Vsse

futboler14 · Post by **futboler14** » Sun Dec 09, 2007 4:27 pm

I have a question about Vsse.

I've tried looking for information from books and the internet about certain configurations that affect your one engine inoperative speed. I need to know how the following factors that will either decease or increase Vsse.

1) extension of landing gear; (I think Decrease)
2) extension of flaps; (I think Deceease)
3) extension of both flaps and kanding gear; ( Decrease?)
4) windmilling propeller of inop. engine (Increase)

Any help would be sweet.

tired of the ground · Post by **tired of the ground** » Sun Dec 09, 2007 5:14 pm

Do you mean Vmc or Vsse?

futboler14 · Post by **futboler14** » Sun Dec 09, 2007 6:03 pm

I know Vmc realy good and I think thats why I'm getting confused. To me Vmc and Vsse sounds like they have pretty similar characteristics.

Intentional safe speed is just a saftey buffer speed above Vmc and stall speed.

Ill just ask my instructor tomorrow morning. I have my multi ride tomorrow and just looked at the Multi standards guide and saw it in there. (woops) I should have looked at it earlier. My fault.

200hr Wonder · Post by **200hr Wonder** » Sun Dec 09, 2007 6:29 pm

I got the Jepp multi engine book and according to them Vsse is the following:

Intentional one engine inoperative airspeed. Vsse is not an airspeed defined by the FAA, but rather an airspeed developed by the manufacturer. It is considered the minimum speed for intentionally rendering one engine inoperative in flight for pilot training.

Which sounds to me like it is simply a speed with a fudge factor above Vmc for safety, so all things that affect Vmc affect Vsse.

idratherbeflying · Post by **idratherbeflying** » Sun Dec 09, 2007 6:47 pm

Vsse is just the speed that if you are below you do not want to intentionally shut an engine down because you can get near Vmc

futboler14 · Post by **futboler14** » Sun Dec 09, 2007 7:09 pm

yah so im assuming the same factors that affect Vmc must also affect Vsse

4Stroke · Post by **4Stroke** » Sun Dec 09, 2007 9:14 pm

the same factors that affect Vmc must also affect Vsse

I believe like was said above, Vsse is just a manufacturer number, and doesn't change like Vmc does for all those factors. You only worry about Vsse when INTENTIONALLY shutting one down.

If it fails on its own accord, I'd be looking at Vyse, Vmc, etc...

4S

200hr Wonder · Post by **200hr Wonder** » Mon Dec 10, 2007 1:58 am

Yes but lets assume that there is a 10knot fudge factor in there between Vmc and Vsse I think it would be prudent for the sake of safety to assume that Vsse changes in the same manner as Vmc.

flight instructor · Post by **flight instructor** » Mon Dec 10, 2007 10:27 am

Nothing affects vsse, because this is not a performance speed. This is a reference speed that has to be used and known by the flight instructor/training captain when he wants to fail one engine for training purpose. Not by the pilot.

However if you wish to increase VSSE because of the flaps, gear, Center of gravity it sounds like a good idea, and increase vsse as vmc increases why not!

I have never seen a flight instructor/training captain waiting vsse to fail one engine. I fail one engine at normal speed (approach speed if during approach, cruise speed if during cruise...) which is well above vsse.

Vsse is the extreme limit concerning the speed at wich the flight instructor can intentionaly fail one engine, whatever the configuration.

V1 Rotate · Post by **V1 Rotate** » Mon Dec 10, 2007 10:29 am

200hr Wonder wrote:Yes but lets assume that there is a 10knot fudge factor in there between Vmc and Vsse I think it would be prudent for the sake of safety to assume that Vsse changes in the same manner as Vmc.

Vmc is a limitation, flight tested for in the certification process, Vsse is derived from that.

Cat Driver · Post by **Cat Driver** » Mon Dec 10, 2007 11:05 am

One thing for certain VMC is something instructors should stay far, far away from.

Hedley · Post by **Hedley** » Mon Dec 10, 2007 11:11 am

What I think is funny is when people decide to do a Vmc
demo at high altitude "for safety" and end up demonstrating
something else entirely

trey kule · Post by **trey kule** » Mon Dec 10, 2007 11:59 am

Cat wrote:

One thing for certain VMC is something instructors should stay far, far away from.

I alway thought that VMC was not only a speed, but also a speed at a certain configuration/power settings

Perhaps you meant doing a VMC demonstration, for as, Hedley posted, unless you really understand what VMC is all about there can be some really nasty surprises.

Having said that Cat, the speed intself is not an issue as you seemed to make it. Where VMC is above the stall speed (it is not always), on most training types of twins you can bring them through the speed and into a stall quite nicely. The understanding is about asymetic thrust, and the other variables.

Many readers here take your advice seriously, and with the misunderstandings I have seen from some of the new hires, perhaps you could clarify or restate your post

THEICEMAN · Post by **THEICEMAN** » Mon Dec 10, 2007 12:02 pm

Cat Driver wrote:One thing for certain VMC is something instructors should stay far, far away from.

Why? Instructors should always give VMC demonstartions to their students....

bin landin · Post by **bin landin** » Mon Dec 10, 2007 12:29 pm

Iceman:

I have had VMC demonstrations in a simulator. Good place to do them.

But in an airplane? Are you going to put weights in the plane to get the C of G in the proper place? fly the plane at gross weight (or the stipulated weight)., and then bring the plane to a place where the rudder is no longer effective in maintaining control? Seems like a very dangerous thing to do, and I question what can be gained from the demonstration unless you are going to lose control before taking corrective action.

Hedley gave some good advice. Instructors in general are not the most experienced pilots in the sky, and this type of thing is, in my opinion not a very smart thing to do. I dont think Cat really stated his point well, but maybe, in retrospect, instructors should take his advice.

Hedley · Post by **Hedley** » Mon Dec 10, 2007 12:38 pm

I question what can be gained from the demonstration

Bingo. Does it pass the cost/benefit ratio test?

http://www.tc.gc.ca/civilaviation/gener ... x6.htm#VMC

It's disappointing that people talk endlessly about irrelevant stuff,
and what's important is never mentioned.

Cat Driver · Post by **Cat Driver** » Mon Dec 10, 2007 12:56 pm

trey kule said:

Many readers here take your advice seriously, and with the misunderstandings I have seen from some of the new hires, perhaps you could clarify or restate your post

bin landin said:

dont think Cat really stated his point well, but maybe, in retrospect, instructors should take his advice.

I was very pointed in my comment knowing I would be asked to explain.

First let me tell you about a friend of mine who survived being in jail under Castro many years ago only to die in a Twin Commanche doing a check ride as a TC inspector.

This guy could really fly until he got below VMC doing a simulated engine out approach doing an IFR re ride.

What the book says about an airplane type regarding speeds such as VMC and how individual airplanes actually perform is to iffy to think you can demo something as critical as VMC during training.

I personally do not venture into that realm of flight just to demonstrate something that might bite me big time.

Now I may not be the best stick in aviation but I have proven I'm safe for the simple reason I'm here.

The object of teaching someone how to fly multi engine airplanes is to instill skills that will ensure the student lives a long life.....playing around at VMC serves no useful purpose.

If the student is not satisfied with a verbal lesson on the risks of VMC then as bin landin suggested do it in a sim that will react exactly like the airplane.

When it comes to playing around in the outer eges of the flight envelope during flight instruction be very careful and make sure you have the right machine to play at that end of the fligth envelope......a normal catagory twin engine airplane is not the best choice.

Far better to be a live chicken than a dead eagle.

THEICEMAN · Post by **THEICEMAN** » Mon Dec 10, 2007 1:03 pm

Depends on the school? Where I went, POH suggested that VMC demonstrations are to be done in flight.
They have been doing it for years, & so fars so good.
Am sure though, that the sim does good VMC demonstartion too.

I have done it several times in real life, with an instructor of course. It was no big deal at all. When getting closer to VMC, you notice that the airplane starts yawing despite rudder....then you get out of it

I don't know about other aircraft, but I did it in an Aztec & it was a piece of cake.

Cat Driver · Post by **Cat Driver** » Mon Dec 10, 2007 1:09 pm

So there you go gang...

You can emulate THEICEMAN with his vast background in flying.

Or you can emulate those of us who may actually know the subject.

THEICEMAN · Post by **THEICEMAN** » Mon Dec 10, 2007 1:21 pm

Cat Driver wrote:So there you go gang...

You can emulate THEICEMAN with his vast background in flying.

Or you can emulate those of us who may actually know the subject.

Oh c'mon Cat Driver! Don't be so critical....
I am not arguing with you.

I am just saying what the policy was for the school I went to. Also, that I didn't find the VMC demo so difficult...
leave it up to the others to make their own conclusions.

why the sarcasm?