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Old 24th Mar 2019, 11:51
  #2458 (permalink)  
edmundronald
 
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Possible data corruption opens a real can of worms.

If there really was a data transmission error, and Boeing designed in a single point of failure with no serious data integrity checking on the digital transmission (each packet with a serial number and with a CRC so none can get lost or corrupted), and no software filtering to see whether values make sense,and restore sanity, it would be literally unbelievable. (You can do that in a lab, not in a transportation machine). But then ALL of the DIGITAL avionics on this plane will be similar, and the whole type becomes suspect, and in fact will need at least a fundamental software refactoring with a bunch of software crosschecks and filtering on all sensors that feed into mission-critical automation - it's not at all obvious that MCAS is the only such novelty on this plane, there may be more stuff hidden away.

I may not be the most competent engineer in the world but I have a Master's in Electronics/Telecoms and a PhD. This is my professional opinion. Feel free to call me incompetent but there needs to be an adult in the room. I am sure there are a bunch of pilots out there who are engineers and can chime in.


Edmund

Originally Posted by Grummaniser
It doesn't take a double bit error to lose one bit of data - somewhere in the system between the RDVT fixed to the AoA vane and the bus, is an analogue to digital converter chip (or array of them) which will not itself be creating any error checking. The error checking will be added further downstream (quite possibly by the chip next to the A-D). A fault in the actual A-D chip could produce single bit errors which could only be identified by duplicating the A-D process.

Last edited by edmundronald; 24th Mar 2019 at 12:14.
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