We're talking about what the MCAS used for input. The aircraft has two AoA sensors and three computers. MCAS used 1 and 1 because it was believed to be non-safe

We're talking about what the MCAS used for input. The aircraft has two AoA sensors and three computers. MCAS used 1 and 1 because it was believed to be non-safety-critical system. Here is a direct quote from Wikipedia's MCAS article: > Though there are two sensors on the MAX only one of them is used at a time to trigger MCAS activation on the 737 MAX. Any fault in this sensor, perhaps due to physical damage, creates a single point failure: the flight control system lacks any basis for rejecting its input as faulty information. There is a whole subsection just about MCAS and AoA sensors.