Attitude indicator design in primary flight display: Revisiting an old issue with current technology

Objective: The experiments investigated the “old issue” of the attitude indicator’s moving-horizon versus moving-aircraft format with current primary flight display technology. Of interest was whether the effects found in earlier studies, favoring the moving-aircraft format, could be replicated with most recent technology including extended horizon displays, which depict the artificial horizon extended over the whole screen with overlaying speed and altitude scales (e.g., B787). Background: Although the moving-horizon format represents the standard approach in Western aviation, human factors research from the 1950s to the 1970s with round electromechanical instruments favored the moving-aircraft format with respect to better support of flight-path tracking and unusual attitude recoveries. However, recent studies using laboratory displays more similar to modern primary flight displays provided inconsistent results. This led to the assumption that the display’s design is a moderating factor of those effects. Method: Thirty-two novices and 13 pilots flew several tracking and recovery tasks in a PC-based simulator equipped with moving-horizon and moving-aircraft formats in classic and extended horizon design. Results: The data show that the previous effects favoring a moving-aircraft format of displaying bank information can be replicated with current primary flight display designs. However, the extended horizon design seems to reduce this effect, at least for pilots. Conclusion: The results suggest reconsidering the format of the attitude indicator at least for new applications, such as control of remotely piloted aircraft