The flight was not a commercial passenger service. Indonesia Air Transport was operating the ATR 42-512, registered as PK-THT, on behalf of the Directorate General of Marine and Fisheries Resources Surveillance - a government agency responsible for monitoring Indonesia's vast territorial waters. The aircraft carried seven crew members and three directorate staff, flying from Adisutjipto Airport in Yogyakarta to Makassar, a route that crosses the Java Sea and approaches South Sulawesi from the north. It was the kind of mission that rarely makes the news: a government charter, a workhorse turboprop, a crew doing unglamorous but essential work patrolling one of the world's richest fishing grounds.

Bantimurung-Bulusaraung National Park sprawls across nearly 44,000 hectares of South Sulawesi, its terrain dominated by tower karst - sheer limestone pillars that rise abruptly from the forest floor. The Maros-Pangkep karst system contained within the park is the second largest of its kind in the world, surpassed only by formations in southeastern China. Within these peaks lie 286 caves, some containing prehistoric wall paintings, others plunging to depths of 260 meters. It is spectacularly beautiful terrain and spectacularly unforgiving to any aircraft that strays into it. Mount Bulusaraung rises within this labyrinth of stone, located in Pangkajene and Islands Regency, roughly 50 kilometers north of Makassar and just 20 kilometers from the airport the ATR 42 was trying to reach.

Local residents near the park reported an explosion and a column of smoke rising from the mountain around the time contact was lost. But the terrain that had claimed the aircraft also impeded the effort to find it. Adverse weather rolled in, shrouding the karst peaks in cloud and rain. The National Search and Rescue Agency mobilized alongside AirNav Indonesia, the Indonesian Air Force, local government teams, and villagers from surrounding communities. Ground teams struggled through dense forest and vertical limestone, while helicopters circled the ridgelines looking for wreckage. At 7:46 the following morning, a rescue helicopter crew spotted pieces of the aircraft's window scattered on a slope. Three minutes later, they found the main debris field: the tail section resting at the bottom of a steep mountain face, surrounded by scorched forest.

Indonesia's National Transportation Safety Committee, known by its Indonesian acronym KNKT, classified the accident as Controlled Flight Into Terrain - CFIT. The designation means the aircraft was intact and under the crew's control when it struck the mountain, a finding that points to navigational or procedural failure rather than mechanical breakdown. Sources reported that the aircraft was not on the correct flight path during its approach. Both flight recorders - the cockpit voice recorder and the flight data recorder - were recovered from the wreckage on 21 January and sent to the KNKT laboratory in Jakarta for analysis. Indonesia has a long and painful history with CFIT accidents in its mountainous terrain. In 2015, Trigana Air Flight 267, another ATR 42, crashed into a mountain in Papua, killing all 54 people aboard under similar circumstances.

By 23 January, search teams had recovered the remains of all ten victims from the wreckage scattered across the steep terrain. The recovery operation itself had been dangerous - rescuers rappelled down cliff faces and cut trails through dense undergrowth to reach the debris field. The dead included pilots, flight engineers, and government officials whose work was to protect Indonesia's marine resources from illegal fishing. Their names joined a list that stretches back decades - aviation professionals lost to Indonesia's demanding geography, where island-hopping routes thread between volcanic peaks and tropical storms are a daily reality. The investigation continues, and the mountain keeps its silence.