Ocean Viking in position 33 51 N 012 51 E informs JRCC Tripoli, with MTRCC and ITMRCC in copy, that she received a distress alert by VHF from Aircraft Colibri 2 about a boat in distress. There is a reasonable certainty that the persons on board are threatened by grave and imminent danger of being lost at sea and require immediate assistance. Ocean Viking informs that she is proceeding towards the target, about 4NM away, ready to provide assistance.