Vmc Roll

NealRomeoGolf

NealRomeoGolf

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I am not multi rated and have never read up on Vmc rolls. If one starts, can you get out of it by pulling both engines to idle quickly or does it roll so fast you have no chance at that point?
 
Yes. Not sure what the present procedural recommendations are, but I had to demonstrate one on my ME ride. At the time (after 5°heading loss) it was pull the throttle 1/2 back and lower nose faster than red line. That may have changed.
 
In a Baron….over it goes even if you close BOTH throttles.
In a Seneca that is usually not true…
 
Depends. If the stall speed and Vmc are the same or very close to same number then it’s going to go on its back no matter how fast you react. If the Vmc is above stall you have a chance.
 
bbchien said:
In a Baron….over it goes even if you close BOTH throttles.
In a Seneca that is usually not true…
Click to expand...
Thank goodness you would close the throttle on the already dead engine.
 
Do your check ride in a rutan defiant; it won't be a problem.
 
Are twins worth it? I've never even flown in a GA twin before, so asking from a zero experience perspective. Given it wants to kill you with an engine out on landing and takeoff, there must be some qualities that twin owners like enough to make them twin owners.
 
Yes if u can afford it…Deep thoughts the airlines all have two engines and two pilots…. If i have a choice in traveling machine i choose two. For flying fun a cub on floats or a lake buccaneer is about as good as it gets. My personal preferences
 
bbchien said:
In a Baron….over it goes even if you close BOTH throttles.
In a Seneca that is usually not true…
Click to expand...
This is one of the reasons Vmc demos are such a waste of time. On airplanes like the Barons, the loss of control is largely due to the vertical stabilizer stalling—a very sudden loss of control. Airplanes designed for the training environment design that out.

plus, as instructors we’re taught to block a rudder pedal to make even the most vicious aircraft into a pussycat for the demo.

I think a much more effective training tool would be a cattle prod if the student gets below blue line with more than about 20” of MP on the good engine.
 
WDD said:
Are twins worth it? I've never even flown in a GA twin before, so asking from a zero experience perspective. Given it wants to kill you with an engine out on landing and takeoff, there must be some qualities that twin owners like enough to make them twin owners.
Click to expand...
Generally speaking, there’s at most a short window on takeoff where a delay in pitching down after an engine failure will result in flirting with Vmc. Shouldn’t be an issue anywhere else.

one of the bigger problems is doing the right thing makes the view out the windshield too scary. But that’s no different than a single.
 
WDD said:
there must be some qualities that twin owners like enough to make them twin owners.
Click to expand...

Single engine plane with an engine failure, you glide to the crash site.

Twin engine plane with an engine failure, you fly to the crash site...

All kidding aside, training and recurrent training in a twin is very important. One hour every two years is NOT enough. On initial twin training one leg WILL get a work out. (usually the left leg gets the work out because most hobbs meters are on the left engine)
 
WDD said:
Are twins worth it? I've never even flown in a GA twin before, so asking from a zero experience perspective. Given it wants to kill you with an engine out on landing and takeoff, there must be some qualities that twin owners like enough to make them twin owners.
Click to expand...
Flying over water, at night, on top of LIFR in a single things will get very interesting with an engine failure.

In a twin, less interesting.
 
NealRomeoGolf said:
I am not multi rated and have never read up on Vmc rolls. If one starts, can you get out of it by pulling both engines to idle quickly or does it roll so fast you have no chance at that point?
Click to expand...
Yes. Nose down, aileron neutral, both engines to idle. Step on high wing

We did a number of VMC demo's, at least in the case of a Beech Duchess and Piper Aztec it was relatively tame and didn't actually "lose it" until around 60 knots, well below red line. It is dramatic and severe though that initial wing drop. I'm quite certain you would be hosed if it happened close to the ground

You get about five knot warning though with a fairly noticeable buffer

The Duchess and Aztec are tame airplanes, I imagine a 340, Aerostat, etc would be handful
 
MauleSkinner said:
plus, as instructors we’re taught to block a rudder pedal to make even the most vicious aircraft into a pussycat for the demo.
Click to expand...
Interesting, we didn't do this. I had my foot on the floor until over it went. Recovery was swift after closing both engines and pushing the nose down. But to your point, this was in trainers or a big lopey easy to fly twin
 
WDD said:
Are twins worth it? I've never even flown in a GA twin before, so asking from a zero experience perspective. Given it wants to kill you with an engine out on landing and takeoff, there must be some qualities that twin owners like enough to make them twin owners.
Click to expand...
Yes, totally worth it. But you have to stay proficient. An IFR rating is not worth it either if you never fly IMC and your only 'experience' is the obligatory 6 approaches every 6 months with a safety pilot friend.

My experience is with tame twins, a Beech Duchess (purpose built trainer) and an Aztec. Both have low VMC speeds and by the time you rotate you're generally near blue line away, at least above red line for sure

Losing an engine in the 15 seconds between rotation and getting the gear up and a few hundred feet of altitude/over blue line is (A) super bad luck and (B) potentially deadly in any airplane. Many urban airports don't have a good spot to glide a 172 down either.

Losing an engine during landing or approach is not as bad, you're already descending, you already have the good engine making less power. Follow the process, you oughta be fine

Losing one in cruise. Fairly mundane. You don't hear about successful single engine landings often, a friend recently had a 421 lose oil pressure in an engine at FL200. They reduced power, and ultimately shut the good engine and did an uneventful landing. There was an Aerostar at Ramona a few years ago who lost an engine (like properly lost it, jug came off) they made it. And a Duchess around here recently had an engine failure (unknown cause yet) and they also had an uneventful landing.

Totally totally worth it, unless you're flying <50 hrs a year and can't be bothered to maintain proficiency.

Mind you, virtually all your multi training is focused around inoperative engines. This becomes a familiar site after a while:
upload_2022-4-27_12-9-52.png
 
WDD said:
Are twins worth it? I've never even flown in a GA twin before, so asking from a zero experience perspective. Given it wants to kill you with an engine out on landing and takeoff, there must be some qualities that twin owners like enough to make them twin owners.
Click to expand...
Twins are like instrument ratings and any other upgrade in capability: they all require a corresponding upgrade in your commitment to maintain proficiency, but give you the ability to do things you otherwise couldn’t. The same is true of four wheel drive pickups. You can go more places than in a two wheel drive, but you actually have to be more careful because, when you get stuck, it will be a lot harder to get unstuck. (A similar analogy applies to driving in two wheel drive mode until you get stuck, then using four wheel drive to get out instead of using the added capability to just get stuck worse.)

For me, the twin versus single provides:
  • More weather capability. I don’t have a FIKI plane but the hot props and boots plus faster climb mitigate some of the risk of inadvertent icing.
  • More options in the event of an engine failure, especially during night, IMC, or over inhospitable terrain. I won’t clear a 14,000-foot peak on one engine at gross weight, but when I don’t load the thing to the gills and plan well I have a very good chance of landing at an airport if an engine fails.
  • More speed. For the $200 double cheeseburger (which is the twin-engine version of the $100 hamburger), it doesn’t matter. But on a 1,000-mile trip it makes a real difference, especially because headwinds are a smaller fraction of your TAS and thus don’t hurt as bad.
  • More load carrying ability. I can fill the tanks and the seats, provided that seats 5 and 6 are considered “full” when a child sits in them. This also means a lot more margin in normal flying when the tanks and seats are all half full and I’m flying around 800 lbs under gross.
It just costs more and requires more of me. But I love flying and apparently hate money, so it’s a good trade.
 
it really depends on the aircraft and the airfoil designs used. trainers such seminoles, apache's, and the duchess have a more benign VMC roll over. higher performance twins like the baron and twin comanche have a more pronounced snap like entry. with any twin the problem is really bad once the rotation starts, due to the momentum of the rotation, it is often impossible to overcome the rotation. mauleskinner is right, the VMC demo is worthless, instructors tend to teach how to do a Vmc demo, not what needs to be taught, how to recognize the plane is not happy and how to fix it NOW. Vmc is one of those things where you have a small window to fix it before it becomes deadly.
 
Tantalum said:
Yes, totally worth it. But you have to stay proficient. An IFR rating is not worth it either if you never fly IMC and your only 'experience' is the obligatory 6 approaches every 6 months with a safety pilot friend.

My experience is with tame twins, a Beech Duchess (purpose built trainer) and an Aztec. Both have low VMC speeds and by the time you rotate you're generally near blue line away, at least above red line for sure

Losing an engine in the 15 seconds between rotation and getting the gear up and a few hundred feet of altitude/over blue line is (A) super bad luck and (B) potentially deadly in any airplane. Many urban airports don't have a good spot to glide a 172 down either.

Losing an engine during landing or approach is not as bad, you're already descending, you already have the good engine making less power. Follow the process, you oughta be fine

Losing one in cruise. Fairly mundane. You don't hear about successful single engine landings often, a friend recently had a 421 lose oil pressure in an engine at FL200. They reduced power, and ultimately shut the good engine and did an uneventful landing. There was an Aerostar at Ramona a few years ago who lost an engine (like properly lost it, jug came off) they made it. And a Duchess around here recently had an engine failure (unknown cause yet) and they also had an uneventful landing.

Totally totally worth it, unless you're flying <50 hrs a year and can't be bothered to maintain proficiency.

Mind you, virtually all your multi training is focused around inoperative engines. This becomes a familiar site after a while:
View attachment 106428
Click to expand...

Do you feel safe in a twin now?
 
unsafervguy said:
Vmc is one of those things where you have a small window to fix it before it becomes deadly.
Click to expand...
to this point, even in the relative safety of 7K agl you go from "this feels wrong" to "wow this feels very wrong buffeting" to "yup, there goes the wing!" I can't imagine that happening down low, in IMC, in a hike workload, etc. But to me at least practicing the demo helped me take this from a theoretical concept to seeing how it feels in real life, mainly, the second or three just before the rudder stalls and the wing drops. Moral of the story, never get that slow or behind the plane

unsafervguy said:
the VMC demo is worthless, instructors tend to teach how to do a Vmc demo, not what needs to be taught, how to recognize the plane is not happy and how to fix it NOW.
Click to expand...
I suppose we'll never really know if my, or anyone's instruction, is adequate until you're in a spot dealing with an engine failure in real life. In my experience the VMC demo was most valuable to understand how it feels as you approach it

High performance twins are awesome, but the thing that keeps me coming back to the Aztec is how easy it is fly. Polar opposite from the Cirrus I was flying before, but I appreciate its handling qualities.
 
PaulS said:
Do you feel safe in a twin now?
Click to expand...
I don't really feel unsafe in any plane necessarily, but I like seeing two engines out there. I'm a believe in CAPS, but I prefer a second engine. It's not strictly about safety, as the post above pointed out that second engine gets you an added degree of flexibility a single simply doesn't
 
unless we know the #’s of how many twins lost an engine, in flight, and then landed safely because they had a second engine, there’s no way to quantify the safety, or danger, of the second engine.
 
Tantalum said:
Yes, totally worth it. But you have to stay proficient. An IFR rating is not worth it either if you never fly IMC and your only 'experience' is the obligatory 6 approaches every 6 months with a safety pilot friend.

My experience is with tame twins, a Beech Duchess (purpose built trainer) and an Aztec. Both have low VMC speeds and by the time you rotate you're generally near blue line away, at least above red line for sure

Losing an engine in the 15 seconds between rotation and getting the gear up and a few hundred feet of altitude/over blue line is (A) super bad luck and (B) potentially deadly in any airplane. Many urban airports don't have a good spot to glide a 172 down either.

Losing an engine during landing or approach is not as bad, you're already descending, you already have the good engine making less power. Follow the process, you oughta be fine

Losing one in cruise. Fairly mundane. You don't hear about successful single engine landings often, a friend recently had a 421 lose oil pressure in an engine at FL200. They reduced power, and ultimately shut the good engine and did an uneventful landing. There was an Aerostar at Ramona a few years ago who lost an engine (like properly lost it, jug came off) they made it. And a Duchess around here recently had an engine failure (unknown cause yet) and they also had an uneventful landing.

Totally totally worth it, unless you're flying <50 hrs a year and can't be bothered to maintain proficiency.

Mind you, virtually all your multi training is focused around inoperative engines. This becomes a familiar site after a while:
View attachment 106428
Click to expand...

I have like 100 hours in 3803E!
 
Mxfarm said:
unless we know the #’s of how many twins lost an engine, in flight, and then landed safely because they had a second engine, there’s no way to quantify the safety, or danger, of the second engine.
Click to expand...
We’d have to know the same unknowable information about singles.
 
Mxfarm said:
there’s no way to quantify the safety, or danger, of the second engine.
Click to expand...

Haven’t insurance companies done that?

If twins produced fewer bad crashes, liability insurance would cost less than for singles.
 
I asked the question thinking about the Richard Collins revelation that at the time the idea was 2 engines are safer because of the redundancy, but he pointed out that this wasn't true, that they were actually were statistically worse than SE when an engine failed. Pilots were flubbing it and lawn darting into the ground.

I'm considering going multi, it seems the risk can be mitigated with recurrent training and maintaining proficiency. Just like most flying.
 
bbchien said:
In a Baron….over it goes even if you close BOTH throttles.
In a Seneca that is usually not true…
Click to expand...

Yep. I can vouch for that.

The little twins are pretty docile intentionally, for training. Dutchess and Seminole have plenty of control authority at stall speed. Aztec is so wing heavy, it just sort of slowly rolls over, then stops with both engines at idle.
 
Did it once in the sim with 2 engines out in a 747 many years ago. I was heads down running the checklist to put out out the fire on the second failed engine while the captain, who was flying, got slow and I wasn't watching him closely enough. A kiss of stick shaker, so he added full power on 3 and 4, the thing immediately went on its back at 3000 AGL. Game over, no surviving. Pretty solid nightmare fuel for me.

From what I remember in the Seneca 1 and Baron 55 I trained in, the VMC demos were a non event because we blocked rudder at 10 knots or so above published VMC. That was 20 years ago though.
 
Tantalum said:
Interesting, we didn't do this. I had my foot on the floor until over it went. Recovery was swift after closing both engines and pushing the nose down. But to your point, this was in trainers or a big lopey easy to fly twin
Click to expand...

That is very scary. I got my MEI in about 1985 and even that far back the FAA was expecting (demanding?) we block the rudder to simulate VMC at a higher IAS. Part 23 airplanes are pretty tame, but intentionally going beyond the edge of controllability . . . no thanks.
 
Arnold said:
That is very scary. I got my MEI in about 1985 and even that far back the FAA was expecting (demanding?) we block the rudder to simulate VMC at a higher IAS. Part 23 airplanes are pretty tame, but intentionally going beyond the edge of controllability . . . no thanks.
Click to expand...
Who knows in that case, maybe we did? This was a couple years ago at this point. What I do know is you'd have to get pretty far behind the plane to get to that point. You get plenty of warning from the plane that it's not happy. But people also land gear up.. so, I digress
 
Tantalum said:
Who knows in that case, maybe we did? This was a couple years ago at this point. What I do know is you'd have to get pretty far behind the plane to get to that point. You get plenty of warning from the plane that it's not happy. But people also land gear up.. so, I digress
Click to expand...

Never been in a twin. You’re saying as the yaw starts to go push the nose, pull the throttles and you should be good?

The issue is the urge to pull vs push close to the ground?
 
Tantalum said:
Who knows in that case, maybe we did? This was a couple years ago at this point. What I do know is you'd have to get pretty far behind the plane to get to that point. You get plenty of warning from the plane that it's not happy. But people also land gear up.. so, I digress
Click to expand...
I’m thinking your instructor was blocking the rudder and you forgot or didn’t notice. The point of blocking is to provide some margin if the student doesn’t recover from the Vmc correctly. It’s not there to make it more tame. More like survivable if the student screws up.
 
Terry M - 3CK (Chicago) said:
Never been in a twin. You’re saying as the yaw starts to go push the nose, pull the throttles and you should be good?

The issue is the urge to pull vs push close to the ground?
Click to expand...
#1 close both throttles, that's a big part of it
#2 get the nose down, you want both wings flying again

Are the two big steps, yes, I would assume if you're at 200' closing the throttles and pushing the nose down are not going to feel right. But the point is more to not get there in the first place. These maneuvers really should be trained often.

btw, Beech did a whole series of spin tests in the Duchess, including with a failed engine. Yes, it's a humble and docile trainer (in Beech's eyes, an "unsophisticated wing"), but still pretty wild to see a larger plane (relative to 172/182/PA28) doing these kinds of maneuvers, tumbling out of the sky
 
^also an educational video, PS, about twins and how they stall / spin
 
I wonder if there's demand for a new twin engine single prop experimental design for general aviation? 2 engines feeding power into a transmission for 1 prop. Some dual engine helicopters achieve this right? Perhaps a smaller version of Soloy Dual Pac? https://www.soloy.com/dual-pac.html
 
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