What happened
On December 19, 1997, a SilkAir Boeing 737-300, registered 9V-TRF, was performing a scheduled international passenger service from Jakarta to Singapore. The flight departed Soekarno-Hatta International Airport at 08:37 local time under Instrument Flight Rules. After takeoff from Runway 25R, the aircraft was cleared to climb to 35,000 feet with a direct heading toward Palembang.
As the aircraft progressed through its climb, the crew requested a change in navigation to proceed directly to the PARDI waypoint. Air traffic controllers instructed the flight to maintain its current path and report once it reached its assigned altitude. The crew confirmed they had reached Flight Level 350 at 08:53 local time. Shortly thereafter, the controller cleared the aircraft to fly directly to PARDI.
At approximately 09:05, the cockpit voice recorder stopped functioning. At 09:10, the controller notified the crew that they were abeam Palembang and instructed them to maintain their altitude and contact Singapore Control upon reaching the waypoint. Following this final acknowledgment from the crew, no further radio communication was received.
Radar monitoring indicated the aircraft remained at its assigned altitude until 09:12, when a sudden drop of 400 feet was detected, followed by a rapid descent. The last flight data recorder entry occurred at 09:11, and subsequent radar tracking showed the plane descending through Flight Level 195. During this descent, the aircraft's empennage separated in mid-air. The wreckage impacted the Musi river delta, roughly 50 km north-northeast of Palembang, at approximately 09:13. There were 104 fatalities and no survivors.
Findings
An investigation conducted by the NTSC faced significant challenges due to the extreme fragmentation of the wreckage and the difficult location of the crash site. The investigators noted that the flight recorders ceased providing data during the final moments of the flight sequence. Ultimately, the investigation yielded no conclusive evidence to explain why the aircraft departed from its assigned altitude or why the flight recorders stopped operating.