Examining pilot safety performance indicators at critical phases of flight across multiple flight legs during commercial airline trips

Primary author: Rhiannon Soriano Smith
Co-author(s): Amanda Lamp; Ian Rasmussen; Ewa Basiarz; Chandler Keller; Gregory Belenky

Primary college/unit: Elson S. Floyd College of Medicine
Campus: Spokane

Abstract:

Prior simulation and operational studies began to address whether the number of consecutive flight segments negatively affects cognitive performance, fatigue, and sleepiness, without reaching a clear consensus. This study expands this literature by determining whether there are significant changes in cognitive performance, fatigue, and sleepiness at critical phases of flight across multiple flight segments, while accounting for the number of segments, flight direction, trip day, and time-of-day.
Fifty commercial airline pilots were studied, each flying two separate short-haul trips ranging from 1-4 days and 1-10 flight segments. Cognitive performance, fatigue, and sleepiness were assessed at top-of-climb (TOC) and top-of-descent (TOD) of each flight segment and trip day. Cognitive performance, fatigue, and sleepiness were assessed using Psychomotor Vigilance Task (PVT) speed, Samn-Perelli (SP) ratings, and Karolinska Sleepiness Scale (KSS) ratings, respectively. Data were analyzed using Wilcoxon t-tests and verified using ANOVAs.
Mean PVT speed (d =0.57), SP (d = 0.73), and KSS (d = 0.63) were significantly worse at TOD than TOC (p < 0.001); and varied across flight segments (p<0.001). Cognitive performance, fatigue, and sleepiness were consistently degraded around the fifth flight segment, improved around the sixth to eighth flights segments, and were subsequently degraded around the eighth to tenth flight segments.
The results indicate that cognitive performance, fatigue, and sleepiness vary across flight segments, trip day, and phase of flight. Results suggest that these safety performance indices degrade after five segments, and further degrade after eight flight segments. The results presented could inform future airline scheduling and regulation.