Publications

The Graphical Weather Service (GWS) is a data link application that will provide near-real-time graphical weather information to pilots in flight. To assess the effect GWS, as well as to aid in the proper design, implementation and certification of the use of GWS in aircraft, two human factors studies have been conducted. The second study conducted (Phase Two) is the topic of this report. Phase Two was conducted to determine the maximum level of compression-induced distortion that would be acceptable for transmission of weather images to the cockpit. To make this determination the following data were collected and analyzed: pilot subjective ratings of the perceived amount of distortion of a compressed image, pilot subjective ratings of the acceptability of a compressed image for use in the flight task, and pilot route selections as a function of the amount of compression presented in an image. Results indicated that images of low to moderate compression levels were generally acceptable for transmission to the cockpit, while images that were highly compressed were generally unacceptable. In addition, computed measures of image quality have been identified to enable the establishment of a criteria for transmitting images to aircraft.

With the sponsorship of the Federal Aviation Administration, MIT Lincoln Laboratory is developing the Graphical Weather Service (GWS), a data link application that provides near-real-time ground-based weather information to pilots. Through the use of GWS, the pilot will be able to access both graphical and text weather information for any location in the contiguous United States. In-cockpit access to near-real-time weather information may substantially affect the situational awareness and subsequent decision making of pilots. In developing and evaluating this service, a human factors approach has been taken. This paper is an overview of the human factors activities performed in the development and evaluation of GWS.

This report documents the findings of a human factor study conducted to estimate the effects of the Graphical-Weather Service (GWS) on general aviation (GA) aircraft utility, pilot situational awareness, and the weather dissemination workload on ground personnel. GWS is a data link application, being developed at MIT Lincoln Lbaoratory through the sponsorship of the Federal Aviation Administration, that will provide near-real time graphical weather information to the General Aviation pilot in the cockpit. Twenty instrument-rated pilots participated in the study. Subjects were presented with recorded actual weather information in the context of a series hypothetical pre-flight briefings and accompanying "flights." GWS images were accessible on a Macintosh TM Computer. The study design enabled the analysis of the effects of GWS and the determination of whether those efforts were influenced by the experience level of the pilot/user. Objective and subjective measures of effectiveness were collected. Results indicate that GWS had a substantial effects on weather-related decision-making. This was true for pilots with varying levels of instrument experience. Subject confidence in the ability to assess the weather situation was markedly increased when GWS was used. Subjects with GWS made fewer calls for weather information to weather dissemination ground personnel, thus indicating a potential decrease in ground personnel workload. Subjects found GWS to be very useful and were enthusiastic about receiving data link services in the GA cockpit in the future.