Is suspected as much! This part was interesting to me. :-)
The AFK appears to be used mostly for landing if i understand the modes correctly:
Mode 1: Is engaged when the landing gear lever is set to IN, and sets a speed of 550km/h
Mode 2: Is engaged when the landing gear lever is set to OUT and sets a speed suitable for landing at 12° AoA, that would be a normal landing.
Mode 3: Is engaged when the landing gear lever is set to OUT and the switch α 15.5° is pressed. This sets a landing speed suitable for a 15.5° landing, as mentioned this would likely be a road base landing.
I noticed from the diagrams that the landing gear lever is not on the front panel, instead it's on the left side panel at the very rear, that to me appears quite unusual.
Btw, reading this manual gives me flashbacks to reading the SAAB 105 (SK-60) service manual in school. xD