Envelope Protection

or, how to build a workforce that has never once met the edgeIn Normal law, an Airbus A320 will not let you stall it. You can haul the sidestick fully aft and hold it there with the sincerity of a man wrestling a bear, and the aeroplane will decline. It will fly at maximum lift, mushing along like an offended cat, and it will not depart. Somewhere in three redundant flight control computers there is a rule, and the rule outranks you. You are not the pilot in command. You are a well-regarded source of suggestions. This is one of the great engineering achievements of the twentieth century, and I mean that without irony, which for me is a considerable sacrifice. Envelope protection did not reduce a category of accident. It deleted several. Stall on approach. Overbank into a spiral. Pulling the wings off in a recovery you initiated yourself in a panic. Whole species of catastrophe, once responsible for enormous quantities of human misery, now largely extinct in the fleets that adopted it.…