how do you explain a rotation 20kts before V1if he is in the habit of scanning his PFD and engine instruments?
Err, a stuffup (assisted in large part by a non-standard and misunderstood call from the RHS)?
because they are not ultimately responsible for the operation of the aircraft there is usually a knowledge gap.
Actually, it's the other way round.
Any Captain who is relying completely on the F/O to notify a failing engine is not doing the job properly.
Obviously.
Any Captain who doesn't take over and conduct an RTO before the F/O notices any problems is not doing the job properly.
Obviously. By definition, if the captain is taking over, he was the PNF, and he would have spotted the engine failure first...