Lotus 38
Flight of British Airways 38 occurred on January 17, 2008 at 12:42 in London (England). Boeing 777 British Airways crashed just before the threshold of the runway during landing at Heathrow Airport, after over ten-trip from Beijing. Of the 152 persons on board (136 passengers and 16 crew members) no one was killed, and injured 47 people. It was the first serious accident Boeing 777.
The investigation did not take a long time, investigators have at their disposal almost entirely preserved aircraft flight data recorders and cockpit conversations, and all passengers and crew. Still, after more than a year after the disaster – still did not know what caused the collapse of Flight 38
Finally, after hundreds of hours of tests and simulations, it was concluded that the cause of the crash was ice deposition in fuel, which is then clogged heat exchangers of both motors, leading to cut off fuel supply.
Boeing 777-200ER is a twin-engine, wide-body passenger aircraft sustained range (eng. Extended Range). The machine, which has been delivered to crash British Airways May 31, 2001, after which it was given the registration number G-YMMM. It was a 342 Boeing 777 and produced over more than six years he spent 28 678 hours in the air. The machine was powered by two Rolls-Royce engine Trent 800.
The aircraft was able to accommodate 236 people in four classes (13 First Class, 48 ​​Club Class, 48 ​​Business Economy, 127 Traveller Class). As the British carrier bears the number 36 on the list of customers of the manufacturer, model aircraft was designated as a Boeing 777-236.
The crew of British Airways flight 38 on January 17, 2008 consisted of 16 people. They were:
Also on board were 13 crew members serving the passenger cabin (superior was Sharon Eaton-Mercer).
British Airways Flight 38 began in Beijing at 2:09 when the plane took off. On board were 16 crew members and 136 passengers. Travel is scheduled for 10 hours and 33 minutes, at an altitude of 10 400 meters (FL341) with a reduction to 9600 meters (FL315) due to extremely low temperatures along the border between China and Mongolia. After checking the flight plan and weather conditions along the route of flight, the crew agreed to fueling of aircraft 79 000kg of fuel. Flight proceeded calmly, when the London ILS set the plane on the runway 27L axis – the plane hit the light gusts of wind. In the case of turbulence automatic pilot more responsive to fluctuations in aircraft than pilots, so the crew decided to leave the machine turned on for longer than usual.
2 minutes before landing when the aircraft was at an altitude of 360 meters above the ground – the first officer John Coward took the reins at this time Captain Peter Burkill rearranging papers and watching for that place on the strip has been released by the previous landing aircraft. At a height of 150 meters above the ground there is a problem. Coward was off the autopilot, when he noticed that the engines have no power and can not increase the turnover. For instruments, indicating the power of the engines, the value dropped to zero. The right engine stopped working, and seven seconds later the left. Machine with a group of 152 people on board began to fall. Quickly messages appeared too low speed, rainfall of 550 meters per minute. Just before the threshold of the runway is a gas station and Hatton Cross Underground station – fall in this place could mean 100% of the victims in the plane and a lot of dead people on the ground. The captain knew that even if they manage to pass the buildings, they hit on a busy highway A30 or antenna at the airport. As later reported the media, this time heading to Heathrow Airport, the then British Prime Minister Gordon Brown, the aircraft flew less than 8 feet above the car, in which it is located.
Captain had 30 seconds between the realization of failure and stroke, during which time he had taken two important decisions. The first was to hide the chassis, which produces the greatest air resistance. Without the chassis plane could be heard on bypassing the buildings, but at the time of the fall of the extended circle take the first brunt of impact. The captain decided to leave the chassis in the extended position. The second was to hide the flaps, which would reduce the resistance, but the strength carrier. The plane could go on, but opadaÅ‚by faster. The captain had to decide what is more important, after a moment’s hesitation, he slipped flap 5 ° which gave the crew a few extra meters. 3 seconds before hitting the ground the captain gave the message "Mayday".
The plane hit the soft mud and grass about 300 meters before the runway threshold. Shin main landing gear broke through the wings, the front landing gear broke, engine cover fell off and the rotors etched into the earth and concrete. Given the scale of the devastation aircraft crew surprising was the fact that nobody was killed and only 47 people were wounded.
Airport emergency services appeared immediately. Information about the accident flight 38 was dominated by information media, it was the most serious accident in 30 years, which occurred at Heathrow.
The investigation into the crash led specialists AAIB (called "Air Accidents Investigation Branch"). Researchers have several hypotheses concerning the simultaneous arrest of both engines. One of them was the lack of fuel, it is rare, but in aviation it happened that the crew made an error in converting gallons to metric units. Investigators found that at the crash site could smell the characteristic odor of jet fuel that poured out of engines and fuel lines, also checked the contents of the tanks, which were still out of fuel. The hypothesis was quickly rejected. In parallel, its quality has been studied on the basis of samples taken from different locations of the fuel system. It could contain particles and biological substances that clog filters and restrict the flow, depriving the machine drive. Fuel refueled flight 38 was produced in South Korea, compared with more than 1,200 samples of fuel from the UK, turned out to be very good quality. During the test, the fuel system found several pieces of tape and red scraper, what brought investigators to mind the possibility of congestion. Subjects entered the tanks probably during the construction of the aircraft. It proved negligence of the manufacturer, but there was no indication that these objects have played any role in the fall of Flight 38 were so small that they do not caused the blockage would wires.
While searching for answers came to light that another 777 had similar problems. Less than three years before the crash at Heathrow, August 1, 2005 Boeing 777 lines Malaysia Airlines after takeoff from Perth, Australia, was at the height of more than 11 000 m, when suddenly the automatic pilot raised the nose up sharply machine, which could lead to a stall. The crew managed to control the situation turning off the autopilot and taking over the reins. The investigation revealed that the cause was the fault of the computer system. Researchers British Airways flight crash began to assume that the computer system 777 may be a fault. Such a request skompromitowałby producer and this would mean that all the 777 around the world could potentially be subject to disasters.
At the same time investigators began to analyze the weather conditions on the day of the accident. The air over Siberia was very cold, ambient temperature was -74 degrees Celsius. Such conditions are dangerous if you do not take the remedial measures. In extremely low temperatures of aviation fuel begins to secrete wax, the viscosity increases and consequently ceases to flow. The crew of Flight 38 to monitor the temperature of the fuel on instruments, not allowing to its fall below -34 degrees. When the jet was coming to London – the fuel temperature increased significantly. Another cause of the crash was excluded. Commission began to run out of ideas, and the aerial environment and the media began to push for a quick explanation of the causes of the accident.
Specialists from the AAIB decided to examine the flight to the smallest detail and catch any anomalies, including to turn to operators of aircraft powered by Rolls-Royce engines to send data to compare. Soon, the Commission’s premises in Farnborough released information from around the world, they had to test data from 144 000 flights. At the same time, large parts of the fuel system of the machine, which has been a disaster, transferred to a hangar Commission and re-assembled. The investigators considered all possibilities – from design defects errors occurring in this particular plane. The researchers found no faults, and the investigation has stalled.
In the course of the investigation still was growing suspicion that the perpetrator of the crash was ice. Three months after the crash, Brian McDermid (AAIB) flew to Seattle to aid mechanics airplane manufacturer to carry out research into this possibility. They conducted tests, which concluded that the only place in the fuel system, in which congestion can restrict the flow of less than 2.5 tons of fuel per hour, the inlet heat exchanger between engine oil and fuel. Cold fuel is heated while cooling the oil. They are an important part of the fuel system, used to prevent problems that are likely to occur in flight 38.
Reconstituted the environmental conditions that the aircraft encountered during flight, yet the ice did not appear in quantities that could endanger the flow of fuel. However, when the fuel temperature increased, there was a breakthrough. When the temperature exceeded -20 degrees, crystals began to combine and accumulate inside the wires. Investigators have found that below this temperature, the ice crystals are too hard to associate with the walls of pipes, but in the range of -20 to -8 degrees ice sticks to the fuel lines. Despite this, the researchers do not know exactly how the ice led to the crash Flight 38, still analyzed data flights uploaded by other operators, in which less than 1% took place in the same environmental conditions. Then on 26 November 2008, more than 10 months after the disaster, there was a similar case. Boeing 777 Delta Air Lines was located at an altitude of 11km above the ground when one of the engines stopped working. However, in this case, the engine started and the plane landed safely in Atlanta. Increased concern that the Boeing 777 has a serious design flaw, and all aircraft of this type are at risk. Researchers from the AAIB investigated the Delta flight, the aircraft was equipped with engines of the same type as the nakierowało study on the same issue. As it turned out, the engines of the Delta responded very similarly to those of the 777 at Heathrow.
Within a year of the disaster simulation and conducted hundreds of millions of dollars spent on research, and still have not been able to produce the fuel lines of ice, which could clog the heat exchanger. Investigators examined the fuel consumption during the flight, as it turned out the whole time he was relatively stable until the approach to Heathrow. Then began to turbulence, by which engines have abrupt changes in speed, increasing power consumption fuel. Simulation of reproducing these events. The result was a breakthrough – an accumulation of ice in the fuel lines broke and clogged inlet heat exchangers, almost completely shutting off the fuel supply to the engine. It was a mistake in the construction of 777.
The final report was published more than two years after the crash – 9 February 2010.
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