UAt exactly 3:30 pm, the flight with the number D8542 hovered over the German capital Berlin. The model on the road from Finland to Spain: a Boeing 737 Max 8, run by the well-known Norwegian airline Norwegian Airlines – exactly the type of plane that crashed on Sunday morning near Addis Ababa as an Ethiopian airline flight.
The passenger plane of the Boeing manufacturer is considered a bestseller – and it is not far from the famous tourist routes used: 350 aircraft have been brought from service 2017, another 5000 machines should be ordered.
Within a few months it is the second accident of the model – in October, the same model crashed in Indonesia with 181 passengers on board. Now the Boeing producer is put under pressure: the Chinese air traffic control authorities have banned the flight operations with the new edition of the well-known 737, at the moment, even Indonesia and Ethiopia have stopped work.
Several other airlines, including TUI, have announced they are considering a temporary launch ban. The share price of the Boeing producer fell on Monday up to 13.5% – the biggest daily loss in trading since the terrorist attacks in New York on September 11, 2001.
What is known about the last flight of the new Boeing 737 of the ETH 302 flight? Ethiopian Airlines 737 Max 8 with registration number ET AVJ took off at Addis Ababa airport at 8:38 local time, and only six minutes later air traffic controllers lost contact with the aircraft in Following a pilot emergency report: the plane crashed near Bishoftu a field, 149 passengers and eight crew members died in the crash.
26 descents without human intervention
During only six minutes of flight, the aircraft showed an atypical flight profile for a start. According to an analysis of the portal Flightradar24 the car has passed several times briefly in a fast descent with a maximum of 2000 feet per minute – only then to get up. The data are based on the transponder data of the so-called ADS-B system automatically sent by the aircraft, with which air traffic controllers and other aircraft trace the position of the aircraft. These may be damaged, for example due to sensor errors. However, registration is an indication that the flight ETH302 failed an aircraft system that was already in the autumn of 2018 for the accident of a Boeing 737 lawsuit.
According to the raw data of the ET transponder the AVJ has become steadily faster during the ascent. The engines therefore provided sufficient energy. However, the aircraft went several times briefly downhill and lost altitude. This happens because a pilot or autopilot lowers the nose of the aircraft by pressing the control wheel forward, or because an automatic system cuts the plane at the top.
On board the new 737 Max 8 is a new automatic trim system that has exactly this task: Boeing developed specifically for the new aircraft, the "Maneuvering Characteristics augmentation system" (MCAS), which intervenes in some extreme trajectories for prevent a crash, but why could it be the cause of an accident in the case of ETH302 itself?
A look at the investigation of the crashes of the Lion Air 610 flight helps: On October 29, 2018 crashed a car of the Indonesian budget company Lion Air shortly after the start in Jakarta. The aircraft was down 26 times before the crash, without any assistance from the pilots, and the pilots had reported an emergency. Cause was, according to a preliminary report, a failure of sensors that measure the position and speed of the aircraft through the air – had given the contradictory values of the MCAS, this had then lowered the snout of the flyer.
The US authorities warned of the security system
Boeing had installed the MCAS in the only Max version of the tried and tested 737 delivered since 2017, as the aircraft differs in crucial points compared to previous versions: The new low power consumption engines of the "Leap 1B" type manufacturer CFM International were originally for the new Airbus 320NEO developed and have larger diameters than their predecessors with originally 1.54 meters. However, they did not fit under the slightly smaller and lower Boeing 737 wing. To be able to build the engine with a turbine diameter of 1.75 meters, Boeing extended the suspension forward – the "Leap 1B" does not crash, but in front of the wing.
The new approach, however, modifies the flight characteristics of the 737, and in some extreme situations, the machine tends to nod towards the top, interrupting the flow of air through the wings. The MCAS should compensate this automatically and within a few seconds. But what if the sensors only play this attitude and the plane is actually on a completely normal climb?
So pilots must suddenly and unprepared to control an automatic start from the MCAS descent. The only two ways to turn off the MCAS is to turn off all automatic trim systems or extend the flaps. After the Lion Air incident, Boeing had sent a security notice to all the airlines using the 737 Max 8. But if the pilots dominate this quick move to the switch while simultaneously lifting the nose of the 39; aircraft is questionable – and in the take-off phase the plane flies so low that they have little time to do so.
According to the circuit diagrams of the 737 Max 8, which were distributed in the network after the LionAir incident, only one attitude sensor (AOA) provides the systems upstream of the MCAS with sensor data – unusual for a system that is so important for flight safety. As a result, the United States Air Traffic Control Authority (FAA) also issued a warning on the system in the autumn and urged airlines to retrain pilots.
TUI controls the prohibition of provisional start
Because if this sensor were to fail and the pilots were overwhelmed by the shutdown of the MCAS, the aircraft would show exactly the flight profile that registered Flightradar24: again and again, the MCAS would have made the nose down, again and again, the pilot would try to compensate for this – until they finish the altitude and the plane touches the ground. Meanwhile, the Ethiopian authorities report that the black box of the 737 crashed was found. His evaluation will show if the MCAS is the cause of another incident of the new machine.
The best known buyer of the German accident model is probably TUIfly, which flies with TUI and other tour operators, including the Mediterranean region, the Canary Islands, Madeira and Egypt, with 36 aircraft. In mid-April, it will become the first German airline to commission two Boeing 737 Max 8 aircraft, which will be located in Hannover and Düsseldorf; two other cars at the end of April in Cologne and Frankfurt. By the end of the year, Max Jets number five and six will join the fleet.
Among the group airlines, the German branch is the last airline to receive the new medium-range model. TUI is now examining the need for a temporary launch ban for its machines of the type in question. "We are in close contact with Boeing and will assess the situation with the manufacturer," TUIfly spokesperson Aage Dünhaupt said on Monday. The fleet of the world's largest travel group TUI now includes 15 such jets, which are in use in the United Kingdom and the Benelux countries.
Even the popular travel company SunExpress has ordered Boeing the car in question. In total, the company ordered 32 jets of the type – the delivery of the first five aircraft according to the last state of planning in the summer 2019. "We are in constant dialogue with Boeing and if there will be an update of our planning of the 737 fleet, we will officially announce ", Confirms the company upon request to the world. Last year, sales manager Peter Glade told the airliners.de industry portal that Boeing models could serve new destinations, such as West Africa or Dubai.
The German company Lufthansa and the well-known companies of easyJet, Air France, KLM, Condor, SAS and British Airways have confirmed WELT's request that they have no questionable models in their fleets and that they have not placed orders for this type of aircraft. British Airways refers to the use of Airbus A320 family aircraft.