Change management in the ATM system: integrating information in the preliminary system safety assessment

The increasing air transport demand suggests looking at Air Traffic Management (ATM) as a continuously and evolving process. The procedures and equipment we use today will not continue coping with next air traffic requirements. It is thus necessary to provide ATM services for the current operating scenarios. This paper proposes a systematic tool, i.e. the Preliminary System Safety Assessment Tool (PSSA-T) to help the decision makers in evaluating safety implications of system changes. PSSA-T relies on the definition of two indexes, based on the Aerospace Performance Factor (APF) methodology. These indexes allow a structured safety analysis of any proposed change: the first compares the evolutionary scenario with the current one and the second one considers the effects of a failure of the changed agent (equipment or procedure) in a future scenario. The paper illustrates a case study for the Flight Progress Strip (FPS) change to Electronic FPS.