Commercial Fixed Wing
Air Traffic Control Fully Certified
Air Traffic Control Time Certified In Pos 1 (yrs) 4
Situational Awareness
ATC Issue All Types; Deviation - Track / Heading All Types; Deviation / Discrepancy - Procedural Clearance; Inflight Event / Encounter CFTT / CFIT
Air Traffic Control Provided Assistance
Human Factors
I was working Local Center and was told to pick up Local West as well because that Controller had a physiological matter that needed immediate attention. I departed Aircraft X off Runway 16R heading 295. I departed Aircraft Y behind them heading 295 as well. I observed Aircraft X start their turn and switched them to Departure. It then appeared Aircraft X stopped their turn heading southwest directly at a mountain. I called Departure but Controller was not there yet; so I reached out to Aircraft X who was still with me. I did my best to get them to climb and turn away from the rapidly rising MVA's and am not sure if he cleared them or not. I also stopped the turn and climb of Aircraft Y so they didn't cut each other off west of the airport. I ran Aircraft Y right along the higher MVA line and then climbed them again. I believe I got a good read back on the heading for Aircraft X and I do not know why they started to turn then stopped. I did my best to get them turned away from the higher terrain and climbing while missing the traffic that was departing behind them to the northwest as well. Another option for Aircraft Y may have been to keep them going in a southern direction.
SLC Tower Controller reported an aircraft suddenly stopped its climb and turn heading towards higher terrain.