This paper summarizes the results of analyses to identify characteristics of flight deck information automation systems which can lead to potential human factors issues. Information automation systems are responsible for the collection, processing, analysis, and presentation of information to the flightcrew. Information automation systems can pose human factors issues and challenges particular to this type of automation. This paper presents a formal definition of information automation and identifies characteristics and associated human factors issues in the domain of aircraft flight deck systems. A method was developed to identify a set of consistent and independent characteristics of information automation. Characteristics, a set of properties or attributes which describe its operation or behavior, can be used to identify and assess potential human factors issues. This effort lays the groundwork for providing data to support the development of recommendations specific to different characteristics of information automation.