More details here, in English, though it´s not exactly certain in which order things actually happened:
The Air Force told reporters in Jyväskylä that the aircraft's crew had been practicing pulling out of a dive at a height of more than nine kilometres (29,500 feet) when the aeroplane suffered a tail slide.
The crew ejected at a height of about 4.5 kilometres after failing to restore manoeuvrability. The aircraft was flown during the test flight by a captain, 32, and a lieutenant-colonel, 44. The aircraft had been recently built at a cost of some 15 million euros from two airframes, one of which had been damaged in a mid-air collision in 2001.
NewsRoom Finland