Airworthiness Directives; Eurocopter France (ECF) Model EC 155B and EC155B1 Helicopters

We are adopting a new airworthiness directive (AD) for the specified ECF model helicopters. This AD results from a mandatory continuing airworthiness information (MCAI) AD issued by the European Aviation Safety Agency (EASA), which is the Technical Agent for the Member States of the European Community. The MCAI AD states that freezing of the route display on the navigation display (ND) in the Sector mode occurs for flight plans that include procedures in the terminal zone (departure or arrival). The MCAI AD prohibits the use of the UNS-1D navigation system (also known as the Flight Management System (FMS)) for Standard Instrument Departure (SID), Standard Instrument Terminal Arrival Route (STAR), and instrument approach procedures. The actions are intended to prevent the flight crew from relying on a frozen route ND, unanticipated increases in flight crew workload, pilot confusion in the terminal airspace environment, and subsequent loss of control of the helicopter.