Area navigation (RNAV) and required navigation performance (RNP) procedures are fundamental to the implementation of a performance based navigation (PBN) system, which is a key enabling technology for the Next Generation Air Transportation System (NextGen). As new RNAV and RNP procedures are developed, they are published as chartsfor use by appropriately qualified pilots. These chartsand procedures describe paths that must be flown preciselyfor improveduse ofairspace and safety.In this document, we considerhow chartsfor both conventional and PBN procedures are designedfrom ahuman factors perspective.First, we document current charting challenges and mitigation strategies. Next, wedescribe areview ofprocedures thatwas done to discover whichfeatures wererelated to difficulty of use or visual complexity. The moredifficult instrument approachcharts depict procedures with moreflight paths, path segments, and radius-to-fix legs.Standard instrument departure procedures that are more difficult show more flight paths. Standard terminal arrival route procedures that are more difficult have more total altitude constraints and path segments.Finally, we describe the process for designing and implementing new instrument procedures, whichinvolves significant coordination both inside and outside the government