Heavy Transport
Air Traffic Control Fully Certified
Air Traffic Control Time Certified In Pos 1 (yrs) 1
Communication Breakdown; Situational Awareness; Training / Qualification; Workload
ATC Issue All Types; Conflict Ground Conflict; Critical
Air Traffic Control Issued New Clearance; Flight Crew Requested ATC Assistance / Clarification; Flight Crew Took Evasive Action
Human Factors; Procedure; Staffing
I was working Tower Controller in Charge (CIC). A supervisor was on Local Control getting proficiency time. Ground Control coordinated a crossing at a taxiway a heavy. Local Control put an aircraft in position once an arrival touched down. Ground Control started crossing after the arrival passed the taxiway. Local Control told the arrival to exit the runway and as they did; he cleared the prop aircraft for takeoff. I did not hear the clearance for takeoff given by Local Control. Neither did Ground Control. Ground Control wasn't sure if Local Control remembered he had a crossing coordinated; so he announced; 'I'm still crossing.' I looked to check the runway at that; but I did not see the small prop aircraft since it was on the far end of the runway. Local Control did not say anything. I don't know if he didn't hear Ground Control; or if he forgot he had cleared an aircraft for takeoff. The aircraft on takeoff roll called up and said he was cancelling his takeoff. He was able to depart from his current position once the heavy was off the runway.A Supervisor working during this complex and unfamiliar configuration is probably not the best option.
SAT Tower Controller reported that a Supervisor cleared an aircraft for takeoff while another aircraft was crossing the runway.