V/x and safety

[Blue Side Down]

I read an article RE Vx on takeoff a while back...

Seems to me that the conclusion was that the only time to use Vx is when there is a significant chance of your takeoff being foiled by some terrestrial obstacle residing at the far end of the runway. In short- only take the risk of climbing out at Vx when the risk of hitting a tree or similar is greater.

Speculating about whether is sounds right that the airplane will have enough energy to flare after experienceing an engine failure at 60' while at Vx is fun to do, sure, but really dosen't help anyone. Why not someone out there with a 152/ 172/ cheap to fly/ etc go out there and try the experiment again:

1. Climb to a safe altitude and call it ground- say 3000'
2. Slow to Vx
3. Put the coals to 'er and maintain Vx
4. At 3070' chop the power- or better yet- have your buddy do it at a random altitude between 3000' and 3100'
5. Stuff'er down and see if you can bring the VSI to zero when you get back to 3000' before stalling.

Useful? Maybe. Interesting? Probably. Going to change anyones mind about the procedure? Probably not

Blue skies-

[Chuck Ellsworth]

It's pilot told the tower that this will be an "overgross takeoff".

But the pilot is known and respected,

As a pilot?

[MichaelP]

As a pilot?

Yes...

I had offended someone well known apparently by pointing out my concerns about such an act.
I was told that he does this sort of thing all the time and is approved to do it.

Call me a chicken, I don't care, but you'd never find me flying any aeroplane loaded as that one was unless the survival of many people relied upon it.

In my youth I was a member of a World renown club...
So and so would come in, used to fly a Tiger Moth in the good old days you know, hasn't flown one for years, but he'd be alright.
I almost cried over the damaged aircraft after such occasions!

There are a lot of these clubs today, though less overt and official.

On the topic of Vx, I use it every time there's a strong wind down 12.
You can watch the tower descend vertically as you climb into the positive windshear
It amuses me somewhat

I have given engine failure after engine failure to people after takeoff.
If you are at Vx, there's no problem.
Below Vx, or if you are asleep, then there is a problem!

The sixty foot mark is at 6 or 7 seconds after takeoff...

If you raise the nose to the climb attitude when you see Vx, you are doing more than Vx when you do it. The ASI lags.

Here's another thing... I do an hour or so in the circuit with my students with the ASI covered up.
Flying attitude and power, is that dangerous?

I once was told I was doing 100 KIAS on base when I should be doing 70 KIAS.
I looked down and sure enough it said 100! I tapped the panel and 70 obediently appeared as the stuck needle reset itself.

A Cessna twin went off the end of the runway damaging its undercarriage.
While the crew was having coffee, the engineer noticed the pitot covers had been left off... he put them back on.

If I knew the aeroplane well I would have flown it as Power + Attitude = Performance and the wheels would have survived.

[Chuck Ellsworth]

Michael....check your PM's::

I was told that he does this sort of thing all the time and is approved to do it.

He has an amendment to the type certificate to exceed the gross weight limit of the airplane?

Here's another thing... I do an hour or so in the circuit with my students with the ASI covered up.
Flying attitude and power, is that dangerous?

Dangerous??

I do the same exercise and we do one minute circuits left and right alternating.....to " not " teach them to fly attitude and power without the airspeed would be wrong.

An airspeed indicator in a light airplane is an aid not a must have item safety wise.

[Chuck Ellsworth]

Phuck.

[Shiny Side Up]

F/OCrunch:

You have brought up the issues that I started the thread for.

Flying at Vx close to the ground can be risky in the unlikely event the engine quits ( like maybe fuel vent unporting with low fuel level in the tank/s ) however we all agree that training a student to fly at Vx is part of learning to fly and it is nothing more than flying at full power at a high angle of attack and being accurate in pitch control.

One might add that flying close to the ground at any speed is particularly risky, so why are we suddenly worried about at Vx?

The next question that we should ask is how often does a pilot get into a situation where she/he has to do a maximum performance take off and fly at Vx or they will hit an obstacle on the take off path? ( Alaska Super Cub Bush pilots disregard this question. )

Can someone maybe answer that question, and explain how the pilot got into that situation?

The last bit is probably the part that needs to be worked on more - the whole PDM side of things. Teaching shortfield/max performance take offs landings, climbs and other manuvers is great, but most of all when NOT to use them...

[Strega]

What I am doing is getting a discussion going so people remember the risks involved in doing it wrong as well as the risks surrounding practicing these manouvers close to the ground....there is a fine line between being in control and out of control.

In my experience this engine produced its power when density altitude was taken into account.

What exactly does this mean?

[MichaelP]

There's different contexts within the quote.

My sentence:
No engine produces its rated power when it is not at sea level at standard temperature and pressure.