CoolP asks: Lou, regarding the aborted takeoff, did you guys have strict guidelines with e. g. the 747? I mean she can really take some faulty engine and become airborne, safely. Also being able to land safely, so this abortion with "just" one lost engine may be far more dangerous than any 3 engine flight ever could be, right?
I think it's the Captain's decision and even if he's below V1 he may call "continue!" or something to avoid the maybe dangerous stop situation. Depends on the cause of the engine failure of course, so there some heavy loaded split-second to expect I think.

CoolP you bring up a very interesting question. The balanced field calculation does not care what kind of plane we are talking about. Each plane is looked at with its performance calculations for each runway and weather condition. Wind, slope, temperature and field elevation are all taken into consideration along with the type of surface and if it is wet or dry.

The term V-1 (accelerate - stop speed) is what is called the decision safety speed. If something happens before this speed the plane can safely stop in the remaining runway without the use of reverse thrust. If the event happens after the speed is reached the plane can continue the takeoff and be at 35 feet by the end of the runway. All great on paper!

There are many things that can cause a pilot to abort the takeoff. Engine failure is just one of the things considered. Sure, the 4 engine 747 can fly on just three engines, but did the engine just quit because it ran out of gas or did it quit because the fuel line broke and fuel is spraying out all over the place and it's on fire? An abort is the most critical decision a pilot can be called on to make. The plane is at it's most critical condition - heavy, full of fuel. You are going down the runway at a good clip and the tires are already hot from a long taxi. Not a pretty picture is it, to try to stop the beast?

We used to kid about certain airports having a V-1 of break release since the runway was soooo short! Each plane has different characteristics. The 727 was a good stopper, but a poor climber. The 757 was good at many things - stopping and going! The 747 was a long roll out plane requiring many feet of runway to stop without burning up the brakes. Look at the video of the 747-800F doing its certification stop. If this was a normal flight out of KJFK on a departure in the hot summer with a 3 or 4 mile taxi at max takeoff weight and having to abort just before V-1, I would bet it would be pretty exciting to say the least! Brake fires, panicked people opening doors and sliding down into hot brake fire with maybe fluid leaks causing even more fire... well, you get the picture.

I talk about the long taxi because the flexing of the sidewall of the tire during taxi builds up a lot of heat and ware on the tire alone. now add to this hot tire a hot brake and you can see what's next.

Lou