A method is provided for indicating the boundaries of a required navigational performance (RNP) corridor on an aircraft's map display. The method includes the steps of producing an aircraft leg segment symbol on the map display, establishing an RNP value, and scaling the RNP value to the map display field of view. The method further includes the step of generating an RNP corridor boundary graphic on the map display offset from the aircraft leg segment symbol by the scaled RNP value.