Air Fiji flight 121 departed Nausori for Nadi at 05:25. At 05:33 the crew contacted Nausori ATC that they were maintaining 6000 feet on the direct track to Nadi. When the crew didn’t contact Nadi ATC at 05:35 several attempts were made to get in touch with the aircraft. The aircraft was later found to have crashed on the slope of a ridge. The aircraft had apparently descended below the 5400 feet safety altitude until the right wing struck a tree on a ridgeline at 1300 feet altitude. The Bandeirante then broke up and impacted the slope of a ridge 1,3 km further on. The tail section and right wing were found 150 m from the main wreckage. Weather at 05:00 was good: nil wind, 40 km visibility, scattered clouds at 2200 feet and an insignificant small shower band. Investigation revealed a.o. that the captain had insufficient rest prior to the flight and that he had consumed an above-therapeutic level of antihistamine prior to the flight, which would have degraded his ability to safely pilot the aircraft. Also Air Fiji’s published standard operating procedures were inadequate for the Bandeirante aircraft.