What happened
On the morning of January 7, 2019, a Saab 340B operated by A/S RAF-AVIA was performing a repositioning flight from Riga, Latvia, to Savonlinna, Finland. The flight crew, which included the captain, first officer, and a company mechanic, arrived at Savonlinna ahead of schedule due to favorable wind conditions.
At the time of the arrival, maintenance personnel had been working to clear snow from the airfield. Although the runway surface itself was reported to be free of ice, significant snow accumulation was present at the runway edges. A friction measurement vehicle had inspected the runway shortly before the aircraft's arrival, reporting poor friction levels and a 4 mm layer of dry snow across the cleared area. Additionally, snow banks measuring 40 cm in height were located just inside the runway edge lights.
During the landing roll, the aircraft veered off the runway. There were no fatalities or injuries reported in the incident.
The investigation
The Finnish Safety Investigation Authority (OTKES) examined the sequence of events, the runway maintenance procedures, and the communication between the air traffic service provider and the flight crew. The investigation reviewed flight data recorder (FDR) and cockpit voice recorder (CVARG) data, as well as maintenance records and weather reports. The investigation also looked into the procurement processes for the flight services and the adequacy of the emergency response coordination between the air traffic service and emergency dispatch centers.
Findings
- The primary cause of the excursion was the poor friction levels and the presence of snow on the runway surface.
- The runway width was effectively reduced to 37 meters due to the presence of snow banks located within the runway lighting perimeter.
- There were discrepancies in the timing and communication regarding the completion of runway cleaning; the air traffic controller informed the crew that cleaning was ongoing, but the runway was opened for use shortly thereafter.
- The investigation noted that the emergency dispatch center's assessment of whether the event constituted an accident or an incident could impact the nature of the emergency response dispatched.
- The investigation also highlighted concerns regarding the procurement of flight services, noting that the selection of the operator was based solely on the lowest price without specific safety-related criteria being weighted in the tender process.