When a computer has a) the judgement to navigate safely around or through a dynamic environment like a Terminal area with changing weather , traffic , a malfunction or two and dwindling fuel reserves , b) the judgement to discontinue or continue an approach , c) the judgement to think like an experienced and seasoned human aviator , and when a computer achieves all this at lower cost , with built in triple or quadruple redundancy in an environment that significantly adds value and safety , then perhaps we are 20 years to it being implemented. Not before. Not going to happen anytime soon folks.