Zeffy "Though MCAS was new on the MAX version of the 737, Boeing argued that it wasn’t new and novel because a similar system “had been previously implemented on the 767” tanker for the Air Force.
Yet MCAS on the MAX was triggered by just one of the jet’s two angle-of-attack sensors, whereas MCAS on the 767 tanker compared signals from both sensors on the plane. When asked after the second crash to explain why the airliner version lacked this same redundancy, Boeing’s response was that the architecture, implementation, and pilot interface of the KC-46 tanker MCAS were so different that the two systems shared little but the acronym."
It's a dessert topping, AND a floorwax!