Definition
A change of flight plan to a destination other than the originally intended airport, made in response to a condition that makes continuing to the planned destination unsafe or impractical — such as an inadvertent icing encounter, deteriorating weather, a mechanical issue, or a medical emergency.
Plain English
Choosing to land somewhere other than where you originally planned, because something has changed and the new airport is the safer or smarter choice.
Context Anchor
In an inadvertent icing encounter, a pilot may need a flight diversion to leave icing conditions or land at a safer airport.
Derivation
From the Latin divertere, meaning 'to turn aside.' A diversion is literally turning the flight aside from its planned path to a different airport.
Why Pilots Care
A diversion requires recalculating fuel, updating ATC, and ensuring the alternate airport can be reached safely, directly impacting flight safety in icing conditions.
Intuition Check
A flight diversion is not a failure to complete the flight. It is a deliberate change of plan to keep the flight safe.
Example Sentence 1
After picking up unexpected ice in the clouds, the pilot requested a flight diversion to the nearest suitable airport.
Example Sentence 2
In the event of an inadvertent icing encounter, air traffic control may suggest a flight diversion to an alternate with better weather.