Terence Wilson wrote:
Subject line says it all. In the PTS for CFI this is mentioned, but
for the life of me I can't seem to find anything in the AIM. Would be
grateful if someone could help me out.

TIA
I'll give it a try for the Gipper:
for aircraft on collision courses, there is a critically high approach
rate beyond which, the collision is unavoidable.
Think - reaction time from first recognition of the danger is greater
than time to collision.
Therefore, the greater the approach rate, the greater the hazard.

Brian W