Originally Posted by notEnuf

This is why the CA is designated to decide and execute. The ultimate responsibility dictates the CA be the one executing an abort. If the FO does it and messes it up the fault still lies with the CA. This is also why CAs are encouraged to land single engine. The reason we have a highspeed regime is to simplify the decision and speed the execution of an abort. Anything distracting from this adds additional risk unnecessarily. It's not about the FOs experience or ability but about a methodical approach to eliminating risk.

As PIC the option always exists to take control of the airplane. CFIs who train new students are good at identifying and intervening because they have a much wider SA and are trained to react when the aircraft (by malfunction or pilot action) is not performing as anticipated. The transfer of controls should be a non-issue. The only thing that has made it an issue is automated RTOs. The captain has to decide if the spoilers are up and the brakes are working. I actually default to manual brakes and grab for the spoilers more than DAL would like because that's the way my primary training was in a non-autobrake and spoiler airplane. A hesitation after saying "abort I have the airplane" doesn't mean incapacitation. It is likely tracking center line or being corrected to it and if the systems are working the airplane is slowing itself when thrust is idle and then emergency reverse. It is difficult to stay off the brakes and allow the spoilers to deploy automatically.