Flight History
On 24 August 2012, a Piper Chieftain PA-31-350 aircraft, registered PK-IWH, operated by PT. Intan Angkasa Airservice, departed from Temindung Airport (WALS), Samarinda at 0751 local time (2351 UTC) for an aerial survey (aero magnetic) flight north of Bontang, East Kalimantan. The flight had four persons on board: one pilot, one security officer, and two surveyors. According to the flight plan, the aircraft was to fly at 3,000 feet AMSL en route and 500 feet AGL while surveying. Fuel endurance was 6 hours. The aircraft was equipped with an Emergency Locator Transmitter (ELT).
At 0004 UTC, the pilot informed the Temindung Control Tower that the aircraft was abeam Tanjung Santan, descending from 3,000 feet, and established contact with Bontang Info. A minute later, the pilot reported an altitude of 300 feet and an estimated over Bontang at 0011 UTC. Bontang Info acknowledged and asked the pilot to report when leaving the Bontang Area.
At 0010 UTC, the SureTrack flight following system stopped receiving data. The last recorded data showed a speed of 138 knots, heading 352°, at coordinates 0°8’33” N, 117°12’54” E.
Search and Rescue
At 0600 UTC, the aircraft engineer inquired about the flight after fuel endurance was exceeded. Temindung Tower contacted Bontang Info, which attempted to contact the pilot twice without reply. Bontang Info also checked with Tanjung Bara Airstrip but received no information. Temindung Tower declared INCERFA at 0610 UTC, ALERFA at 0630 UTC, and DETRESFA at 0700 UTC.
At 0730 UTC, a search and rescue team was assembled, comprising Temindung Airport Authority, National Search and Rescue, Indonesian Police, Army, and Airforce. The search used three helicopters for ground and air operations.
Wreckage
On 26 August 2012 at 0850 UTC, the wreckage was located by a ground team on a ridge of Mayang Hill, Bontang, at approximately 1,200 feet AMSL, coordinates 00°12’34.3”N, 117°16’57.3”E, 12 NM from Bontang Aerodrome on a bearing of 294°. The accident site was within the planned survey area. All four occupants were fatally injured, and the aircraft was destroyed by impact force and post-impact fire.
Probable Cause
The official findings determined the accident was typical of a Controlled Flight into Terrain (CFIT). Low altitude VFR flying in a low visibility environment limited the pilot’s visibility and increased the probability of impact with terrain.