Flight Details
On 19 January 2014, a PA-31-350 Piper Chieftain, registered PK-IWT, operated by PT. Intan Angkasa Air Service, departed Sentani Airport in Jayapura on a positioning flight to Juanda Airport in Surabaya for aircraft maintenance. The flight plan included refueling stops at Dumatubun Airport in Langgur, Tual, Maluku, and Haluoleo Airport in Kendari, Southeast Sulawesi. The aircraft departed Sentani at 2351 UTC (0851 WIT) on the first sector, with an estimated arrival time at Langgur of 0320 UTC. On board were one pilot, two company engineers, and one ground staff member.
Accident Sequence
At 0240 UTC, the pilot contacted the Langgur Flight Information Service Officer (FISO) and reported the aircraft's position as 85 nautical miles from Langgur at an altitude of 10,000 feet, requesting weather information. The FISO advised that the weather included rain and thunderstorms and that runway 09 was in use. Later, as the aircraft passed through 5,000 feet, the pilot reported a position 50 nautical miles from Langgur and reiterated the estimated arrival time of 0320 UTC. The FISO acknowledged and instructed the pilot to contact when on long final for runway 09.
At 0318 UTC, the pilot contacted the FISO, reporting a position 25 nautical miles from Langgur at 2,500 feet, and requested use of runway 27. The FISO advised the pilot to contact on final for runway 27. At 0325 UTC, the FISO attempted to contact the pilot but received no reply. At 0340 UTC, the FISO was informed by local residents that the aircraft had crashed. The wreckage was located approximately 1.6 nautical miles northeast of Langgur Airport at coordinates 5°38'30.40"S; 132°45'21.57"E.
Investigation Findings
The accident resulted in fatal injuries to all four occupants, and the aircraft was destroyed by impact forces and a post-impact fire. The aircraft was not equipped with flight recorders, and communications between the pilot and the FISO were not recorded. No eyewitnesses observed the aircraft before impact. Investigators relied on available information, primarily from the wreckage, including the wings, engines, and propellers. The level of damage precluded examination of some components, such as the cockpit.
Probable Cause
The investigation concluded that the left engine most likely failed during approach and the propeller did not set to feather, resulting in significant asymmetric forces. These forces created a yaw and roll tendency, causing the aircraft to become uncontrolled and subsequently impact the terrain.