Originally Posted by Lugar

But how many times can you check your position, check your altimeters, check actual vs planned performance, tune VOR’s ahead, check flight and engine instruments, check the weather, brief and study arrivals, approaches, and taxi routes, etc? At some point, you create a legitimate fatigue issue by overworking yourself, and then you’re just beat tired (and dangerous) where it matters the most .. the approach, landing, and taxi phase.