The purpose of this research is to investigate long term effects of cognitive skill degradation through theuse of automation. Even though advanced studies have looked into information automation (IA) in aviation,the amount of empirical data on the effects of these systems on the retention of cognitive skills is lessdeeply examined. Measurement and analysis of the effects of IA on cognitive performance is an importantfirst step in understanding cognitive skill degradation, which should be considered during the design ofthese systems. The use of an automation aid is expected to result in a high level of performance degradationover time. Participants were randomly placed into three experimental groups (manual, alternating, orautomation) and asked to perform flight planning calculations as an experiment task. Participantsperformed the task five times, once every two weeks. The manual group used the manual methodthroughout the experiment, the alternating group switched between the manual and automated methodevery trial. The automation group used the manual method for the first trial, the automated method for thethree consecutive trials and then went back to using the manual method during the last trial. Theautomation group showed the most performance degradation and highest workload, while the alternatinggroup presented reduced performance degradation and workload, and the manual group showed the leastperformance degradation and workload. This work provides the foundation for the design of guidelines andrecommendations for IA systems in order to prevent cognitive skill degradation.