Human issue can degrade every aspect of human capability

Human fatigue is a cause of other impairments, such as
poor judgment, decision-making, slowed reaction time, lapses in memory,
difficulty concentrating, and loss of situation awareness and control. Pilot
fatigue is a serious issue can degrade every aspect of human capability and
affecting the safety of the traveling public in air transportation (Lerman et al., 2012).
 In this experiment, fatigue experienced
by pilots was compared between a flight mission with multiple take-offs and
landings versus a flight mission of equal duration with a single take-off and
landing. Twenty-four active-duty regional airline pilots (4 Expert and 4 Novices;
age range 24– 33) participated in the study. Each pilot flew a medium-fidelity,
full-flight (motion) Boeing-52 flight simulator during two consecutive 4-hour flight
missions each starting at 08:15 AM. In randomized order, one flight mission
contained four flight segments and the other flight mission contained one
flight segment. The simulator flights were the same for all pilots and were
flown like normally operated. The experimental conditions were operationally
realistic to the highest degree possible within a simulator facility. During
each of the two flight missions, 8 fatigue test bouts were administered. In the
multi-segment flight mission, the fatigue test bouts occurred immediately after
top of climb (while on autopilot) and immediately after landing. The fatiguing
effect of the multiple take-offs and landings was comparatively modest. In the
single-segment flight mission, the fatigue test bouts occurred at times of day
matching those in the multi-segment flight mission. All test bouts contained
the Samn- Perelli (SP) Subjective Fatigue Check card, a 10-minute Psychomotor
Vigilance Test (PVT), and the Karolinska Sleepiness Scale (KSS). During the
course of the flight, the pilots wore a wrist activity monitor to measure their
sleep times.  The study results showed a
greater build-up of fatigue in the multi-segment flight mission than in the
single-segment flight mission, both objectively assessed (PVT) and subjectively
reported (SP and KSS).