Possibility that pilots were not aware of the system operation of Boeing 737 MAX 8 which caused 2 crash in 4 months
A simulation of the Lion Air 610 crash in Indonesia in October 2018, which was reproduced at the time of the accident, was conducted. A procedure for disabling the automatic control system that caused a malfunction in the accident aircraft Boeing 737 MAX 8 The simulation was revealed to the New York Times that the time to accept was very short and that the disabling process might not have been sufficiently trained by the pilot.
In Test of Boeing Jet, 40s Seconds to Fix Error-The New York Times
Lion Air 737 MAX crew had seconds to react, Boeing simulation finds | Ars Technica
In order for the plane to fly, it is necessary to raise the wing angle ( attack angle ) to the air flow. However, if the angle of attack is increased too much, the aircraft will suddenly stall and become unstable. Therefore, the system for controlling maneuver characteristics (MCAS) is a system that automatically lowers the nose to adjust the attack angle so as not to stall.
In the Boeing 737 MAX 8 which was operated in October 29, 2018, when the Lion Air 610 crash and on October 10, 2019, the Ethiopian Airlines 302 crash , 'the problem with the attack angle of the aircraft is Even though it is not, it is likely that the nose has fallen automatically due to a malfunction of MCAS and it crashed. ' In addition, it was also reported that the pilot complained that 'The MCAS mounted on the MAX 8 is completely different from the conventional 737 system and has not been sufficiently trained.'
Pilot finds complaints about the Boeing 737 MAX 8 that had two crash incidents-GIGAZINE
When the aircraft's nose begins to fall with MCAS, the pilot can press the switch on the control with the thumb to temporarily cancel MCAS control. However, when the simulation was performed based on the data collected from the Lion Air 610 flight, MCAS was activated three times immediately after takeoff until the nose fell and crashed, resulting in an unrecoverable level. It turned out that it took only 40 seconds until it had dropped sharply.
by Live from the Flight Deck
The data collected indicates that the pilot of the Lion Air 610 has pressed the switch more than 24 times, which is not a measure to make multiple adjustments to the nose by trim control. It is guessed.
In order to completely disable MCAS, it is necessary to turn off the motor for automatic control and manually turn the console trim wheel to reestablish manual control. The pilot who was in charge of the simulation knew that he could switch to manual control safely because he knew in advance the means to invalidate the MCAS, but the pilot of the Lion Air 610 flight knew the method to invalidate this MCAS. It is expected that it might not have been done.
by Thai Civil Rights and Investigate (TCIJ)
Boeing spokesman said that after the crash of Lion Air 610, the pilots were trained in the procedure for MCAS invalidation procedures, 'The software update adds system restrictions and security measures to the crew Staff's workload will be reduced. '