SilkAir Flight 185 was a scheduled SilkAir passenger flight from Jakarta, Indonesia to Singapore, which crashed into the Musi River near Palembang in southern Sumatra, Indonesia on 19 December 1997, killing all 97 passengers and 7 crew members on board.
There was immense controversy as to the cause of the crash, which was investigated by two independent agencies. The Indonesian National Transportation Safety Committee (NTSC) led by Engineering Professor Oetarjo Diran stated in its report that it could not determine a cause of the crash due to inconclusive evidence.
The United States’ National Transportation Safety Board (NTSB) also participated in the investigation, given that the mishap aircraft was built by Boeing in the United States. Led by NTSB lead investigator, Greg Feith concluded, from their interpretation of the absent black box data, that the crash was the result of deliberate flight control inputs, most likely by the captain.
Following an independent and private investigation into the this crash, a jury under the Superior Court in Los Angeles, which was not allowed to hear or consider the NTSB conclusions, given that these were deductions based on the absence of evidence, decided that the crash was caused by a prominent issue inherent in other 737 crashes: a defective servo valve inside the Power Control Unit (PCU) which controls the aircraft’s rudder, had been forensically examined by the NTSB and the manufacturer of the PCU, and passed as non-defective, but was again examined under a scanning electron microscope by independent investigators who concluded that minute defects in the PCU had caused a rudder hard-over and a subsequent uncontrollable crash. The manufacturer of the aircraft’s rudder controls and the families later reached an out of court settlement.
Flight 185 has the third highest death toll of any aviation accident in Indonesia after Garuda Indonesia Flight 152 and Mandala Airlines Flight 091.