Incident Description
A runway incursion and collision occurred when an air traffic controller cleared a landing aircraft while another was still holding on the same runway. The holding aircraft, designated SKW5569 (registration N683AV), had been cleared to runway 24L at intersection 45 to position and hold. The local controller, preoccupied with another aircraft, forgot that SKW5569 was on the runway and subsequently cleared USA1493 (registration N388US) for landing on the same runway. After the collision, both aircraft slid off the runway and struck an unoccupied fire station.
Contributing Factors
Investigation revealed that tower operating procedures did not require flight progress strips to be processed through the local ground control position. As a result, the local controller did not have the strip for SKW5569, leading to misidentification of an aircraft and the issuance of the landing clearance. Additionally, the Technical Appraisal Program for air traffic controllers was not being fully utilized due to a lack of understanding by supervisors and the unavailability of appraisal histories.
Investigation Findings
The incident was attributed to the controller's preoccupation with another aircraft, which caused her to forget that she had placed SKW5569 on the runway. The missing flight progress strip further compounded the error, allowing the controller to mistakenly clear USA1493 for landing. The investigation also noted deficiencies in the utilization of the Technical Appraisal Program for air traffic controllers.