Incident
The aircraft, a Fellowship christened 'Mamberamo', departed Palembang Airport at 1732 local time on a scheduled flight to Medan. After being cleared for an NDB approach to runway 05 at Polonia Airport, the crew began a descent in limited visibility. While descending at an altitude of 5,560 feet during nighttime, the airplane impacted the slope of Mount Sibayak, which rises 2,194 meters above sea level and lies approximately 38 kilometers southwest of Medan-Polonia Airport. The collision totally destroyed the aircraft, and all 61 people on board were killed.
Probable Cause
According to the official investigation, the probable cause was that, for reasons unknown, the crew initiated the descent prematurely and continued the approach below the glide path, leading to a controlled flight into terrain. The lack of visibility was cited as a contributing factor.