What happened
On 8 March 2024, a Pilatus PC-6/B2-H4 aircraft, registration PK-SNE, crashed into a mountain ridge in the North Kalimantan region of Indonesia. The aircraft, operated by PT Smart Cakrawala Aviation, was performing a scheduled cargo flight from Tarakan to Binuang under Visual Flight Rules (VFR).
The flight departed Tarakan at 0825 LT with a pilot, an aircraft engineer, and 583 kg of cargo on board. After passing through Malinau at 0854 LT, the pilot's communications with air traffic control ceased. The final position report received via the flight following system placed the aircraft approximately 12 NM northeast of Malinau at 0900 LT. GPS data later revealed that the aircraft began descending from its 8,500-foot cruising altitude at 0906 LT, eventually passing through 5,000 feet at a rate of 700 feet per minute. The aircraft was discovered the following day on a mountain ridge at an elevation of approximately 4,800 feet, roughly 5 NM southeast of Binuang.
The investigation
The KNKT investigation examined the flight's trajectory, weather conditions, and operational procedures. Investigators analyzed GPS logs, which showed the aircraft's descent and final heading before impact. Meteorological data from satellite imagery indicated the presence of stratocumulus, cumulus, and middle-level clouds around the crash site at the time of the accident.
The inquiry also reviewed the operator's internal navigation resources. While the aircraft was equipped with a GPS for waypoint navigation, the investigation found that the official aeronautical charts did not include a specific VFR route for the Tarakan to Binuang leg. Furthermore, the investigation noted that the operator's internal manual (OM-C) provided limited route information, specifically covering only the Malinau to Binuang segment.
Findings
- The aircraft was airworthy and operating within its weight and balance limits at the time of departure.
- The pilot had valid licenses and had passed a medical examination on the day of the flight.
- The absence of specific route guidance for the Tarakan to Binuang leg was identified as a significant issue.
- Satellite imagery confirmed cloudy conditions, including stratocumulus and cumulus clouds, in the vicinity of the accident site.
- The aircraft's GPS logs recorded a steady descent from 8,500 feet starting at 0906 LT.
Safety action
To address the lack of navigational support, the KNKT has issued a safety recommendation to Smart Aviation. The operator is advised to develop and implement formal route guidance for flights between Tarakan and Binuang to ensure pilots have sufficient information regarding terrain and route characteristics, as required by the company's own operations manual.