SilkAir flight 185

SilkAir flight 185
An identical Boeing 737-300 from SilkAir
Accident summary
Accident type	alleged pilot suicide
place	Musi River, Palembang , Indonesia
date	December 19, 1997
Fatalities	104
Survivors	0
Aircraft
Aircraft type	Boeing 737-36N
operator	Silk Air
Mark	9V-TRF
Departure airport	Soekarno-Hatta Airport , Jakarta , Indonesia
Destination airport	Singapore Airport , Singapore
Passengers	97
crew	7th
Lists of aviation accidents

On December 19, 1997, a Boeing 737-36N of the Silk Air 9V-TRF , with which a flight from Jakarta to Singapore was carried out, was flown into the Musi River on SilkAir flight 185 . All 104 people on board the machine were killed in the accident. According to NTSB investigators, the incident involved pilot suicide .

plane

The affected machine was a Boeing 737-36N, which was finally assembled at the Boeing plant in Renton , Washington state and which made its maiden flight on January 27, 1997. The aircraft had the factory number 28556, it was the 2851. Boeing 737 from ongoing production. The machine was built for the aircraft leasing company GECAS , to whose customer Silk Air the machine was delivered brand new on February 14, 1997. The twin-engine narrow-body aircraft was equipped with two Turbojettriebwerken type CFMI CFM56-3B2 equipped. By the time of the accident, the machine had completed a total of 2,238 operating hours, which accounted for 1,306 take-offs and landings.

Passengers and crew

The cockpit crew consisted of the 41-year-old Singaporean flight captain and former A-4 Skyhawk pilot Tsu Way Ming (朱卫民) and the 23-year-old first officer Duncan Ward from New Zealand. Captain Tsu had 7,173 hours of flight experience, of which he had completed 3,614 hours in the cockpit of the Boeing 737. First Officer Ward had 2,501 hours of flight experience, including 2,311 hours in the Boeing 737. There were also five Singaporean flight attendants on board.

Passengers

The flight from Jakarta to Singapore had taken 97 passengers from 13 countries.

nationality	Passengers	crew	total
Singapore	40	6th	46
Indonesia	23	-	23
Malaysia	10	-	10
United States	5	-	5
France	5	-	5
Germany	4th	-	4th
United Kingdom	3	-	3
Japan	2	-	2
Bosnia and Herzegovina	1	-	1
Austria	1	-	1
India	1	-	1
Taiwan	1	-	1
Australia	1	-	1
New Zealand	-	1	1
total	97	7th	104

Course of the flight and course of the accident

Debris of the machine

The Boeing 737 took off at 3:37 p.m. local time (08:37 UTC) from runway 25R of Soekarno-Hatta International Airport in Jakarta . The flight time to Changi Airport in Singapore should be 80 minutes. The weather was good along the route, only near Singkep Island , 120 kilometers south of Singapore, should there be some thunderstorms.

The crew were cleared to climb to flight level 350, approximately 35,000 feet (11,000 meters), and fly directly to Palembang. At 3:47:06 p.m., during the climb, when the crew was at an altitude of 24,500 feet (7,468 meters), asked for permission to fly directly to the PARDI waypoint . At 3:53 p.m., the crew reported that they had reached cruising altitude at flight level FL350. Air traffic control gave clearance to fly directly to the PARDI point and instructed the pilots to report as soon as they fly over Palembang . At 4 p.m., Captain Tsu May Wing left the cockpit. The Cockpit Voice Recorder (CVR) stopped recording at 4:05 p.m. At this point only First Officer Duncan Ward was in the cockpit. It was later suspected that the flight captain Tsu May Wing had deliberately deactivated the main switch of the CVR while walking out of the cockpit. At 4:10 p.m., the air traffic controller informed the crew that the aircraft was abeam Palembang and instructed the pilots to maintain flight level FL350 and to contact Singapore approach control when they reached PARDI. First Officer Ward confirmed the instruction. At 4:11 p.m. the recording of the flight data recorder also stopped . The investigators later put forward the thesis that Captain Tsu must have lured the first officer Ward out of the cockpit shortly before on a pretext. After this happened, Tsu locked the first officer out of the cockpit before deactivating the data recorder. It has been suggested that Tsu did this to make sure there was no record of what he would do next.

The aircraft remained at flight level FL350 until it went into a fast and almost vertical dive at around 1612 . During the dive, some parts of the aircraft, including a large part of the tail unit , broke off the fuselage of the machine. This was due to the high forces, as the machine almost reached the speed of sound during the dive . Less than a minute after the start of the dive, the plane hit the surface of the Musi River near Palembang in Sumatra . All 104 people on board were killed. Parts of the wreck were pushed up to 4.6 meters into the soil of the river bed.

The plane began to break apart prior to impact, with the debris stretching for several kilometers, although most of the wreck was concentrated in a single 60 meter by 80 meter area on the river floor. No entire bodies, body parts, or limbs were found. Only six human remains found were later identifiable.

Accident investigation

The accident was investigated by the Indonesian aviation safety authority NTSC, which was supported by expert groups from the USA, Singapore and Australia.

Parts of the wreckage were recovered with a weight corresponding to 73% of the machine. Both aircraft recorders , the cockpit voice recorder and the flight data recorder were recovered from the river after a long search and their data was retrieved and analyzed.

It was initially speculated that First Officer Duncan Ward deliberately crashed the plane since he was the only person in the cockpit when the CVR stopped the recording. This was quickly ruled out, however, as Ward's friends, family and colleagues testified that he had shown no signs of depression or thoughts of suicide during his career at SilkAir and that he was in a good mood on the morning of the accident flight.

Captain Tsu left the cockpit at 4:00 p.m. and recording stopped five minutes later. Tests have shown that a click will be heard at the end of the CVR recording when the CVR breaker trips normally, but not when it is manually pulled out. Since there was no click, it was suspected that Captain Tsu pulled out the CVR circuit breaker after leaving the cockpit. NTSC and NTSB investigators believed that if Captain Tsu was responsible for the crash, then he must have come up with an excuse to get the first officer out of the cockpit before deactivating the FDR there in the event of deactivation, a warning would have been displayed immediately on both pilots' control screens. As recorded by the Indonesian ground radar, the machine went into a steep dive a few minutes later, broke apart and fell into the Musi River.

On December 14, 2000, the Indonesian NTSC published its final report after a three-year investigation. The NTSC chairman overruled his investigators' findings that the crash was caused by intentional input from the pilot, so the report found that the evidence was inconclusive and that the cause of the accident could not be determined.

The US NTSB, which was also involved in the investigation, concluded that the evidence was compatible with deliberate tampering with the flight recorders and that this tampering was most likely caused by the captain. In addition, the nosedive characteristics speak in favor of actively steering the machine into the nosedive, as no conceivable scenario of a technical failure could result in such a steep flight angle. Examination of all actual evidence would thus be consistent with the conclusions that: 1) no aircraft-related mechanical malfunctions or failures caused or contributed to the accident, and 2) the accident could be explained by deliberate actions by the pilot. In particular a) the flight profile of the aircraft involved in the accident agrees with ongoing manual flight control inputs; b) the evidence suggests that the cockpit voice recorder (CVR) was intentionally disabled; c) the airplane could be intercepted from a dive but was not attempted; and d) it is more likely that the flight control inputs were made by the master than the first officer.

Possible motive

Following the crash, several possible reasons for the captain's alleged extended suicide have been suggested. Tsu Way Ming has recently suffered $ 1.2 million in financial losses from stock deals. He also had a life insurance policy of $ 600,000 a week prior to the accident, which was due to take effect on the day of the accident. Furthermore, he had received several disciplinary measures from the airline in the recent past, one of which involved improper manipulation of the CVR circuit breaker, and as an Air Force pilot he had four comrades in his unit during his military service exactly 18 years to the day before the crash Flight training lost. Tsu also had several conflicts with Ward and other first officers who had questioned his leadership. Investigations later found that his total assets were greater than his liabilities, although his cash assets could not cover his immediate debts; his monthly income was less than his family's monthly expenses; and he had some outstanding credit card debt.

An official investigation by Singapore Police found "no evidence that the pilot, copilot or crew member had suicidal tendencies or any motive for deliberately causing the plane to crash".

Theory of a rudder malfunction

In the early 1990s there were incidents in which full rudder deflections caused a malfunction of the control unit on Boeing 737 aircraft, such as United Airlines Flight 585 on March 3, 1991 and September 8 1994 crashed on USAir Flight 427 . During the investigation into the crash on USAir Flight 427, the NTSB found that the control unit's twin servo valve could also jam and move the rudder in the opposite direction due to a thermal shock. Based on this finding, the Federal Aviation Administration (FAA) ordered the servovalves to be replaced and a new training program for pilots to be developed to cope with unexpected movements of flight rudders.

The examination of the rudder control unit of the affected machine did not reveal any evidence of such a malfunction, whereby the steep dive characteristics of the machine did not correspond to a rudder malfunction, but rather to a conscious steering of the machine into the ground.

swell

• Accident report B-737-300 9V-TRF in the Aviation Safety Network (English), accessed on April 9, 2020.
• "Aircraft Accident Report SILKAIR FLIGHT MI 185 BOEING B737-300 9V-TRF MUSI RIVER, PALEMBANG, INDONESIA DECEMBER 19, 1997" , National Transportation Safety Committee, December 14, 2000.
• Operating history of the machine on planespotters.net
• Richard C. Paddock: A jet crash that defies resolution , Los Angeles Times , September 5, 2001.
• Letter from NTSB Chairman Jim Hall to Prof. O. Diran regarding the NTSB's final report on the accident , National Transportation Safety Board , December 11, 2000.

Individual evidence

1. ↑ Police News Release: Investigation into the Police Report lodged on 25 Aug 99 by the Singapore-Accredited Representative to the National Transportation Safety Committee, 14 Dec 2000 , Singapore Ministry of Home Affairs

Coordinates: 2 ° 27 ′ 30 ″  S , 104 ° 56 ′ 12 ″  E