Air crash caused by hydraulic system failure

Swissair 1 flight (SR306) was a scheduled flight from Zurich to Rome via Geneva. 1963 crashed shortly after taking off on September 4th, leaving 80 passengers and crew on board dead.

The flight is scheduled to take off at 6 am UTC. There was a dense fog at Zurich International Airport that day. The flight leaves for runway 34 at 6: 04 am. After an eight-minute inspection of the runway fog, we returned to the starting point of runway 34 and took off at 6: 13. However, about four minutes after take-off, black smoke emerged from the left wing of the plane. At 6: 20, the flight altitude was about 2700 meters, and the plane began to stall. At 6: 2 1, the captain made the last call. At 6: 22, the plane crashed in Dürren? Sch), about 35 kilometers from Zurich International Airport.

accident cause

When the plane runs to the runway, some tires explode and catch fire because of the high temperature caused by the brakes, and some burning tire fragments damage the hydraulic system and fuel tank of the plane. For the aircraft with damaged hydraulic system, the loss of internal hydraulic oil caused the pilot to lose control of the aircraft, which led to this result.

Flight 298 1 arrived from Istanbul 1 1 that morning and landed in orly airport. On its maiden voyage, DC- 10 passenger plane carried 167 passengers and 13 crew members, of which 50 passengers disembarked in Paris. The second flight will fly from Paris to London Heathrow Airport. In this flight, 265,438+06 passengers boarded the plane, including 65,438+07 members of the British rugby team, who returned home after participating in the match with the French team the day before. Four British models and 48 Japanese bank management interns also went to the United States. The rest 147 people come from other 12 countries. Normally, flights from France to London are not full, but at that time, a strike of an airline in Britain affected passengers, so that all flights between Britain and France needed to surge.

In the afternoon 12: 30, the plane took off from eastern orly airport to Heathrow Airport, and then turned north to avoid Paris. When Flight 98 1 flew over Motown, the air traffic controller received an unknown call from the flight. The plane lost pressure, too. The speeding warning was broadcast in Turkish, and the conversation including the co-pilot was recorded: "The fuselage exploded!" Flight 98 1 immediately disappeared on the radar screen of air traffic controllers, and later the wreckage of Flight 98 1 was found in a forest in Elmenonville.

[Editor] Investigation

Investigators checked the flight data recorder and cockpit recorder of the black box and found that when the plane flew over Motfontein, the plane issued an alarm to remind the crew that the plane exploded to decompress. After the explosion, the plane rose slightly, then descended and turned left. Captain Nigel Burke? Z and co-pilot Oral Ulusman tried to control the passenger plane, but they found that there was no hydraulic pressure to control the elevator and rudder, and the plane went straight to the ground in a nearly vertical posture. Although the plane began to flatten the fuselage before it crashed, it had lost too much height. Finally, 72 seconds after the explosion, it fell into the forest at a high speed of 800 kilometers per hour. Of the 346 people on board, only 40 bodies can be identified from the appearance. In the end, 9 people will never be identified. As for the wreckage of the plane, it has become a pile of fragments, and the investigators can't find out which part of the plane is missing. Later, in a radish field 15 km south of the plane crash site, a cargo door at the tail of the plane was found with six guest chairs on it, and the bodies of passengers were also placed on the chairs.

So the French investigators concluded that the hatch of the cargo hold exploded in mid-air to decompress, which led to the air crash. The cabin door of other passenger planes is opened by pushing inward, and the door is slightly larger than the door frame. This design is to prevent the cabin door from being opened by pressure when the plane loses pressure at high altitude. However, the cargo door of DC- 10 is designed to open outward to make room in the engine room and increase the cargo capacity. They found that there was something wrong with the design of the cargo door itself. From the outside, the cargo door is closed, but not necessarily locked. The lock design of the hatch is complicated, and the position of the lock hook may be deviated. If the door is not closed properly, the plane will explode in mid-air. However, this way of closing the door is very difficult, and the ground crew needs to spend a lot of effort to press the pressure bolt. Even if the door is obviously unlocked after closing the door, the door display light in the cockpit will still go out, indicating that the door has been closed. The plane lost hydraulic pressure because a large amount of air was sucked out of the plane after the cargo door fell off, which caused the cabin floor with the same design problem to stay and crushed the wires and hydraulic pipes connecting the tail wing. This cargo door should have been instructed to be improved long ago. Because in June 1972 and 12, the same accident happened to American Airlines Flight 96, and the cabin door of the aircraft was also decompressed by explosion. Fortunately, the hydraulic pressure of the plane was not completely damaged, and finally it was able to land successfully. Immediately after the accident, national transportation safety board (NTSB) instructed McDonnell Douglas to change the design of the cargo door and passed the safety test. However, NTSB is not binding, which leads McDonnell Douglas to continue to produce two DC- 10 on the production line, one of which is DC- 10 made by Turkish Airlines. McDonnell Douglas later made up for it and improved the design of the hatch.

Flight 98 1 was the worst air crash in history at that time, and it was not until March 27th, 1977 that the plane crash in Tenerife was broken. The most serious single plane crash was broken by JAL 123 flight on August 1985. However, flight 98 1 is still one of the top ten civil aviation air crashes in history [1], and this accident was caused by the design problem of DC- 10, so it was also regarded as one of the top ten scientific and technological disasters in the 20th century. [2]

Although there was no similar air crash in DC- 10 after the door was improved by McDonnell Douglas, at that time, the air crash deeply shocked the entire aviation industry, which also hit the public safety of DC- 10. It will take some time for passengers to regain their confidence in taking DC- 10, and the sales of DC- 10 of McDonnell Douglas are far less than expected because of this air crash. At the end of 1970s, DC- 10 suffered several air crashes indirectly due to design problems, which once caused the global DC- 10 to be grounded, and finally led to the financial difficulties of McDonnell Douglas, which was acquired by Boeing in 1997.