The closest message, the French takes wreck plane black case, after decipher board of inquiry of accident of Ethiopia of data pass on, accident of dust boat aviation accident investigates the first phase to finish, gotten preliminary verdict, do not give expect as before, with lion boat aviation accident very old rate is similar, it is dust ship aircraft started MCAS system automatically likely extremely, dive for many times cause aircraft accident.
About MCAS system, everybody knows, this is Boeing company attacks part greatly to solve 737MAX plane easy stall, and of designed development fly accuse systematic patch, from the design it is good for jumping-off place: Make sure the flight is safe.
MCAS system relies on nose to attack horny sensor data to decide to start an opportunity
But carry out rise, turn hole dad into goods, this is the good intention that common weighs does bad thing.
The MCAS system that announces now has a lot of kinds of views, but Boeing company approbatory is, MCAS system monitors plane stall through studying horny sensor data, achieve stall angle to just can start MCAS, this logic is normal, but what Boeing company did not think of is, in using a process, the sensor that attack part can give trouble, design logic from hardware for, the sensor that attack part is the sensor of commonly used air current of the plane, plane in nose two side installed 2.
The logic from aircraft safety design is reasonable, least 2 hardware configuration, bad one still has, but the software design of Boeing says to oneself, use the left sensor that attack part to make merely give priority to sensor, offer to MCAS system start the crucial reading that attack part, the system serves as backup on the right side of, this kind of design is original also give no cause for more criticism, but the worst is, boeing company software is designed and did not introduce real time to eliminate breakdown sensor function, in controlling a system, this flies in any planes is inevitable fundamental common sense.
The sensor that attack part is very important, certain and large airlines installed 4 unexpectedly, nose a side installs 2!
Why is MCAS system being planted the meeting below the circumstance is started, why to plant the time-out below the circumstance, why to plant below the circumstance permanent stop? This becomes the heat of aviation group.
The black box data that we get from lion boat aviation accident, the answer that can be clear about quite this problem.
MCAS system, 20 degrees of or so meetings are achieved to start in the data that attack part, need data of the left sensor that attack part to exceed bid merely can, and height of the speed that start is not restricted! The lowermost height that start is mere 120 meters!
Lion boat aviation accident flies before today, flight height is mere 120 meters, MCAS system started suicidal dive automatically
How does MCAS work?
The plane detects after the data that attack part, make the same score the plane end to raise 2.5 degrees up instantly, this kind of movement causes a plane to lower his head badly to dive instantly, hold 10 seconds, pause next, after waiting 5 seconds, discovery attacks horny data to suspend the work then normally, if horny data is studied after 5 seconds,return abnormal, start a dive instantly!
Can the MCAS below which kind of condition pause?
Say very do laugh, flap puts down MCAS system to be able to pause, this also is logic of a design, when flap is put down, plane rate is very low, height is very low also, the dive of MCAS system is designed, very malapropos below this kind of circumstance.
Still have a kind of case, this is air man pull rod when MCAS system can pause, if air man stops pull rod, MCAS resembles the devil of an eye covetously, launch attack instantly, buy person at the deathtrap!
Can see, air man up MCAS does not work during pull rod movement, but stop pull rod, send instantly power!
Graphic specification: Blue line is air man above operate, the line on x-axis represented air man to pull nose, the blue line below x-axis is head of air man press, the helm face movement that the earthy yellow that La Xianzhi issues is aircraft control system is recorded, the square that is down continuously is started on behalf of MCAS system and enter death to dive!
Record of black box of lion boat aviation accident is below, among them we can see intermediate purple curve is flap handle position, most begin flap to be in the 5th (put down completely) later plane climb is controlled to 1500 feet, air man controls flap, after flap is packed up, MCAS system starts dive program instantly, be in above grid of khaki of x-axis lower part is.
Lion boat aviation accident records: Flap is packed up, MCAS begins suicidal dive, diamonds of the color of loess inside red circle is
Another does laugh business quite is, air man pull rod when, MCAS system pauses, be not what imagine like the public in that way, direct man-machine defies.
Is system of the MCAS below which kind of circumstances permanent stop?
737MAX passes aviation accident twice, grounding of aircraft of whole world outcry, boeing company lowers his head to acknowledge a mistake eventually
? Very simple, stopped a plane to drive automatically function, complete hand is moved operate can, want of course fast, if the plane just takes off, flap is packed up, speed height does not have how many leeway, MCAS system enters dive, be very hard there's still time!
