Definition
A mismatch between a pilot's internal body clock (circadian rhythm) and the external schedule they are required to fly, work, or sleep on. It commonly occurs after crossing time zones, flying at night, or working irregular shifts, and produces fatigue, reduced alertness, and degraded performance even when total sleep hours appear adequate.
Plain English
Your body is on one clock, but your flying schedule is on another. Even if you got enough sleep on paper, your body is awake when it wants to be asleep, or asleep when it wants to be awake — and that drop in alertness is real.
Context Anchor
Seen in fatigue discussions, especially when considering night flying, early starts, changing schedules, or crossing time zones.
Derivation
From 'timing' (when something happens) and 'disruption' (a break or interference). The term points directly to the body's natural timing being thrown off — your internal schedule no longer lines up with what you're asking of yourself.
Why Pilots Care
It increases the chance of late or mistimed control inputs during critical phases of flight.
Grounding Statement
A pilot who normally sleeps at night may have trouble staying fully alert during a late-night flight because the body is still expecting sleep.
Intuition Check
Timing disruption does not simply mean being late or off schedule. Here it means the body’s sleep-and-alertness rhythm has been disturbed.
Example Sentence 1
After landing in London on a red-eye from New York, the captain noted the timing disruption and built in a longer layover before the return leg.
Example Sentence 2
Fatigue caused timing disruption that lengthened the pilot’s instrument scan cycle beyond safe limits.