Using Terrain-depicting Primary Flight Displays for performing instrument-referenced tasks: Can we empirically test for ‘Equivalent level of safety’ ?

Abstract

A study was conducted to determine if primary flight displays (PFDs) depicting terrain could be used with a level of safety equivalent to electronic attitude-direction indicators (EADIs) without terrain. Five groups of 8 pilots each flew scenarios in a flight simulator using one of three PFDs with or without guidance cues. Performances of instrument-referenced maneuvers using the EADI were measured, followed by trials with an experimental format. Performance measures included initial response time, total recovery time, and control reversals. Traditional parametric analyses found no significant performance differences between groups. Analyses using confidence intervals to assess equivalence of distributions showed group performances were essentially the same. Pilot preferences were examined and are reported. It was concluded that the specific terrain representations did not reduce the level of safety for these specific maneuvers. This technique is recommended for applicants wishing to demonstrate a level of safety equivalent to existing systems.