Minnesota Crash

[Will.iam]

There was an F-15 accident where after the plane was fixed by maintenance the pilot did a high speed flyby and at the end of the runway tried to pull to go vertical but instead snapped both wings and the body of the aircraft fell before the pilot could eject. The post accident investigation noted the flight computer was not set correctly for the practice bombs on board and thus at the weight he was at could only pull 7 g’s safely not the 9 g’s the pilot could normally do when he didn’t have bombs or external tank on board. The flight data recorded 9 g’s when the wings let go. I know it’s not the same type aircraft just pointing out a pilot can demand more than an aircraft can withstand  even by accident when the aircraft is loaded heavy the  designed for high loads has to be lowered.  This mooney had three adults on board that’s alot of weight at the center of the wings. 

[Hank]

4 hours ago, 1980Mooney said:

The counterweight looks to be attached to the outboard end of the elevator.  The left elevator broke in half but the counterweight is still there where it should be.

Debris from fatal plane crash lands in man’s yard (wowt.com)

Yep. He's carrying the elevator using the counterweight as a handle.

[jlunseth]

That is the video I saw a week or so ago but could not find any longer. That’s great. I see the counterweight is there. But that begs the question why it is not in the longer video. Looking at the elevator in the Channel 9 video, the outboard end has the same half moon shape as the piece that does not have the counterweight, so it appears that the elevator in the Ch 9 video is the inboard half. But as far as the departure of the counterweight is concerned, that just puts the issue back where it was. When the counterweight departed it took a piece of the elevator with it. Why did the outboard end with the counterweight tear off? And why is the left elevator in two pieces?

[Browncbr1]

It seems to be plausible that they entered a grave yard spiral following spatial disorientation given the turning… that perhaps exceeded Vne, maybe the yoke was yanked when breaking out 1000agl.  Like yanking the wheel going down the freeway.   Whatever happened, it’s really sad

[LANCECASPER]

If this was spatial disorientation due to loss of attitude indicator (or vacuum) it adds validity to the ever increasing number of ifr pilots that refuse to fly imc without a certified backup.

Unless N9156Z had a panel upgrade since this picture was taken, it appears not to have a backup attitude indicator.

[carusoam]

“Unless N9156Z had a panel upgrade since this picture was taken, it appears not to have a backup attitude indicator.”
 

Beyond the standard TC…

The TC is a dying instrument….  
+1 for having a back up AI when flying in IMC…

The TC was good back in its day… that day has come and gone….

PSA message for times like this… 

Best regards,

-a-

[Mike A]

On 8/30/2021 at 5:52 PM, LANCECASPER said:

If this was spatial disorientation due to loss of attitude indicator (or vacuum) it adds validity to the ever increasing number of ifr pilots that refuse to fly imc without a certified backup.

Unless N9156Z had a panel upgrade since this picture was taken, it appears not to have a backup attitude indicator.

Is the autopilot in this plane rate based/ tied to the AI and would it follow a failing AI if it is?

[exM20K]

39 minutes ago, Mike A said:

Is the autopilot in this plane rate based/ tied to the AI and would it follow a failing AI if it is?

The photo above looks like a KFC150, which would follow the AI

-Dan

[Mike A]

17 hours ago, exM20K said:

The photo above looks like a KFC150, which would follow the AI

-Dan

So with that would the autopilot try and maintain a level horizon in the AI, even if in reality that meant flying upside down?  And if they were IMC the pilot thinking they are straight and level the whole time?  That would explain a lot. Ride the AP till you break free and realize the situation although it is too late at that point?

[jlunseth]

On 8/29/2021 at 2:30 PM, 1980Mooney said:

You can see the additional point of attachment of the control linkage to the elevator from below. It must have momentarily fluttered and jerked free probably breaking the elevator in half.  It was then followed by the left horizontal stabilizer snapping 6 inches from the vertical stabilizer where it is attached to the empennage per the NTSB.

 

That control attachment point in your photo exists only on the right side of the aircraft, there is no such control attachment on the left, and the left and right elevators are separate assemblies other than the control rod that runs through the tail and connects them. They are not a single panel like the stabilator on a Piper. The drawing appears to be the right stabilizer, not the left. Since the left and right are separate elevator panels it does not make sense that flutter in the right side would affect the left severely enough to cause the left to tear off but not the right. Also, the left elevator tore roughly in half. Flutter is generally more severe in the least rigid and most unsupported part of a structure, in this case the outer end of the left elevator. That appears to have torn off first, followed shortly by the destabilized and torn inner half of the left elevator. There is no indication or evidence that the control attachment to the right elevator was severed at all or that the right elevator left the aircraft prior to impact. The NTSB may have more information, but they have not said anything about departure of the right side assembly, either the elevator or stabilizer, prior to impact.

[Shadrach]

On 9/2/2021 at 12:46 AM, jlunseth said:

That control attachment point in your photo exists only on the right side of the aircraft, there is no such control attachment on the left, and the left and right elevators are separate assemblies other than the control rod that runs through the tail and connects them. They are not a single panel like the stabilator on a Piper. The drawing appears to be the right stabilizer, not the left. Since the left and right are separate elevator panels it does not make sense that flutter in the right side would affect the left severely enough to cause the left to tear off but not the right. Also, the left elevator tore roughly in half. Flutter is generally more severe in the least rigid and most unsupported part of a structure, in this case the outer end of the left elevator. That appears to have torn off first, followed shortly by the destabilized and torn inner half of the left elevator. There is no indication or evidence that the control attachment to the right elevator was severed at all or that the right elevator left the aircraft prior to impact. The NTSB may have more information, but they have not said anything about departure of the right side assembly, either the elevator or stabilizer, prior to impact.

I’m confused by this statement.  What do you mean there’s no such control attach point on the left-hand side?

[Hank]

1 hour ago, Shadrach said:

I’m confused by this statement.  What do you mean there’s no such control attach point on the left-hand side?

There's only one pushrod, coming out the rear fuselage and attaching to the left elevator. There is nothing doing this on the right elevator. It's circled in black in the picture of what looks like an Ovation tail.

[Shadrach]

5 minutes ago, Hank said:

There's only one pushrod, coming out the rear fuselage and attaching to the left elevator. There is nothing doing this on the right elevator. It's circled in black in the picture of what looks like an Ovation tail.

So the Ovation differs from the F model?

 

[Hank]

@Shadrach, That's interesting. I'll check my C this weekend, I only recall two rods:  one to an elevator, one to the rudder. It may have been a cost reduction, my C is 1970, isn't your F from '67?

[jlunseth]

4 hours ago, Shadrach said:

I’m confused by this statement.  What do you mean there’s no such control attach point on the left-hand side?

Mine is on the right only, I did check it. It also is different in appearance than the photo you posted. There is a fairing coming out on the right side below the elevator that covers the rod. The one in the photo 1980mooney posted is also on the right. I would not think it was a cost reduction, there were changes to the elevator for the longer bodies. 

[Vance Harral]

Our 1976 M20F has connecting rods to both elevators, so they were still doing this - for F models at least - well after 1970.

I'm guessing the difference in elevator connectivity across different models has to do with changes in the elevator trim and feedback system across different models.  There are a couple of old Mooneyspace threads that discuss this:

 

 

 

[Shadrach]

2 hours ago, jlunseth said:

Mine is on the right only, I did check it. It also is different in appearance than the photo you posted. There is a fairing coming out on the right side below the elevator that covers the rod. The one in the photo 1980mooney posted is also on the right. I would not think it was a cost reduction, there were changes to the elevator for the longer bodies. 

Yes, but yours is the same fuselage as mine.

[Shadrach]

4 hours ago, Hank said:

@Shadrach, That's interesting. I'll check my C this weekend, I only recall two rods:  one to an elevator, one to the rudder. It may have been a cost reduction, my C is 1970, isn't your F from '67?

67 indeed. It was a good year in Kerrville. 

[Guest]

3 minutes ago, M20Doc said:

There are some misconceptions here on the elevator control system.  There are a series of push rods running through the belly, to a walking beam in the back of the fuselage, from there another single push rod goes to another walking beam in the tail cone, from there TWO control rods go aft to the elevators.  Every one is the same.

Clarence

 

[Shadrach]

On 9/3/2021 at 6:03 PM, jlunseth said:

Mine is on the right only, I did check it. It also is different in appearance than the photo you posted. There is a fairing coming out on the right side below the elevator that covers the rod. The one in the photo 1980mooney posted is also on the right. I would not think it was a cost reduction, there were changes to the elevator for the longer bodies. 

I suspect you are confusing your elevator and rudder linkages. The rudder has a fairing on the right side  there is no fairing on the elevator links. The links move more fore and aft than up and down.

[Blue on Top]

The elevators (left and right) are and always have been (including the wood empennage) separate control surfaces.  They have to be because their hinge lines are not co-linear.  

As @M20Doc and @1980Mooney have illustrated above, there have to be two push-pull tubes coming from the last idler bellcrank to drive each elevator independently.  It is this way on every airplane that I know about that has a swept hinge line.  

Some airplanes have a swept horizontal surface, but the hinge line is straight and have a single elevator horn on the centerline of the airplane.  The Cessna Citation CJ/CJ1 comes to mind.

[Raymond J1]

[Pilot boy]

On 9/3/2021 at 3:42 PM, Hank said:

@Shadrach, That's interesting. I'll check my C this weekend, I only recall two rods:  one to an elevator, one to the rudder. It may have been a cost reduction, my C is 1970, isn't your F from '67?

My 64 E has a rod on the underside of both sides of elevator.  So 2 rods and a separate one for rudder

[hoot777]

Caruasam said it pretty well. Hope we find some answers.

[hoot777]

Any updates on this accident???