Doug tests Billy on the process of getting set up to monitor their position enroute to First Flight (KFFA) using NAV radios. This is a backup practice that Doug uses frequently in case he has a GPS failure. It's also the way Doug flew before the advent of GPS. It's old school by today's standards but it is a real back up, increases situational awareness and keeps a pilot busy.

You can see more cross radial work on the KAVL > KDNL leg and highlights from Day 2.