Flying a Tunnel-in-the-sky Display within the Current Airspace System

Enhancing aircrew situational awareness has become recognized as a critical element in reduction of overall aircraft accident rates. Improved display concepts have been investigated for several decades as a means of enhancing awareness of position, flight path, and terrain in three dimensions. One of the most promising is the “Tunnel-in-the-Sky” primary flight display, which presents a three-dimensional depiction of the world with the desired flight path shown as a tunnel or series of hoops. A prototype system was developed to explore the real-world implications of the Tunnel-in-the-Sky display concept. This paper documents flight testing on a Beechcraft Queen Air to investigate real-world operations within the current Air Traffic Control system. A series of tunnel “overlay approaches” was designed on top of existing, published instrument procedures to demonstrate advantages for nonprecision approaches, closely spaced parallel approaches, and noise abatement. Results indicated an order of magnitude reduction in cumulative flight technical error on approach. The flight tests also showed that Tunnel-in-the-Sky displays could improve aircrew situational awareness and operational flexibility during these flight operations.