Skyhawk 172/Cutlass 172
Air Traffic Control Fully Certified
Air Traffic Control Time Certified In Pos 1 (yrs) 2
Communication Breakdown; Situational Awareness
Aircraft Equipment Problem Critical; Conflict Ground Conflict; Less Severe; Ground Incursion Runway
General None Reported / Taken
Procedure; Aircraft; Human Factors
I was CIC; I had just got on position. There were no aircraft in the Class D airspace. There were two aircraft departing. The first aircraft was Aircraft X headed VFR to ZZZ. He was cleared for takeoff on Runway XX. Approximately a half mile from the airport he was switched to departure. The Local Controller then cleared Aircraft Y; for departure on Runway XX. Right after he did this departure called and said that Aircraft X requested priority handling and had an engine out. The Local Controller let departure clear the aircraft to land Runway YY. In the meantime; he gave Aircraft Y a 230 heading but did not cancel his takeoff clearance. Aircraft X landed Runway YY with Aircraft Y holding on the runway. Take off clearance was canceled but late.I think more training in case of unusual circumstances is needed especially when the traffic is so slow.
Tower Controller reported that failure to cancel takeoff clearance with a priority aircraft inbound resulted in a runway incursion.