limit of the wing. Look at fighter jets when they do airshows it’s always a roll then a pull or pull then a roll never a roll while pulling.  And even upset training we now get in the airlines they explained that you have to unload the wing first and then roll to a level horizontal then pull the nose back up. If you rolled while pulling it would over g the airplane and you had to try the maneuver again.  They explained that the sim has the data  derived from airbus test pilots with sensors mounted to the structure and performing upset recovery and then establishing the limits to not exceed in the sim.  
so even if the mooney wing was tested to over 9 g’s that was not a rolling g test and the wings will snap sooner than a straight g pull.