On the 30th of March at about 15:46 after spotting the hoist and preparing the carrier for rig up, the crew were at their viewpoint positions and the driller on the controls for the mast raising operation. The driller was raising the mast from the horizontal position and through to vertical. As the mast was passing vertical to negative set back position, the derrick platform starts its natural movement away from the mast. The derrick platform’s fall arrestor broke from its base and released from being caught, throwing it in the opposite direction and falling about six meters to the ground.