York University

Advisory Systems - Help or Hindrance

Modern aircraft are packed with software driven electronic systems capable of providing the pilot with data on the aircrafts situation and state. However, not all of these systems are designed and developed to the requisite level of integrity to allow their output to be used by the pilot as command systems i.e. without cross reference to other sources of information. The introduction of these systems into aircraft are then supported in safety arguments as �advisory only�, which bypasses the integrity argument and seeks to mitigate hazards by appealing to the availability of alternative sources of information.
Nancy Leveson points out in the draft of her new book that �The �head in the sand� approach of simply denying that software is safety-critical when it only provides information and does not directly release energy (a common attitude in some applications, such as air traffic control) is becoming less and less acceptable as software plays an increasingly important role in accidents. Consequently, the hazards associated with the provision of this information are possibly going uncontrolled.