Some Technical Details of Boeing 737 Max Problem

[xul]

Flawed analysis, failed oversight: How Boeing, FAA certified the suspect 737 MAX flight control system

In short:

1. Boeing mounted 2 larger new engines on the old 373 fuselage to save itself R&D costs and its customers' pilots training costs. The approach resulted the max models aerodynamically unstable and couldn't pass FAA certification, so Boeing added MCAS on these models trying to fix the problem, or exactly to cover the problem up.

This is why MCAS is still on even if the auto-pilot is turned off-----because the plane is unsafe without it. And MCAS wasn't mentioned in the manuals for the same reason----if customers knew the true purpose of MCAS, who would buy these planes?

2. The design of MCAS has many fundamental flaw. The whole system merely depends on single Angle of Attack sensor, no redundancy at all. Which means if the AoA sensor fails the plane will continue nose down until crash.

3.Due to lack of funds, FAA out-sourced certification jobs to India...LOL, I'm joking. But India might be better since it's still a third party. FAA actually delegated most of certifying work to Boeing. Which means Boeing certified its own planes and the third party certification became meaningless.

4. Using false data passed FAA certification. The FAA document shows each time MCAS only adjusts 0.6 degrees horizontal tail, but after Lion Air crash, Boeing document shows the limit is 2.5 degrees, 4 times greater than what FAA knew. 

It seems like the whole system wasn't designed by engineers but conceived by CEO and MBAs. If you have never met a CEO or MBA in real world, there is an example:

 

Edited March 22, 2019 by xul

[Owly]

On 3/21/2019 at 9:51 PM, xul said:

Flawed analysis, failed oversight: How Boeing, FAA certified the suspect 737 MAX flight control system

In short:

1. Boeing mounted 2 larger new engines on the old 373 fuselage to save itself R&D costs and its customers' pilots training costs. The approach resulted the max models aerodynamically unstable and couldn't pass FAA certification, so Boeing added MCAS on these models trying to fix the problem, or exactly to cover the problem up.

This is why MCAS is still on even if the auto-pilot is turned off-----because the plane is unsafe without it. And MCAS wasn't mentioned in the manuals for the same reason----if customers knew the true purpose of MCAS, who would buy these planes?

2. The design of MCAS has many fundamental flaw. The whole system merely depends on single Angle of Attack sensor, no redundancy at all. Which means if the AoA sensor fails the plane will continue nose down until crash.

3.Due to lack of funds, FAA out-sourced certification jobs to India...LOL, I'm joking. But India might be better since it's still a third party. FAA actually delegated most of certifying work to Boeing. Which means Boeing certified its own planes and the third party certification became meaningless.

4. Using false data passed FAA certification. The FAA document shows each time MCAS only adjusts 0.6 degrees horizontal tail, but after Lion Air crash, Boeing document shows the limit is 2.5 degrees, 4 times greater than what FAA knew. 

It seems like the whole system wasn't designed by engineers but conceived by CEO and MBAs. If you have never met a CEO or MBA in real world, there is an example:

 

I agree. The angle of attack sensor seems to have malfunctioned and sent the wrong message to the MCAS system. Maybe it just stuck and on rotation continued to tell the rest of the system the aircraft was still in level flight at relatively slow speed and therefore instructed the MCAS to lower the nose. If only the pilots had of been properly instructed as to how to over ride that system.