Thursday, July 11, 2019

Software Fix

"Boeing designers also gave MCAS [Maneuvering Characteristics Augmentation System] too much authority, meaning that they allowed it to autonomously move the horizontal stabilizer to the full nose-down limit.

And MCAS was allowed to move the stabilizer in large increments, rapidly and repeatedly until the limit was reached.  Because it moved stabilizer trim intermittently, it was more difficult to recognize it as a runaway trim situation (an uncommanded and uncontrolled trim movement emergency), as appears to have happened in the first crash."

-- Chesley B. 'Sully' Sullenberger III in a statement to the Subcommittee on Aviation of The United States House Committee on Transportation and Infrastructure, 19 June 2019



The Boeing 737 MAX aircraft crashed twice in a 5-month period, killing 346 passengers and crew.  As a software guy, I hate that the proposed fix is a software update.  I know software sometimes gets people killed, and it's only going to get more complex with time.  I just hope other software guys do their due diligence, and are persistent in pursuit of safety when their work has life-safety implications.

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