Large Transport
Air Traffic Control Fully Certified
Air Traffic Control Time Certified In Pos 1 (yrs) 2
Training / Qualification
ATC Issue All Types; Conflict Airborne Conflict; Deviation - Track / Heading All Types; Deviation / Discrepancy - Procedural Clearance; Deviation / Discrepancy - Procedural Published Material / Policy
Air Traffic Control Separated Traffic
Human Factors; Procedure
Aircraft X on  a STAAV6 departure; had departed runway 25R. The departure essentially flies out then makes an arcing right turn to an approximately 030 heading. (There are RNAV points on the departure plate that plot the exact route of flight.) Aircraft Y [a turboprop]  was cleared for takeoff behind Aircraft X and ordered to maintain visual separation with Aircraft X. Aircraft Y complied with the instruction and turned to the assigned heading 290 off of Runway 25R. By this time; Aircraft X is talking to departure and Aircraft Y has been switched to departure. The 290 heading pointed Aircraft Y right at Aircraft X that was in it's right. The departure controller turned Aircraft Y farther right than the 290 heading to avert Aircraft X. This all occurred approximately 9 [miles] northwest of the airport.At the time; training was being conducted in Local 1. The On the Job Training Instructing (OJTI) didn't think it was the best practice to apply visual separation with Aircraft Y because of it's extreme performance as a Turbo-prop. The OJTI allowed it for training purposes so the developmental can understand how Aircraft Y performs. In the future; the developmental knows to give a bit more 'room' for this turbo-prop versus jet powered aircraft. Anytime separation and/or safety may be compromised; the training should be scaled back instead of allowing the developmental to make a possible error.
LAS Tower Controller reports on the use of visual separation during a training session; with the second aircraft performing better than the trainee expected. TRACON Controller turned aircraft further to avoid more separation issues.