Northwest only permits powerbacks at the three hubs that DC-9s visit - MSP
, and MEM
. Furthermore, there are gates at each of those airports that powerbacks are not allowed to be performed from (too small an alley, close side-by-side arrangements, etc.).
The pilots know beforehand from the ground crew if they'll be doing a powerback and they inform ramp control of this upon initial contact after receiving the clearance. When the clearance for the powerback is given the ramper in front of the cockpit gives the ready-to-go signal and puts his goggles on.
Both pilots take their feet off of the rudder pedals and put them on the floor. The captain pushes the power just enough to breakaway thrust and rolls the jet forward a few feet to get the tires off of the soft spots so that minimal reverse thrust is needed. After moving forward these couple of feet, he or she goes back to idle and thing brings both engines into reverse thrust and keeps an eye on the ramper ahead of the cockpit who is now giving the both-hands-twirling "continue powering back" signal. I was pretty surprised at how fast it moves backwards after watching it the first few times from the jumpseat. It continues and the two wingwalkers will give a signal to the cockpit ramper that it's time to stop. He will signal that to the cockpit and the captain takes off the reverse thrust and lets idle thrust bring the jet to a stop. A little forward thrust and by this time the FO is already getting the taxi clearance.