When might defueling occur during a flight operation?

Defueling during a flight operation is primarily associated with the need to decrease the aircraft's weight for safety and efficiency reasons. When a mission is changed to a shorter flight, the aircraft may not need as much fuel as originally planned. Reducing fuel weight can improve the aircraft's performance, enhance safety, and allow for more efficient handling, especially during landing and emergency scenarios. This makes it logical to defuel in order to meet operational requirements while ensuring fuel reserves are appropriate to safely complete the new mission profile.

In contrast, other scenarios such as inclement weather, a full fuel tank, or a change to a longer flight wouldn't necessitate defueling. The focus during such situations is typically on maintaining sufficient fuel levels or reallocating resources rather than reducing fuel load.