What happened
On the night of 31 January 2008, a Job Air SAAB 340B, registration OK-CCD, was performing a scheduled flight from Helsinki to Lappeenranta. During the landing roll on runway 06, the aircraft began to deviate left of the centerline. As the crew applied propeller braking to decelerate, the right engine failed, likely due to snow being kicked up by the nose gear as it passed through a snow bank. This failure created asymmetric braking forces, causing the aircraft to pivot sharply to the left and slide off the cleared portion of the runway. The aircraft eventually came to a halt on a grassy area perpendicular to the runway. There were no injuries among the 13 passengers and 3 crew members, though the tips of the left engine propeller blades were damaged during the event.
The investigation
The investigation examined the environmental conditions, runway maintenance, and crew performance. At the time of the incident, visibility was approximately 1500 meters in heavy snowfall with a low cloud base of 30 meters. While the runway had been plowed to a width of 33 meters, fresh snow had accumulated on the cleared surface, and the friction coefficient was poor. The investigation established that the runway centerline markings were obscured by snow, and the crew was unaware of the height of the snow banks left by plows. Furthermore, the investigation noted that the crew's experience with local winter operations and specific runway maintenance practices was limited. The investigation also found that the crew attempted to taxi the aircraft back to the runway using a single engine after the incident, which caused more snow to strike the propeller.
Findings
- The primary cause of the excursion was the asymmetric braking resulting from the right engine failure following the application of propeller brakes.
- A contributing factor was the visual confusion caused by snowflakes illuminated by landing lights, which may have obscured the aircraft's true direction relative to the runway.
- The lack of information regarding the height of snow banks and the obscured centerline markings contributed to the loss of directional control.
- The pilots had limited experience operating in these specific local winter conditions and with the current runway maintenance methods.
- The decision to land was made based on insufficient information regarding the exact state of the runway surface.