Originally Posted by
tdracer
I no longer have access to the various FCOMs, but I believe that is common to all Boeing models.
The important thing is to get the reversers out as soon as practical after touchdown - even at reverse idle the ram drag at landing speeds is huge.
Because of that velocity squared thing, the ram drag (and hence the reverser effectiveness) drops rapidly as you slow - plus if you have any reverse thrust asymmetry, directional control can become difficult as you slow and you lose rudder effectiveness.
Interestingly, the deceleration on the DFDR plots is constant from the TR deploy until they’re stowed the first time. I would have thought it would be steeper at high speeds given the brakes weren’t working and the TRs were at Max.