FAA Office of Aerospace Medicine
Civil Aerospace Medical Institute

Report No: DOT/FAA/AM-21/29

Title and Subtitle: Exploring the Relationship between Flight Technical Error and NASA-TLX Subscale Ratings when Using HUD Localizer Takeoff Guidance in Lieu of Currently Required Infrastructure

Report Date: November 2021

Authors: Kratchounova D, Choi I, Mofle TC, Miller L, Stevenson S, Humphreys M

Abstract: This was an exploratory in nature follow-on research. Our previous efforts were focused on the operational impact of using head-up display (HUD) with localizer guidance in lieu of Centerline Lights (CLL) for takeoff in low visibility conditions. Herein, the primary goal was to examine the relationship between the subjective NASA-TLX workload ratings and Flight Technical Error (FTE) as the objective measure of performance. Instead of the total weighted scores, we analyzed the raw, unweighted NASA-TLX subscale ratings. Based on the analyses conducted, we proposed methods to utilize FTE data in predicting individual pilot workload ratings and vice versa.

The results indicated that the single best subjective predictor of FTE was the NASA-TLX Performance subscale in both normal and abnormal operations. Nonetheless, the most noteworthy finding was that when the abnormal condition included a trained failure (e.g., engine failure during takeoff), the ratings on the NASA-TLX Temporal Demand subscale had an inverse relationship with FTE. That is, during trained abnormal events, the increased time pressure was associated with improved pilot performance. The immediate automatic response was to prioritize maintaining aircraft directional control and to compartmentalize tasks by priority. In contrast, when the pilots were presented with an abnormal event that they had not been trained on, this automatic response was absent. The discussion also includes methodological limitations and future research.

Key Words: Head-up Display (HUD); Aviation Human Factors; Flight Technical Error; Crew Workload; NASA-TLX

No. of Pages: 26