Charlie Gibbs wrote
>On 2018-12-12, Jan Panteltje  wrote:
>
>> Martin Gregorie
>>
>>>- 737 autotrim has a major bug: it gets confused if the dual AOA sensors
>>>  disagree. In this case one had failed so of course they disagreed.
>
>So it's a single-point failure in disguise.  

It is a programming fault,
the program SHOULD check for altitude, and it did not.
Also as to airspeed it should use at least 2 sensors and do arbitration and
disable itself and give a clear
warning to the pilots if an abnormal condition occurred.

If it was me I would add a GPS and display speed over ground or even use that
in arbitration.
It is a design error, and I would sue the sh*t out of Boeing if it concerned
me.


>>>- the crew for the previous flight had a less serious occurrence of the
>>>  same problem, which they overcame, but didn't tell anybody about it.
>>
>> Same problem, no understanding of the system you use.
>
>Not understanding the system you use is a point of pride for many people.

It is not always possible to in depth understand what you use, we know for
example not exactly
what is in that ARM chip in a raspberry...
And what is matter and what is 'us' even (to get into philosophy)
but basics like handling your car is required for a driving license.
These days pilots get less and less real flying experience and more and
more is done on autopilot.

Now there are automatic subways.. next there will be automatic airplanes,
and many will die before all the bugs are out.

Airbus had similar problems in the past with 'fly by wire'.

Not so long ago an other passenger plane fell out of the sky near Amsterdam
airport, frozen airspeed sensor IIRC.
Totally insane in a world with GPS.
It is a re-occurring problem .

Some pilots are worse than bad bus drivers, and sometimes loaded with alcohol.

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