If I recall correctly, the certification requirements for four-engine civil aircraft are that they be able to maintain a “positive climb rate” if they lose two engines on takeoff.
I think the article is concerned about the time between when the aircraft is going too fast to stop on the runway, but still too slow to take off.
“If I recall correctly, the certification requirements for four-engine civil aircraft are that they be able to maintain a ‘positive climb rate’ if they lose two engines on takeoff.”
It is only the loss of ONE engine, the “critical engine” (term of art) for which a positive rate of climb is required for each take-off. Pilots must calculate this as part of flight prep to determine V1.
Definition of “Critical Engine”
http://en.wikipedia.org/wiki/Critical_engine
Definition of V speeds:
http://www.bing.com/search?q=wiki+v1+vr&form=IE10TR&src=IE10TR&pc=MALNJS