Small plane with five people on board went down before landing in the airport at Oksibil of Papua, Indonesia on Saturday morning, killing the pilot and seriously injuring the four passengers, a rescuer told Xinhua over phone. The Cessna plane operated by the Association Mission Aviation firm fell at mountainous area at about 7:30 a.m. local time Saturday (2230 GMT Friday), an official in charge of the National Search and Rescue Office told Xinhua over phone. Evacuation was underway, he said.It is not clear yet about the cause of the accident in the easternmost of Indonesia. Plane accidents have been rampant in Papua, particularly small plane crashes, due to the unfavorable mountainous terrain.