cosmo, #23/25 … "unable or unsafe to fly" .... is a ridiculous wording"
I agree with the hint of futility, the phrase does little to enhance practical safety.
For those who insist on only the Captain taking action in an RTO, do you add a speed/distance margin to account for the time taken to change control if the FO is handling? Failure to consider this might invalidate the basis of aircraft performance certification.
AC25 7C page 37 onwards.