Originally Posted by
Smythe
There is a threshold to where a new version is easily certified for use, (ie expedited review) but that is usually reserved for corrections or modifications to existing code. MCAS was an additional feature, so that would have caused a major level upgrade and the extended certification process.
The original MCAS was reviewed and fully disclosed to the FAA.
The problem was the later modifications to that code were not seen as significant and thus not subjected to the higher level scrutiny.