V1 is called the decision speed, at which the decision to abort or to continue a takeoff must have been made.
Folks,
This is a very common misconception, see a very useful little book:
http://www.faa.gov/other_visit/aviat...off_safety.pdf
In particular, page 2.10.
V1 is the speed at which the takeoff should be continued if the abort has not already been commenced.(unless is a catastrophic failure and the aeroplane will not become safely airborne -- cf; PANAM on 34 (L) in Sydney, multiple engine failure at gross weight)
The effect of this has been incorporated, with a number of useful amendments, from the original SFAR 422B through to the present amendment level of FAR 25. The words in italics appear elsewhere in FAA Docs. Not withstanding all of the above, in many other FAA Docs., they persist in calling V1 the "takeoff decision speed" ---- confusing, unless you accept it for what it is, the decision to take off ---- what it is NOT, is the stop/go decision speed.
Despite the best efforts of airline training departments, and I can speak of three on this subject, United, Delta and Qantas, V1 being referred to as the stop/go decision speed persists, including being incorrectly defined in several well known training texts, and many training school course notes.
Tootle pip!!