What happened
On the morning of January 23, 2018, a serious runway incursion occurred at Helsinki-Vantaa Airport. During a period of snow removal operations, air traffic control (TWR) authorized three maintenance vehicles—tractors T56 and T54, and snow blower L46—to clear lights on runway 22L/04R. Shortly after, the controller cleared an ATR-72 operated by Nordic Regional Airlines (flight FIN3PU1) for takeoff from runway 22L. While the aircraft was performing its takeoff roll, it passed over tractor T54, which had entered the runway from taxiway ZR. The snow blower L46 driver also observed the aircraft accelerating toward the vehicle.
The following day, January 24, 2018, a second serious incursion took place. A Bombardier Challenger 60 operated by Jetflite Oy was taxiing toward the runway following a delay. Due to heavy snow and poor visibility, the flight crew became focused on completing their pre-takeoff checklists. During this process, the aircraft crossed a red stop bar and entered the runway area without sufficient situational awareness of the airfield's active boundaries.
The investigation
The OTKES investigation examined the coordination between airport maintenance and air traffic control, the visibility of ground vehicles on controller displays, and the flight crew's operational procedures during taxiing in adverse weather. The investigation also reviewed the technical capabilities of the air traffic control electronic strip (eStrip) system and the effectiveness of the airline's checklist implementation protocols.
Findings
- Lack of coordination: In the first incident, the agreement between airport maintenance and air traffic control regarding work coordination was not followed, and the runway had not been formally closed to traffic.
- Controller awareness: The air traffic controller failed to account for the presence of ground vehicles that had authorization to be on the runway when issuing the takeoff clearance.
- Display limitations: On the controller's electronic strips, ground vehicle identifiers did not clearly distinguish themselves from aircraft and runway information.
- Crew distraction: In the second incident, the crew's focus on checklist completion led to a loss of situational awareness regarding the aircraft's position relative to runway holding points.
- Environmental factors: Poor visibility caused by snow spray from maintenance equipment and heavy snowfall contributed to the difficulty in maintaining a clear mental picture of the airfield status.