What happened
On December 2, 2010, at approximately 08:20 local time, a Cessna 441 Conquest II was attempting a scheduled flight from Wiener Neustadt Ost (LOAN) to Cagliari (LIEE). The aircraft had been prepared for departure by removing much of the snow and ice from its surfaces, though some frozen residue remained on parts of the right forward cockpit glazing.
During the takeoff roll on runway 28, the pilot initially corrected a leftward yaw. However, a subsequent rightward movement around the vertical axis became uncorrectable. As the aircraft reached a speed of approximately 30 knots, the right propeller struck a snowbank located at the edge of the runway. This impact caused the aircraft to abruptly rotate 90 degrees to the right, leading the left propeller to also strike the snowbank. The aircraft came to a halt approximately 8 meters right of the runway. There were no injuries to the pilot or the passenger.
The investigation
The SUB investigation examined the runway conditions, the pilot's pre-flight preparations, and the aircraft's mechanical state. Investigators reviewed the SNOWTAM report, which had indicated ice across every third of the runway and poor braking action. The investigation also looked into the airport's snow removal procedures, noting that the use of snowplows had created 50cm-high snowbanks approximately 1 meter from the runway edge. Technical inspections of the Cessable 441 Conquest II revealed no mechanical failures or system malfunctions prior to the collision. The investigation also noted that the pilot had only checked NOTAMs up to FL60, despite a flight plan that intended to reach FL270.
Findings
- The aircraft's loss of directional control was caused by the icy runway surface.
- The runway surface condition did not meet the required friction standards for safe operations.
- The pilot did not initiate an aborted takeoff despite the loss of directional control.
- The pilot failed to account for operational restrictions regarding icy surfaces outlined in the aircraft's Operations Manual and EU-OPS 1.
- The airport operator did not close the runway despite the presence of significant snow accumulation and poor braking coefficients.
- The snowbanks created by clearing operations acted as obstacles that the aircraft struck during the excursion.