> Boeing decided to make the two systems monitor each other so that each computer can halt an erroneous action by the other I thought the whole point was that

> Boeing decided to make the two systems monitor each other so that each computer can halt an erroneous action by the other I thought the whole point was that you needed 3 computers monitoring each other because if you have only two, you can't tell which one is faulty and which one is correct. How can they make it work here ?