Flying Curved Approaches and Missed Approaches: 3-D Display Trials Onboard a Light Aircraft

Cockpit displays that enhance situational awareness in light aircraft are becoming feasible through the rapid development of enabling technologies including differential GPS, inexpensive computers, and ruggedized color LCD panels. A prototype glass cockpit system was developed and used to explore implementation and operational issues through flight testing. The display provided an “out the window” three-dimensional (3-D) perspective view of the world, making the horizon, runway, and desired flight path visible to the pilot even in instrument flight conditions. The desired flight path was depicted as a tunnel through which the pilot flew the airplane. Predictor symbology was added in response to pilot requests for better guidance and presentation of pathfollowing errors. Piloted simulations and flight tests on a four-seat Piper Dakota demonstrated enhanced accuracy and capability on a variety of trajectory types. These included curved approaches with one constant-radius turn, segmented approaches, and complex missed approaches with multiple curved segments, climbs, and descents. Flight technical error and position histories document system performance. Hardware, sensors, and computational issues specific to the problem of practical 3-D perspective flight displays are discussed. The results demonstrate that an intuitive display can allow precise navigation on complex flight paths and increase safety through improved situational awareness. In addition to enhancing typical passenger aircraft operations, such systems would be valuable for applications requiring precise path following in low-visibility situations