Swearingen SA226-TC Metro II – Pilot Error during Training Takeoff

C-FGEW, a Swearingen SA226-TC Metro II aircraft operated by Sunwest Aviation, was conducting local training flight CNK216 from Camrose, AB (CEQ3). The training flight was being conducted with the pilot flying (PF) seated in the right seat and the training pilot, pilot not flying (PNF), seated in the left seat. During the takeoff roll on Runway 32 while accelerating through 40 KIAS, the PF’s finger slipped off the nose wheel steering button on the power lever. While trying to press the button again, the PF didn’t notice the aircraft veering to the left. The PNF was not immediately aware of the deviation as they were both setting power. The PNF alerted the PF of the deviation and while the aircraft was accelerating through 60 KIAS, the PF rejected the takeoff. At that time, the aircraft was half way between the runway centerline and the runway edge. The PF was unable to regain directional control using nose wheel steering. The PNF took over and attempted to regain control by using differential power and braking. The left main wheels caught the snow, the aircraft departed the runway at an approximate 45° angle and came to rest approximately 150 feet from the runway edge. There were no injuries and the aircraft did not sustain any damage.