Originally Posted by
silverstrata
Not my understanding. The logic of the system was posted in the extensive Indonesian thread, and if I recall correctly the MCAS system will continue operating as long as it thinks the aircraft is in a stall situation. So it gives 10 secs of trim, 5 secs waiting, and then another 10 secs of trim. That is why the Indonesian aircraft got multiple trim events (about 12 or so) in quick succession.
The system was obiously never designed to recognise that the aircraft was not stalled - it took the word of one AoA sensor as being gospel. Never mind that the airspeed and attitude were correct, the system reacted solely, and incorrectly, to the erroneous AoA sensor.
It did not even bother checking with the other AoA sensor. All you need is one line of code that says: “if AoA1 not equal to AoA2, deactivate system”. I mean, how hard was that? Ok, it would be nice to have three sensors, but even two can resolve that there is an error somewhere, so the system should not start trimming.
And while we are at it, why was there not a line of code that says: “if ASI greater than 210 kts, deactivate system”. I mean, how hard was that? Please don’t say that high speed stalls are a real problem with the Max, because I will not buy that one.
Silver
The Australian Civil Aviation Safety Authority (CASA) has taken action. The article's vague about what's actually suspended but I think it must be temporary suspension of the type C of A. That's noteworthy as CASA usually take the lead from the FAA on US manufactured equipment.
It won't directly affect many flights as there are no Max 8s in service with Australian carriers yet (Virgin Australia have over 30 on order). Only Fijian among the operators flying Max 8s to Australia hadn't already stopped operations.
https://www.abc.net.au/news/2019-03-...ralia/10894426