Cessna Aircraft Undifferentiated or Other Model
Air Traffic Control Fully Certified
Air Traffic Control Time Certified In Pos 1 (yrs) 11.0
Situational Awareness; Training / Qualification; Communication Breakdown
ATC Issue All Types; Conflict Ground Conflict; Critical; Deviation / Discrepancy - Procedural Published Material / Policy
Flight Crew Requested ATC Assistance / Clarification
Human Factors; Procedure
Off frequency the trainee on ground control coordinated to cross the runway behind Aircraft X on a half mile final. I told him that would be fine. He then keyed up to record the crossing coordination and I said 'Behind the Aircraft X short final; cross Runway 25L at taxiway B5'. I then turned my attention to Aircraft Y who was landing long on runway 25L. Aircraft Y was still airborne; roughly 10 feet above the runway when the trainee on ground control keyed up the frequency and said 'crossing complete'. I then turned and saw Aircraft Z turning onto taxiway c from C5 and realized that the ground trainee had crossed the runway in front of Aircraft Y as [it] was over the runway landing. Aircraft Y said nothing about the [aircraft] that had crossed about 2000 feet in front of him. The ground trainer should have heard the trainee issue the crossing and stopped it from happening. My view of Aircraft Z was also obscured by the support beam on the window in the tower. I had to move to the side to see Aircraft Z.
[Report narrative contains no additional information.]
A Local Controller observed an aircraft taxiing across the same runway as a landing aircraft landing was touching down.