PC-12
Air Traffic Control Fully Certified
Air Traffic Control Time Certified In Pos 1 (yrs) 1.5
Training / Qualification; Distraction; Workload
ATC Issue All Types; Conflict Airborne Conflict; Deviation - Speed All Types; Deviation / Discrepancy - Procedural Clearance; Deviation / Discrepancy - Procedural Published Material / Policy
General None Reported / Taken
Procedure; Human Factors
I was training in the tower all positions combined. The workload was moderate with light difficulty. We were advertising ILS Runway 6 due to haze in the area. Aircraft Y checked on and was cleared to land. Then Aircraft X checks on and my trainee cleared him to land. I prompted him to issue a wake turbulence advisory. Aircraft X was 4 miles in trail when he checked on with an 80 KT overtake. I was training so my view of the data tag was not clear as they overlapped. My trainee issued the cautionary advisory. I believed there was a VA in the y scratchpad. The Aircraft Y landed as the Aircraft X was on roughly a 3 mile final. I was scanning the ground traffic; when I looked up and Aircraft X was on a 1/2 mile final and I did not observe the VA in the y scratchpad. We were essentially handed a compression error immediately; and my failure to read the full data tag led to us not taking care of the issue appropriately. By the time I had realized and the phase of flight the Aircraft X was in I felt it safer they land instead of sending them around.I discussed with my trainee we cannot provide visual separation in instances of wake turbulence. He said he had them in sight; however this does not matter. My trainee has 6 years of experience working in a VFR tower so I assumed he knew this rule. He said he observed nothing in the scratchpad but thought he was providing legal separation. In the future I will acquire all necessary data from the tag and pay closer attention to the tag to make sure the separation we are using is legal and take action accordingly. I discussed these 'outs' with my trainee. Call the traffic to the trailing aircraft and have them provide visual; or send them around if a 'VA' is not observed in the scratchpad. I will verify all information for myself instead of assuming anything; including my trainee knowing the rules.
RSW Instructing Controller reported a loss of separation due to the following aircraft being faster and the lack of visual separation. Wake turbulence was involved and though they could provide visual separation; it is not allowed in this instance. Instructor could not read data tag due to overlapping of tags and did not move the tags to determine if visual separation was being used correctly.