Bonanza breakup video analysis, how does it affect Mooney?

[201er]

Scott Perdue describes the recent in flight break up of N47WT. In the video he explains the importance of spiral divergence recovery training and demonstrated some G load math for varying airplanes including Mooney. 
 

Here is a good explanation of spiral divergence: 

https://aerospacenotes.com/flight-dynamics/spiral-divergence/

 

I’m not aware of any in flight break ups of a Mooney. Has it ever happened? Do Mooneys end up a smoking crater intact when they experience spiral dive due to spatial disorientation? 
 

What insight or advice do you have on this topic as it pertains to Mooneys specifically?

 

 

[Hank]

As far as I know, exactly one Mooney, a Bravo I think, has broken up in flight a couple of years ago. Spatial disorientation led to a high speed dive, and when he fell out of the clouds he pulled up too hard, folded both wings, ripped off the horizontal stabilizers and pancaked in someone's front yard.

It was the pull up that broke the plane; the recent Bo broke up simply from exceeding Vne, also due to spatial disorientation.

Each airframe has its own weaknesses, and both are slippery and accelerate quickly when pointed down.

[exM20K]

1 hour ago, 201er said:

I’m not aware of any in flight break ups of a Mooney. Has it ever happened? Do Mooneys end up a smoking crater intact when they experience spiral dive due to spatial disorientation? 

there has been a handful of breakups.

The Bravo @Hank mentions

This one: https://aviation-safety.net/wikibase/37799

I recall a Rocket that flew into convective weather, also.

I haven't tried the hands-off spiral and roll-level in a mooney.  It is reasonable to assume it tries to pitch for trim airspeed like any other plane.

-dan

 

[PT20J]

I've tried it. I had a discussion long ago with aeronautical engineer and handling qualities consultant Roger Hoh who pointed out that not all airplanes wind up tighter and tighter and faster and faster until making a smoking hole in the ground. Spiral divergence is caused by the directional stability being greater than than the lateral stability. But the longitudinal stability can be a factor also. Normally a Mooney phughoid lasts about 2-1/2 cycles. If you get the airspeed right (trimmed to about maneuvering speed) and the airplane is well rigged, I've let a spiral start power off and watched it stabilize in about a 45-degree bank and get almost to redline before the nose started up and then it got almost to stall before the nose came back down and then did this another time and a half with lower amplitude each time until it finally stabilized at trim speed in a 45 degree descending turn. This was long ago in my 1978 M20J. I haven't tried it in my 94 J.

[Ragsf15e]

I get that there’s a lot of aerodynamics and design in this, but the basic vfr and ifr recovery techniques still apply perfectly.  First, practice instruments a lot so you don’t get in an unintentional spiral.  If you do, power off, roll level, pull up (gently).  I would expect my instrument students to successfully recover from a (admittedly not near Vne) spiral during unusual attitude training.  If we’re not current and end up in a bad situation, or delay the appropriate recovery long enough there are a myriad of ways to hit the ground or rip the wings off any airplane.

[jlunseth]

When the Victoria crash (the Bravo) happened several of us did some research on incidents where a Mooney “came apart” in flight. As I recall there had been about four prior to the Victoria crash, but in the prior incidents the failure was in the negative. I say “about” because at least one of the prior reports was fairly cryptic and it was a little difficult to determine what the failure mode was. The Bravo crash is the only one that I recall reading about where the failure was in the positive. It was unfortunately dramatic, there was door cam footage of the plane hitting the ground nose high with both wings failed upward. One side of the horizontal stabilizer had also departed. 

[Jerry 5TJ]

6 hours ago, Ragsf15e said:

If we’re not current and end up in a bad situation, or delay the appropriate recovery long enough there are a myriad of ways to hit the ground or rip the wings off any airplane.

The most important thing is to maintain control as loss of control in IMC rarely turns out well.  In-flight breakup is often a result of LOC, not the cause of the accident:  It matters little if the wings are intact at impact.  

[201er]

12 minutes ago, Jerry 5TJ said:

The most important thing is to maintain control as loss of control in IMC rarely turns out well.  In-flight breakup is often a result of LOC, not the cause of the accident:  It matters little if the wings are intact at impact.  

If the wings remain attached, it still leaves some possibility of a late recovery 

[dkkim73]

11 hours ago, Ragsf15e said:

I get that there’s a lot of aerodynamics and design in this, but the basic vfr and ifr recovery techniques still apply perfectly.  First, practice instruments a lot so you don’t get in an unintentional spiral.  If you do, power off, roll level, pull up (gently).  I would expect my instrument students to successfully recover from a (admittedly not near Vne) spiral during unusual attitude training.  If we’re not current and end up in a bad situation, or delay the appropriate recovery long enough there are a myriad of ways to hit the ground or rip the wings off any airplane.

This got me thinking about how unusual attitudes come to pass in IMC. The scenarios I can envision at first blush are: 

-autopilot mode confusion (it's not flying the airplane, and the pilot is looking at Foreflight ;))

-autopilot-facilitated trim stall and upset (in any ALT mode other than PIT(ch) and get out of sync on power setting, eg. reducing to descend on intermediate segment, got distracted, etc)

-bad turbulence

-handflying with a paper chart out of nostalgia and got distracted (ok less likely except in failure situation)

 

The Scott Perdue video mentions a "spiral divergence exercise" to get a sense of the natural progression, starting 45 degrees bank from straight-and-level, no trim change, with KIO criteria of 160kts and 60degrees bank. Not clear what speed he starts at.   @PT20J describes an interesting experiment. To the CFI(I)s here: what would be good entry conditions for such an exercise in a Mooney? 

D

[201er]

3 hours ago, dkkim73 said:

The Scott Perdue video mentions a "spiral divergence exercise" to get a sense of the natural progression, starting 45 degrees bank from straight-and-level, no trim change, with KIO criteria of 160kts and 60degrees bank. Not clear what speed he starts at.

 

[dkkim73]

Excellent, thank you. That's a good video.

Trim for 100KIAS in the setup, roll to 45 and let it go, for those that don't watch it. I imagine that's not crazy far off what would be reasonable in a Mooney, given the cruise speeds, though a bit faster would be better simulation (eg. 120-140 KIAS for busy instrument phases in the long bodies). 

While I like crisp, fast roll (some of the most fun GA flying was the Super Decathlon), this video makes me happy that my IFR commuter bird is a *Mooney* (fist bump) not a doctor-killer, er, I mean Bonanza...

D

 

 

 

[GeeBee]

There are some questions here if the top wing wing tension bolt let go before maximum design loading. If so, look for a lot of moaning from the Bonanza community as they got the same issues as the Beech 18 and the earlier King Airs. Can anyone say, "spar strap"?

[Fly Boomer]

I was trying to follow Perdue's math lesson and, if I understood correctly, he said VNE on a Mooney is 175.  I don't know what Mooney he is talking about, but I think 175 cruise is available to many of our birds.

[201er]

46 minutes ago, Fly Boomer said:

I was trying to follow Perdue's math lesson and, if I understood correctly, he said VNE on a Mooney is 175.  I don't know what Mooney he is talking about, but I think 175 cruise is available to many of our birds.

Yeah, wondered about that too. That lines up with about the bottom of my yellow arc.

Maybe someone who followed his math can actually translate that into real Mooney numbers?

[Hank]

14 hours ago, Fly Boomer said:

I was trying to follow Perdue's math lesson and, if I understood correctly, he said VNE on a Mooney is 175.  I don't know what Mooney he is talking about, but I think 175 cruise is available to many of our birds.

Vne for my C is 200 mph = 175 knots.

Older models have lower Vne. 175 mph? 185 mph? I forget.

This is where units are important. 175 mph is indeed the top of the green / bottom of the yellow on my airspeed indicator. 

[Fly Boomer]

9 hours ago, Hank said:

Vne for my C is 200 mph = 175 mph

Did not realize that.  I just got my dander up a little because his list showed Mooney as slower than all the Bonanzas he discussed.

[Brandt]

2 hours ago, Fly Boomer said:

Did not realize that.  I just got my dander up a little because his list showed Mooney as slower than all the Bonanzas he discussed.

I pointed out his error to him in the comments section on the youtube video. 

[Hank]

2 hours ago, Fly Boomer said:

Did not realize that.  I just got my dander up a little because his list showed Mooney as slower than all the Bonanzas he discussed.

Oops! Just edited my response above, because 200 mph = 175 knots.

Also, Bonanza start at 235hp for the older ones, and the newer ones are 285hp. I'd expect them to all cruise faster than any vintage Mooney, plus K, M and R models with lesser power.

The 310hp models should all be faster, as should the turbocharged models, although there are many turbonormalized Bos out there.

Comparing the speed of my 180hp Vintage Mooney against any Bonanza is unfair. But I'll go up against any of them on nautical miles per gallon!

[cliffy]

The Bonanza actually started with a 125 HP Lyc O-290 (1st airframe test unit)

Then it went to the Cont E-185 with 165 HP and then to the E-185 with 185 HP

From  there many variants were added O-470. Io470, Io-520 nd the IO-550. 

In the original 165 HP model the performance was similar to our C model airplanes.

[Shadrach]

12 hours ago, Fly Boomer said:

Did not realize that.  I just got my dander up a little because his list showed Mooney as slower than all the Bonanzas he discussed.

Scott seems like a nice guy. I don’t think it’s intentional but as a Bonanza guy, it becomes second nature to represent other makes as inferior.
What he’s done here is take the the Vne of the vintage birds and early 201 and the clean stall speed of some other heavier Mooney.

The numbers to calculate for my bird would be as follows:

Vne = 175kias
Vs1 = 58kias 

Max G available = 9.103

He uses:

Vne = 175kias
Vs1 = 63kias 

Max G available = 8

The number’s he uses are not representative of any Mooney with which I am familiar.

[jetdriven]

5 hours ago, Hank said:

Oops! Just edited my response above, because 200 mph = 175 knots.

Also, Bonanza start at 235hp for the older ones, and the newer ones are 285hp. I'd expect them to all cruise faster than any vintage Mooney, plus K, M and R models with lesser power.

The 310hp models should all be faster, as should the turbocharged models, although there are many turbonormalized Bos out there.

Comparing the speed of my 180hp Vintage Mooney against any Bonanza is unfair. But I'll go up against any of them on nautical miles per gallon!

We’ve air raced  a few 225 horse bonanzas and a good J model is about the same speed. But with all the 285 hp bonanza, the Mooney bravo, Acclaim, and Ovation can take it. Remember the ovation can cruise at 185 kn and those 285 Bonanzas they are about 172 to 175. 

[hais]

Are A/P level buttons approved for recovery? I can't seem to find approval nor prohibition in our POH supplements.

Appears safe for some models, would be nice to know for our models.

https://airfactsjournal.com/2020/08/recovery-from-spirals-with-the-lvl-button/

[RescueMunchkin]

I watched the youtube video posted above and am having trouble understanding why the recovery they stated is to push forward on the yoke.  Here's what's happening as I understand it:

After rolling to 45 and letting go, the plane gets faster and the bank angle wants to increase.  They recover at 60 degrees of bank or 140KIAS, whichever comes first

Recovery is to roll back to wings level and push forward on the yoke, but why push forward?  Wouldn't pushing forward cause even more increase in speed?  Or is it that the trim of the aircraft is trying to cause too much pitch up and potentially overstresses the airframe if pitch is left unchecked?

[Fly Boomer]

1 minute ago, RescueMunchkin said:

Or is it that the trim of the aircraft is trying to cause too much pitch up and potentially overstresses the airframe if pitch is left unchecked?

That's what I was imagining.  As you approach VNE, if it's still trimmed for a lower speed, it will probably want to go straight up unless you push.

[EricJ]

15 minutes ago, RescueMunchkin said:

Or is it that the trim of the aircraft is trying to cause too much pitch up and potentially overstresses the airframe if pitch is left unchecked?

Yes, it's trimmed for a much lower speed, so it tries to pitch up to reduce airspeed.   Pushing forward reduces the rate of pitch-up to reduce the g-load in the recovery.