Distractions, task prioritization, loss of situational awareness, or disorientation.

Bottom line

When a pilot becomes task saturated, there is no awareness of input from various sources, so decisions may be made on incomplete information and the possibility of error increases. Many flight deck distractions begin as a minor problem, such as a gauge that is not reading correctly, but result in accidents as the pilot diverts attention to the perceived problem and neglects to properly control the aircraft. When a work overload situation exists, a pilot needs to stop, think, slow down, and prioritize.