Misplaced Pages

#163836

81-569: 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

162-573: A rigid fixture . These formers are then joined with lightweight longitudinal elements called stringers . These are in turn covered with a skin of sheet aluminum, attached by riveting or by bonding with special adhesives. The fixture is then disassembled and removed from the completed fuselage shell, which is then fitted out with wiring, controls, and interior equipment such as seats and luggage bins. Most modern large aircraft are built using this technique, but use several large sections constructed in this fashion which are then joined with fasteners to form

243-514: A $ 600,000 life insurance policy the previous week, which was to have gone into effect on the day of the accident (though it later emerged that this was a routine policy taken out as part of a mortgage requirement), his receipt of several recent disciplinary actions on the part of the airline (including one that related to improper manipulation of the CVR circuit breaker), and the loss of four squadron mates during his military flight training, 18 years earlier on

324-464: A 737-300, crashed near Pittsburgh , Pennsylvania, killing 132 people. Four more incidents occurred where a 737 rudder PCU malfunction was suspected. The Seattle Times devoted a series of 37 articles to Boeing 737 loss-of-control malfunctions. The accident occurred in the middle of a controversy over the NTSB's role in accidents caused by the rudder control unit. During the investigation of Flight 427,

405-472: A cause to the crash of Flight 185 due to a defective PCU servo valve-unit (manufactured by Parker-Hannifin), an independent and private investigation refocused on and further examined the recovered PCU device whose malfunctioning has been pointed out in other sudden Boeing 737 crashes. The manufacturer's records relating to this particular unit revealed that it had failed some routine tests, but they claimed to have corrected these problems. A metals expert, with

486-485: A design is intended to be "self jigging", not requiring a complete fixture for alignment. Early aircraft were constructed of wood frames covered in fabric. As monoplanes became popular, metal frames improved the strength, which eventually led to all-metal-structure aircraft, with metal covering for all its exterior surfaces - this was first pioneered in the second half of 1915 . Some modern aircraft are constructed with composite materials for major control surfaces, wings, or

567-407: A federal law disallowed them from using the NTSB final report as evidence in the company's favor during the lawsuit. The lawyer representing the plaintiffs, Walter Lack, stated that the law only disallowed using the NTSB report's conclusion and suggestions, while statements of fact are admissible. USC §1154 (Discovery and use of cockpit and surface vehicle recordings and transcripts) states: "No part of

648-416: A flight augmentation system that adjusts the stabilizer automatically at low speed, low weight, aft center of gravity and high thrust with autopilot disengaged. Most frequently it can be observed during takeoffs and go-arounds. The system relies on most of the same hardware and software used in autopilot mode. STS is not fail-safe in that it uses only one of each sensor types required for its functionality and

729-641: A loan by the Canadian government for CA$ 3.4 million (2018) which is equivalent to CA$ 4.1 Million (or US$ 2.9 million) in 2024. The converted 737 FireLiner can carry 4,000 US gal (15 m ) with a flow rate of 3,000 US gal (11 m )/s, and retains 66 seats. The first was completed in 2018 and deployed to Australia. The prototype of the -300 rolled out of the Renton plant on January 17, 1984, and first flew on February 24, 1984. After it received its flight certification on November 14, 1984, USAir received

810-492: A nearly finished product) is prevalent in the series production of many modern sailplanes . The use of molded composites for fuselage structures is being extended to large passenger aircraft such as the Boeing 787 Dreamliner (using pressure-molding on female molds). This is the preferred method of constructing an all- aluminum fuselage. First, a series of formers in the shape of the fuselage cross sections are held in position on

891-447: A portion of the external load (i.e. from wings and empennage, and from discrete masses such as the engine) is taken by the surface covering. In addition, all the load from internal pressurization is carried (as skin tension ) by the external skin. The proportioning of loads between the components is a design choice dictated largely by the dimensions, strength, and elasticity of the components available for construction and whether or not

SECTION 10

#1733093921164

972-648: A report of the Board, related to an accident or an investigation of an accident, may be admitted into evidence or used in a civil action for damages resulting from a matter mentioned in the report." A memorial for the victims was erected at the burial site, which is located within the Botanical Gardens near Palembang. Another memorial is located at Choa Chu Kang Cemetery in Singapore. The Discovery Channel Canada / National Geographic TV series Mayday (also called Air Crash Investigation or Air Disasters ) dramatised

1053-528: A scratch pane near the passenger. Acrylic is susceptible to crazing  : a network of fine cracks appears but can be polished to restore optical transparency , removal and polishing typically undergo every 2–3 years for uncoated windows. " Flying wing " aircraft, such as the Northrop YB-49 Flying Wing and the Northrop B-2 Spirit bomber have no separate fuselage; instead what would be

1134-454: A series of metallic snaps (presumed to be the sounds of the captain's seatbelt being removed and chair moving); 13.6 seconds later, the CVR stopped recording. Tests indicated that a click would be heard on the CVR recording if the CVR circuit breaker had tripped normally, but not if it had been pulled out manually. As there was no click, Captain Tsu likely pulled out the CVR circuit breaker while leaving

1215-403: A single computer. Such a single-channel design is not common for augmentation systems that have full control of the stabilizer. This design was considered acceptable because of the ability for the aft and forward column cutout switches as well as center console cutout switches to constrain its malfunction. The limited flight envelope protections on the 737 Next Generation series, as well as MCAS on

1296-412: A strengthened wing spar . The prototype rolled out on January 26, 1988, and flew for the first time on February 19, 1988. The aircraft entered service on September 15, 1988, with launch customer Piedmont Airlines (25 aircraft ordered). The last two Boeing 737-400s, the last Boeing 737 Classics, were delivered to CSA Czech Airlines on February 28, 2000. The 737-400 was replaced by the 737-800 in

1377-445: Is composed of 4–6 panels, 35 kg (77 lb) each on an Airbus A320 . In its lifetime, an average aircraft goes through three or four windshields , and the market is shared evenly between OEM and higher margins aftermarket . Cabin windows, made from much lighter than glass stretched acrylic glass , consists of multiple panes: an outer one built to support four times the maximum cabin pressure, an inner one for redundancy and

1458-461: Is recorded by the CVR when the CVR circuit breaker trips. The investigators could not find this sound on Flight 185's CVR, which made them conclude that the CVR circuit breaker was manually pulled out. The radio continued to work after the failure of the CVR, which indicates that power failure was not the cause. The documentary Silkair 185: Pilot Suicide? claimed that this FDR had previously failed for periods lasting between 10 seconds and 10 minutes in

1539-489: Is the first and only fatal hull loss for SilkAir in the airline's history. SilkAir issued a press release on 19 December 1997 with a passenger count by nationality, and another the following day with crew details and a complete passenger manifest. Among those killed in the crash was Singaporean model and author Bonny Hicks . The accident was investigated by the Indonesian NTSC, which was assisted by expert groups from

1620-520: The Boeing 757 . The family also featured a redesigned vertical stabilizer with a dorsal fin at the base. In March 1981, USAir and Southwest Airlines each ordered 10 aircraft of the 737-300 series, with an option for 20 more. That aircraft, the initial model of the 737 Classic series, first flew in February 1984 and entered service in December of that year with Southwest Airlines. A further stretched model,

1701-496: The Farnborough Airshow . The new series featured CFM56 turbofan engines, yielding significant gains in fuel economy and a reduction in noise, but also posing an engineering challenge given the low ground clearance of the 737 – a trait of its 707 -derived fuselage. Boeing and engine supplier CFM International solved the problem by placing the engine ahead of (rather than below) the wing, and by moving engine accessories to

SECTION 20

#1733093921164

1782-456: The Lockheed Vega ) was built using molded plywood , where the layers of plywood are formed over a "plug" or within a mold . A later form of this structure uses fiberglass cloth impregnated with polyester or epoxy resin as the skin, instead of plywood. A simple form of this used in some amateur-built aircraft uses rigid expanded foam plastic as the core, with a fiberglass covering, eliminating

1863-608: 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

1944-503: The Singapore Police Force into evidence of criminal offence leading to the crash found "no evidence that the pilot, copilot, or any crew member had suicidal tendencies or a motive to deliberately cause the crash of [the aircraft]". Tsu was formerly a Republic of Singapore Air Force pilot, and had over 20 years of flying experience in the older T/ A-4S Skyhawks , as well as the newer T/ A-4SU Super Skyhawks . His last appointment

2025-508: The -300/400/500 variants as the 737 Classic. In total, 1,988 aircraft were delivered from 1984 until production ended in the year 2000: 1,113 -300s, 486 -400s and 389 -500s. Following the success of the Boeing 737-200 Advanced , Boeing wanted to increase capacity and range , incorporating improvements to upgrade the plane to modern specifications, while also retaining commonality with previous 737 variants. Development began in 1979, and in 1980, preliminary aircraft specifications were released at

2106-527: The -500 is similar in length to the original 737-200 and can fly 110 to 132 passengers. The 110-foot-long (34 m) -300 can seat 126 to 149 passengers while the 120-foot-long (37 m) -400 accommodates 147 to 168 seats. It competed with the McDonnell Douglas MD-80 series, then with the Airbus A320 family which prompted Boeing to update its offer with the 737 Next Generation , thus designating

2187-634: The 1990s, when regular Boeing customer United Airlines bought the Airbus A320 , this prompted Boeing to update the slower, shorter-range 737 Classic -400 into the rewinged, updated, more efficient, longer 737NG -800. Production of the 737 Classic continued alongside that of the Next Generation for a period of time; the first 737-700 was completed in December 1996; the last 737 Classic was completed in February 2000. Six former Southwest Airlines 737-300s are modified and operated for aerial firefighting by British Columbia -based Coulson Group, supported by

2268-562: The 25 hours preceding the crash. Testing of the unit by the NTSC found no evidence that a malfunction or failure caused either recorder to stop recording data. Starting in 1991, several accidents and incidents involving the Boeing 737 were the result of uncommanded movement of their rudders. On 3 March 1991, United Airlines Flight 585 , a 737-200, crashed in Colorado Springs , Colorado, killing 25 people. On 8 September 1994, USAir Flight 427 ,

2349-533: The 737 MAX, are later extensions of this system. Throughout the 1980s, the 737 Classic series attracted large orders from airlines in the United States and Europe, with its order totals exceeding those of preceding 737 models. By far, the most successful model was the 737-300, with deliveries totaling 1,113 aircraft (the 737-400 and -500 reached 486 and 389 deliveries, respectively). Major operators included US carriers, small national airlines, and charter carriers. By

2430-457: The 737-200, accommodating up to 140 passengers. Both glass and older style mechanical cockpits arrangements were available. Using the CFM56-3 engine also gave a 25% increase in fuel efficiency over the older -200s P&W engines. The 737-500 was launched in 1987, by Southwest Airlines, with an order for 20 aircraft, and flew for the first time on June 30, 1989. A single prototype flew 375 hours for

2511-677: The 737-300 with a new set of instruments, hardware, and software, to improve commonality with the 737-700, as well as to support the Required Navigation Performance initiative, but that order was later cancelled and the retrofits never took place. The 737-300 can be retrofitted with Aviation Partners Boeing winglets. The 737-300 retrofitted with winglets is designated the -300SP (Special Performance) first entered service in June 2003. Used passenger -300 aircraft have also been converted to freighter versions. The 737-300 has been replaced by

SilkAir Flight 185 - Misplaced Pages Continue

2592-869: The 737-300. While a few 737-300s are slated for freighter conversion, there is no demand for a -500 freighter conversion. On September 5, 2016, Southwest Airlines flew their last 737-500 revenue flight, Flight 377 from El Paso to Dallas. As of July 2019, 692 Boeing 737 Classic aircraft were in commercial service. This includes 297 -300s, 261 -400s, and 134 -500s. Many countries operate the 737 passenger and cargo variants in government or military applications including Brazil , Chile , China . Colombia , India , Indonesia , Kuwait , Mexico , Niger , Peru , South Korea , Taiwan , Thailand , United Arab Emirates , Venezuela and others. (Not all are shown) As of January 2021 , 64 hull losses of Boeing 737 Classic series aircraft have occurred, with 1,298 fatalities. An analysis by Boeing on commercial jet airplane accidents in

2673-511: The 737-400, was launched with an order for 25 aircraft with 30 options from Piedmont Airlines in June 1986. That aircraft first flew in February 1988 and entered service later that year with Piedmont Airlines. The final model of the series, the 737-500, was launched with an order for 30 aircraft from Southwest Airlines in May 1987. That aircraft, which was designed as a replacement for the 737-200 and had similar passenger capacity and dimensions, as well as

2754-468: The 737-500, first flew in June 1989 and entered service in 1990. Compared to the original series, the classic series was re-engined with the CFM56 , a high-bypass turbofan , for better fuel economy and had upgraded avionics. With a 133,500–150,000 lb (60.6–68.0 t) MTOW , it has a range of 2,060 to 2,375 nautical miles [nmi] (3,815 to 4,398 km; 2,371 to 2,733 mi). At 102 feet (31 m)

2835-407: The 737-700 in the Boeing 737 Next Generation family. The 737-400 design was launched in 1985 to fill the gap between the 737-300 and the 757-200 , and competed with the Airbus A320 and McDonnell Douglas MD-80 . It stretched the 737-300 another 10 ft (3.05 m) to carry up to 188 passengers. It included a tail bumper to prevent tailscrapes during take-off (an early issue with the 757), and

2916-640: The Boeing 737 Next Generation family. The 737-400SF (Special Freighter) is a 737-400 that has been converted to haul cargo. Alaska Airlines was the first to convert one of their 400s from regular service to an aircraft with the ability to handle 10 pallets. The airline has also converted five more into fixed combi aircraft for half passenger and freight. These 737-400 Combi aircraft were retired in 2017 and replaced with 737-700Fs. In November 2018, VX Capital launched an ABS secured on 35 737-400 freighters valued at $ 250 million (an average of $ 7.1 million), to be leased for $ 100,000 per month each. The -500 series has

2997-465: The Boeing 737 departed Jakarta's Soekarno–Hatta International Airport 's runway 25R at 15:37 local time (08:37 UTC ) for a 80-minute flight to Singapore's Changi Airport . At the controls were Captain Tsu Way Ming ( Chinese : 朱卫民 ; pinyin : Zhū Wèimín ), 41, of Singapore, a former A-4 Skyhawk pilot, and First Officer Duncan Ward, 23, of New Zealand. Generally fair weather was expected for

3078-605: The NTSB had discovered that the PCU's dual servo valve could jam, as well, and deflect the rudder in the opposite direction of the pilots' input, due to thermal shock, caused when cold PCUs are injected with hot hydraulic fluid. As a result of this finding, the FAA ordered the servo valves to be replaced and new training protocol for pilots to handle unexpected movement of flight controls to be developed. The FAA ordered an upgrade of all Boeing 737 rudder control systems by 12 November 2002. According to

3159-412: The NTSB's conclusion but were overruled by their boss. In the aftermath of the crash, several potential motives for the captain's alleged suicide and homicide were suggested, including recent financial losses of $ 1.2 million (his share-trading showed trading of more than one million shares and his securities-trading privileges had been suspended 10 days before the accident due to nonpayment), his obtaining

3240-516: The US, Singapore, and Australia. Around 73% of the wreckage (by weight) was recovered, partially reconstructed, and examined. Both of the aircraft recorders, the CVR and the FDR, were retrieved from the river and their data were extracted and analyzed. The investigators tested 20 different simulations for various equipment-failure scenarios, and found that the only scenario that matched the actual radar trajectory of

3321-426: The accident can be explained by intentional pilot action. Specifically, a) the accident airplane’s flight profile is consistent with sustained manual nose-down flight control inputs; b) the evidence suggests that the cockpit voice recorder (CVR) was intentionally disconnected; c) recovery of the airplane was possible but not attempted; and d) it is more likely that the nose-down flight control inputs were made by

SilkAir Flight 185 - Misplaced Pages Continue

3402-452: The accident in a 2012 episode titled Pushed to the Limit (broadcast in some countries as Pilot Under Pressure ). The accident was also featured in a 2006 National Geographic documentary titled SilkAir 185: Pilot Suicide? . Singaporean singer JJ Lin 's 2013 song "Practice Love" ( Chinese : 修煉愛情 ) from the album Stories Untold ( 因你而在 ) is based on this incident, as a close friend of

3483-410: The addition of supported lightweight stringers, allowing the fabric covering to form a more aerodynamic shape, or one more pleasing to the eye. Geodesic structural elements were used by Barnes Wallis for British Vickers between the wars and into World War II to form the whole of the fuselage, including its aerodynamic shape. In this type of construction multiple flat strip stringers are wound about

3564-520: The aircraft entered a rapid descent, disintegrated, and crashed into the Musi River. On 14 December 2000, after three years of investigation, the Indonesian NTSC issued its final report. The NTSC chairman overrode the findings of his investigators—that the crash was caused deliberately by pilot input—so that the report stated that the evidence was inconclusive and that the cause of the accident could not be determined. The US NTSB, which also participated in

3645-408: The allegation that the crash was caused by the pilot, after each had rejected a compensation offer of $ 200,000 (£143,000). In October 2001 the claims were turned down by a Singapore High Court judge who ruled that "the onus of proving that flight MI185 was intentionally crashed has not been discharged." Although the NTSB and Parker-Hannifin had already ruled out the possibility of mechanical failure as

3726-493: The artist, Xu Chue Fern, was killed on the flight. Boeing 737 Classic The Boeing 737 Classic is a series of narrow-body airliners produced by Boeing Commercial Airplanes , the second generation of the Boeing 737 series of aircraft. Development began in 1979 and the first variant, the 737-300, first flew in February 1984 and entered service that December. The stretched 737-400 first flew in February 1988 and entered service later that year. The shortest variant,

3807-524: The captain than by the first officer. Geoffrey Thomas of The Sydney Morning Herald said, "a secret report confirmed that the Indonesian authorities would not issue a public verdict because they feared it would make their own people too frightened to fly." Santoso Sayogo, an NTSC investigator who worked on the SilkAir 185 case, said that the Indonesian investigators submitted a report which was similar to that of

3888-476: 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

3969-472: The certification process, and on February 28, 1990, Southwest Airlines received the first delivery. The 737-500 has become a favorite of some Russian airlines, with Nordavia , Rossiya Airlines , S7 Airlines , Sky Express , Transaero , UTair , and Yamal Airlines all buying second-hand models of the aircraft to replace aging Soviet -built aircraft and/or expand their fleets. Aerolíneas Argentinas replaced its 737-200s with second-hand 737-500s. The 737-500

4050-430: The cockpit. At 16:11, the FDR stopped recording. The NTSC and NTSB investigators thought that if Captain Tsu was responsible for the crash, he must have made up some excuse to get the first officer to leave the flight deck before disabling the FDR (which would have immediately triggered a Master Caution on both pilots' control panels), so that his actions would not be noticed. At 16:12, as recorded by Indonesian ground radar,

4131-616: The complete fuselage. As the accuracy of the final product is determined largely by the costly fixture, this form is suitable for series production, where many identical aircraft are to be produced. Early examples of this type include the Douglas Aircraft DC-2 and DC-3 civil aircraft and the Boeing B-17 Flying Fortress . Most metal light aircraft are constructed using this process. Both monocoque and semi-monocoque are referred to as "stressed skin" structures as all or

SECTION 50

#1733093921164

4212-410: 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. Carrying 97 passengers and a crew of seven,

4293-415: The crew reported reaching the cruise altitude of FL350 and was cleared to proceed directly to PARDI, and to report abeam Palembang. The cockpit voice recorder (CVR) ceased recording at 16:05. The documentary television series Mayday argues Captain Tsu may have taken the opportunity of leaving the cockpit for tripping the CVR circuit breaker to turn off the CVR. At 16:10, air traffic controllers informed

4374-417: The descent and crash of the flight was a high-speed steep dive commanded by one of the pilots. Furthermore, the investigators had found the trim jackscrew for the horizontal stabilizer, which revealed that flight inputs from one of the pilots had moved the stabilizer from level flight to a full nose-down descent. First Officer Duncan Ward was initially speculated to have deliberately crashed the aircraft, as he

4455-441: The engine accessory gearbox was moved from the bottom of the engine (the 6 o'clock position) to the 9 o'clock position, giving the engine nacelle its distinctive flat-bottomed shape, which is often nicknamed the "hamster pouch ". The overall thrust was also reduced, from 24,000 to 20,000 lbf (107 to 89 kN), mostly due to the reduction in bypass ratio . The 737 Classic saw introduction of Speed Trim System (STS),

4536-529: The entire fuselage such as the Boeing 787. On the 787, it makes possible higher pressurization levels and larger windows for passenger comfort as well as lower weight to reduce operating costs. The Boeing 787 weighs 1,500 lb (680 kg) less than if it were an all-aluminum assembly. Cockpit windshields on the Airbus A320 must withstand bird strikes up to 350 kn (650 km/h) and are made of chemically strengthened glass . They are usually composed of three layers or plies, of glass or plastic :

4617-432: The exact date of the crash. He had also had several conflicts with Ward and other co-pilots who had questioned his command suitability. Investigations later revealed that his total assets were greater than his liabilities, although his liquid assets could not cover his immediate debts; his monthly income was less than his family's monthly expenditure; and he had some outstanding credit card debts. An official investigation by

4698-456: The few recovered human remains. The aircraft involved was a Boeing 737-36N with serial number 28556, registered as 9V-TRF, and powered by two CFM56-3B2 engines. Having completed its maiden flight on 27 January 1997, the aircraft was delivered to SilkAir on 14 February, 10 months before the crash. At the time of the accident, it was the newest aircraft in SilkAir's fleet and had accumulated more than 2,200 flight hours in 1,300 cycles. This

4779-433: The first aircraft on November 28. It proved a very popular aircraft: Boeing received 252 orders in 1985, and over 1,000 throughout its production. The 300 series remained in production until the last aircraft was delivered to Air New Zealand on December 17, 1999, registration ZK-NGJ. By then, 1,113 Boeing 737 -300s had been produced over more than 15 years. In December 2008, Southwest Airlines selected Boeing to retrofit

4860-459: The flight that it was abeam Palembang and instructed the aircraft to maintain FL350 and to contact Singapore Control upon reaching PARDI. First Officer Ward acknowledged this call. At 16:11, nearly 6 minutes after the CVR ceased recording, the flight data recorder (FDR) also stopped recording. Mayday shows that Tsu is thought to have come up with an excuse to get Ward out of the cockpit. Having done so,

4941-515: The formers in opposite spiral directions, forming a basket-like appearance. This proved to be light, strong, and rigid and had the advantage of being made almost entirely of wood. A similar construction using aluminum alloy was used in the Vickers Warwick with less material than would be required for other structural types. The geodesic structure is also redundant and so can survive localized damage without catastrophic failure. A fabric covering over

SECTION 60

#1733093921164

5022-485: The fuselage is a thickened portion of the wing structure. Conversely, there have been a small number of aircraft designs which have no separate wing, but use the fuselage to generate lift. Examples include National Aeronautics and Space Administration 's experimental lifting body designs and the Vought XF5U-1 Flying Flapjack . A blended wing body can be considered a mixture of the above. It carries

5103-634: The inner two are 8 mm (0.3 in.) thick each and are structural, while the outer ply, about 3 mm thick, is a barrier against foreign object damage and abrasion , with often a hydrophobic coating. It must prevent fogging inside the cabin and de-ice from −50 °C (−58 °F). This was previously done with thin wires similar to a rear car window but is now accomplished with a transparent, nanometers-thick coating of indium tin oxide sitting between plies, electrically conductive and thus transmitting heat. Curved glass improves aerodynamics but sight criteria also needs larger panes. A cockpit windshield

5184-409: The investigation, concluded that the evidence was consistent with a deliberate manipulation of the flight controls, most likely by the captain. In a letter to the NTSC dated 11 December 2000, the NTSB wrote: The examination of all of the factual evidence is consistent with the conclusions that: 1) no airplane-related mechanical malfunctions or failures caused or contributed to the accident, and 2)

5265-505: The longest range of any member of the 737 Classic family, first flew in June 1989 and entered service with Southwest Airlines in 1990. Boeing selected the CFM56-3 exclusively to power the 737-300 variant. The 737 wings were closer to the ground than previous applications for the CFM56, necessitating several modifications to the engine. The fan diameter was reduced, which reduced the bypass ratio, and

5346-527: The necessity of fabricating molds, but requiring more effort in finishing (see the Rutan VariEze ). An example of a larger molded plywood aircraft is the de Havilland Mosquito fighter/light bomber of World War II . No plywood-skin fuselage is truly monocoque , since stiffening elements are incorporated into the structure to carry concentrated loads that would otherwise buckle the thin skin. The use of molded fiberglass using negative ("female") molds (which give

5427-539: The period 1959–2017 showed that the classic series had a hull loss rate of 0.71 per million departures versus 0.17 for the Next Generation series and 1.75 for the original series. Related development Aircraft of comparable role, configuration, and era Related lists Fuselage This type of structure is still in use in many lightweight aircraft using welded steel tube trusses. A box truss fuselage structure can also be built out of wood—often covered with plywood. Simple box structures may be rounded by

5508-409: The pilot then proceeded to lock his co-pilot out of the flight deck before disabling the FDR; Tsu is presumed to have done this to ensure that no record would be made of what he was going to do next. Flight 185 remained level at FL350 until it started a rapid and nearly vertical dive around 16:12. While descending through 12,000 ft (3,700 m), parts of the aircraft, including a great extent of

5589-438: 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

5670-514: The route, except for some thunderstorms near Singkep Island , 120 km (75 mi; 65 nmi) south of Singapore. The aircraft was cleared to climb to flight level 350 (FL350), about 35,000 ft (11,000 m), and to head directly to Palembang . At 15:47:06, while climbing through 24,500 ft (7,468 m), the crew requested clearance to proceed directly to waypoint PARDI ( 0°34′S 104°13′E  /  0.567°S 104.217°E  / -0.567; 104.217 ) . At 15:53,

5751-588: The series Mayday , the rudder issue had been corrected before construction started on the accident aircraft. Nevertheless, the theory of a rudder malfunction was investigated with the possibility of corrosion of and/or debris getting stuck in the PCU, and was disproved. SilkAir paid USD$ 10,000 compensation to each victim's family, the maximum under the Warsaw Convention . Boeing also paid an undisclosed amount of compensation. In July 2001 six families began court proceedings against SilkAir for damages, based on

5832-455: The sides (rather than the bottom) of the engine pod, giving the 737 a distinctive noncircular air intake. The wing incorporated a number of changes for improved aerodynamics . The wing tip was extended 9 inches (23 cm). The leading-edge slats and trailing-edge flaps were adjusted. The flight deck was improved with the optional electronic flight instrumentation system, and the passenger cabin incorporated improvements similar to those on

5913-422: The smallest dimensions of the 737 Classics. The -500 was offered, due to customer demand, as a modern and direct replacement of the 737-200, incorporating the improvements of the 737 Classic series in a model that allowed longer routes with fewer passengers to be more economical than with the 737-300. Though smaller than the -300 and -400, the fuselage length of the -500 is 1 ft 7 in (48 cm) longer than

5994-503: The structure completed the aerodynamic shell (see the Vickers Wellington for an example of a large warplane which uses this process). The logical evolution of this is the creation of fuselages using molded plywood, in which several sheets are laid with the grain in differing directions to give the monocoque type below. In this method, the exterior surface of the fuselage is also the primary structure. A typical early form of this (see

6075-436: The tail section, started to separate from the aircraft's fuselage due to high forces arising from the nearly supersonic dive. Seconds later, the aircraft hit the Musi River , near Palembang, Sumatra, killing all 104 people on board. The time it took the aircraft to dive from cruise altitude into the river was less than one minute. The plane was travelling faster than the speed of sound for a few seconds before impact. Parts of

6156-406: The use of images from a scanning electron microscope, concluded that the servo valve had 'chip-outs' and numerous burrs "that could easily have interfered with the smooth operation of the valve". After this investigation was complete, in 2004, a Los Angeles Superior Court jury in the United States, which was not allowed to hear or consider the NTSB's conclusions about the accident, found that the crash

6237-461: The wreckage were embedded 15 ft (4.6 m) into the riverbed. The aircraft broke into pieces before impact, with the debris spread over a wide area, though most of the wreckage was concentrated in a single 60-metre (200 ft) by 80-metre (260 ft) area at the river bottom. No complete body, body part, or limb was found, as the entire aircraft and occupants disintegrated upon impact. Only six positive identifications were later obtained from

6318-405: Was caused by a defective servo valve in the plane's rudder . The hydraulic PCU device manufacturer, Parker-Hannifin, was ordered to pay the three families of victims involved in that case US$ 43.6 million. After threatening to appeal the verdict, Parker-Hannifin later compensated all families involved (although it did not accept liability). Parker-Hannifin spokesperson Lorrie Paul Crum stated that

6399-400: Was instructor pilot of a Skyhawk squadron. The CVR and FDR stopped recording minutes before the abrupt descent, but not at the same time. The CVR stopped functioning about 6 minutes before the dive as the captain was leaving the cockpit for a short break. The FDR was deactivated 5 minutes later around 1 minute before the dive. Overload and short-circuit tests show that a distinctive 400-Hz tone

6480-480: Was replaced by the 737-600 in the Boeing 737 Next Generation family. However, unlike the 737-500, the 737-600 was a slow seller for Boeing, with only 69 aircraft delivered since its introduction. As the retirement of all 737 Classic models progressed, with retirement of 300s and -500s reaching 40% in 2012, the 737-500 has faced accelerated retirement because of its smaller size. Aircraft of this series were being retired after 21 years of use, as compared to 24 years for

6561-405: Was the only person in the cockpit when the CVR stopped recording, but this was quickly ruled out, as Ward's friends, family, and co-workers said that he had not displayed any signs of depression nor suicidality during his career at SilkAir, and was in a good mood on the morning of the accident flight. At 16:05, the CVR recorded Captain Tsu stating he was leaving the cockpit to get water, followed by

#163836