So if you guys are trying to convince me that an airliner that burns up 90% of runway to rotate, would have had enough runway at V1 to safely stop the aircraft...your totaly full of boloney. It's just that simple.
ssg,
You need to re-think that
V1 is the speed at which the calculations allow for you to reject and stop in the remaining distance.
Vr is not always the same as V1. It's the speed at which you rotate.
Next time you see a heavy take off, remember that there can be 30 kts difference between the V1 and Vr, especially somewhere like JNB with an elevation of 5000+ feet.
Your decision speeds are based on runway length and ability to clear obsticles. I can't speak for your ops, but if you burn up 9000 ft on a 10,000 ft runway to get to VR, something is rotten in Denmark
A heavy 747/340 etc will often not rotate until the last 1000 feet, especially in high/hot operations. If you use Flex/Derate, you could easily use this much runway (provided the V1 gives you sufficient space to stop
) as the reduced thrust will use the extra distance to attain Vr.
To my limited knowledge, no 4 or 3 engine aircraft is certified below 1,500 feet with 2 engines out. They will only give you figures from 1,500' with a clean aircraft.