Preliminary data based on the notification from the Danish authorities:
After starting up engine number one, engine number two was started, and after a few seconds a loud bang was heard, followed by vibrations in the aircraft. The starting sequence was aborted and both engines shut down. After shutdown aircraft was inspected and a piece of tooling was observed to have been lodged into the leading edge of one of the main rotor blades. Tool stickout was estimated to be a top nut wrench, about 20cm long.