`Party line´ information use studies and implications for ATC datalink communications

As part of the Federal Aviation Administration´s National Airspace System modernization plan, digital datalink communications will be introduced as a means of air/ground information exchange. Care must be taken, however, to continue to provide pilots with the `Party Line´ Information (PLI) that pilots currently overhear on the shared voice frequencies. Several studies have examined the importance of PLI through surveys and simulator studies. Pilots have consistently rated PLI as `Important´, with several specific information elements identified as `Critical´. However, PLI is not a reliable source of information during high workload conditions, and it is not always compelling enough for pilots to commit to a required action for safety. Therefore, several recommendations can be made for datalink communications