The issue is too complicated to cover adequately here. Most accidents involve multiple failures of different components of the system. It is rarely possible to pinpoint one particular failure as the sole cause. There are often powerful and compelling reasons for wanting the blame placed on the human. The human is often called in to save the day after chaos has already begun and then expected to come up with a miracle.
Most accidents result from unanticipated events and conditions.
Thus it is doubtful that computers will be able to cope with emergencies as well as humans do. Expert systems do not help in coping with unanticipated events or conditions. There are many examples of accidents which were averted by a human overruling an errant computer. If the operator had not intervened at the Crystal River Nuclear Power Plant, for example, a catastrophe might have occurred because of the computer error. I think this happened around early September.