Mooney Bravo accident, Victoria MN 8/7/21 NTSB final report

[jaylw314]

Did we miss this?  It apparently came out last month, and they did suggest both spars had failed before the crash  

Report_CEN21FA360_103651_4_21_2023 8_30_04 PM.pdf

[hubcap]

I believe this was discussed in the Safety & Accident forum

[Hank]

The thread is here:  

 

The wing spar failed due to an 8.5g pull up when the Bravo fell out the bottom of the clouds and the ground became visible. 

[jaylw314]

Wow, I missed all that, and I used all the wrong search words, thanks guys

[PT20J]

And, perhaps now we can dispense with the myth that the Mooney wing is unbreakable. 

[Austintatious]

Well, we know the wing is strong, but 8.5 g's ....  holy smokes!

 

also from the report

 

... A friend of the accident pilot stated that the pilot had adopted an instrument flying habit in the
Mooney airplane that involved making turns on approach primarily with the rudder and
adjusting pitch attitude with the pitch trim.

 

Is this a thing?  I have never heard of this, nor would I recommend it.  I may be misunderstanding, but as I read this it would suggest he just used the rudder which would cause uncoordinated flight... something one should avoid in IMC.

[jaylw314]

3 hours ago, Austintatious said:

Is this a thing?  I have never heard of this, nor would I recommend it.  I may be misunderstanding, but as I read this it would suggest he just used the rudder which would cause uncoordinated flight... something one should avoid in IMC.

I guess I sort of get it?  If you're gentle, the plane will eventually roll into the turn, so it allows you to fly hands off the yoke for a while, and I've seen some VFR guys do that in the flying club.  IMC, though?

 

15 hours ago, PT20J said:

And, perhaps now we can dispense with the myth that the Mooney wing is unbreakable. 

I did think the wing spar was not broken.  Not because of the Titanic thing, but because the video recording looked so strange I figured it must be a rolling shutter artifact, so I was surprised to see that the wreckage evidence did suggest both spars had broken.

[PT20J]

6 hours ago, Austintatious said:

Is this a thing?  I have never heard of this, nor would I recommend it.  I may be misunderstanding, but as I read this it would suggest he just used the rudder which would cause uncoordinated flight... something one should avoid in IMC.

All airplanes naturally have some roll-yaw coupling. I believe it was a certification requirement to be able to make turns using the rudder if the aileron control system failed. If the airplane doesn’t  have enough coupling, interconnect springs (like on the Mooneys) are often added. This makes it possible to make small heading changes (less than 5 deg) using the rudder on a precision approach. 

Controlling pitch with trim is only an emergency maneuver because it is very easy to get behind the dynamics (i.e., phugoid) of the airplane and lose control. 

Skip

[Hank]

1 hour ago, PT20J said:

All airplanes naturally have some roll-yaw coupling. I believe it was a certification requirement to be able to make turns using the rudder if the aileron control system failed. If the airplane doesn’t  have enough coupling, interconnect springs (like on the Mooneys) are often added. This makes it possible to make small heading changes (less than 5 deg) using the rudder on a precision approach. 

Controlling pitch with trim is only an emergency maneuver because it is very easy to get behind the dynamics (i.e., phugoid) of the airplane and lose control. 

Skip

The accident pilot does not appear to have been making small course corrections with rudder,rather all course changes such as intercepting final, and usi g the trim to control descent rather than using the yoke to establish descent then trimming it to maintain desired rate thus established. 

That's why we're all confused . . . .

[Austintatious]

13 hours ago, PT20J said:

All airplanes naturally have some roll-yaw coupling. I believe it was a certification requirement to be able to make turns using the rudder if the aileron control system failed. If the airplane doesn’t  have enough coupling, interconnect springs (like on the Mooneys) are often added. This makes it possible to make small heading changes (less than 5 deg) using the rudder on a precision approach. 

Controlling pitch with trim is only an emergency maneuver because it is very easy to get behind the dynamics (i.e., phugoid) of the airplane and lose control. 

Skip

While what you say is true, still, pushing the rudder only will put you out of coordinated flight.... Seems like a really bad idea to me in IMC, but what do I know.

[Austintatious]

Yeap, the virtigo aspect is exactly why I think it is a bad idea.

 

When I first started instrument flying, I almost always got virtigo, BAD.  For a long time I thought it was that way for everyone and that was why I had to trust my instruments... I flew a lot of approaches leaning against the side of the airplane...  wasnt fun but it made me really good on instruments!   It went away after a year or so.  Haven't had it for a long time.

[PT20J]

5 hours ago, Austintatious said:

While what you say is true, still, pushing the rudder only will put you out of coordinated flight.... Seems like a really bad idea to me in IMC, but what do I know.

Not really. For very small corrections, like 2 or 3 degree heading changes, the amount of control input is so small whether you use the rudder or ailerons that the sideslip angle is negligible. Making these tiny corrections with the ailerons is actually more workload because the roll angle required is so small and it has to be immediately removed as soon as the heading starts to change and mechanical heading indicators had some lag for small changes due to internal friction.

This is a technique taught by some from the old days of flying raw data ILS where the proper technique is the stop, hold, and then reverse localizer needle movement by making and holding very small heading changes. In my experience though, very few pilots could hold a heading accurately enough to  utilize it and most just chase the needles around. It takes a lot of practice to be able to fly a raw data ILS without an HSI down to 200’ (and below) with the needles centered.   Nowadays, with my flight director, it’s a piece of cake.

Skip

[Hank]

15 minutes ago, PT20J said:

Not really. For very small corrections, like 2 or 3 degree heading changes, the amount of control input is so small whether you use the rudder or ailerons that the sideslip angle is negligible. Making these tiny corrections with the ailerons is actually more workload because the roll angle required is so small and it has to be immediately removed as soon as the heading starts to change and mechanical heading indicators had some lag for small changes due to internal friction.

This is a technique taught by some from the old days of flying raw data ILS where the proper technique is the stop, hold, and then reverse localizer needle movement by making and holding very small heading changes. In my experience though, very few pilots could hold a heading accurately enough to  utilize it and most just chase the needles around. It takes a lot of practice to be able to fly a raw data ILS without an HSI down to 200’ (and below) with the needles centered.   Nowadays, with my flight director, it’s a piece of cake.

Skip

What's an HSI? I've flown many ILSes using the VOR head in my C. Didn't seem especially challenging, just did one on my IPC last year.

[PT20J]

34 minutes ago, Hank said:

What's an HSI? I've flown many ILSes using the VOR head in my C. Didn't seem especially challenging, just did one on my IPC last year.

Not an issue if you learned that way, and stay proficient. On many IPCs I’ve given, the ILS needles look like a sword fight.