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0 pointsKurtz796y ago0 comments

"If the software was changed to reconcile 2 sensors, it would then lead to a new "AOA Disagree" indicator which would raise doubts to the FAA that Boeing could just give pilots a simple iPad training orientation instead of expensive flight-sim training."

I always liked this quote from the "Mythical Man-Month": “Never go to sea with two chronometers, take one or three”.

https://blog.ipspace.net/2017/01/never-take-two-chronometers...

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jasode6y ago

>I always liked this quote from the "Mythical Man-Month": “Never go to sea with two chronometers, take one or three”.

(I can't tell if you're making a side comment or specifically replying to the categorization of "software bug".)

Yes, the 737 MAX only has 2 AOA sensors instead of 3 like Airbus A320. This is a physical design of sensors mounted on the airframe. But this aerospace engineering design detail seems outside the scope of assigning blame to software programmers writing code. (There isn't a software coding methodology that makes a 3rd AOA sensor appear.)

Kurtz79OP6y ago

It was mostly a side comment, but it seemed appropriate in this context.

For such an important system, I would think that a single instance would be too little (single point of failure: even in less mission critical system it wouldn't be allowed), while using two you would not be able to resolve a reading conflict between them (which is the point of the quote), so three is probably a reasonable number.

Even if applied to design and not to software programming, the concept is still sound. The point was what the quote meant, not its source.

weaksauce6y ago

Using two would have been strictly better a design than just one. Obviously three is better but two disagreeing and shutting down mcas would be much, much preferable than relying on one to the grave.

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