The Complex Cognitive Process Needed to Understand Airport Guidance Signs

Airport guidance signs are a visual information system. It can be equated to a street sign arrangement for conveying runway and taxiway assistance. Pilots have to learn, comprehend, and interpret each sign's meaning for understanding to occur. The FAA makes this simple by dictating the standardization of signs. Flight crews still have a daunting task of assimilating the message in the brief time that each sign is viewed. When combining simple colors, symbols, letters, and numbers, these elements form an elaborate organization of meaning. The cognitive mental process that takes place is complex. This diversity is complicated even more with the many exceptions to the rule that apply. One must filter through the different scenarios to grasp the sign's message. Introduction At the beginning and end of each flight, a pilot needs to use the airport guidance sign system to navigate around an airfield. Each airport is laid out differently so there is no universal set plan. Some airports are simple, while others are complex. A pilot needs to have an increased situational awareness when the aircraft is on the airport's movement area. This is where the greatest congestion is experienced. To maneuver on an airport, guidance signs help a pilot navigate hisher way around the complex system of runways and taxiways. They assist in aiding the aircraft to reach its final destination whether it is (a) the runway, (b) the hanger, or (c) the gate. The airport sign system is a safety critical system, which is commonly certified with an extremely low probability of failure per hour of use (Boy, 2000). Airport signs come in a number of colors containing lettering, andlor symbols so as to convey a message. They . are a fixed information system located throughout the airport to help the pilot make correct decisions related to the movement of their aircraft. Pilots need to have a cognitive understanding of the meaning of each type of sign to achieve their objective of navigating the airport pavement (Boy, 2000). This conveyance system can become quite complex. By changing the color of a background or the message lettering, the meaning of the sign changes entirely. The intricate mental processing a pilot's brain has to perform to interpret a sign is one that comes fiom education and experience. History At air carrier airports, long before any aircraft ever touched down on a runway, airport management and the Federal Aviation Administration (FAA) decided the layout of the field. Once this had been established, an airfield guidance sign plan needed to be conceived and approved (see Figure 1). The airport determines the (a) requirement, (b) size, and (c) location of each sign. Then, both the airport and the FAA sign off on the plan to become an official document that is part of the Airport Certification Manual (ACM). When the airfield is ready for operation, the pilot becomes the end user of this system. JAAER, Winter 2009 Page 25 1 Adrian: The Complex Cognitive Process Needed to Understand Airport Guidan Published by ERAU Scholarly Commons, 2009 Understanding Airport S i p Figure 1. An example of a guidance sign plan. a h N ' El -a 1, m= m A W ,EL rn m37q ,DL m A . 1 CI P, a Conventional design methods are based on goaldriven methods, ie., designers start with an overall goal in mind and attempt to decompose this goal into sub-goals until basic actions can be derived and effectively preformed (Boy, 2000). These plans can become very complex, for each map shows the signage faces and orientation of every unit. As signs are added or deleted, the plan is reviewed by both parties and approved for revision. When a pilot travels down the taxiway and gazes at a guidance sign, it should be known that many people put a lot of time and thought as to why that sign should be there. Sign Standardization The FAA' in their oversight role mandated that guidance signs be standardized. This implies that for any airport one visits in the United States, the message will have the same connotation. A properly designed and accepted sign arrangement is an essential component of any surface guidance control system, which increases the overall safety of the operation at an airport. A sign plan should (FAA, 2004): Provide the ability to easily determine the NOT TO SCALE designation or name of any taxiway on which the aircraft is located. Readily identify routes toward a desired destination. Indicate the mandatory hold positions, including hold positions used to maintain aircraft separation during low-visibility weather operations. Identify boundaries for approach areas, Instrument Landing System (ILS) critical areas, Precision Obstacle Free Zones (POFZs), and runway safety areaslobstacle free zones (OFZs). On an airport there are two varieties of guidance signs (a) elevated and @) surface painted. Both sign types are similar in appearance and have identical meaning. These assortments of differing signs are m e r broken down into six categories: