What happened
On the morning of January 28, 1999, a serious runway incursion occurred at Helsinki-Vantaa Airport involving two Finnair aircraft. A DC-9-82, registration OH-LMH (callsign FIN 715), was cleared for takeoff from runway 04. Simultaneously, a DC-19-51, registration OH-LYY (callsign FIN 330), was on short final for runway 15, having been instructed to continue its approach.
As the DC-9-82 began its takeoff roll, the flight crew observed another aircraft on their TCAS (Traffic Collision Avoidance System) display at approximately 600 feet, positioned to their front-left. Upon visual confirmation of the approaching aircraft on runway 15, the crew requested the tower controller to verify their takeoff clearance. The controller, unaware of the intersecting traffic, initially reconfirmed the clearance before the crew alerted him to the approaching plane. The controller then cancelled the takeoff clearance and cleared the arriving aircraft to land.
The investigation
The investigation examined the actions of the tower controller and the coordination between various air traffic control positions. Investigators found that the controller had received information regarding the use of the intersecting runway 15 on three separate occasions: via a coordination call from approach control, through the electronic hand-over process from arrival radar, and via a direct radio report from the aircraft itself.
The investigation also looked into the controller's workload, noting that the controller was managing the transition between night and morning shifts, processing a flight plan for a helicopter (OH-HKP), and handling various ground vehicle requests. The investigation confirmed that the controller had manually updated the flight strip to reflect the use of runway 15 but failed to verify the actual traffic situation via radar, strips, or visual scanning before issuing the departure clearance.
Findings
- The primary cause of the incident was the controller's error in failing to account for the intersecting runway traffic when issuing the takeoff clearance.
- The controller's attention was diverted by the need to process an unprocessed flight plan for a helicopter and the administrative tasks associated with the shift change.
- While the controller had been notified of the intersecting runway use multiple times, he did not perform a thorough verification of the traffic situation.
- The crew of the departing DC-9-82 prevented a collision by actively monitoring their surroundings and using TCAS to identify the conflict.