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The effect of adding track angle error (TAE) information to general aviation aircraft cockpit displays used for GPS nonprecision instrument approaches was studied experimentally. Six pilots flew 120 approaches in a Frasca 242 light twin aircraft simulator using crosswind and turbulence. Twenty-five-mile-long approach geometries were used, with and without 45 degree dogleg turns on final approach. Performance and workload using three TAE display formats were compared against results with two control formats presenting cross track error (XTE) only. Pilots found that the TAE displays simplified determination of wind correction angle, and that they consistently chose to use analog rather than numeric TAE data. Statistically significant differences between display formats and between pilots were found. The largest average improvement in initial leg intercept and tracking performance resulted when the conventional 'ten dot' XTE display was supplemented with a sliding pointer display of TAE, moving in the same direction as aircraft bank. A second TAE format, a sliding/rotating pointer integrated display, yielded the greatest improvement (35%) in the width of the short final approach flight technical error envelope, but pilots reported occasional problems interpreting this display. Both of these TAE formats improved final approach intercept and tracking performance after 45 degree turning maneuvers. The addition of TAE information to the receiver display helped pilots create outer Loop Lead, and yielded approach performance improvements comparable to relocating XTE information to an HSI within the pilot's primary scan. Bedford workload scores were not significantly influenced by display format, but were found to depend on approach geometry and phase.

This report describes the research program being conducted at the Volpe National Transportation Systems Center on the development of electronic aeronautical charts. The design of electronic aeronautical navigation charts raises many interrelated human factors issues including those pertaining to the physical aspects of the display screens (e.g., location in the cockpit, screen resolution, color capability, brightness range) and those affecting the piLot interaction with the software (i.e., pilot interpretation of the information presented). A limited amount of research has been conducted on the design of electronic chart systems for instrument approach procedure (IAP) charts. The results have indicated that not all of the information printed currently on paper IAP charts is needed to fly instrument approaches. Current issues in electronic chart design are discussed in this report. Results from a study that compared three alternative design formats are also provided. Based on the findings from this study, it was determined that electronic charts are a benefit to pilot situation awareness. Newer design formats that use small amounts of display space are also presented., Prepared in collaboration with John A. Volpe National Transportation Systems Center, Cambridge, MA 02142.

Instrument approach procedure (IAP) charts can be densely packed with information. This high information density can make information difficult to find, particularly in a poorly lit cockpit during turbulence. The Volpe Center's Cockpit Human Factors Program conducted a series of evaLuations to format IAP chart information to more closely conform to the way pilots actually use the information. All of this work has contributed to the evolution of the VoLpe prototype lAP chart format. The prototype's major design features are the briefing strip and iconic missed approach procedure instructions. The briefing strip consists of three rows of tabularized information at the top of the chart. This feature is designed primarily for use in preparing for the approach. Each information eLement is given in the order in which it will be used. The piLot no longer has to search through the entire chart to assemble this data. In the profile view, the 'up and out' portion of the missed approach instructions is depicted in icons rather than text. This critical information is more easily located than if it were embedded in text. The objective of this study was to determine if the prototype IAP chart format would allow pilots to find information faster and more accurately during actual flight. Ten licensed piLots rated for instrument flight participated as subjects in this experiment. Each of the approaches were depicted in two chart formats: National Ocean Service (NOS) and the VoLpe prototype. Pilots took advantage of the prototype's briefing strip to search for information to answer questions.

This document is a checklist designed to assist Federal Aviation Administration (FAA) certification personnel and global positioning system (GPS) receiver manufacturers in the evaluation of the pilot-system interface characteristics of GPS receivers to be certified according to TSO C129 A1, TRCA/DO-208, and AC 20-138. Its main focus is on controls, displays, and operating characteristics. The document is comprised of three sections, the Bench Test, the Flight Test, and the Appendices. The Bench Test is designed to evaluate GPS receiver design characteristics that do not require aircraft installation and flights. The Flight Test is designed to evaluate receiver design characteristics and functions under actual flight conditions. The Appendices, extracted portions of original documents, provide reference material for the specific topics covered in the checklist.

Long range navigation (Loran) and global positioning system (GPS) receivers are widely used in aviation. The Loran and GPS receivers are similar in size and function but derive their navigation signals from different sources. The design of the controls, displays, and computer logic is usually similar for the two types of receivers from a single manufacturer, but differs substantially among manufacturers. Some or all of the designs may provide a suboptimal human-computer interface, which may result in simple time delays or in serious risks if the pilot cannot use the system effectively and efficiently. The design variations also make it difficult to certify receivers for different applications. As a result, the Volpe National Transportation Systems Center has sponsored a program of research to address issues in Loran and GPS receiver design. This report first reviews the literature on user experiences with Loran and GPS receivers and other types of similar, automated equipment. Second, the report reviews the major human factors references, texts, and individual journal articles that are relevant to the regulatory requirements for the receivers. Finally, specific human factors principles and guidelines are proposed for the design and certification of GPS and Loran receiver controls, displays, and control-display integration., Prepared in collaboration with Anacapa Sciences, Inc., Ft. Rucker, AL.

Discussions were held with a variety of private, Coast Guard, and off shore airplane and helicopter pilots who use Loran-C for navigation. These discussions revealed a number of problems concerning the design and use of the controls and displays of Loran-C receivers. The results are also relevant to GPS receivers that have many operational characteristics in common with Loran.... Loran-C, GPS, Human Factors, User Survey.

This report is concerned with the influence of display needle sensitivity on the accuracy with which pilots can fly nonprecision approaches. Twelve private pilots flew an instrumented single engine airplane on 144 approaches at six different sensitivity levels. The study was conducted to determine the influence of course deviation indicator (CDI) sensitivity on pilot tracking error. The sensitivities ranged from 15,190 feet (2.5 nautical miles) to 475 feet (0.08 nautical miles) for a full-scale deflection. Increase in sensitivity of this magnitude decreased crosstrack Root Mean Square error from an average of 0.22 to 0.04 nautical miles. Magnitude of the error influence of sensitivity on that increases in sensitivity on that magnitude were affected by distance from the missed approach point. Pilots reported that increases in sensitivity increased their-workload and changed their distribution of attention among the aircraft instruments used for navigation and directional control.