What happened
On January 29, 2000, an Air Botnia Fokker 28 Mk 4000, registration SE-DGU, experienced a partial loss of control during its takeoff roll at Turku Airport. The aircraft, operating flight KFB665, was carrying nine passengers and a crew of four.
During the takeoff roll, the aircraft reached a speed of approximately 80 knots when a sudden wind gust caused the nose to swing into the wind. In an attempt to maintain the centerline, the pilot applied full right rudder, which caused the aircraft to skid toward the right edge of the runway. The aircraft passed within 2–3 meters of the runway edge lights before the pilot was able to regain control and lift off at the normal rotation speed. There were no injuries and no damage to the aircraft or airport property.
The investigation
The investigation examined the flight preparation, runway maintenance, and weather information dissemination. Investigators found that the crew relied on outdated weather information from a pre-flight briefing (RODOS) and did not seek updated reports from flight services. While the crew listened to the ATIS, the runway friction information provided in the ATIS was several hours old and did not reflect the recent onset of sleet and snow.
Furthermore, the investigation reviewed the runway maintenance activities. Although maintenance crews were working to clear slush, the high winds prevented effective clearing of the entire runway width. The investigation also analyzed radio communications, noting that the controller provided information regarding the runway's cleared width, but also provided a wind reading that was misleading relative to the actual conditions experienced during the takeoff.
Findings
- The primary cause of the incident was the pilot's decision to perform a takeoff in conditions where the crosswind component exceeded the maximum allowable limit for the aircraft type, given the slippery runway surface.
- The crew's flight preparation was inadequate, as they failed to verify the most recent runway friction and wind conditions.
- The pilot did not use the aircraft's aerodynamic controls (ailerons and rudder) effectively to counteract the crosswind during the initial stages of the takeoff roll.
- The air traffic controller provided wind information that was misleading in the context of the actual weather conditions.
- Runway maintenance capacity was insufficient to maintain a sufficiently wide cleared path during active snowfall and high winds.
- There was a failure in the dissemination of updated runway friction data (SNOWTAM) to the pilots.