VMC Demo Question

[bobbysamd]

Vmc recoveries

I would think that this instructor is rather wrong.

. . . and does not understand elementary aerodynamics to boot.

Think about it. You have full power going on the "good" engine, generating, among other things, lift over its wing by its propwash, with that lift being assymetric to the wing with the "bad" engine. And, of course, there is the critical altitude, at which stall speed and Vmc converge. Don't forget the yawing moment from the "good" engine. Combine the assymetric lift, stall speed, yaw and Vmc, and you have the recipe for a spin. And, as Cornholio noted, light twins do not go through spin testing as part of certification.

Good discussion.

 

[ktulu34535]

yeah... well its riddle

Well, the scary part is that this instructor told me that the standards people at Riddle are the ones promoting this. He said that they will no longer block the rudders and that they were wanting us to recover from VMC in the case of a stall with a recovery from a stall.

Scary crap coming from the people in charge of administering tests for ratings.

 

[bobbysamd]

yeah... well its riddle

Well, the scary part is that this instructor told me that the standards people at Riddle are the ones promoting this . . .

That doesn't surprise me. Sometimes, Riddle promoted some strange ideas. I instructed at ERAU-Prescott from late 1988-mid 1991. I remember a few discussions about blocking rudders during Vmc demos, but I didn't block rudder as a regular practice. We flew Seminoles, which don't have a true critical engine, and I might have done it once or twice during a multi course just so that students could see what Vmc might look like in a "real" twin. I also didn't block rudder when I gave stage checks. Other than that, I took it to about 55 kts, or wherever/whenever "Vmc" or a stall occurred first.

 

[DGdaPilot]

<cough> multi training should be done in a real multi airplane, not twin arrows <cough>

 

[great cornholio]

ktulu
When I first read this i thought Riddle was in it somehow...I went there so Im allowed to talk about it haha. But right before I got this job all the schools in DAB were talking about blocking the rudder or not to block. I actually think that the new PTS actually says something about NOT blocking it. Im not sure though cause the new PTS came out last august and I was lucky enough to land my current 121 job in Sept so I dont remember what was the deal with the new PTS but I do know it is addressed. You might want to look at your PTS if you have it handy. Mine is in a box somewhere so I cant look it up any info would be nice about it though. The other thing about DAB is that seneca crash about 2 years ago by Phil. If you dont remember or dont know he was checking out 2 MEI's and the crashed just short of 24 at flagler. They were doing a single engine landing with the RIGHT engine actaully shut down and feathered and were doing RIGHT HAND traffic then on base to final they VMC rolled it into the hiway. Phil almost lost his foot and one of the MEI's got burned real bad and was in the hospital for like a year. Anyways ever since that accident VMC has been a big deal down there in DAB. I would say that you need to ask your instructor "what does he mean by recover from it as a stall" hopefully he would say bring the power to idle and lower the nose to gain speed then bring up the power nice and slow. If he says add full power then ask him about entering a spin from the assymetric thurst. This way you can find out excactly what he meant and if he is wrong maybe you can right him before he teaches too many more students the wrong way and maybe save him from killing you or someone else.

 

[bobbysamd]

Real multis

<cough> multi training should be done in a real multi airplane, not twin arrows <cough>

Yep.

Wanna try a Bamboo Bomber or a Beech 18?

In all seriousness, though, DGdaPilot has a point. There is no way to truly replicate a Vmc demo in a Seminole, Duchess, etc.

Now, here's one that will get you. There were some MEIs at ERAU when I was there who dropped a notch of flaps when doing a Vmc demo in our Seminoles. Wrong-o! As I recall, the Chief Flight Instructor put a stop to that soon enough.

 

[Rick1128]

DG has a very good point. Having been a Training Captain and Check Airman for many years, I have noticed that pilots who have had their initial training on a 'real' multi engine aircraft perform much better on engine out manuvers. This seems especially true with pilots whos initial training was in an Apache. The Apache is so underpowered in its original form that even if you did everything right, it might not climb. But the difference between doing everything right and an error in procedure is very noticable. Also the systems of the aircraft are complex enought to require good systems management.

Personally, I believe that Beech and Piper forgot what they were really trying to develop when these aircraft were developed. They were trying to develop training aircraft. And as training aircraft they have to be forgiving, easy to fly and safe. But they also need to properly teach and allow the student to learn. And I personally believe that these aircraft are somewhat lacking in that regard.