Norwegian investigators have opened an inquiry into a near-stall incident involving a Boeing 737-800 on approach.
The aircraft, operated by low-cost carrier Norwegian, had been conducting a domestic Finnish service from Helsinki to Kittila.
Norway's investigation authority SHT says flight DY5630 had been established on the instrument landing system approach to runway 34.
But as the aircraft descended through 3,250ft (990m), with its autopilot engaged, it began an "unintentional steep climb" under full engine power, SHT says.
The aircraft's trailing-edge devices had been configured in the "flaps 5" position.
SHT says the aircraft climbed 1,500ft but adds that the airspeed bled away. "The aircraft came close to a stall," it says, although it does not indicate whether any alarms or protections activated. "However, the pilots managed to regain control of the aircraft."
It landed safety at Kittila and subsequent test flights of the twinjet (LN-DYM), which had been delivered new to Norwegian in 2011, did not indicate any problems.
Weather conditions at Kittila on the day indicate good visibility and temperatures around minus 20°C.
SHT has classified the 26 December 2012 incident as a "serious event". It has obtained flight-data recordings and opened a probe, in co-operation with Boeing and the US National Transportation Safety Board.