Minnesota Crash

[cujet]

I'm thinking about the way a CCD chip scans the pixels and the high rate of speed the aircraft descends through the frame. Remember, we typically see objects move left to right in video frames. In this case the object moves top to bottom.

We would need to know the CCD sensor used and how it was scanned. Looking at the pics above, I suspect those are artifacts of sequential or block scan, and a falling object. 

We've all see how odd a prop blade looks in video, and many of us simply chalk that up to the rolling shutter of the camera or sensor. Look at the prop blades in the pic below and notice the difference in the blade's horizontal movement and their vertical movement. 

 

 

http://resourcemagonline.com/wp-content/uploads/2015/11/Effects-of-Rolling-Shutter-on-a-Propeller.jpg

 

Edited August 8, 2021 by cujet

[Shadrach]

On 8/8/2021 at 2:47 PM, DXB said:

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

Burgundy underside of the wing splits the side windows in almost the exact place, rest of the wing area in the image is blurred. I don’t see anything radically different, just lower resolution.

I’m not saying I’m correct, just stating my observation.

I would further state that I have tried to hold my F model in a falling leaf and it never falls flat; it always falls off on one wing eventually.

Again, I could be wrong but the odds of the airframe falling tail low almost straight down with the fuselage level in roll axis seems unlikely to me. It seems more likely it the wings were folded like a shuttlecock..

 

Edited August 10, 2021 by Shadrach

[MikeOH]

28 minutes ago, DXB said:

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

Hmm, they look pretty consistent to me.  Look at the left wing underside red paint at the leading edge: it is lined up nearly with the top of the pilot's side window in both frames.  The first image is just cutting off the ends of the wings as they are out of frame.

[MikeOH]

1 minute ago, Shadrach said:

Burgundy underside of the wing splits the side windows in almost the exact place, rest of the wing area in the image is blurred. I don’t see anything radically different, just lower resolution.

I’m not saying I’m correct, just stating my observation.

I would further state that I have tried to hold my F model in a falling leaf and it never falls flat; it always falls off on one wing eventually.

Again, I could be wrong but the odds of the airframe falling tail low almost straight down with the fuselage level in roll axis seems unlikely to me. It seems more likely if the wings were folded like a shuttlecock..

 

You type faster

[MikeOH]

1 hour ago, cujet said:

I'm thinking about the way a CCD chip scans the pixels and the high rate of speed the aircraft descends through the frame. Remember, we typically see objects move left to right in video frames. In this case the object moves top to bottom.

We would need to know the CCD sensor used and how it was scanned. Looking at the pics above, I suspect those are artifacts of sequential or block scan, and a falling object. 

We've all see how odd a prop blade looks in video, and many of us simply chalk that up to the rolling shutter of the camera or sensor. Look at the prop blades in the pic below and notice the difference in the blade's horizontal movement and their vertical movement. 

 

 

http://resourcemagonline.com/wp-content/uploads/2015/11/Effects-of-Rolling-Shutter-on-a-Propeller.jpg

 

While that sounds plausible, why would this type of digital artifact affect ONLY the image of the wings, and not the fuselage?  BOTH are moving downward in the frame.

Props are turning; wings not so much

[carusoam]

Note the wheels…

• They are all down by procedure, and mechanics….
• yet one shows up in the right place, while the wings appear bent above the roof…
• In the video one wheel is seen escaping the wreckage and circling around…

The oddity here is… the video seems to be challenged with showing the landing gear extended in the right place… before hitting the ground.

One frame shows one MLG near the right location…

The wings folded up don’t show wheel wells at all…

 

Note about the tail….  The rudder seems to be missing… the pics look more like a Mooney tail after the rudder has been removed…. 
 

 

Question for the audience… Where does the 9,000 fpm descent number come from?

I didn’t see it in the flight aware data…

 

A fully developed E-descent under full control is about half that…

A free fall would be more than that…

2k’ to the ground doesn’t leave much time to develop much, or recover from very much…

especially if we are relying on one minute between data points…for interpolation.

Whatever happened was over within seconds…

-a-

[Flyfalcons]

Panic pull well above Va is all it takes to end up in a position like this.  The Twin Cessna that went down in California somewhat recently played out just like this, except the wing sections fully separated from the aircraft.  Come screaming out of the cloud base disoriented, panic pull, wings fail and fuselage continues its downward, suddenly nose-high trajectory.  The video of that was painful to watch as well.

Edited August 8, 2021 by Flyfalcons

[Shadrach]

1 hour ago, carusoam said:

Note the wheels…

• They are all down by procedure, and mechanics….
• yet one shows up in the right place, while the wings appear bent above the roof…
• In the video one wheel is seen escaping the wreckage and circling around…

The oddity here is… the video seems to be challenged with showing the landing gear extended in the right place… before hitting the ground.

One frame shows one MLG near the right location…

The wings folded up don’t show wheel wells at all…

 

Note about the tail….  The rudder seems to be missing… the pics look more like a Mooney tail after the rudder has been removed…. 
 

 

Question for the audience… Where does the 9,000 fpm descent number come from?

I didn’t see it in the flight aware data…

 

A fully developed E-descent under full control is about half that…

A free fall would be more than that…

2k’ to the ground doesn’t leave much time to develop much, or recover from very much…

especially if we are relying on one minute between data points…for interpolation.

Whatever happened was over within seconds…

-a-

Looks like it has a rudder to me. When you see a vertical stab without a rudder, it looks almost pointed at the top.

[A64Pilot]

5 minutes ago, Flyfalcons said:

Panic pull above Va is all it takes to end up in a position like this.  The Twin Cessna that went down in California somewhat recently played out just like this, except the wing sections fully separated from the aircraft.  Come screaming out of the cloud base disoriented, panic pull, wings fail and fuselage continues its downward, suddenly nose-high trajectory.

Except that I don’t think it’s ever happened in a Mooney, ever? Add in that airspeed wasn’t all that high, then add in the unlikely event that both wings break exactly at the same moment so that the airframe remains level, and as has already been pointed out in other aircraft that have had high speed breakups from being over G’d, usually the horizontal goes first as it’s developing a shed load of downward force to force the nose up in a high G situation, remember the center of balance is forward the center of lift.

‘Not saying the wings didn’t break, but if they did staying in a nose up attitude and level is I think really unusual.

‘I’m betting in some kind of video phenomena that is over my head to understand as it seems more likely, and for whatever reason the aircraft was in a deep stall, but again to be wings level is sort of unusual, so my guess is he saw the ground rush and did what any of us would do and pulled hard.

We won’t know until the report comes out, but I do think then we will.

[MikeOH]

14 minutes ago, Flyfalcons said:

Panic pull well above Va is all it takes to end up in a position like this.  The Twin Cessna that went down in California somewhat recently played out just like this, except the wing sections fully separated from the aircraft.  Come screaming out of the cloud base disoriented, panic pull, wings fail and fuselage continues its downward, suddenly nose-high trajectory.  The video of that was painful to watch as well.

At this point, I think that's the most plausible conclusion based on the limited evidence we have.  It's just incredible odds that the wings failed nearly at the moment of impact.

[ArtVandelay]

Except that I don’t think it’s ever happened in a Mooney, ever? Add in that airspeed wasn’t all that high, then add in the unlikely event that both wings break exactly at the same moment so that the airframe remains level, and as has already been pointed out in other aircraft that have had high speed breakups from being over G’d, usually the horizontal goes first as it’s developing a shed load of downward force to force the nose up in a high G situation, remember the center of balance is forward the center of lift.
‘Not saying the wings didn’t break, but if they did staying in a nose up attitude and level is I think really unusual.
‘I’m betting in some kind of video phenomena that is over my head to understand as it seems more likely, and for whatever reason the aircraft was in a deep stall, but again to be wings level is sort of unusual, so my guess is he saw the ground rush and did what any of us would do and pulled hard.
We won’t know until the report comes out, but I do think then we will.

We only know ground speed, FlightAware is know to have anomalies, especially when at lower altitudes. You can be descending at 200 knots and have a low ground speed.
I would not make any conclusions based on the data or video available.

[MikeOH]

6 minutes ago, A64Pilot said:

Except that I don’t think it’s ever happened in a Mooney, ever? Add in that airspeed wasn’t all that high, then add in the unlikely event that both wings break exactly at the same moment so that the airframe remains level, and as has already been pointed out in other aircraft that have had high speed breakups from being over G’d, usually the horizontal goes first as it’s developing a shed load of downward force to force the nose up in a high G situation, remember the center of balance is forward the center of lift.

‘Not saying the wings didn’t break, but if they did staying in a nose up attitude and level is I think really unusual.

‘I’m betting in some kind of video phenomena that is over my head to understand as it seems more likely, and for whatever reason the aircraft was in a deep stall, but again to be wings level is sort of unusual, so my guess is he saw the ground rush and did what any of us would do and pulled hard.

We won’t know until the report comes out, but I do think then we will.

If you accept an assumption that there was a PRE-existing defect (bad repair or corrosion) in the main spar then the video evidence is plausibly consistent.  The spar then becomes the weak point vs. the horizontal stab.  Further, that type of defect in the center section would result in BOTH wings breaking at the same time.

The nose up attitude is again consistent with the incredible timing of capturing this right at the moment of failure.

Still waiting for what kind digital video artifact would apply only to the image of the wings but not the fuselage???

[jaylw314]

From https://www.aircraft.com/aircraft/1207543/n9156z-1991-mooney-m20m-bravo

You can clearly see that the vertical stabilizer has no white above the color stripe, and that the wings are maroon top and bottom but only at the root.

[eman1200]

has anyone posted the link to the audio?  do we know yet if there was more than 1 person aboard?

[carusoam]

7 minutes ago, eman1200 said:

has anyone posted the link to the audio?  do we know yet if there was more than 1 person aboard?

The audio is posted early on in a thread… with a video to simulate what the plane was doing based on the data available….  
 

Oddly, the N number is used, but the plane visualized is something other than a Mooney…

 

Give it a listen… See if you hear anything…

-a-

[jaylw314]

2 hours ago, MikeOH said:

While that sounds plausible, why would this type of digital artifact affect ONLY the image of the wings, and not the fuselage?  BOTH are moving downward in the frame.

Props are turning; wings not so much

I suspect there is also video compression artifact combined with rolling shutter.  Put the two together and you can have some unpredictable effects.

[irishpilot]

Anybody keeping a list or a data base?  We had the one in NORCAL that precipitated so much debate a month or so ago.  

I run the yearly fatal and general Mooney accidents and the top causes. I pull this from the NTSB and search for all Mooney's. As stated in this thread, it lags about 18-24 months before I have a complete year to run. You can see the 2017 and 2018 accident analysis stickies in the Safety Section.

Also, I'm moving this thread to the safety section. Please keep the discussion going.

-Safety Mod

Sent from my Pixel 4a using Tapatalk

[Schllc]

38 minutes ago, MikeOH said:

If you accept an assumption that there was a PRE-existing defect (bad repair or corrosion) in the main spar then the video evidence is plausibly consistent.  The spar then becomes the weak point vs. the horizontal stab.  Further, that type of defect in the center section would result in BOTH wings breaking at the same time.

The nose up attitude is again consistent with the incredible timing of capturing this right at the moment of failure.

Still waiting for what kind digital video artifact would apply only to the image of the wings but not the fuselage???

Perhaps because the wins and fuselage are not moving at the same rate, the moment the frame is captured?

[eman1200]

15 minutes ago, carusoam said:

The audio is posted early on in a thread… with a video to simulate what the plane was doing based on the data available….  
 

Oddly, the N number is used, but the plane visualized is something other than a Mooney…

 

Give it a listen… See if you hear anything…

-a-

only thing I was thinking was if there was pilot incapacitation and maybe a right seater was attempting to fly the plane.  obviously total speculation.

[toto]

38 minutes ago, 1980Mooney said:

Family confirms 3 on board

Some new details on KR including a video interview with the NTSB rep.  Notably, he said that portions of the left elevator and left horizontal stabilizer were found two blocks away from the crash.

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

[EricJ]

21 minutes ago, toto said:

Some new details on KR including a video interview with the NTSB rep.  Notably, he said that portions of the left elevator and left horizontal stabilizer were found two blocks away from the crash.

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

So potentially multiple structural failures.    And that would also help explain the difficulty in reconciling the wing and horizontal stab aspects in the vid captures.

Yikes.   This will be an interesting one, for sure.

 

[aviatoreb]

Yikes for sure. :-(

[Yetti]

I don't normally comment on crash videos.   but I do video.   Slowed down.  There is some weird ghosting/artifacts.   https://youtu.be/ZGf7B9X7_dg

 

[Yetti]

14 minutes ago, JohnZ said:

Yeti, I see what you mean with the ghosting. Thanks for pointing that out. 
 

Was the video you posted captured with an SD card or did you record the screen with another camera? 

downloaded from youtube.  Here we are panned over.

https://youtu.be/StTXvdm9x_8

 

[MikeOH]

2 hours ago, Schllc said:

Perhaps because the wins and fuselage are not moving at the same rate, the moment the frame is captured?

Well, if the wings really are attached then how would they be moving at a different rate?

If they are moving at a different rate, then that's tantamount to them failing!

The only other possibility would be a very high roll rate.  Two problems I see with that theory: 1) the two images show the fuselage without any detectable roll difference. 2) One wing would be moving up and the other down.  Hard to imagine both would cause the same apparent artifact; i.e. appearing as both moving upwards relative to the fuselage.