B737. I used to teach datums and encourage guys to monitor N1% every so often on approach to anticipate changes when they had unwittingly set the wrong N1% for whatever configuration and manoeuvre was required.
On one occasion, on 3nm finals, I could see that the power set from F25 - F40 was going to cause the speed to decay PDQ. I waited and watched his eyes to see if they were alert. Nothing happened, so I called 'Power' which was where the error lay, but before the speed had decayed below Vref and followed the descending green arrow. His eyes were fixated outside, and without looking inside he reduced power. My follow up hand restored the correct setting and he landed. Afterwards he said that, without thinking, I had meant he had too much power.
I reflected and wondered what would have been better.
"Check power!" Proactive.
wait for speed to decay, "Speed" (SOP) reactive.
"increase power" proactive, but that could have caused a without thought agricultural handful.
"Set 62%" proactive (non SOP.)
"Power" was not an SOP call out, but that was the root cause of what was going to be an error that would have triggered an SOP call out. Being plots were are taught to be proactive. I thought I was being correct, but human nature defeated me.
At least he learnt the lesson and took away the need to check more than the damned FD and looking outside. Energy management has various parameters under our control.