Apologies; I've been away. And I'm sure most heads will be aware of it on here, I just find in conversation with a lot of pilots they are unaware of the logic behind autobrake Med on the A320 family...
MED has two phases:
Phase 1) Limited declaration is progressively applied without delay until the attitude is less than 1 degree or T= 5 seconds. The limit initially is 2m/s here.
Phase 2) Once attitude is less than 1 degree or T = 5 seconds; full MED decel is progressively applied - 3m/s.
Now I notice it on the line when people are keen to make an exit but also make efforts to overly gently lower the nose and there is a distinct two phase decel and we sail past the exit after all the careful calculations are done. 5 seconds at 140 knots being 'progressively decelerated to only .3m/s above autobrale LO eats up a lot of runway.
After discussion, I find, pilots are unaware of the above logic. This is because in our FCOM and previous airline FCOM it is not mentioned. The above numbers are found in the AMM. There is a nice graphical representation in my one at AMM Figure 32-42-00-31600-00-A / Sheet 1 Auto Brake Control Modes.
I hope that illuminates the area and I would be interested if other operators provide that info in their FCOM available to crew.