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 (EADI, full-color terrain, uniformly brown terrain) with or without guidance cues. Performances of recoveries from unknown attitudes using the EADI were measured...

"Under normal circumstances, a test specimen is reported as "negative" when the response of the analyte is absent. However, if the intensity of the internal standard (IS) is low, indicating interference factors, the test could be considered "inconclusive." A quantitative hypothesis, A = (RxIxS)/L, serves as the "cutoff" for the acceptable signal-to-noise (S/N) ratio for the IS in making "negative/inconclusive" decisions, where A: acceptable S/N ratio...