How much time can jet planes make up?

[Guest Howard Hughes]

Hi Nev, what is the recovery technique for a high speed stall? Or is that what you are describing above?

 

Cheers, Mark.

 

 

[facthunter]

Just slow up if you can or go to a lower altitude. Your cruise charts should take this into acount. Some guys used to get a higher altitude assigned to stop someone else getting it.( The get in early syndrome) They go there and are too high for their weight and at risk till the fuel burns off. Talking Int'l stuff. On a very long trip being kept down by other traffic will cost a lot of fuel. Companies try to make you lift max payload. da de dah... Nev

 

 

[Sapphire]

I was ina high speed stall towing a glider. In the stall the center of pressure moves back and so the nose will come down without any control imputs- just help a bit easing the stick forward.

 

FH said: On a very long trip being kept down by other traffic will cost a lot of fuel.

 

Say you are flying Sydney to LA, would there be that much traffic that you cant fly your preferred altitude? How much separation is required?

 

 

[facthunter]

Don't know. SY -LA shouldn't be that busy. In asia or the caribean-chicago, middle east-europe. Sydney Melbourne is one of the world's busiest routes they say. Different en route separation standards apply around the world. Tends to be reduced when possible to save fuel.

 

We should be careful in describing stalls. The mach limited one shouldn't be referred to as a high speed stall really. Some aircraft have all sorts of problems, when they approach the speed of sound ( control and buffetting extra drag etc.) Nev

 

 

[Gentreau]

.....We should be careful in describing stalls. The mach limited one shouldn't be referred to as a high speed stall really. Some aircraft have all sorts of problems, when they approach the speed of sound ( control and buffetting extra drag etc.) Nev

I wasn't sure what to describe that as, but since the wing loses lift, it has the same effect as a stall.

 

If it looks like a duck, and quacks like a duck .....

 

 

[facthunter]

The terminology causes confusion. People call a dynamic load induced stall a high speed stall too. I wouldn't call a shock wave on the top surface of a wing a "stall". That's just my view. It can be something of a non event in itself. The plane certainly doesn't fall out of the sky, but some planes not designed for high subsonic speeds will experience control difficulties before that point. Nev

 

 

[Mark11]

It sounds like the commercial airlines are not as safe as I might have thought.... Very little margins between low speed stall and the higher speed issue....

 

With such a small margin, I'm surprised more accidents like the Airfrance Airbus aren't occurring - seems the computers are all that stop this?

 

 

[facthunter]

I would think knowing your plane and it's limits is more important. The Airfrance co-pilot did something that no -one can understand. Why the Captain entrusted the operation of the aircraft to the junior pilots when the anticipated worst weather en route was occurring is another mystery. The failure of the pitot's complicated things but should not have resulted in the outcome that unfortunately happened. A completely intact aeroplane fell all the way to the sea stalled.. Nev

 

 

[Gentreau]

The failure of the pitots may have complicated things more than some realise.

 

If they provoked a change from Normal Law to Alternate or Direct Law.

 

Pilots with the habit of flying in Normal Law, would have it in their minds that you can't stall the plane, however in ALT and DIR, you can.

 

 

[Sapphire]

The Airfrance co-pilot did something that no -one can understand. Why the Captain entrusted the operation of the aircraft to the junior pilots when the anticipated worst weather en route was occurring is another mystery.

 

 

 

 

 

 

That has happened before eg Exon Valdez. People take risks to relieve boredom or mistake uneventful close calls as the norm. One ex airline instructor I had rememberd a captain he had who took off with one of the stewardess on his lap. When he yelled pull, she was instructed to pull back on the control column.

[boingk]

Bingo.

 

Personally though, if you stall an aeroplane... eyes go on the altimeter, artifical horizon and indicated airspeed. Stick pushes forward until those instruments - airspeed in particular - start giving flyable readings.

 

A good demonstration of a similar phenomenon is given in the Aircrash Investigations 'The Plane That Flew Too High' episode. Essentially this plane was piloted above its safe altitude for that flight and its weight. Autopilot gave increasing nose-up attitude to try and maintain altitude and eventually the airplane was stalled. The pilots failed to recover it.

 

- boingk