 9V-TRF, the aircraft involved, seen in May 1997 | |
| Occurrence | |
|---|---|
| Date | 19 December 1997 |
| Summary | Crashed into the Musi river from cruise altitude; cause disputed |
| Site | Musi River, Palembang, Indonesia 2°27′30″S 104°56′12″E / 2.45833°S 104.93667°E |
| Aircraft | |
| Aircraft type | Boeing 737-36N |
| Operator | SilkAir |
| IATA flight No. | MI185 |
| ICAO flight No. | SLK185 |
| Call sign | SILK AIR 185 |
| Registration | 9V-TRF |
| Flight origin | Soekarno–Hatta Int'l Airport, Jakarta, Indonesia |
| Destination | Singapore Changi Airport, Singapore |
| Occupants | 104 |
| Passengers | 97 |
| Crew | 7 |
| Fatalities | 104 |
| Survivors | 0 |
SilkAir Flight 185 was a scheduled international passenger flight operated by a Boeing 737-300 from Soekarno–Hatta International Airport in Jakarta, Indonesia to Changi Airport in Singapore that crashed into the Musi River near Palembang, Sumatra, on 19 December 1997, killing all 97 passengers and 7 crew members on board.
The investigation into the cause of the crash was led by investigators from the National Transportation Safety Committee (NTSC), who were joined by the National Transportation Safety Board (NTSB). The NTSB, which participated in the investigation due to Boeing's manufacture of the aircraft in the U.S., investigated the crash under lead investigator Greg Feith. In its final report, the NTSC found "no concrete evidence" to support the pilot suicide allegation, with the previously suspected Parker-Hannifin hydraulic power control unit (PCU) having already been determined by the manufacturer to be defect-free. The final statement from the NTSC was that they were unable to determine the cause of the crash and was thus inconclusive. On the other hand, in a letter sent to the NTSC, the NTSB found that the crash was most likely the result of deliberate flight-control inputs that were "most likely by the captain".
Although the NTSB and PCU manufacturer Parker-Hannifin had already determined that the PCU was properly working, and thus not the cause of the crash, a private and independent investigation into the crash for a civil lawsuit tried by jury in Los Angeles County Superior Court, which was not allowed to hear or consider the NTSB's and Parker-Hannifin's conclusions, concluded that the crash was caused by a defective servo valve inside the PCU based on forensic findings from an electron microscope, which determined that minute defects within the PCU had caused the rudder hard-over and a subsequent uncontrollable flight and crash. The manufacturer of the aircraft's rudder controls and the families later reached an out-of-court settlement.