What happened
On the morning of 23 June 2022, a Pilatus PC-6/B2-H4 aircraft, registration PK-BVM, was performing an unscheduled passenger flight from Timika to Duma, Papua. The flight, operated by PT ASI Pudjiastim (Susi Air), departed at approximately 05:34 local time under Visual Flight Rules (VFR). The aircraft was carrying one pilot and six passengers.
During the flight, the pilot requested and received clearance to descend to a cruising altitude of 4,500 feet. While navigating the mountainous terrain, the aircraft was observed by local residents flying at a low altitude and traveling in a direction that did not indicate an intention to land at the Duma airstrip. Shortly thereafter, the aircraft struck a tree approximately 30 meters tall. The wreckage was located about 3 nautical miles north of the Duma airstrip at an elevation of 5,400 feet. The accident resulted in serious injuries to the pilot and minor injuries to five passengers, while one passenger escaped without injury.
The investigation
The Indonesian National Transportation Safety Committee (KNKT) conducted the investigation with support from the STSB (Switzerland), TSB (Canada), and NTSB (USA). Investigators examined the aircraft's flight following data, which showed the aircraft was near the Duma airstrip at 05:52 local time before the system lost contact.
Technical analysis focused on the aircraft's Global Positioning System (GPS) and the operator's documentation. Investigators found that while the GPS was capable of flight data logging, the SD card containing the flight data for this specific occurrence was missing from the Multi-Function Display. Furthermore, the investigation reviewed the company's operational manuals and navigation aids, noting that the specific coordinates used for the flight were not officially documented in company materials.