Originally Posted by
bsieker
- I seem to recall that on the first flight with divergent AoA values, the Flight Control Computer operated the MCAS based on the correct AoA sensor, so there was no problem for the pilots (except the stick shaker: continuing with that is also a very ... interesting decision), whereas on the accident flight, the MCAS used the faulty AoA sensor so continued to trim nose-down. It did not do so on the previous flight. So yes, in this case the airline not rectifying the problem was a causal factor, but it is just as credible that this could have happened on the first flight on which the fault appeared, and then the airline would have no part in this
That's not true. Look at the FDR, it is quite clear MCAS operated on the previous flight.
They used the cutout and trim wheel:
As we are unsure of the MCAS system architecture it seems the other FCC being active doesn't mean MCAS only triggers for one of the FCCs when one AoA is high.
Also didn't i read somewhere both FCCs get both AoA values as an input?
The 2 flights before that were not plagued by the incorrect AoA but some other problem, at least that's how i read the various news reports.
(Edit: There are no news reports to that effect my memory tricked me. But looking at the FR24 data and the altitude excursion MCAS produced on the last two flights it is reasonable to assume that an AoA problem that severe did not exist on the flights before the sensor replacement)
The vastly wrong AoA value was most likely introduced due to the replacement of the AoA sensor in Denpasar.
(Be it due to a defective / wrong part or some unbelievable hackery no one knows)
If you want to look at the FDR graphs yourself please check out the pdf in the attachment: