Cardinal 177/177RG
Air Traffic Control Fully Certified
Conflict Ground Conflict; Critical
Air Traffic Control Issued New Clearance
Human Factors
After being relieved at Local Control position by Developmental and his Trainer the Developmental cleared a Cardinal holding at Runway 28L for take off with the Husky on short final. Another Controller in the Tower Cab recognized the conflict and advised the Developmental and Trainer in a timely fashion; however the Cardinal had already proceeded past the hold short lines and was taking the runway at which time the Husky turned to avoid the aircraft taking the runway where he was cleared to land. [We need more] awareness of Trainer and assessment of Developmental level of performance. There were a few distractions at the time; the main one being the Trainer wanting to clear people out of his workspace which resulted in a few people looking away from the runway rather than out the window.
I was working the Clearance Delivery position. The Local Control 1 position had just done a position relief briefing and training was in progress. A Supervisor was monitoring for a skill check for the Trainee and the relieved Controller was still monitoring for the 2 minute overlap. A Husky was in the south pattern for Runway 28L and a Cardinal was holding short of Runway 28L for departure. While monitoring the Local Control 1 position I observed the trainee clear the Cardinal for take off on Runway 28L. I scanned the final and observed the Husky on short final and instructed to send the Husky around and cancel the take off clearance for the Cardinal. The Cardinal had started to roll onto the runway past the runway hold short lines. The Trainee told the Cardinal cancel take off clearance and hold short of Runway 28L but he was already past the lines and the Husky came very close to flying over the other aircraft. This occurred after a position relief briefing. We must be extra vigilant during the change over.
Tower Controller described a conflict event when a Trainee assuming Local Control cleared an aircraft for takeoff with traffic on very short final; the reporter noting that during the relief no one was looking out of the window.