Design of Instrument Approach Procedure Charts: Comprehending Missed Approach Instructions Coded in Text or Icons

The objectives of this experiment were to determine whether coding missed approach instructions in text or icons would result in more efficient information transfer, and if the information transfer efficiency for either coding technique was dependent upon the level of information content. Twelve pilots currently licensed for instrument (IFR) flight participated as subjects. Text instructions were either taken directly or developed from instructions found on National Ocean Service (NOS) instrument approach procedure charts. These instructions possessed one of three levels of information content: low, medium, and high. Across the range of information content levels, iconic missed approach instructions were comprehended more quickly and as accurately as instructions coded in text of the font style and size used by NOS. Regardless of coding technique, report accuracy was significantly worse for instructions with a high information content level. Pilots indicated that in single pilot IFR conditions, they would rather have the iconic than the text version of the missed approach instructions.