SilkAir Flight 185

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SilkAir Flight 185

Summary
Date	December 19, 1997
Type	Disputed
Site	Palembang, Indonesia
Fatalities	104
Injuries	0
Aircraft
Aircraft type	Boeing 737-300
Operator	SilkAir
Tail number	9V-TRF
Passengers	97
Crew	7
Survivors	0

SilkAir Flight 185 was a scheduled passenger service from Jakarta, Indonesia to Singapore. On December 19, 1997, the ill-fated flight was being operated by a Boeing 737-300, registration 9V-TRF.

All 97 passengers and 7 cabin crew, including the Singaporean captain, Tsu Way Ming and the co-pilot, New Zealander Duncan Ward, died when the aircraft, in a nearly vertical attitude, impacted the Musi River near Palembang, Sumatra following an abrupt descent. The aircraft broke into pieces before impact, as commercial aircraft are not designed to handle such intense forces and speed. The debris spread over several kilometres, with the debris of one engine falling far away from the main body. There was not a complete body, body part or limb found, as the entire aircraft and passengers disintegrated upon impact.^[1]

Contents 1 Accident Analysis 2 See also 3 References 4 External References

[edit] Accident Analysis

After the crash, there was substantial speculation that the pilot deliberately crashed the aircraft in a mass homicide/suicide. A 2004 court decision by the Los Angeles Superior Court in the United States ruled, however, that the crash was caused by a defective servo valve in the plane's rudder. The rudder manufacturer, Parker Hannifin, was ordered to pay the three families of victims involved in that case US$44 million.^[2]

In the aftermath of the crash, several potential motives for Tsu's suicide were suggested, including recent financial losses, his taking out of insurance on his life the previous week, his receipt of several recent disciplinary actions on the part of the airline. He had also reportedly had several conflicts with Ward, the co-pilot.^[3] However, investigations later discovered his assets were greater than his financial losses, therefore that was not a clear motive for suicide.

An official investigation by the Singapore Police Force into evidence of criminal offence leading to the crash found that there was no motive nor reason for any of the crew to deliberately cause the crash of the aircraft.^[4]

Tsu was formerly a Republic of Singapore Air Force pilot and had over twenty years of flying experience in the A-4SU and TA-4SU Super SkyHawks. His last appointment was instructor pilot of a SkyHawk squadron. Due to his flying experience, it was also highly unlikely that the aircraft lost control or fell into a stall of spin, as he would have had the experience to overcome such stalls and spins.

The circuit breakers for the cockpit voice recorder and flight data recorder were tripped minutes before the abrupt descent, but not at the same time. The radio continued to work after the failure of the recorders, which indicates that power failure was not a cause, however there was no conclusive evidence whether this was the action of the pilot or otherwise. This flight data recorder was old and had several periods of malfunction during the last days. It was precisely this lack of conclusive evidence, because of the switched off data and voice recorders, that made the case against Tsu impossible to prove.

The Indonesian National Transportation Safety Committee, which led the investigation, was not able to find any conclusive cause and even several years after the fact, many conspiracy theories remain. Skeptics point to other difficult to explain accidents involving 737s which showed signs of quirky flight controls such as uncommanded rudder deflection, including USAir Flight 427 and United Airlines Flight 585.^{[citation needed]} The pilot suicide theory and controversy is very similar to that of EgyptAir Flight 990.

FAA has ordered an upgrade of all B-737 before November 12, 2008.^[5] All airlines must install a new rudder control system that includes new components such as an aft torque tube, hydraulic actuators, and associated control rods, and additional wiring throughout the airplane to support failure annunciation of the rudder control system in the flight deck. The system also must incorporate two separate inputs, each with an override mechanism, to two separate servo valves on the main rudder power control unit (PCU) and an input to the standby PCU that also will include an override mechanism.

Among those killed in the crash were Singaporean author Bonny Hicks.

[edit] See also

• List of accidents and incidents on commercial airliners

[edit] References

1. ^ *ASN Accident description of SilkAir Flight 185
2. ^ "SilkAir crash families finally receive answers with court verdict", Channel NewsAsia, July 15, 2004.
3. ^ Laurinda Keys, Suicide is possible cause of jet crash, officials say pilot had history of troublesome behavior. Associated Press, March 11, 1998.
4. ^ Singapore Police Force, Investigation into the Police Report lodged on 25 Aug 99 by the Singapore-Accredited Representative to the National Transportation Safety Committee, December 14, 2000.
5. ^ B-737 rudder design defect upgrade, [1], November 12, 2002.

[edit] External References

• Boeing 737 Rudder Design Defect