Boeing 737 Max 8 MCAS – Is the proposed Fix good enough?

Boeing 737 Max 8 MCAS – Is the proposed Fix good enough?

Swiss cheese. You hear that a lot in systems design and engineering.

It is often not possible to fail safe a system with 100% certainty.

Especially true when there is an unforeseen and/or unintended consequence and a fix is proposed to a problem.

Root cause may not be known with certainty, however, a fix could be put in place as a short term remedy to alleviate the cascade catastrophic failure.

Swiss cheese.

If you stack up a few of them, then the likelihood of a through and through hole is quite low.

In fact, the entire aircraft systems design is based on this principle. With several redundancies and backup and backups for backups.

Engines being the most obvious example. There is computers, sensors etc that also have redundancies. Which is why the 737 Max and other Aircrafts cost $100Million.

So why then was this Autonmous MCAS System basing it’s entire activation on a single sensor input?

The proposed fix:

It appears that Ethiopian Air AOA sensor offset was also 20 degrees!!

What does that imply? MCAS won’t activate with 20 degree offset with the above fix.

However, it doesn’t fix the root of the issue. What is causing this offset?

Could there be a deeper issue here which could be impacting other systems as well?

Could this be more than the unintended consequences of the MCAS algorithm discussed here:

MCAS Algorithm & The Unintended Consequences – Boeing 737 Max


To be continued…thoughts in progress.

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