In my day, the A/THR would go into THR LOCK mode if you did that. The thrust (N1 on the CFM-56 engine, or EPR on the V2500) would remain where it was. Has something changed?
FCTM OP-030 – AP / FD / ATHR:
1) USE OF INSTINCTIVE DISCONNECT (I/D) PUSHBUTTON If the I/D pushbutton is pressed when the thrust levers are in CL detent, thrust will increase to MAX CL. This will cause an unwanted thrust increase and may destabilize the approach.
Therefore, the recommended technique for setting A/THR to off is: - Return the thrust levers to approximately the current thrust setting, by observing the TLA symbol on the thrust gauge - Press the I/D pushbutton
This technique minimizes thrust discontinuity, when setting A/THR to off.
I guess it must have changed as that's how it's always been in my time (just under 3.5 years)
I do try to fly manual thrust once a week and have flown aircraft dispatched with ATHR U/S and thus flown man thr through the whole profile. You make a good input though and I too would recommend it. I'm fortunate to be in a comany where its no problem to do so.
What does it recommend in your FCOM? After a windshear event, if the speed is "going berserk", due to the A/THR being too slow to reduce thrust after you've brought the throttle levers back to the CLB gate, you might be better doing what you would always do if the automatics are not coping: SWITCH THEM OFF.
There is no recommendation other than to 'keep the automatics'. It was a 'tip' from a TRE in an LOE and it worked very well. By moving back to climb thrust and resetting ATHR using the FCU pb it all settles down ...... At least it did in the sim.
If you're a real pilot, get to know your aircraft!
There are those who don't know and those who don't know they don't know! I learn something new on this plane every week.