What happened
On March 20, 1998, at approximately 15:30 local time, a runway incursion occurred at Kuopio Airport. A Finnish Air Force P28T light aircraft, operating under callsign H49, was performing a landing on runway 33. At the same time, a maintenance vehicle, a Saab 900, was performing an inspection on the same runway.
The aircraft had requested a change to its flight plan to approach from the Juankoski direction. During the approach, the air traffic controller was engaged in lengthy telephone calls to AFIS units in Mikkeli and Varkaa to coordinate a student pilot's navigation flight. While the controller was occupied with these calls, the maintenance crew requested permission to enter the runway. The controller granted the request and placed a magnetic symbol on the flight progress strip to indicate runway activity, but did not verify the vehicle's entry point or intended direction.
As the P28T approached for landing, the maintenance personnel, who were walking back to their vehicle, noticed the aircraft on short final. The crew quickly drove the vehicle off the runway via taxiway D. The pilot of the aircraft, attempting to extend the landing roll slightly, passed taxiway D while still airborne. A collision was avoided only because the maintenance crew spotted the aircraft and moved out of its path.
The investigation
The investigation was initiated by the Safety Investigation Authority after two similar incidents had occurred within a short period. Investigators examined radio communications, controller training records, and interviewed the air traffic controller and the maintenance personnel involved.
Findings
- The air traffic controller failed to verify that the runway was clear before issuing landing clearance, neglecting both visual monitoring and radio confirmation.
- The controller's attention was diverted by non-essential telephone calls to other aerodromes, which lasted longer than usual.
- Radio communications between the controller, the aircraft, and the ground vehicle did not strictly adhere to standard phraseology.
- The maintenance vehicle did not communicate its specific entry point or direction of travel on the runway, and the controller did not seek this information.
- While the controller had properly marked the runway activity on the flight progress strip, the lack of active monitoring of the landing pattern was a critical failure.
Safety action
It is recommended that on-the-job training and monitoring procedures for air traffic controller trainees be improved. Specifically, tools should be developed to better assess whether trainees have fully internalized and are consistently applying fundamental air traffic control requirements during low-traffic periods.